Full Version - Department Of Otorhinolaryngology, Head And ...

Copy and paste this link to your website, so they can see this document directly without any plugins.



Keywords

Figure, from, dissection, with, nerve, flap, muscle, artery, arrow), manual, posterior, thyroid, lateral, skin, anterior, incision, inferior, border, that, tissue, divided, medial, neck, this, facial, (yellow, STEP, between, then, lower

Transcript

D
ISSE
C
T
IO
N
A
N
D
R
E
C
O
N
ST
R
U
C
T
IO
N
M
A
N
U
A
L
H
EA
D
&
N
EC
K
ANDREW VAN HASSELT • EDDY WY WONG
T H E C H I N E S E U N I V E R S I T Y O F H O N G K O N G
D I S S E C T I O N A N D R E C O N S T R U C T I O N M A N U A L
HEAD & NECKThis dissection manual contains detailed descriptions and all- inclusive illustrations on the full range
of surgical procedures in the head
and neck. It also includes meticulous
dissection technique guidance on
reconstruction operations. The manual
provides readily available access to
valuable experience accumulated by
expert Head and Neck surgeons. In
compiling this manual the editors have
delivered a comprehensive guide and
reference both within the laboratory
and when preparing for the operating
room.
“The Head & Neck Dissection and Reconstruction Manual, compiled by the Chinese
University of Hong Kong faculty, contains the key information that dissectors require to be
able to proceed through the surgical steps of common head and neck and reconstructive
surgery operations, and will be an important companion in the dissection room.”
— Johan Fagan
Professor and Chairman
Division of Otorhinolaryngology
University of Cape Town
“We have created this manual to guide, complement and enhance value to be gained
from the priceless opportunity of dissecting specimens of excellent quality. It is indeed a
privilege to gain hands on experience in the totally safe setting of the laboratory.”
— Eddy Wong
Associate Consultant, Department of ENT
Prince of Wales Hospital, Hong Kong
— Andrew van Hasselt
Professor of Surgery (Otorhinolaryngology)
The Chinese University of Hong Kong
department of otorhinolarynology,
head and neck surgery
the chinese university of hong kong
D I S S E C T I O N A N D R E C O N S T R U C T I O N M A N U A L
HEAD & NECK
The Chinese University Press
D I S S E C T I O N A N D R E C O N S T R U C T I O N M A N U A L
HEAD & NECK
Editors
Dr. Eddy WY Wong
Associate Consultant
Department of ENT
Prince of Wales Hospital
and
Professor Andrew van Hasselt
Professor
Department of Otorhinolaryngology,
Head and Neck Surgery
The Chinese University of Hong Kong
Contributing Authors
Dr. Jason YK Chan
Assistant Professor
Department of Otorhinolaryngology,
Head and Neck Surgery
The Chinese University of Hong Kong
Dr. Tor Chiu
Consultant
Division of Plastic, Reconstructive &
Aesthetic Surgery
Department of Surgery
Prince of Wales Hospital
Dr. Siu Kwan Ng
Consultant
Department of ENT
Prince of Wales Hospital
Dr. Alexander C Vlantis
Associate Professor
Department of Otorhinolaryngology,
Head and Neck Surgery
The Chinese University of Hong Kong
Dr. Eddy WY Wong
Associate Consultant
Department of ENT
Prince of Wales Hospital
Foreword
A major challenge when learning head and neck surgery is to master the detailed
3-dimensional anatomy of the head and neck and cranial base. This is very difficult to learn
from textbooks and videos, and some trainee surgeons do not have adequate opportunity
to master the surgical anatomy in the operating room during their training. Hence the
importance of head and neck cadaver dissection courses.
I had the privilege of serving as faculty member on two head and neck dissection courses
held at the Chinese University of Hong Kong. The Chinese University of Hong Kong head
and neck dissection course is truly international, with delegates traveling from all over the
world to attend. What impressed me was the excellent organisation of the course, the
attention to detail, the incredible enthusiasm of the local faculty and their high level of
surgical expertise.
The Head & Neck Dissection and Reconstruction Manual, compiled by the Chinese
University of Hong Kong faculty contains the key information that dissectors require to be
able to proceed through the surgical steps of common head and neck and reconstructive
surgery operations, and will be an important companion in the dissection room. I am
particularly pleased that it will be made available as an open access resource for others
around the world to use when running or participating in such cadaver dissection courses.
Johan Fagan MBChB, MMed, FCS (ORL)
Professor and Chairman
Division of Otorhinolaryngology
University of Cape Town
Cape Town
South Africa
Foreword
The successful publication of the “CUHK Head & Neck Dissection and Reconstruction
Manual” represents a major achievement towards education and clinical training in
the field of Head and Neck surgery, both regionally and internationally. The material
reflects many hours of combined teamwork with our colleagues in the Department of
Otorhinolaryngology, Head and Neck Surgery facilitated by the contribution from our “Silent
Teachers”, who have generously donated their bodies to the Faculty of Medicine, for
education, training and research purposes.
Our Faculty launched the “Silent Teacher Body Donation Programme” in 2011. With
intensive coordinated efforts of Faculty members together with organizations involved in
life and death education and services, the body donation program has been well received
by the Hong Kong community. Not only has the number of bodies received increased
by more than 20 fold over the past 5 years, but the registration of donors has also
grown exponentially. With the community engagement, it is clear the public is prepared
and through this program, is actively participating in educating our future doctors. Our
laboratory is thus enabled to engage with colleagues in clinical departments to offer
advanced training and surgical skills development in diverse surgical specialties.
This superb publication pays tribute to our donors and their family members. We constantly
appreciate and recognize their generosity. Our team members are clear on their caretaking
role and are committed to work diligently with all colleagues in our faculty to provide the
best education for tomorrow’s doctors, so that they may be knowledgeable, skilled and
compassionate.
Professor Hector Sun-On Chan
Professor
School of Biomedical Sciences
Assistant Dean (Education)
Faculty of Medicine
PreFace
The head and neck is characterized by its complex anatomy that performs vital functions
and is affected by diverse pathology. Head and Neck surgical and reconstructive techniques
continue to evolve and mature. An in depth knowledge of the anatomy and safe dissection
skills are essential talents for professionals practicing in this area to achieve optimal
patient outcomes and to avoid unnecessary complications and suffering. The Chinese
University of Hong Kong, Head & Neck Dissection and Reconstruction Course aims to
educate trainees and head and neck surgeons to advance their knowledge and refine their
skills in performing head and neck operations in a safe environment. We have included
comprehensive coverage of the various reconstructive flaps and microvascular techniques
as these are an integral component of the repertoire of head and neck patient care.
This manual not only acts as a reference for those who participate in our courses, but
also provides a template to organize and run similar courses elsewhere. It also provides a
valuable reference for any surgeon doing or planning these operations in clinical practice.
Our team has spent considerable time detailing the procedures in this manual, emphasizing
important steps for each operation. We aimed for a step by step guidance with simple and
clear instructions. Every effort has been made to complement the text with oriented atlas
like photographs that include labelling of key structures.
First and foremost we acknowledge the persons who bequeathed their bodies to our
institution for educational purposes. Mr. James Ting and his able staff in the dissecting
laboratory are credited for their care and preparation of cadavers. Dr. Jacky Lo and Dr.
Kelvin Chow assisted with dissection when preparing the manual. Dr. Zenon Yeung captured
excellent photographs during dissections and Miss Janet Fong crafted the professional
diagrams from our amateur illustrations. Our department has provided generous support
for this project. Lastly we recognize that without our families’ selfless support, our daily work
would not be possible.
We have created this manual to guide, complement and enhance value to be gained
from the priceless opportunity of dissecting specimens of excellent quality. It is indeed
a privilege to learn and advance our operative skills through hands on experience in the
totally safe setting of the laboratory.
Dr. Eddy WY Wong
Associate Consultant
Department of ENT
Prince of Wales Hospital
Professor Andrew van Hasselt
Professor
Department of Otorhinolaryngology,
Head and Neck Surgery
The Chinese University of Hong Kong
Head and Neck: Dissection and Reconstruction Manual
Edited by Andrew Van Hasselt and Eddy WY Wong
© The Chinese University of Hong Kong 2015
All rights reserved. No part of this publication may
be reproduced or transmitted in any form or by any
means, electronic or mechanical, including photocopying,
recording, or any information storage and retrieval
system, without permission in writing from
The Chinese University of Hong Kong.
ISBN: 978-962-996-772-7
Printed in Hong Kong
01 PArotideCtomy 1
02 submAndibulAr glAnd exCision 9
03 trAnsCerviCAl APProACh to the PArAPhAryngeAl sPACe 15
04 seleCtive neCk disseCtion 21
05 modiFied rAdiCAl neCk disseCtion tyPe ii 33
06 thyroideCtomy 47
07 totAl lAryngeCtomy 57
08 gortex thyroPlAsty 71
09 midline steP mAndibulotomy And mAndibuleCtomy 77
10 mAxillAry swing APProACh to the nAsoPhArynx 85
11 lAtissimus dorsi thorACodorsAl Artery PerForAtor FlAP 109
12 mediAl surAl Artery PerForAtor FlAP 117
13 lAterAl Arm FlAP 125
14 AnterolAterAl thigh FlAP 131
15 rAdiAl ForeArm FlAP 139
16 PeCtorAlis mAjor FlAP 145
17 FibulA FlAP 153
18 deeP inFerior ePigAstriC Artery PerForAtor FlAP 161
19 miCrovAsCulAr teChniques 167
Contents
Parotidectomy 1
01
PArotideCtomy
Jason YK Chan
2 dissection manual
Parotidectomy 3
STEP 1 INCISION AND
ELEVATION OF SKIN FLAP
Create a modified Blair Figure 1 or facelift
incision. Figure 2
Raise a superficial cervico-fascial flap
b e t w e e n t h e S u p e r f i c i a l M u s c u l o
Aponeurotic System (SMAS) layer and the
parotid fascia until the anterior border of
the parotid gland is reached. Figure 3
STEP 2 IDENTIFICATON
OF GREAT AURICULAR
NERVE
Identify the great auricular nerve (GAN)
and the external jugular vein (EJV) at the
anterior border of sternocleidomastoid
muscle (SCM) .
The posterior branch of the GAN is
dissected toward the ear lobe and
preserved. The anterior branch of the GAN
is divided. Figure 4
STEP 3 SEPARATE
PAROTID GLAND FROM
SCM
The anterior border of SCM is skeletonized
and separated from the parotid gland.
The posterior belly of the digastric muscle
is identified by retracting the parotid gland
superiorly.
STEP 4 IDENTIFICATION
OF LANDMARKS FOR
FACIAL NERVE
The tragal pointer is identified by following
the cartilaginous external auditory canal
medially.
Identify all the following landmarks for
the facial nerve.
PArotideCtomy
4 dissection manual
• Tragal pointer. The facial nerve is 1 cm
deep and inferior.
• Tympanic ring.
• Tympanomastoid suture line. This line
leads directly to stylomastoid foramen
medially.
• Posterior belly of digastric muscle. The
facial nerve is at the same depth, just
above the muscle.
• Palpate the styloid process The facial
nerve is located in the angle between
the styloid process and the posterior
belly of the digastric muscle. The
nerve crosses the styloid process more
anteriorly.
Identify the main trunk of the facial nerve
by blunt dissection with a fine haemostat.
Figure 5
STEP 5 DISSECT FACIAL
NERVE FROM PAROTID
GLAND
Identify the Pes Anserinus then trace the
upper and lower divisions of the facial
nerve anteriorly.
Use fine curved blunt tipped scissors for
the remainder of the nerve dissection.
Tunnel and spread the tissues overlying
the facial nerve and its branches and
divide the parotid tissue overlying the
nerve. It is important to dissect directly
on the nerve so as not to lose sight of
it. Never divide parotid tissue beyond
exposed facial nerve. Wearing loupes
(e.g. with 2.5x magnification) assists with
the dissection and enables the surgeon to
PArotideCtomy
Parotidectomy 5
Figure 4
Posterior branch of GAN dissected
toward the ear lobe (yellow arrow)
Figure 5
Main trunk of facial nerve (yellow arrow)
with reference to posterior belly of
digastric (blue arrow) and tragal pointer
(red arrow)
Figure 3
SMAS is continuous with platysma
muscle, GAN (yellow arrow) and
External jugular vein (blue arrow)
SMAS
platysma
Figure 6
Upper (red arrow) and lower (blue arrow)
divisions of facial nerve
Figure 1
Modified Blair incision
Mastoid tip
Figure 2
Facelift incision
Mastoid tip
6 dissection manual
better distinguish between blood vessels
and nerves. Use bipolar diathermy and fine
silk ties for haemostasis. Figure 6
Divide the parotid fascia and parotid tissue
superiorly and inferiorly to release the
parotid posteriorly and to permit anterior
mobilisation of the gland/tumour.
Dissect carefully along each branch and
strip the superficial lobe off the branches
of the facial nerve.
Identify the retromandibular vein as it
crosses medial to the facial nerve. Figure 7
Remove the tumour with a cuff of the
superficial parotid lobe.
TOTAL PAROTIDECTOMY
OR DEEP LOBE TUMOUR
STEP 6
FREE UP THE FACIAL
NERVE
Taking care to avoid unnecessary traction
on the nerve, ident i fy, d issect and
circumferentially free up the facial nerve
from the underlying deep lobe or tumour
to provide access to the deep lobe.
The tumour can delivered either between
the branches or below the facial nerve.
The deep lobe of the parotid/tumour
i s bordered media l l y by fa t o f the
parapharyngea l space and can be
delivered from the parapharyngeal space
by blunt dissection.
PArotideCtomy
Parotidectomy 7
KEY POINTS
1. Raise a flap deep to the SMAS.
2. Preserve the posterior branch of the GAN.
3. Locate all landmarks for identifying the facial nerve.
4. Use a fine haemostat superficial to the nerve and identify the
Pes Anserinus and subsequent divisions.
5. Only divide tissue overlying the nerve with the nerve in view at
all times.
6. For total parotidectomy, minimal traction on the facial nerve is
the key to avoid prolonged facial nerve paresis.
Figure 7
Retromandibular vein (blue arrow) deep
to the facial nerve
Parotidectomy 9
02
submAndibulAr
glAnd exCision
Jason YK Chan
submandibular Gland excision 11
STEP 1 INCISION
The skin incision is made at the hyoid
level or 3 cm below the inferior border of
mandible. Figure 1
Elevate subplatysmal flaps up to the
inferior border of mandible.
STEP 2 HOW TO
PROTECT THE MARGINAL
MANDIBULAR NERVE
Identify the facial vein at the notch of the
mandible and at the superior border of the
submandibular gland.
The marginal mandibular nerve may then
be exposed above the facial vein through
dissection of the superficial cervico-fascial
layers. Figure 2
Alternatively, the facial vein is divided and
slung superiorly to protect the marginal
mandibular nerve (Hayes Martin maneuver).
STEP 3 IDENTIFY
LINGUAL NERVE AND
HYPOGLOSSAL NERVE
Free the submandibular gland (SMG) from
the anterior belly of digastric and the
lateral surface of mylohyoid mucle. Divide
the mylohyoid vessels. Figure 3
The free edge of the mylohyoid muscle
is identified and retracted superior and
laterally to expose the lingual nerve,
hypoglossal nerve and Wharton’s duct.
Figure 4
After ligating the facial artery and vein
superiorly, the SMG is retracted inferiorly
to identify the submandibular ganglion that
is then divided to free the lingual nerve,
taking care not to place the tie across the
main nerve. Figure 5
submAndibulAr
glAnd exCision
12 dissection manual
STEP 4 IDENTIFY AND
DIVIDE THE FACIAL
ARTERY
The Wharton’s duct is divided after
identification of hypoglossal nerve. During
surgery for sialolithiasis, the surgeon
should follow and divide the duct anteriorly
close to the floor of the mouth, so as not
to leave behind a calculus.
The SMG can then be reflected inferiorly
and the facial artery identified, ligated
and divided where it exits from behind
the posterior belly of the digastric muscle.
Figure 6
The SMG is then completely excised
following completion of the dissection
off the tendon and posterior belly of the
digastric muscle.
submAndibulAr
glAnd exCision
submandibular Gland excision 13
Figure 3
Mylohyoid vessel (red arrow) exposed after
anterior belly of digastric is retracted
Figure 4
Mylohyoid muscle retracted to expose
the lingual nerve (LN), submandibular
duct (SMD) and hypoglossal nerve (HP)
Figure 5
Submandibular gland (SMG) retracted
downward to show the lingual nerve (LN) and
the submandibular ganglion (blue arrow)
Figure 6
Facial artery (red arrow) passes behind
the posterior belly of digastric (DG)
Figure 1
Upper neck incision at hyoid level
Figure 2
Marginal mandibular nerve (yellow
arrow) crosses the facial vessels
SMD
LN
HP
SMG
LN
SMG
DG
14 dissection manual
KEY POINTS
1. Skin incision 3 cm below the border of the mandible.
2. Preserve the marginal mandibular nerve through direct
identification or subcapsular dissection.
3. Identify and free the lateral surface of the mylohyoid muscle to
permit its retraction.
4. Identify the lingual nerve, hypoglossal nerve and Wharton’s duct.
5. Divide the Wharton’s duct as anterior as possible in sialolithiasis.
6. Divide the submandibular ganglion.
7. Preserve the lingual nerve and hypoglossal nerve.
8. Ligate the facial artery twice: Once superiorly and again
inferiorly as it crosses the digastric muscle.
transcervical aPProach to the ParaPharynGeal sPace 15
03
trAnsCerviCAl APProACh
to the PArAPhAryngeAl
sPACe
Jason YK Chan
16 dissection manual
transcervical aPProach to the ParaPharynGeal sPace 17
STEP 1 INCISION
Access to the parapharyngeal space is
gained via an upper neck incision at the
level of the hyoid bone.
Subplatysmal flaps may be raised or a
subcapsular dissection is performed to
raise the capsule of the submandibular
gland (SMG) together with the skin flap to
protect the marginal mandibular nerve.
Anterior border of SCM, the SMG and
digastric muscle are identified.
STEP 2 MOBILIZE THE
SUBMANDIBULAR
GLAND
The facial artery is identified posteroinferior to the gland where it emerges
medial to the posterior belly of digastric.
The facial artery is then ligated and divided
superior to the posterior belly of digastric.
The SMG is mobilised with gentle finger
dissection in a posterior-to-anterior
direction taking care to leave the thin
fascial layer over the ranine veins and the
hypoglossal nerve intact. Figure 1
STEP 3 ENTER THE
PARAPHARYNGEAL SPACE
(PPS)
By retracting the posterior belly of digastric
posteriorly, the mandible superiorly and
the submandibular gland anteriorly, the
surgeon can pass a finger/instrument
directly into the prestyloid PPS. The access
can further be improved by dividing the
stylo-mandibular ligament. Figures 2, 3 The
positive identification of hypoglossal nerve,
vagus nerve, carotid artery and internal
jugular vein before dissecting the tumour
will ensure protection of these structures.
trAnsCerviCAl APProACh
to the PArAPhAryngeAl
sPACe
18 dissection manual
SMG
SCM
Figure 3
Endoscopic view of PPS after removal
of tumour DG–Digastric muscle SH–
Stylohyoid muscle HP–Hypoglossal nerve
SCM–sternocleidomastoid muscle SMG–
Submandibular gland
SH
DG
HP
SMG
SCM
Figure 2
Entrance to the PPS (blue arrow) LG–lingual
nerve DG–Digastric muscle SH–Stylohyoid
muscle HP–Hypoglossal nerve CCA–common
carotid artery
LG
DG
HP
SH
CCA
Figure 1
Submandibular gland (SMG) mobilized
anteriorly to expose the digastric tendon (blue
arrow) and hypoglossal nerve (yellow arrow)
transcervical aPProach to the ParaPharynGeal sPace 19
KEY POINTS
1. Neck incision adequately below the border of the mandible.
2. Subcapsular dissection over the submandibular gland to
protect the marginal mandibular nerve.
3. Full length of the posterior belly of digastric and the anterior
border of SCM skeletonized.
4. Facial artery ligated as it emerges deep to the posterior belly of
the digastric muscle.
5. Submandibular gland reflected anteriorly.
6. The stylo-mandibular ligament divided.
7. Retract mandible, posterior belly of digastric and submandibular
gland to facilitate access to PPS.
8. Identify hypoglossal nerve, vagus nerve, carotid artery and
internal jugular vein before tumour dissection.
9. Access the prestyloid parapharyngeal space.
20 dissection manual
transcervical aPProach to the ParaPharynGeal sPace 21
04
seleCtive neCk
disseCtion
Alexander C Vlantis
22 dissection manual
selective neck dissection 23
STEP 1 INCISION
It is important to know the anatomy and
boundaries of the anatomical triangles of
the neck.
A horizontal upper neck skin incision is
made from the anterior border of the
SCM to the midline of the neck just below
the level of the hyoid bone. The incision
should provide access from the lower
border of the mandible to tissue at the
level of the cricoid cartilage. Figure 1
Subplatysmal flaps are elevated up to the
lower border of mandible and inferiorly to
the level of the cricoid until the omohyoid
muscle is seen. The external jugular
vein and great auricular nerve should be
identified lying on the SCM. Figure 2
The skin flaps can be anchored superiorly
and inferiorly with 2–O silk sutures.
STEP 2 LEVEL I
DISSECTION
Start the dissection at Level Ia with
clearance of f ibrofatty t issue in the
submental triangles until both anterior
bellies of the digastric (the lateral borders
of the triangles) and the mylohyoid muscle
(the floor of the triangles) are exposed,
and inferiorly to the position of the upper
border of the hyoid bone (the inferior
border of the triangle). Figure 3
The surgeon next addresses Level Ib of the
neck.
Subcapsular dissection: The fascia
(capsule) overlying the submandibular
gland is incised horizontally over the
midpoint of the gland and is dissected
from the gland in a superior direction in a
subcapsular plane so as to avoid injuring
the marginal mandibular nerve. With
this technique the marginal mandibular
seleCtive neCk
disseCtion
24 dissection manual
nerve is not routinely identified. The
assistant however watches for twitching
of the lower lip as this indicates proximity
to the nerve during live surgery when no
muscle relaxant has been administered.
Positive identification of marginal
mandibular nerve: The mandibular nerve
crosses the facial artery and vein which are
both identified by blunt dissection with a
fine haemostat at the mandibular notch
where the facial vessels cross the mandible.
Once they have been identified, find the
marginal nerve crossing superficial to the
vein. After identification of the nerve the
facial vein is divided inferior to the nerve
and slung upwards to protect the marginal
mandibular nerve during the dissection. This
method is recommended when clearance of
perifacial lymph nodes in oral cavity cancer
is indicated. Figures 4, 5
Next attention is directed to the fibrofatty
tissue anterior to the gland between the
anterior belly of digastric and mylohyoid
musc le . Nodes here are espec ia l ly
important to remove in malignancies of
the anterior floor of mouth. To resect
these nodes the anterior belly of digastric
is retracted forward and the tissue is
delivered using electrocautery dissection
with the plane of deep dissection being
the mylohyoid muscle. Vessels and nerves
to the mylohyoid muscle are encountered
and need to be divided. Figure 6
To identify the lingual and hypoglossal
nerves, the posterior free edge of the
mylohyoid muscle is retracted with a
right angle retractor. Inferior traction
on the gland brings the lingual nerve
and the submandibular duct into view.
Parasympathetic secretomotor fibres
that travel from the lingual nerve to the
submandibular ganglion are divided under
direct vision taking care not to injure the
lingual nerve. The duct is divided after
clear identification of both the lingual
(superficial to its plane) and hypoglossal
level i
disseCtion
selective neck dissection 25
Figure 1
Upper neck incision
Figure 4
Marginal mandibular nerve (yellow arrow) cross
the facial vessel at the mandibular notch
SCM – sternocleidomastoid muscle
Figure 2
Subplatysmal flap (red arrow) raised to identify
great auricular nerve (yellow arrow) and
external jugular vein (blue arrow)
Figure 3
Level Ia to expose the digastric muscles (DG)
and mylohyoid muscle (MH)
SCM
DGDG
MH
26 dissection manual
(deep to its plane) nerves. By exposing the
posterior belly of digastric the proximal
portion of the facial artery that loops from
its superior border into the gland can be
identified and divided. Figures 7-9
STEP 3 LEVEL II
DISSECTION
Dissect fatty tissue containing lymphatics
in the anterior parts of Levels II and III from
the underlying infrahyoid strap muscles in
a posterior direction towards the carotid
sheath. The dissection also follows the
medial or deep surface of the SCM and
exposes deeper structures including the
IJV and omohyoid muscle. A number of
small segmental vessels entering the SCM
are encountered and cauterized. The
dissection is carried posteriorly along the
deep or medial surface of the muscle in a
subepimysial plane to the posterior edge
of the SCM. Figure 10
LEVEL IIB CLEARANCE
Use retractors to pull the upper part of the
SCM and the tail of parotid laterally. This
will expose the accessory nerve and Level
IIb lymphatic tissue. With a haemostat,
create a tunnel immediately posterior
to the IJV down to the prevertebral
muscles. This manoeuver speeds up the
subsequent dissection of Level IIb by
clearly delineating the posterior wall of
the IJV. The transverse process of the C1
vertebra can be palpated immediately
posterior to the accessory nerve and IJV
and serves as an additional landmark for
the position of these structures in difficult
surgical cases. The accessory nerve should
be freed from the surrounding fibrofatty
tissue atraumatically using a haemostat.
Fibrofatty tissue is mobilized from the
postero-superior corner (medial to the
retracted SCM) with anterior traction on
the fibrofatty tissue. The occipital artery
passes across to the top of Level IIb and its
level ii
disseCtion
selective neck dissection 27
Figure 10
Dissection along the medial surface of SCM to
expose the IJV and OH-omohyoid muscle
IJV
OH
SCM
Figure 5
Close up view for the marginal mandibular
nerve (yellow arrow)
Figure 7
Posterior border of mylohyoid muscle (red
arrow)
Figure 8
Lingual nerve (yellow arrow) identified after
mylohyoid muscle retracted
Figure 6
Mylohyoid artery (red arrow) exposed with
anterior belly of digastric retracted
Figure 9
Identification of lingual nerve (LN), submandibular duct (SMD) and hypoglossal nerve
(HP)
LN
SMD
HP
28 dissection manual
branches may need to be tied should they
be severed while dissecting the superior
part of Level IIb. Dissect through the
fibrofatty tissue and onto the deep muscles
of the neck which are seen to course in
a postero-inferior direction. Once the
fibrofatty tissue of Level IIb has been fully
mobilized from the underlying muscles,
pass the tissue antero-inferiorly under the
mobilized accessory nerve. Figures 11-15
STEP 4 LEVEL IIA & III
DISSECTION
While retracting the SCM posteriorly
and the fibrofatty tissue of Levels II and
III anteriorly with sharp-toothed rake
retractors, dissect the fatty tissue of Levels
II and III in an anterograde direction from
the medial or deep posterior border of
SCM. The deep dissection plane is the
muscular floor of the neck, encountered
by dissecting between the branches of the
cervical plexus which need to be identified
and preserved. Figure 16
The phrenic nerve and brachial plexus
are not seen in this dissection, but are
relevant if Level IV is dissected. Continue
the anterograde dissection with a scalpel
or scissors until the ansa cervicalis, the
carotid sheath containing the common and
internal carotid arteries, vagus nerve and
IJV are sequentially exposed. The carotid
sheath is incised along the full course of
the vagus nerve and the neck dissection
specimen is dissected off the IJV by
dissecting inside the carotid sheath.
Continue dissecting the fat and lymphatics
from the anterior aspect of the IJV until the
common carotid artery is again reached.
Divide and ligate tributaries of the IJV with
ligatures.
Inferiorly, the fibrofatty tissue at the junction
of Levels III and IV is divided at the level
level iii
disseCtion
selective neck dissection 29
Figure 11
Accessory nerve (yellow arrow) identified at
Level II, DG–posterior belly of digastric and
SCM–sternocleidomastoid muscle
Figure 12
Accessory nerve (yellow arrow) and Level IIb
llb
Figure 13
Level IIb dissected free from the underlying
prevertebral muscle (PM) and accessory nerve
(yellow arrow)
llb
PM
Figure 16
Cervical plexus (yellow arrows)
Figure 14
Level IIb tunnel under the accessory nerve
(yellow arrow)
SCM
llb
Figure 15
Completed Level IIb dissection, accessory
nerve (yellow arrow), Internal jugular vein-IJV
and Prevertebral muscle-PM
IJV
llb
PM
DG
SCM
30 dissection manual
of the omohyoid (in a supraomohyoid
neck dissection). Identify and preserve the
superior thyroid artery where it originates
from the external carotid artery. Figure 17
STEP 5 LEVEL IV
DISSECTION
With a lateral neck dissection, Level IV
is dissected by applying traction to the
fibrofatty tissue deep to the omohyoid
muscle in a cephalad direction and to the
omohyoid muscle in a caudal direction,
while dissecting the fibrofatty tissue from
Level IV. The transverse cervical vessels
may be encountered and its ascending
branches need to be ligated. A finger
may also be used to establish a dissection
plane between the fat of Level IV and the
brachial plexus and phrenic nerve. Be
vigilant for the thoracic duct (left neck)
or right lymphatic duct (right neck) or
their tributaries which may unknowingly
be transected resulting in a chylous leak.
Figure 18
The final step is to strip the neck dissection
specimen off the infra-hyoid strap muscles.
Remember to take care not to injure the
hypoglossal nerve and pharyngeal veins
superiorly.
level iv
disseCtion
Figure 17
A bifurcated internal jugular vein (IJV) and its
tributary (blue arrow)
level II
level III
IJV
SCM
Figure 18
Level IV lymphatics (on top of the curved
artery) and the relationship with the transverse
cervical artery (red arrow) and phrenic nerve
(yellow arrow)
selective neck dissection 31
KEY POINTS
1. A horizontal incision from the anterior border of the SCM to the
midline of the neck just below the level of the hyoid bone is
made.
2. Level Ia dissection clears tissue between the anterior bellies of
both digastrics and off the mylohyoid muscle.
3. Incising the submandibular capsule horizontally over its
midpoint and dissecting the gland in a subcapsular plane
avoids injuring the marginal mandibular nerve which is not
routinely identified.
4. If the facial artery and vein are identified with a fine haemostat
at the mandibular notch, the marginal nerve will be found
crossing superficial to the vein.
5. Fibres that travel from the lingual nerve to the submandibular
ganglion are divided under direct vision so that the lingual
nerve is not injured.
6. The submandibular duct is divided after identifying both the
lingual (superficial to its plane) and hypoglossal (deep to its
plane) nerves.
7. Identify the accessory nerve from its position adjacent to the
IJV superiorly deep to the posterior belly of digastric to its
entry into the SCM.
8. Dissect all fibrofatty tissue from the posterior border of the
SCM in an anterior direction preserving the branches of the
cervical plexus, vagus nerve, carotid artery and off the IJV.
9. Identify and preserve the superior thyroid artery where it
originates from the external carotid artery, this is the medial
limit of dissection.
10. Establish a dissection plane between the fat of Level IV, the
brachial plexus and phrenic nerve, and be vigilant for the
thoracic duct.
32 dissection manual
selective neck dissection 33
05
modiFied rAdiCAl neCk
disseCtion tyPe ii
Alexander C Vlantis
34 dissection manual
modified radical neck dissection tyPe ii 35
INCISION
Various incisions can be used for a neck
dissection. The incision depends on
whether the neck dissection is an isolated
procedure or is to be combined with a
procedure to resect a primary tumour.
For incisions with a three point junction,
avoid placing the junction directly over the
carotid artery. Figures 1, 2
STEP 1 INCISION AND
FLAP RAISING
The skin incision is made to expose the
platysma which is then also incised. The
skin and platysma flap is raised in the
subplatysmal plane by following the deep
surface of the platysma. Expose the inferior
border of the mandible superiorly, the
clavicle inferiorly, the anterior border of the
trapezius posteriorly and the midline of the
neck anteriorly. Give attention to elevating
the flap over the posterior triangle as the
platysma is usually absent here, by keeping
sufficient subcutaneous tissue on the skin.
This is done by placing a finger under the
flap to gauge the thickness of the flap
while it is being raised and to provide
adequate counter traction. This will also
prevent button-holing the skin. Identifying
the spinal accessory nerve is the best way
to prevent it from being injured. In thin
patients, the accessory nerve can be very
superficial and can be injured during flap
elevation. Figure 3
STEP 2 LEVEL I
DISSECTION
Start the dissection at Level Ia with
clearance of fibrofatty tissue in the submental triangle to expose both anterior
bellies of the digastric (DG) muscles and
the mylohyoid (MH) muscle between them.
Figure 4
modiFied rAdiCAl
neCk disseCtion
tyPe ii
36 dissection manual
The surgeon next addresses Level Ib
SUBCAPSULAR DISSECTION
The fasc ia ( capsu le ) over l y ing the
submandibular gland is incised midway
over the gland and is dissected from
the gland in a superior direction in a
subcapsular plane so as to avoid injury to
the marginal mandibular nerve. Using this
technique the marginal mandibular nerve
does not need to be routinely identified.
The ass i s tant however watches for
twitching of the lower lip as this indicates
proximity to the nerve.
POSITIVE IDENTIFICATION
OF MARGINAL
MANDIBULAR NERVE
The marginal mandibular nerve crosses
the facial artery and vein. The facial artery
and vein are identified by blunt dissection
with a fine haemostat at the mandibular
notch where the facial vessels cross the
mandible. After identification of the nerve,
the facial vein is divided and slung upwards
to protect the marginal mandibular nerve
during the dissection. This method is
recommended for clearance of perifacial
lymph nodes in oral cavity cancer.
Figures 5, 6
Next, attention is directed to the fibrofatty
tissue anterior to the gland between the
anterior belly of digastric and mylohyoid
muscle. These nodes are especial ly
important to resect with malignancies of
the anterior floor of mouth. To resect these
nodes, retract the anterior belly of digastric
anteriorly and deliver the tissue using
electrocautery dissection with the deep
dissection plane being on the mylohyoid
muscle. Figure 7
To identify the lingual and hypoglossal
nerves, the posterior free edge of the
mylohyoid muscle is retracted with a right
Figure 1
T incision, avoid placing the 3 point junction
over the carotid artery
Figure 2
Horizontal incision to avoid a 3 point junction
modified radical neck dissection tyPe ii 37
Figure 3
Platysma muscle (red arrow), External jugular
vein (blue arrow) and Great auricular nerve
(yellow arrow) Figure 5-6
Marginal mandibular nerve (yellow arrow)
Facial vessel (red arrow)
Figure 7
Lymphatic tissue removed with the digastric
muscle (DG) retracted and the artery to
mylohyoid exposed (red arrow)
DGMH
Figure 4
Level Ia dissection, DG-anterior belly of
digastric, MH – Mylohyoid muscle
MHDG
DG
38 dissection manual
angle retractor. Figure 8 Inferior traction on
the submandibular gland (SMG) brings the
lingual nerve and the submandibular duct
into view. The submandibular ganglion can
be divided under direct vision with special
care taken not to injure the lingual nerve.
The duct can also be divided after clear
identification of both the lingual and hypoglossal nerves. Figure 9 By following the
posterior belly of digastric, the proximal
portion of the facial artery and vein can be
identified and divided. Figure 10
STEP 3 IDENTIFY
ACCESSORY NERVE
(CN XI)
The accessory nerve is identified 1-2 cm
posterior to the exit site of the GAN at the
posterior border of SCM. Figure 11 The
nerve is traced distally until it goes under
or deep to the trapezius muscle as well
as proximally towards the IJV by dividing
the SCM. The branches to SCM need to
be divided and occasionally there will be
a contribution to the accessory nerve from
the cervical plexus at the posterior border
of SCM. Figure 12
STEP 4 LEVEL IIB
DISSECTION
The pa ro t id t a i l and the supe r io r
attachment of the SCM can be divided
with a knife or cautery until the fatty tissue
of Level IIb is exposed. Figure 13 Level IIb
lymphatics are further dissected down to
the deep muscle that runs in a posteroinferior direction. The occipital artery is
usually encountered and needs to be
divided during the dissection. Figures
14,15 The contents of Level IIa and IIb are
dissected off from the IJV and the deep
muscles of the neck until the cervical
plexus comes into view. The dissected
accessory nerve is translocated posteriorly
and the dissection of Levels IV and V
continues.
modiFied rAdiCAl
neCk disseCtion
tyPe ii
modified radical neck dissection tyPe ii 39
Figure 8
Lingual nerve (yellow arrow)
Figure 9
Lingual nerve (yellow arrow), Submandibular
duct (blue arrow) and Hypoglossal nerve (red
arrow)
Figure 10
Facial vessel (red arrow)
Figure 11
Accessory nerve (CNXI) identified 1 cm
posterior to GAN at the posterior border of
SCM
Figure 12
Accessory nerve branches, SCM branch (blue
arrow), Trapezius branch (red arrow) and
cervical plexus contribution (yellow arrow)
MH
SMG
GANSCM
CN XI
SCM
SMG
40 dissection manual
STEP 5 LEVEL IV & V
DISSECTION
Divide the SCM approximately 1 cm above
the clavicle while applying continuous
traction. The IJV within the carotid fascia
can be identified after division of the
muscle fibers. The dissection continues
in the supraclavicular fossa but leave the
lymphatic tissue posterior to IJV intact
to prevent injury to the thoracic duct
located in Level IV. Identify the omohyoid
muscle and the external jugular vein in
the supraclavicular fossa and divide the
muscle and ligate the external jugular
vein. Figure 16 The dissection goes deep
until the transverse cervical vessels and
the prevertebral fascia come into view.
The brachial plexus can be identified below
the fascia and should be kept intact.
Figure 17 The dissection is then completed
with a blunt finger or with a dental swab in
an antero-superior direction. The phrenic
nerve will be identified descending on
the scalenus anterior muscle running in
a medial direction. Finger dissection can
also be done postero-superiorly with
care taken not to rupture the transverse
cervical vessels. The dissected accessory
nerve should now be identified again
because the supraclavicular nerve running
in the fibrofatty tissue can be divided with
diathermy or a knife but not the spinal
accessory nerve. The transverse cervical
artery can be dissected free from the
lymphatic tissue by dividing the ascending
branch alone, preserving it for future use.
Figure 18
modiFied rAdiCAl
neCk disseCtion
tyPe ii
modified radical neck dissection tyPe ii 41
Figure 13
Superior attachment of SCM divided to expose
the underlying levator scapulae (LS) muscle
Figure 14
Accessory nerve (yellow arrow)
Figure 15
Level IIb lymphatic dissected free from
accessory nerve (yellow arrow), IJV (blue arrow)
Figure 16
Omohyoid muscle (blue arrow) and
translocated accessory nerve (yellow arrow)
Figure 17
Brachial plexus (yellow arrow) and transverse
cervical vessel (red arrow)
Figure 18
Phrenic nerve (yellow arrow) and cervical plexus
(blue arrows)
llb
lla
llb
SCM
SCM
SCMLS
IJV
42 dissection manual
STEP 6 AVOID INJURY TO
THE THORACIC DUCT
The Level IV lymphatics adjacent to the
IJV should be carefully divided between
clamps and ligated with silk ligatures to
avoid a troublesome chyle leak especially
on the left side. Attention also needs to
be given to the phrenic and vagus nerves
so that they are not clamped as they run
close to the area you are now dissecting.
Figure 19
STEP 7 ANTEROGRADE
DISSECTION OF LEVELS
II-V LYMPHATICS
Anterograde dissection of Levels II-V
lymphatics begins with anterior traction
applied to the fibrofatty tissue. The
surgeon establ ishes a subepimysial
dissection plane on the deep muscles of
the neck, except over the brachial plexus
where the overlying fascia is retained to
protect the nerves. Dissection proceeds
over a broad front until the entire cervical
plexus has been exposed. The phrenic
nerve is identified and preserved as it
descends obliquely across the scalenius
anterior muscle. Figure 20 The cervical
plexus is divided from the phrenic nerve
and the dissection continued anteriorly
onto the carotid fascia. Figure 21
The carotid fascia is incised with a scalpel
and the IJV, common carotid artery
and vagus nerves will come into view.
Tributaries from the IJV will be seen when
the dissection reaches the anterior border
of the IJV. These tributaries need to be
divided and ligated with silk ligatures. The
ansa hypoglossi, which courses either deep
or superficial to the IJV, may be preserved.
modiFied rAdiCAl
neCk disseCtion
tyPe ii
modified radical neck dissection tyPe ii 43
Figure 19
Internal jugular vein (blue arrow), Transverse
cervical vessel (red arrow) and Vagus nerve
(yellow arrow)
Figure 20
Phrenic nerve (yellow arrow) and cervical plexus
(blue arrows)
Figure 21
Divide the cervical plexus away from phrenic
nerve (yellow arrow)
44 dissection manual
The final step is to free the neck dissection
specimen off the infrahyoid strap muscles
to identify and preserve the superior
thyroid vascular pedicle, and to deliver the
neck dissection specimen. Figure 22
modiFied rAdiCAl
neCk disseCtion
tyPe ii
Figure 22
Completed MRND type II, transverse cervical
vessel (red arrow) and accessory nerve (yellow
arrow) on levator scapulae (LS)
IJV
LS
modified radical neck dissection tyPe ii 45
KEY POINTS
1. Choose your incision according to the primary tumour and
avoid 3 point junctions in the post irradiated patient.
2. Identify and protect the marginal mandibular, lingual and
hypoglossal nerves in Level I.
3. Identify IJV and accessory nerve at Level II and make Level IIb
clearance safe and efficient.
4. Accessory nerve can be identified 1 cm posterior to the GAN
at posterior triangle.
5. Keeping the prevertebral fascia intact is the key to avoid
phrenic nerve and brachial plexus injury.
6. Level IV lymphatics should be dissected with caution to avoid a
chyle leak.
7. Identify the vagus nerve within the carotid sheath.
8. Cervical plexus should be divided away from the roots to avoid
injury to phrenic nerve.
9. Tributaries of IJV should be divided and ligated to avoid
troublesome bleeding.
10. Superior thyroid artery should be identified and preserved
during neck dissection.
46 dissection manual
modified radical neck dissection tyPe ii 47
06
thyroideCtomy
Siu Kwan Ng
48 dissection manual
thyroidectomy 49
STEP 1. EXPOSING THE
THYROID GLAND
The collar incision Figure 1 (curvilinear skin
crease incision) is made at 1.5-2 finger
breadths above the clavicular heads (when
the neck is extended)
A subplatysmal flap is elevated up to the
thyroid notch superiorly, to the sternal notch
inferiorly and SCM laterally. Figure 2 Note
that the platysma is absent in the midline
of the neck and is more readily identified at
the lateral part of the incision. Alternatively,
defining the subplatysmal plane can be aided
by finding the anterior jugular veins which are
located immediately beneath that plane.
Identify the midline raphe between the
sternohyoid muscles. Figure 3 This raphe is
divided from the thyroid notch superiorly
to sternal notch inferiorly. The sternohyoid
muscle is retracted laterally to expose the
sternothyroid muscle.
Identify the medial edge of the sternothyroid
(ST) muscle which lies deeper and lateral to
the medial edge of sternohyoid (SH) muscle.
Figure 4
Dissect the sternothyroid muscle off the
thyroid gland surface from upper pole to
lower pole, keeping the dissection plane
close to the muscle. Figure 5 The middle
thyroid vein (of which there can be several
or be absent), if encountered is ligated and
divided
STEP 2. DISSECTION AND
RELEASE OF THYROID
UPPER POLE
The medial 1 cm of the sternothyroid muscle
insertion is coagulated and divided to
facilitate the upper pole exposure. Figure 6
Using Babcock forceps (Kocher forceps
are quite traumatic and may tear the thyroid
parenchyma causing bothersome bleeding),
thyroideCtomy
50 dissection manual
the upper pole of the thyroid is firmly held
and pulled inferiorly and laterally. This
maneuver exposes the avascular space
between the upper pole of the thyroid
and the cricothyroid muscle (the space of
Reeve). Figure 7
Gentle dissection into this space using the
blunt tip of closed Metzenbaum scissors can
facilicate exposure of the external laryngeal
nerve in the majority of patients. Figures 8, 9
The superior pedicle is ligated below the
external laryngeal nerve. Figures 10, 11
STEP 3. DISSECTION OF
TRACHEO-OESOPHAGEAL
REGION
After releasing the upper pole, the whole
thyroid lobe is rotated medially by seperating
the remaining alveolar tissue between the
gland and the sternothyroid muscle. This step
exposes the tracheo-oesophageal region.
Figure 12
Capsular dissection (i.e. dissection close
to the true thyroid capsule) releases the
lower thyroid pole. Attention is drawn to the
presence of the inferior parathyroid gland
which if seen, should be preserved and
dissected off the thyroid gland. The inferior
parathyroid glands are normally located
between the lower pole of the thyroid and
the isthmus, most commonly on the anterior
or the posterolateral surface of the lower pole
of the thyroid, or located in the lower neck in
proximity to the thymus. Sometimes it is not
easy to identify the inferior parathyroid gland.
Figures 13, 14
Figure 2
Subplatysmal flap evevated up to the thyroid
notch superiorly and sternal notch inferiorly
Figure 1
Curvilinear skin crease incision with reference
to cricoid cartilage
thyroidectomy 51
Figure 7
Space of Reeve (SOR) exposed with the upper
pole of thyroid pulled inferiorly and laterally
SOR
Figure 5
Dissect the thyroid gland off the sternothyroid
muscle
Figure 3
Identify midline raphe
Figure 4
Identify the medial edge of the sternothyroid
(ST) and sternohyoid (SH) muscles
ST
SH
Figure 6
Divide the medial 1 cm of sternothyroid muscle
insertion. SH – sternohyoid muscle
SH
52 dissection manual
After the lower pole is released, an attempt is
made to identify the recurrent laryngeal nerve
(RLN) lying within the tracheo-oesophageal
groove (right side would be more lateral).
The RLN is located by carefully dissecting/
teasing apart the tissues in Simon’s triangle
which is formed by the common carotid
artery laterally, the oesophagus medially,
and the inferior thyroid artery superiorly.
Figures 15, 16
After identification of the recurrent laryngeal
nerve, capsular dissection is continued
cranially keeping sight of the recurrent
laryngeal nerve at all times. The branches of
the inferior thyroid artery are divided close to
the capsule so that the blood supply to the
parathyroid glands is preserved. The superior
parathyroid gland is commonly surrounded
by a fat pad. This gland is normally located
at the level of the upper two-thirds of the
thyroid, in a posterior position and is closely
related to the Tubercle of Zuckerkandl,
about 1 cm above the crossing point of
the recurrent laryngeal nerve and inferior
thyroid artery. The parathyroid gland has a
characteristic orange or rich yellow colour.
The gland should be preserved with its blood
supply from the inferior thyroid artery by
peeling the gland off the thyroid capsule.
Figures 17, 18
The recurrent laryngeal nerve is traced
cranially until it enters into the larynx around
0.5 cm caudal to the inferior cornu of the
thyroid cartilage. Berry’s ligament attaches
the thyroid gland to the cricoids and first 2
tracheal rings. The ligament can be carefully
divided while paying attention to the RLN at
its entry point into the larynx. Figures 19, 20
After the division of Berry’s ligament, the
thyroid lobe is dissected off the trachea.
The isthmus is then ligasure coagulated and
divided (or clamped, divided and oversewn
with 3-0 vicryl stitches).
Figure 9
Middle thyroid vein (blue arrow)
Superior thyroid artery (red arrow)
External laryngeal nerve (yellow arrow)
Figure 8
External laryngeal nerve
thyroidectomy 53
Figure 15
Recurrent laryngeal nerve
Figure 11
External laryngeal nerve (yellow arrow)
Figure 10
The superior pedicle (red arrow) is ligated
below the external laryngeal nerve (yellow
arrow)
Figure 12
Exposure of the tracheo-oesophageal region
Figure 13
Dissection of inferior parathyroid gland (yellow
arrow)
Figure 14
Superior parathyroid gland (yellow arrow)
Inferior thyroid artery (red arrow)
54 dissection manual
TOTAL THYROIDECTOMY
Repeat the same procedure on the other
side without dividing the isthmus. The
prelaryngeal area should be dissected and
examined for the presence of a pyramidal
lobe to ensure complete excision of thyroid
tissue.
Figure 16
Recurrent laryngeal nerve (yellow arrow)
Oesophagus (blue arrow)
thyroideCtomy
thyroidectomy 55
Figure 17
Recurrent laryngeal nerve (yellow arrow) and
Superior parathyroid gland (red arrow)
Figure 18
Recurrent laryngeal nerve (yellow arrow)
and Superior parathyroid gland (red arrow)
Oesophagus (blue arrow)
Figure 19
Berry’s Ligament (blue arrow)
Figure 20
Berry’s ligament (blue arrow), Recurrent
laryngeal nerve (yellow arrow)
56 dissection manual
KEY POINTS
1. The skin flap is raised in the subplatysmal plane. The platysma
is more readily identified at the lateral part of the incision.
2. Inadequate seperation of the strap muscles at the median
raphe limits lateral retraction and exposure.
3. Limited separation of the sternothyroid muscle from its medial
insertion on the thyroid cartilage improves the exposure of the
upper pole of the thyroid gland, aiding identification of the
external laryngeal branch of the superior laryngeal nerve.
4. When approaching a very big goiter, the overlying strap
muscles can be transected horizontally to improve the surgical
exposure.
5. Freeing the upper pole of the thyroid gland early in the surgery
improves the mobility of the thyroid lobe. By medially rotating
the lobe out of the thyroid bed, the tracheo-oesophageal
region is opened facilitating dissection and identification of the
recurrent laryngeal nerve.
6. Dissection is kept close to the thyroid capsule. This minimizes
the chance of injury to both the recurrent laryngeal nerve (before
its identification) and the parathyroid glands.
7. Routine identification of the recurrent laryngeal nerve has been
shown to reduce the chance of injury.
8. Atraumatic forceps should be used to hold the thyroid tissue
during dissection.
9. The Zuckerkandl lobe can be quite big in some patients giving
the erroneous impression that the recurrent laryngeal nerve
penetrates the thyroid gland.
10. For total thyroidectomy, it is prudent to check for the presence
of a pyramidal lobe which, if present, should also be excised.
total larynGectomy 57
07
totAl lAryngeCtomy
Alexander C Vlantis
58 dissection manual
total larynGectomy 59
STEP 1 INCISION AND
POSITION OF STOMA
A superiorly based apron flap incision is
marked with the horizontal limb placed
about 2 cm above the clavicles with
the vertical limbs parallel to and 1cm
posterior to the anterior borders of the
sternocleidomastoid muscles (SCM).
The stoma is marked immediately below
the horizontal limb so that its future upper
border will be the apron flap. The size of
the stoma should approximate the size of
the patient’s thumb to facilitate the use of
a voice prosthesis, or be about 1.5 times
the diameter of the trachea. The lower
border of the stoma should be 2 cm above
the upper border of the manubrium. It is
important not to place the stoma too low
in the neck, especially when the neck is
already extended for surgery. Figures 1, 2
Musculocutaneous flaps are elevated in
the subplatysmal plane to 2 cm superior to
the hyoid bone above, and to the sternal
notch below.
STEP 2 RETRACTION OF
THE SCM AND DIVISION
OF OMOHYOID MUSCLE
Incise the investing layer of deep cervical
fascia along the anterior border of SCM
and divide the external jugular vein/great
auricular nerve if necessary.
Retract the SCM laterally and then dissect
on the medial surface of the SCM from
medial to lateral and anterior to posterior
to expose the omohyoid muscle and
internal jugular vein (IJV). The segmental
blood supply to the SCM is cauterized
with bipolar diathermy and then the belly
of the omohyoid muscle is divided. With
gentle retraction on the IJV, the middle
thyroid vein is divided between clamps
totAl lAryngeCtomy
60 dissection manual
and ligated. The internal jugular vein and
the lateral border of sternohyoid muscle
are clearly defined at this stage. Figure 3
STEP 3 DIVISION OF THE
INFRAHYOID MUSCLES
Divide and ligate the anterior jugular vein.
The sternohyoid strap muscle is exposed
in and just above the sternal notch. The
sternohyoid muscle and then deep to it
the sternothyroid muscle are divided with
diathermy to expose the thyroid lobe
medially and the IJV laterally beneath
them.
STEP 4 REPEAT STEPS 2 & 3
ON THE CONTRALATERAL
SIDE
Repeat steps 2 and 3 on the contralateral
s ide so that both thyroid lobes are
exposed. The contralateral (the side without larynx cancer) thyroid lobe can
usually be preserved to avoid hypocalcaemia and hypothyroidism if there is no
gross tumour invasion into the thyroid
gland on imaging.
STEP 5 PRESERVATION OF
ONE THYROID LOBE
The thyroid isthmus is divided and oversewn with a suture.
The contralateral thyroid lobe is mobilized
from the trachea and rotated laterally
to free it from the larynx. The recurrent
laryngeal nerve can be identified in the
tracheo-oesophageal groove, but the nerve
is obviously cut in a total laryngectomy.
The oesophagus should be identified and
preserved. The superior laryngeal artery
is divided from the superior thyroid artery
which is preserved to maintain blood
supply to the thyroid lobe.
mobilizAtion oF
lArynx
total larynGectomy 61
Figure 1
Apron incision and the stoma
Figure 3
SCM retracted to expose the omohyoid muscle
(red arrow), IJV (blue arrow) and free edge of
sternohyoid muscle (yellow arrow)
Figure 4
Strap muscle (SM) dissected free from the right
thyroid lobe (TH) and isthmus (*) divided
Figure 5
Thyroid (TH) mobilized from the laryngeal
frame work and the oesophagus (red arrow) is
exposed
Figure 2
Alternative incision with stoma away from the
main incision
*
TH
TH
SM
62 dissection manual
The ipsilateral (the side with larynx cancer)
thyroid lobe is left attached to the larynx
as an additional margin and the recurrent
laryngeal nerve, superior thyroid artery
and inferior thyroid arteries are divided
to free up the larynx. Care must be taken
once again to identify and preserve the
oesophagus.
The superior laryngeal nerve is identified
before it penetrates the thyrohyoid membrane and is divided on both sides.
Figures 4-6
STEP 6 SEPARATING
THE CONSTRICTOR
FROM THE THYROID
CARTILAGE
The larynx is rotated to the contralateral
side and the posterior border of thyroid
ala is palpated. The attachment of the
inferior constrictor muscle at the oblique
line on the thyroid cartilage is incised and
the constrictor muscle together with the
perichondrium is stripped off from the
thyroid cartilage. The mucoperiosteum
continues to be stripped off from the
lateral wall of the pyriform fossa (strip it off
from the medial aspect of the thyroid ala
in a subperichondrial plane with a swab
or sponge held over a fingertip, or with a
Freer’s elevator). If the tumour extends into
the hypopharynx, this step is omitted to
ensure adequate resection margins. The
same procedure is repeated on the other
side. Figures 7, 8
STEP 7 RELEASING
THE HYOID BONE
SUPERIORLY
The hypoglossal nerve which is deep to
the greater cornu of the hyoid bone
must be identified and preserved on
both sides. The muscles attaching to the
mobilizAtion oF
lArynx
total larynGectomy 63
Figure 6
Hypoglossal nerve (blue arrow), superior
laryngeal nerve (yellow arrow) and the superior
laryngeal artery (red arrow) arising from
superior thyroid artery (*)
Figure 8
Piriform fossa mucosa (*) dissected free from
the thyroid cartilage (yellow arrow)
Figure 9
Suprahyoid myotomy with Allis tissue forceps
holding the hyoid bone (*)
Figure 7
Incise at the oblique line (indicated above) to
divide the inferior constrictor muscle
*
*
*
64 dissection manual
superior surface of the body of the hyoid
are divided using cautery with the tip of
the cautery in contact with the superior
border of hyoid bone to avoid injury to the
hypoglossal nerve. The stylohyoid ligament
is divided from the lesser cornu of the
hyoid bone to further mobilize the bone.
Rotate the hyoid bone to the contralateral
side to identify the greater cornu. Using
scissors divide the soft tissue on the medial
and posterior aspect of the greater cornu
of the hyoid to isolate the greater cornus
on both sides. Keeping the tip of the
scissors on the hyoid bone will prevent the
hypoglossal nerve from being inadvertently
cut. Further dissect transversely with
diathermy along the superior margin of
the hyoid bone and then into the superior
aspect of the pre-epiglottic space. Identify
the hyo-epiglottic ligament in the midline.
Dissect superiorly along the hyo-epiglottic
ligament to the epiglottis and then strip
the vallecula mucosa from the anterior
surface of the epiglottis. The tip of the
epiglottis is identified through the mucosa
and is readily grasped with an Allis tissue
forceps. The pharynx is entered by incising
into the mucosa along the superior free
edge of the tip of the epiglottis if the
pharynx is to be entered from above.
Figure 9
STEP 8 DIVISION OF THE
TRACHEA
Just prior to entering the pharynx, the
trachea should be transected between
tracheal rings 2 and 3. Do not cut through
tracheal cartilage but divide cleanly between 2 tracheal rings. Figure 10 The
orotracheal or nasotracheal tube is
withdrawn and the trachea re-intubated
through the neck wound. Make sure to
divide the posterior tracheal wall at least
in the same plane as the tracheal rings
by dividing the posterior wall higher than
mobilizAtion oF
lArynx
total larynGectomy 65
you imagine you should. The posterior
tracheal wall should be slightly longer than
the anterior tracheal wall as this aids in
fashioning the stoma.
STEP 9A ENTRY INTO THE
PHARYNX FROM ABOVE
Grasp the tip of epiglottis with Allis tissue
forceps through the thin mucosa. The
pharynx is entered in the midline at the
tip of the epiglottis and the pharyngeal
incision is continued on the opposite
side to the tumour by hugging the lateral
margin of the epiglottis.
On the non-tumour side, the mucosa of
the pharynx is divided from its attachment
to the larynx by dividing the mucosa of the
medial pyriform fossa under vision. The
larynx can then be rotated to bring the
tumour into view.
On the tumour side and under full view,
the mucosa of the pyriform fossa is divided
with adequate 1-2 cm margins to separate
the larynx from the pharynx laterally.
The inferior aspect of the left and right
pyriform fossa incisions are joined by
tunneling between the cricopharyngeus
and the trachea on each side and then
dividing the postcricoid mucosa and
cricopharyngeus transversely. The laryngeal
specimen is delivered from the wound at
this stage. Figures 11, 12
STEP 9B ENTRY INTO THE
PHARYNX FROM BELOW
Develop the avascular plane between the
trachea and oesophagus and separate
the upper stump of the trachea from the
oesophagus. Do not separate the lower
trachea from the oesophagus. Bilateral
crico-arytenoid muscles and the post
Figure 10
Trachea (blue arrow) transected between 2
tracheal rings
Figure 11
Epiglottis tip (*) grasp with Allis tissue forceps
*
66 dissection manual
cricoid mucosa will gradually be exposed.
The pharynx is entered by incising into the
post cricoid mucosa from the midline and
once the pharynx has been punctured,
the pyriform fossa mucosa opposite to
the tumour is divided with scissors to
expose the hypopharynx and larynx.
The larynx is mobilized by completing
the mucosal incision across the vallecula
and the ipslateral pyriform fossa with
adequate margins. The laryngeal specimen
is delivered from the wound at this stage.
Figures 13, 14
STEP 10 CLOSURE OF
PHARYNX
A watertight seal is essential and is
achieved with a meticulous, multilayered
closure. A feeding tube should be placed
and hemostasis assured prior to inserting
any closing sutures. The initial layer of
closure is a running Connell stitch using 3-0
Vicryl. One suture with needle attached
should be anchored at the inferior portion
of the pharyngotomy, just above the
oesophagus. Closure begins with the
inferior suture proceeding superiorly. The
pharynx can be closed in either a straight
line or T- fashion. Figures 15, 16
The second layer is achieved with interrupted sutures. This closes the fascia over
the incision line again using 3-0 Vicryl. In
the third and final layer of closure, sutures
are used to close either constrictor muscle
or strap musculature over the incision line.
STEP 11 FASHION THE
STOMA
The final portion of the laryngectomy is
completion of the tracheostoma. The
inferior border is addressed first and
sutures of 2-0 nylon are used. The stitch
is placed through the skin and then from
outside to inside the tracheal lumen
Closure oF PhArynx
total larynGectomy 67
Figure 12
The larynx rotated to bring the tumour into
view, Oesophagus (*)
Figure 13
Develop the avascular plane between the
trachea (TR) and oesophagus (*)
Figure 15
Preserved pharyngeal mucosa wide enough to
avoid dysphagia after primary closure
*
* TR
Figure 14
Post cricoid mucosa cut open providing entry
to the larynx, crico-arytenoid muscle (CA) and
Transverse arytenoid muscle (TA)
CA
CA
TA
Figure 16
Closure of pharyngeal mucosa using running
Connell suture
68 dissection manual
Figure 17.
Stoma fashioned with half mattress sutures
Note placement of tracheo-oesophageal valve
just below a tracheal ring. The suture is
then passed back through the skin from
subcutaneous to external, just horizontal
to the initial entry point. In this manner a
half mattress is formed for the tracheal part
of the stitch around the tracheal ring thus
lending strength to the stoma. Figure 17
wound Closure And
FAshion the stomA
total larynGectomy 69
KEY POINTS
1. Mark a superiorly based apron flap with the horizontal limb
placed 2 cm about the clavicles.
2. Do not to place the stoma too low in the neck by ensuring the
lower border of the stoma is 2 cm above the upper border of
the manubrium.
3. After raising the flaps, retract the SCM and divide the
omohyoid muscle and middle thyroid vein.
4. Divide the infrahyoid muscles to expose the thyroid lobes.
5. Preserve the contralateral (the side without larynx cancer)
thyroid lobe to avoid hypocalcaemia and hypothyroidism, if it is
not invaded by tumour.
6. The inferior thyroid artery is preserved, as is the superior
thyroid artery by dividing the superior laryngeal artery from it.
7. The hyoid bone is released superiorly from all attached tissues
while preserving the hypoglossal nerves.
8. The trachea is divided cleanly between tracheal rings and the
posterior tracheal wall is divided in the same plane.
9. The pharynx is entered either superiorly or inferiorly and the
larynx separated from the pharynx under direct vision sparing
as much normal pharyngeal mucosa as is oncologically feasible
and safe.
10. Use a Connell suture to achieve water tight closure of the
pharynx and half mattress sutures to fashion the stoma.
70 dissection manual
total larynGectomy 71
08
gortex thyroPlAsty
Eddy WY Wong
72 dissection manual
Gortex thyroPlasty 73
STEP 1 MARK THE
INCISION
Palpate for the thyroid cartilage.
Identify the thyroid notch, midline and
infer ior border of thyroid cart i lage.
Figure 1
STEP 2 EXPOSE THE
THYROID CARTILAGE
A transverse skin crease incision 5 cm
long is made at the level of mid-thyroid
cartilage from the midline towards the
posterior border of thyroid cartilage.
Small superior and inferior skin flaps are
raised in the subplatysmal plane.
The sternohyoid and thyrohyoid muscles
are divided to expose the thyroid lamina
from the midline to the oblique line (where
the sternothyroid muscle inserts).
The bare cartilage of the thyroid lamina
is exposed by incising and elevating a
rectangular and inferiorly based perichondral flap down to the inferior border of
thyroid cartilage using a Freer’s dissector.
STEP 3 OPENING A
WINDOW IN THE
THYROID CARTILAGE
From the midpoint between the thyroid
notch and lower border of the thyroid
cartilage in the midline, draw a line,
parallel to the inferior border of thyroid
lamina, posteriorly towards the oblique line
(this approximates the level of vocal cord)
Using a 4 mm cutting burr followed by a
diamond burr, open a small window in the
thyroid lamina, 1 cm from midline (parallel
to the above line) and 4 mm above inferior
border of thyroid lamina. Ensure the inner
perichondrium remains intact. Figure 2
gortex thyroPlAsty
74 dissection manual
Then pass a duck-bill dissector (otological
instrument) via the window, hugging the
inner table of the thyroid cartilage, and
dissect and create a subperichondrial
pocket on the inner side of thyroid lamina.
STEP 4 AUGMENTATION
WITH GORTEX STRIP
Fashion the Gortex into a 2 mm strip and
insert it into the inner pocket until optimal
voice or endoscopic confirmation of
adequate medialization is achieved.
Figure 3
Trim the excess Gortex, then reposition
the perichondrial flap and repair the strap
muscles. A small wound drain can be
inserted.
Then close the wound in 2 layers.
gortex thyroPlAsty
Figure 1
Thyroid notch (red arrow), midline (yellow
arrow) and Inferior border (blue arrow)
Gortex thyroPlasty 75
Figure 3
Augmentation with Gortex strip assisted
with duck bill dissector
Figure 2
Landmarks for cartilaginous window
4mm
1c m KEY POINTS
1. Identify the thyroid notch, midline and inferior border of thyroid
cartilage.
2. Expose the inferior border and midline of thyroid cartilage.
3. Identify the landmarks to create the cartilaginous window.
4. Create a subperichondrial pocket on the inner side of thyroid
lamina.
5. The adequacy of augmentation is guided by the voice quality
and endoscopic observation of the position of the vocal cords.
76 dissection manual
Gortex thyroPlasty 77
09
midline steP
mAndibulotomy And
mAndibuleCtomy
Eddy WY Wong
78 dissection manual
midline steP mandibulotomy and mandibulectomy 79
STEP 1 INCISION
Incise the lower lip vertically in the midline
until the periosteum covering the mandible
is exposed and then incise the periosteum
to expose the bone of the mandible.
Figure 1
STEP 2 EXPOSE THE
OSTEOTOMY SITE
Elevate the soft tissues off the mandible
in a subperiosteal plane with a periosteal
elevator so that enough bone is exposed
to accommodate two 4- or 5- or 6-hole
plates and prepare for the osteotomy.
Figure 2
The mental foramen with its nerve is the
lateral limit of elevation on both sides.
Figure 3
Choose the optimal site for the step
osteotomy (two vertical and one horizontal
limbs) to minimize the risk of dental injury.
It may be necessary to remove a tooth to
provide adequate space for the blade in
which case the osteotomy is done through
the centre of the socket.
Choose the optimal site for the two plates
so that the screw holes do not involve
dental roots, while centering the plate on
the planned osteotomy. The minimum
requirement is two 4-hole plates to provide
adequate stability.
A notched or stair-step osteotomy gives
more stability than a straight osteotomy.
STEP 3 MARK THE
OSTEOTOMY SITE AND
CONTOUR THE PLATES
Use the oscil lating saw to mark and
partially start the planned osteotomies.
Contour the plate using plate bending
forceps to snugly hug the bone. Then drill
each hole, one at a time, and screw the
midline steP
mAndibulotomy
80 dissection manual
screw into the bone engaging the plate
if it has a locking screw head. Do not
over-tighten the screw as it needs to be
removed. Take care to avoid stripping the
screw and bone thread. This preparation
will greatly facilitate the realignment and
stability of the mandible after surgery.
Figure 4
Remove the screws and plates and
remember to keep the plates orientated so
that the correct plate is properly positioned
for the final reduction and fixation. Figure 5
STEP 4 COMPLETE THE
OSTEOTOMY
The osteotomy is completed with the
oscillating saw and then a thin osteotome
is gently used to complete the bony
division and to separate the ends if
necessary. Figure 6
Figure 1
Lip split with a notch at the vermillion border
to facilitate closure
midline steP
mAndibulotomy
midline steP mandibulotomy and mandibulectomy 81
Figure 3
Mental nerve (yellow arrow) exiting from
mental foramen
Figure 4
Preplate with 2 x 4 hole mini-plates
Figure 5
Remove the plate before osteotomy
remembering not to damage the holes
Figure 2
Expose the mandible for osteotomy and
plating
Figure 6
Osteotomy completed and mandible can
swing open after dividing the soft tissue
82 dissection manual
A cheek flap is raised to expose a segment
of the mandible to beyond the mental
nerve which is sacrificed. Osteotomy
is performed according to the clinical
requirement to remove a segment of the
mandible. In live surgery, the soft tissue
in front of and behind the mandible
should be stripped from the bone and the
osteotomy site. A malleable retractor is
inserted to protect the tissues. Figure 7
segmentAl
mAndibuleCtomy
Figure 7
Mandible exposed for segmental
mandibulectomy with mental nerve (yellow
arrow) sacrificed
midline steP mandibulotomy and mandibulectomy 83
KEY POINTS
1. A notch at the vermillion border in the lip split improves
cosmetic outcome.
2. The mental nerve is the lateral limit for soft tissue elevation.
3. Step osteotomy gives better stability.
4. Avoid injury to the dental roots by placing the plate below the
root.
5. At least 2 x 4 hole plates are used to guarantee stability of the
osteotomy.
6. Unicortical screws are sufficient for locking plate.
7. Preplating before osteotomy provides better alignment after
mandibulotomy.
84 dissection manual
midline steP mandibulotomy and mandibulectomy 85
10
mAxillAry
swing APProACh
to the nAsoPhArynx
Alexander C Vlantis
86 dissection manual
maxillary swinG aPProach to the nasoPharynx 87
INTRODUCTION
The nasopharynx may contain pathology
that requires surgical intervention. This
may be done endoscopically as a minimally invasive procedure or as an open
procedure. The advantage of an open
procedure is the better surgical access it
offers. There are a variety of open routes
to the nasopharynx including transnasal,
transmaxillary, infratemporal fossa and
transpalatal approaches. The maxillary
swing is a variation of a transmaxillary
approach and offers wide access to
the nasopharynx as we l l as to the
pterygopalatine fossa and pterygomaxillary
fissure. At the same time the approach
preserves soft palate function which is
so vital for speaking and swallowing.
Indications for performing a maxillary
swing approach to the nasopharynx include
the surgical excision of a locally residual
or recurrent nasopharyngeal malignancy
which is usually a carcinoma or resection
of a recurrent juvenile nasopharyngeal
angiofibroma. This approach is also
used for covering an exposed internal
carotid artery with a pedicled or free flap
following radionecrosis of the nasopharynx
after radiotherapy for a nasopharyngeal
malignancy.
SURGICAL STEPS
Pre-operative consent includes but is
not limited to the facial incisions, loss
of sensation in the infraorbital nerve
distribution, possible loss of the maxilla
bone, wound dehiscence and breakdown,
oronasal and oronasopharyngeal fistulae
and ectropion.
The opera t ion may be cons idered
in three stages: First the soft t issue
preparation - the incisions and limited
soft tissue dissection to expose bone for
the osteotomies, second the bone work
involving - miniplate preparation, the
osteotomies and the maxillary swing, and
thirdly the closure.
It is important to complete the soft tissue
dissection and bone exposure before
doing any bone work to avoid excessive
blood loss.
GENERAL PREPARATION
A routine tracheostomy is performed either
under local anaesthesia or following the
administration of a general anaesthetic.
Peri-operative antibiotics are given on
induction of general anaesthesia.
The patient is positioned supine and the
head supported with a head ring. An
ocular lubricant or ointment is placed into
both eyes, such as chloramphenicol eye
ointment if the patient is not allergic to it.
The eyes are protected according to the
institution’s protocol. The contralateral
eye may be covered with a transparent
p r o t e c t i v e a d h e s i v e d r e s s i n g . A
tarsorrhaphy is performed on the ipsilateral
eye taking care not to invert the eyelashes
which avoids corneal abrasions.
The patient’s face and neck are prepared
with the institution’s usual topical solution.
An alcohol based solution, or other
solution that may be irritant to the eyes or
to which the patient is allergic should be
avoided. The oral cavity is also prepared.
The nasal cavity is packed with topical
vasoconstrictor soaked ribbon gauze.
88 dissection manual
The scalp, lower neck and chest are
draped, leaving the forehead, face, upper
neck and both ears exposed.
Using a sterile skin marking pen, draw
an incision 5 mm below and parallel to
the lower eyelid lash line. This incision is
placed close to the palpebral margin so
that oedema of the lower lid above the
scar is avoided after surgery.
At the vertical or parasagittal plane
of the lateral orbital rim, the incision
turns postero-inferiorly towards the 135
degree angle that the inferior border
of the maxillary process of the zygoma
makes with the zygomatic process of
the maxilla. This inferior border can be
palpated through the soft tissues of the
lateral cheek. The incision is marked to the
midpoint of this angled line between the
lateral orbital rim and the inferior border of
the zygoma. This incision is roughly parallel
but posterior to the zygomaticomaxillary
suture line.
The medial end of the lower eyelid incision
is not carried onto the nasal bone as would
be the case for a Weber Ferguson incision
that is made to follow the concept of facial
subunits. Instead this incision avoids the
epicanthal fold and so turns inferior just
before the vertical or parasagittal plane at
the medial canthus to follow the junction
of the cheek and the lateral nose to the
ala. It then follows the alar groove into the
nostril. After a 90 degree notch is made
on the nasal sill of the vestibule floor, the
incision then continues to the midline
junction of the columella and the lip, at
which point it turns inferiorly through 90
degrees and continues in the midline of
the philtrum to the midline of the upper
vermillion border of the lip. Figure 1 A
notch is made at the vermillion border and
the incision continues in the midline of the
lip and through the superior labial frenulum
to the midline gingiva between the upper
central incisors.
mArking the skin And
muCosAl inCisions
maxillary swinG aPProach to the nasoPharynx 89
Use a tonsil or Ferguson Auckland mouth
gag to open the mouth and retract the
tongue to visualize the hard and soft
palates.
On the hard palate mucosa a paramedian
or parasagittal incision is marked 7 mm
from the midline on the side of the swing.
Make a mark from the junction of the
hard and soft palate posteriorly to the
premaxilla mucosa anteriorly where the
incision turns towards the midline and to
the gingiva between the two upper central
incisors.
Identify the maxillary tuberosity and the
bony spines of the pterygoid plates and
pterygoid hamulus immediately posterior
to the tuberosity.
The posterior end of the hard palate
incision is continued laterally through
the soft palate mucosa to the posterior
surface of the ipsilateral maxillary tubercle.
Figure 2
Figure 2
The hard palate paramedian and soft palate
incision
Figure 1
The skin incisions for the maxillary swing
approach. The medial canthal structures
are avoided. A notch is marked in the nasal
vestibule and at the vermillion border
90 dissection manual
All incisions are infiltrated with a vasoconstrictor such as 1:80 000 adrenaline. All
facial skin and palatal incisions are made
with a scalpel and are carried through
from the skin or mucosa to the periosteum
and onto bone. The lower eyelid and soft
palate incisions are exceptions.
With very gentle pressure on the eye, and
with retraction of the cheek skin, the lower
eyelid is put under tension and the skin
incised with a number 15 scalpel blade.
Figure 3
The skin is divided until the stretched
orbicularis oculi muscle is visible. This
muscle is gently stroked with the scalpel
blade until all the fibres are divided taking
care not to incise into the inferior orbital
septum or anterior capsule of the inferior
orbital fat pad. Using single skin hooks
to retract the lower eyelid skin, the skin
and orbicularis muscle are elevated with
sharp dissection as a unit from the orbital
fat pad in a preseptal plane. Using sharp
dissection on the inferior orbital fat pad
septum will preserve facial nerve branches
which innervate the orbicularis muscle on
its deep surface. Figure 4
As the medial end of the lower eyelid
incision turns inferior, the angular vein and
artery will be encountered. They should be
ligated and divided otherwise they tend to
retract and bleed. Figures 5, 6
soFt tissue disseCtion
to exPose bone For the
osteotomies
maxillary swinG aPProach to the nasoPharynx 91
Figure 3
The lower eyelid is put under gentle tension
and the incision made
Figure 5
The angular vessel encountered in the facial
incision (indicated above)
Figure 6
The angular vessels are ligated and divided
Figure 4
The lower eyelid musculocutaneous flap is
elevated off the inferior orbital fat pad (yellow
arrow) in the preseptal plane. OC – orbicularis
oculi
OC
92 dissection manual
The inferior orbital septum fuses with the
periosteum at the superior surface of the
inferior orbital rim. The periosteum of the
inferior orbital rim is incised anterior to this
fusion on the anterior surface of the rim, so
as to preserve the integrity of the inferior
orbital fat pad. Figure 7
Using a periosteal elevator such as a
Howarth’s, the soft tissues of the cheek
are elevated off the upper maxilla in a
subperiosteal plane to the level of the
infra-orbital foramen. Figure 8 The infraorbital nerve and vessels are identified,
ligated and divided. Figure 9
Do not elevate the soft tissue off the
anterior maxilla further inferior than the
infraorbital foramen as the maxilla depends
on the soft tissue of the cheek for its blood
supply.
At the lateral end of the lower eyelid
incision, stay in the subperiosteal plane
and elevate tissue laterally off the zygoma
until the inferior margin of the zygoma
can be palpated with the angled end of
the elevator. It is not necessary to incise
the skin over the entire zygoma, but just
enough to allow the osteotomy to be
made. Usually the skin incision is made to
the midpoint of the zygoma.
Muscles incised with the facial incision
include the orbicularis oculi, nasalis and
orbicularis oris. Figure 10
Once the rim of the ipsilateral pyriform
aperture has been defined, free the nasal
cavity soft tissues from the margin of the
nasal aperture with diathermy.
Retract the nasal ala medially and incise
the lateral wall of the nasal vestibule to
expose the ipsilateral nasal cavity and
inferior turbinate, taking care not to injure
the inferior turbinate or septum so as to
avoid troublesome bleeding.
soFt tissue disseCtion
to exPose bone For the
osteotomies
maxillary swinG aPProach to the nasoPharynx 93
Figure 7
The lower eyelid incision is carried through the
skin and orbicularis muscle. The lower eyelid
musculocutaneous flap is elevated off the
inferior orbital fat pad in the preseptal plane
and the orbital periosteum incised on the
anterior aspect of the inferior orbital rim
Figure 8
The soft tissues of the cheek are elevated off
the upper maxilla in a subperiosteal plane to
the level of the infra-orbital foramen
Figure 10
Facial muscles divided with the facial incision
Orbicularis oris
Orbicularis oculi
Figure 9.
The infra-orbital nerve and vessels (yellow
arrow) are ligated and divided
94 dissection manual
In this way the nasal cavity is entered
through the facial wound. At the inferior
margin of the aperture, use an elevator
to elevate the mucoperiosteum of the
floor of the nasal cavity. Elevate the
entire nasal cavity floor mucoperiosteum
from the septum medially to the lateral
aspect of the inferior meatus laterally and
from the pyriform aperture anteriorly to
the posterior margin of the hard palate
posteriorly, which is the horizontal plate of
the palatine bone. Then incise the elevated
mucosa from anterior to posterior as lateral
as possible to create a medially based
mucoperiosteal flap that will be used to
cover the maxillary osteotomy at the end
of the procedure. Figures 11, 12
A scalpel is used to incise the mucosa
of the hard palate along the planned
paramedian incision onto bone. The
incision is extended laterally on the soft
palate from the posterior edge of the hard
palate incision to the groove between the
maxillary tuberosity and the pterygoid
plates. Figure 2
Use a periosteal elevator in the subperiosteal plane to elevate the hard
palate mucoperiosteum off the hard
palate bone on the non-swing side of the
palatal incision to just beyond the midline.
Figure 12
soFt tissue disseCtion
to exPose bone For the
osteotomies
maxillary swinG aPProach to the nasoPharynx 95
Figure 11
Coronal view of the hard palate and nasal floor
showing mucosa in pink
Figure 12
Coronal view of the hard palate and nasal
floor showing the positions of the respective
mucosal incisions and elevated mucoperiosteal
flaps. The position of the osteotomy is
indicated by the dotted line
96 dissection manual
Refer to the patient’s sagittal imaging to
confirm that the orbital floor does not dip
below the level of the infra-orbital foramen
in the plane of the foramen nor at the mid
point of the orbit. Figures 13, 14
If this is the case, the osteotomy must
be placed below the level of the orbital
floor. If the orbital floor does not bulge
or hang into the antrum, then a straight
horizontal osteotomy is marked at the level
of the inferior margin of the infra-orbital
foramen, from the rim of the pyriform
aperture medially to the malar surface of
the zygoma laterally. Figures 15-18
This osteotomy will separate the boney
orbit superiorly from the remaining maxilla/
zygoma inferiorly. At the lateral end of this
osteotomy, a second osteotomy is marked
at 90 degrees to the postero-inferior border
of the zygoma. This osteotomy completes
the division of the zygoma. Figure 18
A third vertical osteotomy is marked in
the midline of the anterior surface of the
maxilla and extends to between the upper
medial incisors. Figure 15 On the exposed
hard palate bone (the palatine process of
the maxilla and horizontal plates of the
palatine bones), the plane of the vertical
osteotomy is marked just off the midline
on the ipsilateral side so that it divides the
nasal cavity floor from the septum. This
osteotomy divides the maxilla just off the
midline away from the septum, so that the
septum remains intact articulating with the
contralateral maxilla. Figures 12, 15, 24
A 1 cm x 1 cm sagittal saw blade is used
to mark the osteotomies where two 4-hole
miniplates will be placed and their holes
drilled.
Two 4-hole miniplates are contoured to the
bone. One plate is placed in the midline
of the anterior surface of the maxilla where
bone work, miniPlAte
PrePArAtion, osteotomies
And the mAxillAry swing
maxillary swinG aPProach to the nasoPharynx 97
Figure 15
Anterior view of a dry skull showing the
positions of the osteotomies.
Figure 16
Oblique view of a dry skull showing the
positions of the osteotomies.
Figure 13
The sagittal plane of the orbital floor at the
infra-orbital foramen (indicated above).
Figure 14
The sagittal plane of the orbital floor at the
mid-orbit.
98 dissection manual
a very prominent crest may need to be
burred down to facilitate plating. It is
important that the holes avoid the roots
of the teeth by positioning the miniplates
above or between the teeth roots if
the height of the maxilla is inadequate.
Figure 19
The second miniplate is positioned over
the osteotomy that divides the lower lateral
free border of the zygoma. The miniplates
should be positioned at 90 degrees to
the osteotomy Figure 20. As each hole
is drilled a screw is inserted but not
tightened fully. This is done before drilling
the next hole. Drilling all the holes before
inserting screws may lead to misalignment
of the holes. Remove all screws and record
or mark the orientation of the plates. A
drawing using sterile adhesive strips to
attach the orientated plates to the diagram
is suggested.
A heavy curved osteotome is inserted into
the oral cavity and its blade positioned into
the mucosal incision behind the maxillary
tubercle to divide the maxillary tuberosity
from the pterygoid plates. Figures 21, 22
Using a finger to guide the osteotome
and then it is tapped by an assistant
and the osteotomy completed. This
intentional separation ends superiorly
in the pterygomaxillary fissure and the
pterygopalatine fossa. There will be no
movement of the maxilla at this stage
as none of the other osteotomies have
yet been completed. This is done first
while the maxilla is still stable, otherwise
unpredictable fracturing of the pterygoid
process can occur.
The maxilla and zygoma osteotomies
are deepened to the hilt of the more
controllable 1 cm oscillating saw blade,
keeping the blade perpendicular to the
bone work, miniPlAte
PrePArAtion, osteotomies And
the mAxillAry swing
maxillary swinG aPProach to the nasoPharynx 99
Figure 20
Plating the zygomatic osteotomy.
Figure 19
Plating the alveolar osteotomy.
Figure 17
Zygomatic process (blue arrow), Frontal process
(red arrow) and Alveolar process (yellow arrow)
Figure 18
The infra-orbital (yellow arrow) and zygomatic
(blue arrow) osteotomies. The ligated infraorbital neurovascular bundle is visible.
100 dissection manual
bone. The blade is then changed for a
longer 4 cm blade. At some time prior to
this, the axial image should be reviewed
and the anterior-posterior dimension of
the maxillary sinus measured to determine
the distance from the anterior surface of
the maxilla to the posterior wall of the
maxillary sinus. Figure 23
The posterior wall of the maxillary sinus
is thin and will easily fracture when the
maxilla is mobilized. It does not need
to be sawed, which should actually be
avoided. Sawing the posterior wall of the
antrum will lacerate the internal maxillary
artery and lead to torrential bleeding
before the osteotomies can be completed
and the maxilla swung away to gain access
to the bleeding artery.
W h e n m a k i n g t h e i n f e r i o r o r b i t a l
os teotomy i t i s impor tant to keep
the sagittal saw blade horizontal. It is
especially important to know about the
level of the orbital floor and whether
it dips below level of the infra-orbital
foramen, which can be determined from
the preoperative imaging. This is to avoid
injuring the contents of the orbit while
making the osteotomy, the lateral nasal
wall will offer increased resistance medially,
and the lateral wall of the antrum will
offer increased resistance laterally. The
resistance decreases significantly once
these walls have been divided.
When making the midline vertical paramedian or parasagittal maxillary osteotomy
under direct vision, an assistant ensures
that the hard palate mucoperiosteal flap
and the nasal floor mucoperiosteal flap
are both retracted away from the blade
so as not to damage or lacerate them.
Figure 12 The palata l osteotomy is
extended posteriorly to the posterior
margin of the hard palate. Figure 24
A sharp straight osteotome is then inserted
into the anterior osteotomy and gently
twisted to finalize fracturing the bone.
bone work, miniPlAte
PrePArAtion, osteotomies And
the mAxillAry swing
maxillary swinG aPProach to the nasoPharynx 101
Figure 24
The position of the vertical maxillary
osteotomy is just to the ipsilateral side
of the midline to avoid the nasal septum
Figure 21
The (red arrow) indicates the position that
the blade of the curved osteotome is placed
by palpation to divide the maxilla from the
pterygoid process
Figure 22
The blade of the curved osteotome is
placed by palpation into the groove
posterior to the maxillary tubercle in
order to divide the maxilla from the
pterygoid process
Figure 23
The horizontal distance between the infraorbital foramen and the posterior wall of
the antrum should be estimated prior to
the horizontal infra-orbital osteotomy. This
facilitates the appropriate selection of the saw
blade length to avoid lacerating the maxillary
artery.
102 dissection manual
This is usually the thin posterior wall of
the maxillary antrum where it is best that
the oscillating saw blade does not reach
to avoid lacerating the internal maxillary
artery. Figures 25, 26 If the maxilla remains
stable, twisting and tapping a sharp
straight osteotome can be performed at
multiple sites. Take care not to damage the
screw holes.
When the maxilla is loose it is gently
retracted or swung laterally and any
soft tissue that is tethering the maxilla is
divided with a pair of curved mayo scissors.
Figure 27 The maxilla is wrapped in a long
saline soaked swab which is used to retract
and keep the maxilla out of the surgical
field with a Rochester pean forceps or
equivalent.
I f there is signif icant bleeding, it is
usually due to laceration of the internal
maxillary artery and this must be quickly
stopped. Using suction and a long curved
haemostat, the artery is clamped, divided
and tied with a strong silk ligature.
The inferior turbinate is excised and the
posterior nasal septum can be resected for
better exposure of the nasopharynx.
bone work, miniPlAte
PrePArAtion, osteotomies And
the mAxillAry swing
maxillary swinG aPProach to the nasoPharynx 103
Figure 26
The twisting of the osteotome finalizes
the bone work. Soft tissue remains to be
divided before the maxilla is fully swung
laterally
Figure 27.
The position of the maxilla once it has
been fully swung laterally. It remains
based on the soft tissues of the cheek Figure 25
A thin sharp osteotome is placed into
the osteotomy and gently twisted to
complete the fracture of the posterior
wall of the antrum
104 dissection manual
Closure
Bleeding that occurs from the pterygoid
venous plexus may initially be controlled
with packing. Meticulous haemostasis
is achieved with bipolar cautery, suture
ligatures, clips, bone wax, oxidized cellulose polymer and topical haemostatics.
A fine bore nasogastric tube is placed
via the contralateral nasal cavity for postoperative enteral feeding.
Depending on the operation, the nasopharyngeal wound may be left to mucosalize, dressed with a mucosal graft taken
from the inferior turbinate or with a
vascularized septal mucosal flap based
on the posterior septal branches from the
sphenopalatine artery.
The nasopharynx is packed with a dressing
via the ipsilateral nasal cavity, such as a
single length of paraffin gauze, to hold any
graft in place and to aid mucosalization.
A foley catheter is inserted into the
nasopharynx via the contralateral nasal
cavity and the balloon inflated with
sufficient sterile water to prevent the pack
from slipping into the oropharynx.
On the swung maxilla, an inferior meatal
antrostomy is fashioned by carefully elevating the mucosa off the medial wall of
the anrtum and using a bone nibbler to
remove the bone. The mucosa is laid
over the raw bone. In this way the crest
between the nasal cavity floor and antral
floor is removed which allows free drainage
of antral mucus in the future.
The soft and hard palate mucosal incision
is preloaded with 3.0 synthetic absorbable
polyglycolic acid sutures. This will allow
for the accurate placement of the sutures
whi le maximum access is avai lable.
Posteriorly it is best to insert the suture
through the mucosa of the soft palate and
then through the posterior mucosa of the
swung maxilla. Medially it is best to insert
the suture through the mucoperiosteum
of the swung maxilla and then through the
maxillary swinG aPProach to the nasoPharynx 105
mucoperiosteum of the contralateral hard
palate flap. The sutures are kept in order
by clamping each with a haemostat and
sliding its finger grip onto a closed larger
forceps.
The maxilla is then reduced and held
firmly in position. Figure 28 At this point
make sure the mucosal flap of the nasal
f loor or any packing material is not
trapped between the maxilla bones. While
maintaining accurate reduction, the two
4-hole miniplates are securely screwed into
place and each screw tightened but not to
the point of stripping either the bone or
screw thread. Figures 19, 20
The sutures of the palate mucosa are tied
starting posteriorly. Care should be taken
as it will not be possible to reinsert a suture
should it tear out or break.
The facial and lip wounds are closed in two
layers, a deeper subcutaneous layer and
a skin layer. The subcutaneous layer and
lip mucosa are closed using a 3-0 braided
absorbable suture. The skin is closed using
a 4-0 non-absorbable monofilament suture
except for the lower eyelid where a 5-0 is
used.
It is important to securely anchor the
superomedial corner of the cheek flap to
its counterpart. This is to ensure that the
main stress of the cheek flap is taken at
this point and is not transmitted to the
lower eyelid wound. This is accomplished
by preloading four braided absorbable
sutures with sufficient tissue on both sides
of the wound before tying the sutures and
closing the rest of the cheek and eyelid
wounds.
A prefabricated palatal dental splint is
securely placed to maintain apposition
of the hard palate mucoperiosteal flap
against the underlying bone during the
healing phase.
Figure 28
The reduced maxilla at the end of the procedure
before fixation of the miniplates
Figure 29
At the end of the procedure, the wounds are
closed and dressed. The patient has a tracheostomy
tube in place. From the contralateral nostril the
fine bore feeding tube that will be used for enteral
nutrition in the postoperative period is seen, as is the
foley catheter whose cuff is inflated with sterile water
which keeps the pack from falling into the oropharynx.
106 dissection manual
Day 0 - The following are ordered on the
day of the operation or the following day.
Peri-operative antibiotics are continued
for 5 days. A chest X-ray is performed to
confirm the position of the nasogastric
tube prior to feeding. Chest physiotherapy,
t racheostomy care and suct ion ing.
Institution-based mouth care.
Day 1 - The nasopharyngeal foley is deflated after 24 hours
Day 5 - The lower eyelid sutures are
removed.
Day 6 - The nasopharyngeal pack is shortened and loosened on day 6.
Day 7 - The nasopharyngeal pack is
removed on day 7. Start rinsing the nasal
cavities and nasopharynx three times a day
with normal saline. The rest of the facial
sutures are removed.
Day 8 - The tracheostomy tube is removed
if there has been no significant bleeding.
Day 14 - The nasogastric tube is removed
and an oral liquid diet begins on day 14.
Day 21 - A soft diet begins if the palatal
wounds are well healed.
PostoPerAtive Period
Figure 29
The facial scar of a patient who
underwent a maxillary swing procedure.
maxillary swinG aPProach to the nasoPharynx 107
KEY POINTS
1. Complete the soft tissue dissection and bone exposure to
avoid excessive blood loss before doing any bone work.
2. Make the lower eyelid incision close to the palpebral margin,
5 mm below and parallel to the eyelid lash line, to avoid
oedema of the lower lid above the scar.
3. The hard palate mucosal incision is made in a paramedian or
parasagittal plane and 7 mm from the midline on the side of
the swing.
4. The lower eyelid flap (skin and orbicularis muscle) is elevated
off the orbital fat pad in a preseptal plane taking care not to
incise into the capsule of the fat pad.
5. Via the pyriform aperture, elevate the mucoperiosteum of the
entire nasal cavity floor and then incise the elevated mucosa
from anterior to posterior as lateral as possible to create a
medially based mucoperiosteal flap.
6. A heavy curved osteotome is placed behind the maxillary
tubercle to divide the maxillary tuberosity from the pterygoid
plates.
7. A straight horizontal osteotomy is made at the level of the
inferior margin of the infraorbital foramen, from the pyriform
aperture to the malar surface of the zygoma.
8. A straight vertical osteotomy is made just off the midline on the
ipsilateral side to divide the nasal cavity floor keeping clear of
the septum.
9. A thin sharp osteotome is placed into the osteotomies and
gently twisted to complete the fracture of the posterior wall of
the antrum which frees the maxilla.
10. The loosened maxilla is gently retracted laterally and any soft
tissue that is tethering it is divided with a pair of curved mayo
scissors.
108 dissection manual
maxillary swinG aPProach to the nasoPharynx 109
11
lAtissimus dorsi And
thorACodorsAl Artery
PerForAtor FlAP
Tor Chiu
110 dissection manual
latissimus dorsi and thoracodorsal artery Perforator flaP 111
FLAP TERRITORY
The latissimus dorsi (LD) flap is a muscle or
musculocutaneous flap from the back area
that has a long and reliable pedicle. The
skin island may be designed in a vertical,
oblique or transverse fashion overlying the
muscle. It can be used as a pedicled flap
(eg. for breast reconstruction) or a free flap
(eg. for lower limb reconstruction).
Partial LD flaps have been used for facial
reanimation as have perforator flaps based
on the thoracodorsal artery (TDA) creating
a TDAP flap.
A reversed LD flap based on the secondary
perforators is less commonly used but is an
option in back reconstruction.
VASCULAR ANATOMY
The LD muscle f lap is a type V f lap
supplied by a dominant pedicle (TDA) and
secondary segmental pedicles (posterior
intercostal perforators). The TDA arises
from the subscapular artery (third part of
axillary) and usually divides into transverse
and vertical branches which are angulated
at 45° allowing the LD to be split). The
vertical pedicle enters the muscle 8-10 cm
below the axilla approximately 2-2.5 cm
medial to the anterior muscle edge.
Figure 1
FLAP HARVEST
The LD f laps can be harvested with
the patient either prone or in a lateral
decubitus position with the arm abducted
to 90 degrees and elbow flexed to 90
degrees. The TDAP flap can be harvested
in a ‘partial’ or dorsal decubitus position by
placing a vertical block at the spine area.
The tip of the scapula, anterior border
of LD muscle, posterior iliac crest and
the midline of the back are relevant
lAtissimus dorsi And
thorACodorsAl Artery
PerForAtor FlAP
112 dissection manual
anatomical landmarks. Design your skin
island according to need and begin over
the supero-anterior border. The anterior
muscle edge is identified followed by the
pedicle. Figures 2, 3
Bevelling away down to the muscle’s
surface allows for more soft tissue where
needed.
Carefully separate the superior part of
the muscle from the underlying serratus
anterior (SA) and tip of scapula and
divide its bony attachments inferiorly and
posteriorly. Figures 4-6 It is easy to get into
the wrong muscle plane if you start from
inferior to superior.
The pedicle is traced proximally dividing
branches to SA and teres major muscles.
The circumflex scapular artery and vein
can be divided where additional pedicle
length is needed, isolating it up to the
subscapular artery. Figures 7, 8
A TDAP f lap is based on cutaneous
perforators from the vertical/descending
branch of the TDA. The skin island is
usually based over the anterior edge of
the muscle. A preoperative handheld
doppler probe is often used to locate
the perforators. It is important to identify
the leading edge of the LD carefully. It is
common to make the posterior incision
first to allow a posterior/medial to lateral
Figure 1
Vascular anatomy of the LD flap
latissimus dorsi and thoracodorsal artery Perforator flaP 113
Figure 2
Skin flap designed in horizontal pattern
Midline
Iliac
crest
Tip of scapula
Figure 3
Skin flap designed in vertical pattern
Figure 4
Superior border of LD
114 dissection manual
dissection to facilitate localization of the
perforators. However, it is possible to go
lateral to medial from the mid axillary area,
particularly if no preoperative localization
has been performed.
The perforator(s) are dissected to free the
pedicle from the muscle and then traced
proximally to the TDA deep to the muscle.
There are an average of 1-3 perforators
that are greater than 0.5 mm in calibre.
lAtissimus dorsi And
thorACodorsAl Artery
PerForAtor FlAP
latissimus dorsi and thoracodorsal artery Perforator flaP 115
Figure 5
Dividing the inferior attachment of LD
Figure 7
Pedicle (Blue arrow) traced proximally to identify
the thoracodorsal artery (TDA)
Serratus
Anterior Teres
major
Figure 8
Close up view of the TDA (blue arrow)
Teres
major
Figure 6
LD raised from the underlying muscles
Serratus
Posterior
Erector
spinae
External
oblique
LD
116 dissection manual
KEY POINTS
1. The latissimus dorsi flap is supplied by the thoracodorsal artery
(TDA).
2. The pedicle enters the muscle 8 cm below the axilla and
approximately 2 cm medial to the anterior muscle edge.
3. Relevant landmarks include the anterior edge of LD muscle,
iliac crest, tip of the scapula and midline of the back.
4. Dissection is begun by separating the superior part of the LD
muscle from the underlying serratus anterior.
5. The pedicle can be lengthened by dividing the circumflex
scapular artery and vein.
6. TDAP flap is a perforator flap based on the descending branch
of the TDA.
medial sural artery Perforator flaP 117
12
mediAl surAl Artery
PerForAtor FlAP
Tor Chiu
118 dissection manual
medial sural artery Perforator flaP 119
FLAP TERRITORY
The medial sural artery perforator (MSAP)
fasciocutaneous flap was first described
by Cavadas (2001) as a refinement of the
medial gastrocnemius flap. The territory
approximates to the medial half of the
upper third of the posterior calf, an area
of about 8x12 cm. It can be extended
anteriorly to 2/3rd of the distance from the
midline to the anterior tibial margin. It is a
useful alternative to the radial forearm flap
providing thin hairless tissue with relatively
little donor site morbidity particularly when
compared to the posterior tibial artery flap.
Caution should be exercised in patients
with per ipheral vascular disease or
diabetes mellitus. An analogous lateral
sural artery perforator flap can be raised in
most patients as an alternative.
VASCULAR ANATOMY
The MSA usually arises from the popliteal
artery (from a common sural trunk in up to
30%). After a few centimeters, the vessel
enters and runs through the medial belly
of the gastrocnemius muscle and some
branches ‘perforate’ through to the skin.
The MSA usually divides into lateral and
medial branches, this usually occurs in
the substance of the muscle (85%). Some
surgeons prefer to use the lateral (nearer
the midline) row of perforators on the
basis that it is usually dominant. Muscle
devascularisation is not a major concern
as there are other vascular supplies to the
muscle apart from the MSA. Figure 1
There are usually 2-4 perforators of about
1 mm diameter that are concentrated at
an area 4.5 cm from the midline and 8-12
cm from the popliteal fossa crease. The
mediAl surAl Artery
PerForAtor FlAP
120 dissection manual
first perforator is usually 8 cm along a line
drawn from the middle of the popliteal
crease to the medial malleolus. Markings
should be made with the patient lying
on their back and the knee flexed to 90
degrees. Note that frog-legging (external
rotation of the hip) distorts the skin and
vessel positions. Figures 2, 3
The artery is about 2 mm in diameter at
its origin. Depending on the perforator
chosen and amount o f re t rograde
dissection, the pedicle ranges from 9-16
cm.
The posterior cutaneous nerve of the thigh
can be also harvested in instances where a
sensate flap is required.
FLAP HARVEST
Preoperative examination with a handheld
doppler ultrasound probe or duplex
ultrasound helps to locate the perforators.
Some surgeons approximate this to the
intersection of the lines from the popliteal
crease to the medial malleolus and medial
femoral epicondyle to the lateral malleolus.
The flap can be harvested with the patient
either supine (frog-legged, for contralateral
side) or prone. Figures 3, 4
In this dissection, the flap territory is taken
to be the upper third of the posterior
medial calf. A vertical line marks the
midline of the posterior calf and the
dissection begins here in either the
subfascial or suprafascial (more difficult)
plane from midline to lateral (in reality,
the medial side of leg). Starting from the
anterior border of the flap is easier with the
patient in the supine position.
The largest perforator(s) is identified and
then traced back towards the popliteal
ar tery by spl i t t ing the muscle. The
mediAl surAl Artery
PerForAtor FlAP
medial sural artery Perforator flaP 121
Figure 1
Design of the flap
Figure 2
Landmarks to locate the perforator(s)
Figure 3
Design of the flap and measurement to locate
the perforators
122 dissection manual
remaining borders of the flap can be
incised at this point. Figures 5-8
Take care to spare the motor nerve to the
medial belly of the gastrocnemius.
Taking the superficial cutaneous veins (short
saphenous) along with the skin paddle
facilitates alternate/additional drainage.
The donor site can usually be closed
directly if it is 5-6 cm or less in width.
The muscle surface can be aponeurotic
and if skin grafts are needed, it may be
worthwhile trimming the thick fibrous layer
to improve take.
Figure 4
Cross section of the calf
mediAl surAl Artery
PerForAtor FlAP
medial sural artery Perforator flaP 123
Figure 8
Intramuscular course of the medial sural artery
Medial
gastrocnemius
Figure 5
Schematic diagram of a raised medial sural flap
Figure 6
Two perforators
Medial
gastrocnemius
Figure 7
Posterior border of the flap incised with
perforators indicated
Medial
gastrocnemius
124 dissection manual
KEY POINTS
1. The MSAP flap is a useful alternative to the radial forearm flap.
2. The MSA usually arises from the popliteal artery and runs
through the medial belly of the gastrocnemius.
3. The perforators are concentrated at a distance of 8-12 cm from
the popliteal fossa crease.
4. The flap can be harvested with the patient in a frog-legged or
prone position.
5. Take care to spare the motor nerve to the medial belly of the
gastrocnemius.
6. The muscle surface can be aponeurotic and this is best trimmed
if skin grafts are required.
medial sural artery Perforator flaP 125
13
lAterAl Arm FlAP
Tor Chiu
126 dissection manual
lateral arm flaP 127
FLAP TERRITORY
This flap consists of the fasciocutaneous
tissue over the lateral aspect of the arm
between the insertion of the deltoid
muscle and the elbow. It is thin, pliable
and hairless and is suitable for use in
reconstruction of the face and hand
(classically, for preparation for tendon
transfer). The short 5-6 cm pedicle is its
main drawback.
VASCULAR ANATOMY
The flap is supplied by the perforators
from the posterior radial collateral artery
(PRCA) that arises from the profunda
brachii artery. The PRCA runs along the
lateral intermuscular septum (LIS) which
separates the triceps posteriorly and the
brachioradialis anteriorly and classically
forms a network just above the elbow.
Figure 1
FLAP HARVEST
The patient is positioned supine with the
arm on a table in a pronated position or by
the side of the trunk.
The axis of the flap and the PRCA lie
between the deltoid insertion (DI) and the
lateral epicondyle (LE) that also marks the
location of the LIS. Figures 2, 3
The proximal limit of the flap lies at the
deltoid insertion whilst the distal limit
of the flap is the LE (though extended
variants have been described, reaching up
to 8 cm beyond the LE).
Distal lateral arm flap (DLAF) includes the
most distal perforator 4-5 cm above the
LE with the flap centered on the LE/elbow.
Distal skin tends to be thinner.
Dissect ion begins anter ior ly in the
subfascial plane towards the LIS until the
perforators are seen. The elevation of the
lAterAl Arm FlAP
128 dissection manual
posterior flap is performed in a similar
fashion to isolate the LIS which has an
elongated attachment to the humerus. The
tissues of the anterior flap tend to be more
adherent and are difficult to dissect.
Figure 4
The vessels distal to the flap are identified
and ligated and the flap is then dissected
free by dividing the attachment of the
septum to the humerus, from distal to
proximal, deep to the level of the pedicle.
The pedicle is t raced as proximal ly
as possible paying attention to avoid
damage to the radial nerve. Fibres of the
lateral head of triceps may be divided as
necessary. Figures 5, 6
The lower lateral cutaneous nerve (LLCN)
of the arm can be included with the flap
but needs to be divided in any case.
The LLCN of the forearm runs through the
flap and may have to be sacrificed, causing
numbness of the lateral forearm.
lAterAl Arm FlAP
lateral arm flaP 129
Figure 1
Cross section of the upper arm
Figure 2
Design of the lateral arm flap and extended
lateral arm flap
Figure 5
Schematic diagram of raised lateral arm flap
Figure 3
Design of the flap according to the axis of
the humerus from the deltoid insertion (DI) to
lateral epicondyle (LE)
Dl LE
Figure 4
Identification of the pedicle (blue arrow),
posterior cutaneous nerve of the arm (red
arrow) and posterior cutaneous nerve of
the forearm (yellow arrow)
brachialis
triceps
brachioradialis
Figure 6
Isolated lateral arm flap with the cutaneous
nerve to the arm (red arrow), pedicle (blue
arrow) and cutaneous nerve of the forearm
(yellow arrow)
brachialis
brachioradialis
triceps
130 dissection manual
KEY POINTS
1. Lateral arm flap is a thin, pliable and hairless fasciocutaneous
flap.
2. The flap is supplied by the perforators from the posterior
radial collateral artery (PRCA) which runs along the lateral
intermuscular septum (LIS).
3. The axis of the flap and the PRCA lie between the deltoid
insertion and the lateral epicondyle.
4. Dissection begins anteriorly in the subfascial plane towards the
LIS until the perforators are seen.
5. The pedicle is traced as proximally as possible paying attention
to avoid damage to the radial nerve.
lateral arm flaP 131
14
AnterolAterAl
thigh FlAP
Tor Chiu
132 dissection manual
anterolateral thiGh flaP 133
FLAP TERRITORY
This flap is composed of the skin and
subcutaneous tissue of the lateral aspect of
the anterior thigh centred on the septum
between vastus lateralis (VL) and rectus
femoris (RF).
VASCULAR ANATOMY
The flap is supplied in most cases by
perforators from the descending branch of
the lateral circumflex femoral artery (LCFA).
These often pass through the VL muscle to
reach the skin whereas in other cases they
travel in the septum between the VL and
RF.
The more p rox ima l por t ion o f the
anterolateral thigh skin is often supplied by
a vessel from the transverse branch of the
LCFA. Figure 1 This flap would necessarily
have a shorter pedicle.
FLAP HARVEST
Mark a line from the anterior superior iliac
spine (ASIS) to the lateral corner of the
upper border of the patella bone (axis) and
mark its halfway point. Most perforators
reach the skin within 3 cm of this point,
usually in the inferolateral quadrant.
Figures 2, 2.1
Mark an ellipse of a generous size centred
on this axis and point. Figures 3, 3.1
Incise the medial edge of the flap down
through the deep fascia to the muscle,
usually RF or vastus medialis.
Gradually elevate the flap subfascially from
medial to lateral until skin perforator vessels are
visualized. Figure 4
To increase exposure, retract the RF
muscle medially to expose the descending
branch of the LCFA running from medial to
lateral over the aponeurosis of the vastus
intermedius.
AnterolAterAl
thigh FlAP
134 dissection manual
In clinical practice, it is best to trace the
perforator in a retrograde manner from
distal (skin side) to proximal (main pedicle),
dividing the overlying muscle fibres in the
manner of a facial nerve dissection during
a superficial parotidectomy. Figure 5
For the purposes of this course, if you
running out of time, you can estimate and
incorporate the course of the vessel by
taking a cuff of muscle on either side.
If there are no suitable perforators in the
anterolateral thigh (ALT) territory, the flap
can be converted to a tensor fascia lata
(TFL) flap that lies more superiorly or an
anteromedial thigh (AMT) flap medially.
Both have shorter pedicles.
The lateral edge of the f lap can be
incised down to the muscle and elevated
subfascially from lateral to medial, taking
care to preserve the previously identified
perforators. Figure 6
A straight or lazy S incision is made from
the apex of the flap to the area of the
femoral artery which is at the mid-inguinal
point between ASIS and the pubic
symphysis. The skin and subcutaneous
tissue is divided up to the lateral border
of the sartorius muscle. The pedicle can
be traced to its origin from the profunda
femoris.
AnterolAterAl
thigh FlAP
anterolateral thiGh flaP 135
Figure 1
Vascular anatomy of ALT flap
Figure 3.
Design of the flap with respect to the perforators
Figure 2.1
Landmarks for locating perforators
Figure 2
Landmarks for locating perforators
Figure 3.1
Design of the flap with respect to the perforators
136 dissection manual
Figure 4
Perforators (red arrow)
Figure 5
Descending branch of the LCFA (red arrow)
RF
VL
Figure 6
Descending branch of the LCFA and
perforator (red arrow)
RF
VL
anterolateral thiGh flaP 137
KEY POINTS
1. The flap is centered on the septum between vastus lateralis
and rectus femoris.
2. The flap is supplied by perforators from the descending branch
of the lateral circumflex femoral artery (LCFA).
3. Most perforators are located within 3 cm of the midpoint
between a line from the ASIS and lateral upper corner of the
patella bone.
4. Incise the medial edge of the flap first and perforators are then
identified by elevating the flap subfascially from medial to
lateral.
5. Retracting the rectus femoris medially faci l itates the
identification of the descending branch of LCFA.
6. The flap can be converted to a TFL flap or AMT flap if there are
no suitable perforators in the ALT territory.
138 dissection manual
anterolateral thiGh flaP 139
15
rAdiAl ForeArm FlAP
Tor Chiu
140 dissection manual
radial forearm flaP 141
FLAP TERRITORY
This flap consists of fasciocutaneous tissue
from the volar surface of the distal forearm
supplied by branches of the radial artery.
It is most often designed as a free flap
but may be pedicled e.g. distally for hand
defects. The flap can be made ‘sensate’
by inclusion of either the medial or lateral
cutaneous nerves of the forearm.
The flap is based on the axis of the radial
artery. For larger flaps, care should be
taken to ensure that the ulnar pedicle is not
exposed. Instead the flap should extend
over the radial border to the dorsum if
necessary, although this will increase the
sensory deficit.
VASCULAR ANATOMY
Septocutaneous perforators from the
radial artery approach the skin between
the flexor carpi radialis (FCR) and brachioradialis (BR), with drainage through venae
comitantes (VC) and/or cephalic vein. Over
its length there are an average of 9-17
skin perforators that tend to be found in
proximal and distal clusters. The diameter
of the artery is around 2.5 mm. Figure 1
FLAP HARVEST
The pat ient should be p laced in a
sup ine pos i t ion wi th the arm on a
board positioned almost perpendicular
to the body. The operation is often
performed under tourniquet control and
a preoperative Allen’s test should be
performed.
The axis of the flap lies just medial to the
course of the radial artery at the wrist,
approximately along a line connecting the
centre of the antecubital fossa to the radial
border of the wrist where the radial pulse
rAdiAl ForeArm FlAP
142 dissection manual
is palpable, approximating to the course of
the artery. Figure 2
The superficial veins are marked with the
tourniquet tightened.
The skin incision should begin distally,
usua l ly f rom the u lnar aspect , and
dissection proceeds subfascially taking care
to preserve paratenon. Some surgeons
dissect suprafascially first, changing to a
deeper level in the proximity of the vessel
(over the bellies of branchioradialis and
FCR). Figure 3
The perforators lie in the ‘septum’ or
connective tissue between the skin flap
and artery, between the radial border
of the flexor carpi radialis and the ulnar
border of brachioradialis. The septum is
approached from the radial side in a similar
manner, preserving the cephalic vein for
anastomosis when the VC are narrow in
calibre.
Dividing and ligating the distal artery early
makes the flap harvest easier. Figure 4
The pedicle is then traced proximally
dissecting it free from the overlying
brachioradialis. A lazy ‘S’ incision over
the line of the artery may be used. In this
dissection, use an incision over the radial
border of the forearm. Figure 5
rAdiAl ForeArm FlAP
radial forearm flaP 143
Figure 1
Cross section anatomy of the forearm
Figure 3
Distal radial artery and cephalic vein divided and the
flap raised with preservation of paratenon
Figure 2
Course of radial artery (red) and flap design (purple)
Figure 4
Radial artery (red)
Cephalic vein (blue)
Figure 5
Radial artery
144 dissection manual
KEY POINTS
1. This flap consists of fasciocutaneous tissue supplied by
branches of the radial artery.
2. Septocutaneous perforators from the radial artery approach
the skin between the FCR and BR, and drain through venae
comitantes or the cephalic vein.
3. A preoperative Allen’s test should be performed.
4. The skin incision should begin distally and proceed subfascially
taking care to preserve paratenon.
5. Dividing and ligating the distal artery early makes the flap
easier to harvest.
radial forearm flaP 145
16
PeCtorAlis
mAjor FlAP
Tor Chiu
146 dissection manual
Pectoralis major flaP 147
FLAP TERRITORY
The pectoral is major myocutaneous
flap (PMMF) is useful in head and neck
reconstruction. The extent of coverage
and the reach of the flap are dependent
on the anatomy of the patient but the
upper limits are generally considered the
zygomatic arch externally and the tonsillar
bed internally.
VASCULAR ANATOMY
The PMMF is mainly supplied by perforators
of the pectoral branch of the thoracoac romia l a r te ry wh ich runs on the
underside of the PM.
The lateral thoracic artery provides a
secondary blood supply but is usually
sacrificed to maximize the reach of the
flap.
The superior thoracic artery contributes
supply to the lateral superior portion of the
muscle and is usually divided when the flap
is raised.
The course of the pectoral branch of the
thoraco-acromial artery can be identified
by drawing a line from the xiphoid to the
acromion. A second line is made vertically
from the midpoint of the clavicle to
intersect the first line. The course of the
artery corresponds to the line drawn from
the midpoint of the clavicle continuing
to the medial portion of the acromion to
xiphoid line. Figure 1
FLAP HARVEST
Identify the clavicle, ipsilateral sternal
border, xiphoid, and humeral insertion of
the PM.
Design the size and location of the skin
paddle over the PM.
Skin overlying any portion of the muscle
may be utilized. The size and and location
PeCtorAlis
mAjor FlAP
148 dissection manual
of skin paddle depends on reconstructive
requirements. In most cases, the skin
paddle is located at the infero-medial
border of the PM between the nipple and
the edge of the sternum. In women, the
skin paddle can be designed below the
breast in the inframammary fold.
The larger the skin paddle harvested, the
higher the likelihood the skin will survive
the transfer due to the increased number
of myocutaneous perforators.
For additional length, the skin paddle may
be extended as a random-pattern flap
beyond the inferior edge of the muscle.
Excessive thickness of the fatty tissue
is associated with a higher risk of skin
necrosis. Figure 2
The first incision is made from the lateral
edge of the skin paddle toward the
anterior axillary line (defensive incision which preserve the deltopectoral flap).
This incision is carried down to the muscle
and allows identification of the medial and
inferior extents of the muscle. At this point,
the skin paddle can be moved inferiorly
or superiorly so that most of it lies over
muscle.
The other incisions are made down to the
muscle. The skin paddle can be temporarily
sutured to the fascia.
The superior skin flap is elevated to
clavicle whilst preserving perforators to the
deltopectoral flap. A tunnel can be created
to the neck where needed. Figure 3
The inferior skin f lap is elevated to
reveal the lower edge of the PM and the
muscle is then elevated off the chest wall.
There are normally numerous chest wall
perforators at the muscular attachments. In
live patients, take care to control bleeding
as vessels can retract into the chest.
The pedicle can be identified on the deep
surface of the superior part of the muscle.
Figure 4 Cut the muscle close to the sternal
PeCtorAlis
mAjor FlAP
Pectoralis major flaP 149
Figure 1
Schematic diagram to locate the pedicle of PM
flap
Figure 4
PM muscle raised to show the pectoralis minor
(blue arrow) and pedicle (red arrow) running on
the under surface
Figure 2
Design of the skin island in PM flap with “defensive
incision”
Figure 3
Identify the free edge (blue arrow) of PM
muscle and ensure the skin island is “within” the
boundary of PM muscle
150 dissection manual
attachments, taking care with the internal
mammary perforators. Laterally, cut the
muscle taking care to preserve the pedicle.
The lateral thoracic artery is usually
sacrificed to increase length and rotation.
Figure 5
When insetting the flap, take care not
to overly rotate, kink, or compress the
proximal flap.
Flap reach can be increased by dividing
the clavicular portion of the muscle above
the pedicle and by splitting and removing
the middle one-third of the clavicle.
PeCtorAlis
mAjor FlAP
Figure 5
Raised PM flap to show the pedicle (red arrow)
from thoraco-acromial artery
Pectoralis major flaP 151
KEY POINTS
1. The PMMF is mainly supplied by the pectoral branch of the
thoraco-acromial artery and a secondary blood supply from the
lateral thoracic artery.
2. The course of the pedicle can be identified by locating the
landmarks including the xiphoid, acromion and midpoint of the
clavicle.
3. Place the skin paddle over the infero-medial border of the PM.
4. Defensive incision preserves the deltopectoral flap for future
use.
5. Flap reach can be increased by dividing the lateral thoracic
artery and the clavicular portion of the muscle above the
pedicle.
152 dissection manual
fibula flaP 153
17
FibulA FlAP
Tor Chiu
154 dissection manual
fibula flaP 155
FLAP TERRITORY
This flap includes a segment of the fibular
bone with or without the overlying skin
island on the peroneal/ lateral aspect of
the calf.
VASCULAR ANATOMY
The peroneal artery and vein lie on the
medial surface of the fibula, posterior
to the interosseus membrane, making
dissection relatively diff icult. At the
bifurcation (anterior tibial and peroneal
arteries), the vessels start posterior to and
at some distance away from the bone
before moving diagonally downwards to a
position closer to the bone.
There are some important points related to
the vascularity of the leg and its variants.
Peronea arteria magna – a dominant
peroneal artery has reciprocally small
tibial vessels. This condition may be
ipsilateral as other leg may be satisfactory. This is rather rare.
Low bifurcation – the pedicle would be
short (and vein grafts may be necessary).
The skin island may be supplied by perforators from the posterior tibial system
traversing the soleus and thus separate
from the peroneal artery system. It is a
misconception from the pre-perforator
flap era that including a cuff of soleus/
flexor hallucis longus (FHL) will improve
the reliability of the skin island. Although
it requires more dissection, tracing the
perforators to the pedicle will optimize
reliability. Including unnecessary muscle
has adverse implications, in particular
reducing the maximum tolerable ischaemic
time.
FibulA FlAP
156 dissection manual
FibulA FlAP
FLAP HARVEST
Preoperatively, if the pedal pulses (dorsalis
pedis and posterior tibial) are palpable and
strong then this is usually sufficient as a
screening test. In selected patients such as
the elderly, arteriopaths and post traumatic
cases, an angiogram may be useful.
Bend the knee to a 40-60 degree angle
and mark the top and bottom of the
fibula bone. It is conventional to leave
some bone at both ends to preserve the
common peroneal nerve (~4cm above) and
the ankle joint (6cm below) respectively.
Mark the posterior edge of the fibula which
is the axis of the skin island.
Mark an elliptical skin island centred on the
axis along the posterior edge of the fibula
Figures 1, 2 and at the junction of the
middle and lower thirds of the fibula.
Incise the anterior skin edge down through
the fascia to the muscle (usually the
peroneals) and elevate the flap subfascially
from anterior to posterior until you reach
the posterior lateral intermuscular septum
situated posterior to the peroneal muscles.
You should then be able to see the skin
perforators. Figure 3
Incis ing to the fascia and elevating
for a distance supra-fascially Figure 4
helps protect the sural nerve and short
saphenous vein posteriorly as well as
the peroneal tendons anteriorly by not
exposing them.
Adjust your posterior incision if necessary
and incise down to muscle (gastrocnemius/
soleus). Now elevate this posterior flap
(sub)fascially in an anterior direction to
meet the same septum and the perforators
seen before. Perforators that run through
the posterior muscles are more likely to
arise from a system separate from the
peroneal system and will not reliably
supply the skin island. The muscles can
fibula flaP 157
Figure 1
Design of the fibula flap
Figure 4
Suprafascial dissection to protect the sural nerve
Figure 5
Dissect the peroneal muscles away from the
lateral surface of the fibula
Figure 3
Perforator (indicated above) running in the
intermuscular septum
Pe ron
eus
sep
tum
Figure 6
Leaving a thin layer of muscle to ensure that the
periosteum remains intact
Per
one
us sep
tum
Figure 2
Design of the fibula flap, posterior border of fibula
(red colour)
6cm from
distal
4cm from
proximal
158 dissection manual
be separated from the septum with gentle
blunt dissection.
Dissect the peroneal muscles away from
the lateral surface of the fibula in an
anterior direction Figures 5, 6 leaving a
thin layer of muscle to ensure that the
periosteum remains intact. When you reach
the anterior edge of the fibula, incise the
membrane (anterior intermuscular septum)
all the way down to the ankle. You can
also divide the muscles (extensor hallucis
longus and extensor digitorum longus) and
interosseus membrane (IOM) at this point
if you are able to see them. Figure 8
Cut the distal fibula at your selected level.
After you do so, note the proximity of the
peroneal vessels and ligate or divide them.
I f you have ident i f ied the common
peroneal nerve, you can also cut the
proximal fibula at this time to facilitate
mobilization of the bone.
Return to the posterior aspect of the
fibula and divide the muscle attachments
here (flexor hallucis longus and tibialis
posterior). Figure 7 The peroneal vessels
will be seen under this muscle layer. If
you haven’t already divided the IOM then
return to the anterior fibula and divide it.
Divide the proximal fibula, if not already
done (taking an extra segment can help to
improve access to the proximal peroneal
vessels), and trace the vessels to the
bifurcation. Figure 9
FibulA FlAP
fibula flaP 159
Figure 7
Divide the FHL/PT from the posterior aspect of
the fibula
Figure 8
Cross section of the leg
Figure 9
Both the proximal and distal fibula divided and
the peroneal vessel exposed (indicated above)
160 dissection manual
KEY POINTS
1. The peroneal artery and vein supply the fibula bone and the
overlying skin island.
2. The presence of pedal pulses (DP and PT) is usually sufficient
as a screening test. An angiogram is rarely necessary.
3. It is conventional to leave 4 cm of bone superiorly to preserve
the common peroneal nerve and 6 cm bone above the ankle
joint.
4. The axis of the flap is located at the posterior edge of the
fibula.
5. Identi fy the skin perforators at the poster ior lateral
intermuscular septum.
6. Leave a thin layer of peroneal muscle on the lateral surface of
the fibula to ensure the periosteum remains intact.
7. Dividing the proximal fibula facilitates access to the proximal
peroneal vessels.
deeP inferior ePiGastric artery Perforator flaP 161
18
deeP inFerior
ePigAstriC Artery
PerForAtor FlAP
Tor Chiu
162 dissection manual
deeP inferior ePiGastric artery Perforator flaP 163
FLAP TERRITORY
The deep inferior epigastric artery perforator
f lap (DIEP) and super f ic ia l in fer ior
epigastric artery (SIEA) flaps are free
(fascio-) cutaneous flaps of the lower
abdomen below the level of the umbilicus.
VASCULAR ANATOMY
The deep inferior epigastric artery (DIEA)
arises from the distal external iliac artery,
deep to the inguinal ligament and ascends
superomedially towards the umbilicus,
behind the rectus abdominis (RA) between
the transversalis fascia and the peritoneum.
In the majority of cases, the artery enters
the muscle at its middle third and in less
than 20%, at its lower third. It then usually
branches into medial and lateral vessels
that give origin to the rows of perforators
to the skin. Figure 1
The superficial inferior epigastric artery
(SIEA) often arises directly from the
common femoral artery or may share a
trunk with the superficial circumflex iliac
artery (SCIA), 2-5cm below the inguinal
ligament. It starts deep to the Scarpa‘s
fascia and as it ascends, pierces the fascia
to branch out relatively superficially within
the subcutaneous fat. It does not perforate
the RA muscle or its fascia. The venae
comitantes (VC) to the SIEA are usually
very small. A larger separate vein is often
found more medial and more superficial.
If large enough, the SIEA can be used
to harvest a flap instead of the DIEP but
this vessel does not reliably supply tissue
across the midline. The SIEA/SIEV can also
be used for supercharging or superdraining
of the DIEP flap.
FLAP ELEVATION
The patient is positioned supine. The
perforators can be localized preoperatively
deeP inFerior ePigAstriC
Artery PerForAtor FlAP
164 dissection manual
deeP inFerior ePigAstriC
Artery PerForAtor FlAP
with a doppler probe or angiogram and
usually lie close to the umbilicus.
The DIEP flap is designed in most cases
as an elipse on the lower abdomen with
the upper limit at the superior edge of
the umbilicus and the lower limit above
the pubic bone. The usual lateral limits
are the ASIS. Figures 2, 3 The donor
defect is then closed in the manner of an
abdominoplasty.
The contralateral flap is often raised first
to get an idea of the position of the linea
semilunaris and the larger perforators,
however symmetry is not guaranteed.
The inferior skin incision is made with the
initial aim of identifying the SIEA and SIEV
between the 2 layers of the superficial
fascia. Figure 4
The superior incision is then made with
a periumbilical incision taking care to
preserve the umbilical stalk, and the flap
is then elevated at the fascial level from
lateral to medial.
Begin to look for perforators once the
lateral edge of the rectus muscle is
reached. The anterior rectus sheath is
incised around the chosen perforator(s)
that are traced to the DIEA and its VC that
run longitudinally on the deep surface of
the rectus muscle. Figure 5
Expose the proximal DIEA and VC by
retracting the inferior part of the rectus
muscle medially. Continue dissecting until
a sufficient length of pedicle has been
obtained.
Tr i m t h e f l a p a c c o r d i n g t o t h e
requirements. The contralateral side
is sacrificed first as it has the poorest
vascularity. Figure 6
deeP inferior ePiGastric artery Perforator flaP 165
Figure 1
Vascular anatomy of DIEP flap
Figure 4
Superficial inferior epigastric artery (SIEA)
Figure 5
Suprafascial dissection and perforator identified
Figure 2
Design of DIEP flap
Figure 6
Perforator and DIEA identified and flap isolated
Rectus
Figure 3
Design of DIEP flap
Umbilicus
ASIS ASIS
166 dissection manual
KEY POINTS
1. DIEP is a fasciocutaneous flap supplied by the deep inferior
epigastric artery perforator.
2. The DIEP flap is designed as an ellipse on the lower abdomen
with its boundaries at the superior edge of the umbilicus, the
pubic bone and the ASIS.
3. The inferior skin incision is made first with the aim of identifying
the SIEA and SIEV.
4. Begin to look for perforators once the lateral edge of the rectus
muscle is reached.
5. Trim the flap according to the requirements. The contralateral
side is sacrificed first as it has the poorest vascularity.
deeP inferior ePiGastric artery Perforator flaP 167
19
miCrovAsCulAr
teChniques
Tor Chiu
168 dissection manual
microvascular techniques 169
I. BACKGROUND
Microsurgery has become an essential
technique in many surgical specialties.
Microsurgery is a complex task that
requ i res hand-mic roscope-eye coordination, respectful handling of delicate
tissues with microvascular instruments and
steady surgical technique.
Microsurgical skills can be improved with
regular practice. Mastering the technique
is not possible when the surgeon is limited
to observation and performing infrequent
clinical cases.
Various models can be used to train and
assess technical skills and dexterity. The
medical profession is under increasing
pressure to be able to objectively assess skills
and competence.
II. MICROSURGICAL
TECHNIQUE
A. BASIC AIMS
Water-tight anastomosis with the least
number of sutures (arteries 1 mm in
diameter ~5 to 8 and veins ~7 to 10)
Place sutures perpendicular to anastomosis
and equally spaced.
Maximize patency by avoiding constriction or suturing walls together.
B. MICROSCOPE ADJUSTMENT
There is an ON-OFF switch on the main
arm next to the brightest control. When
you switch off the microscope during
breaks, turn the brightness way down
first as – this helps to reduce the risk of
damaging the light.
miCrovAsCulAr
teChniques
170 dissection manual
There is a dial on top of the binocular eye
pieces to adjust the interpupillary distance.
Adjust this as needed to get a binocular
image.
Gross focus is obtained by slowly moving
the lens assembly up or down. There is a
fine focus dial on the side of the base of
the lens assembly.
The magnification is adjusted by the small
dials either side of the lens assembly. The
effective magnification is calculated by
multiplying the figure on the dial with the
objective magnification, usually 10x. Thus
0.4 is equivalent to 4x. Use the middle
range of magnification rather than the
highest as it is easier and has better depth
of field.
C. END-TO-END ANASTOMOSIS
Vessel Exposure & Preparation
Adventitia is cleared from the vessel ends
for about 2 mm to prevent accidentally
incorporating it into the suture line.
”Circumcise“ or pull the adventitia down
over the vessel end, cut it and let it retract
and then carefully trim in a circumferential
fashion.
The vessel ends can be dilated to 1.5 times
normal diameter. Do so judiciously in living
tissue as there is a risk that this may injure
the intima.
Freeing more of the vessel from the
surrounding tissue may help to reduce
retraction when you cut the vessel.
Sutures
8-0 to 10-0 Ethilon is used depending on
the size and thickness of the vessels.
Take full thickness bites, approximately
twice the thickness of the vessel and tie
until the sutures are just visible.
Forcep tips can be gently placed in the
miCrovAsCulAr
teChniques
microvascular techniques 171
Figure 1
Three suture technique. The first two stay sutures are placed at 120 degrees to encourage the posterior wall to
fall away from the anterior wall when traction is exerted laterally
Figure 2
Use of traction and stay sutures to keep the back and front walls apart
172 dissection manual
lumen to protect the back wall and to
provide counter pressure. Alternatively
gently grasp the adventitia.
Interrupted sutures reduce constriction
compared to continuous sutures.
Three suture technique
Place the first two stay sutures approximately 120 degrees apart on vessel‘s
circumference. The back wall will fall away
making it less likely to capture both walls.
Figure 1
Leave the suture ends long for use as
traction sutures. There are various ways of
holding these sutures apart from a framed
clamp, choose the method that suits you
best. Complete the anterior wall. Use a
central stay suture to help you manipulate
the vessel ends. Figure 2
Rotate the anastomosis to expose the
posterior vessel wall and place a traction
stitch 120 degrees from the initial two
traction stitches.
Place stitches in the remaining spaces to
complete the anastomosis
Surgeon’s knots are used for traction or
stay sutures and simple square knots for
the other stitches.
Back wall first
Clamps are not needed with this technique
which allows an improved view of the
back wall. The vessel does not need to
be flipped over and it works well even in
cavities. Figure 3
The first suture is placed in the back wall at
the most difficult point to place a suture (for
right handed surgeons), right-to-left, out to
in and then in to out. An assistant can hold
the vessel ends together while the knot is
tied.
miCrovAsCulAr
teChniques
microvascular techniques 173
Figure 3
Back wall first technique showing the first few sutures.
Figure 4
End to side anastomosis, front wall first technique
174 dissection manual
The remainder of the back wall sutures
are placed left-to-right. The second suture
should be close to the first and subsequent
sutures can be spaced further apart. Make
liberal use of saline to visualize the vessel
intima. "Too few sutures" is easier to fix
than "too many sutures". Front wall sutures
are placed right-to-left.
D. END-TO-SIDE ANASTOMOSIS
The vessel is pinched up and a piece of
wall is carefully removed. Aim for a hole
that is about 1.5x the diameter of the
vessel to be plumbed in. The flap vessel
can be trimmed at an angle to improve
flow though a perpendicular arrangement.
The first suture is placed in the right
corner of the hole from right-to-left, out to
in and in to out.
The placement of the second suture
depends partly on the mobility of the
vessels. A back wall first technique is useful
when there is limited mobility.
Back wall first – subsequent sutures are
placed along the back wall.
Front wall first – the second suture is
placed at the left corner. Figure 4
miCrovAsCulAr
teChniques
microvascular techniques 175
KEY POINTS
1. Anastomoses should be water-tight with the least number of
sutures.
2. Place sutures perpendicularly and with equal spacing.
3. Maximize patency by avoiding constriction or suturing vessel
walls together.
4. Adventitia is cleared from vessel ends for approximately 2 mm
to prevent incorporating it into the suture line.
5. Vessel ends can be dilated to 1.5 times normal diameter.
6. Take full thickness bites, approximately twice the thickness of
the vessel and tie until the sutures are just visible.
7. Interrupted sutures reduce constriction compared to continuous
sutures.
D
ISSE
C
T
IO
N
A
N
D
R
E
C
O
N
ST
R
U
C
T
IO
N
M
A
N
U
A
L
H
EA
D
&
N
EC
K
ANDREW VAN HASSELT • EDDY WONG
T H E C H I N E S E U N I V E R S I T Y O F H O N G K O N G
D I S S E C T I O N A N D R E C O N S T R U C T I O N M A N U A L
HEAD & NECKT his dissection manual contains detailed descriptions and all- inclusive illustrations on the full range
of surgical procedures in the head
and neck. It also includes meticulous
dissection technique guidance on
reconstruction operations. The manual
provides readily available access to
valuable experience accumulated by
expert Head and Neck surgeons. In
compiling this manual the editors have
delivered a comprehensive guide and
reference both within the laboratory
and when preparing for the operating
room.
“The Head & Neck Dissection and Reconstruction Manual, compiled by the Chinese
University of Hong Kong faculty, contains the key information that dissectors require to be
able to proceed through the surgical steps of common head and neck and reconstructive
surgery operations, and will be an important companion in the dissection room.”
— Johan Fagan
Professor and Chairman
Division of Otorhinolaryngology
University of Cape Town
“We have created this manual to guide, complement and enhance value to be gained
from the priceless opportunity of dissecting specimens of excellent quality. It is indeed a
privilege to gain hands on experience in the totally safe setting of the laboratory.”
— Eddy WY Wong
Associate Consultant, Department of ENT
Prince of Wales Hospital, Hong Kong
— Andrew van Hasselt
Professor of Surgery (Otorhinolaryngology)
The Chinese University of Hong Kong
department of otorhinolarynology,
head and neck surgery
the chinese university of hong kong

PDF Document reader online

This website is focused on providing document in readable format, online without need to install any type of software on your computer. If you are using thin client, or are not allowed to install document reader of particular type, this application may come in hand for you. Simply upload your document, and Docureader.top will transform it into readable format in a few seconds. Why choose Docureader.top?

  1. Unlimited sharing - you can upload document of any size. If we are able to convert it into readable format, you have it here - saved for later or immediate reading
  2. Cross-platform - no compromised when reading your document. We support most of modern browers without the need of installing any of external plugins. If your device can oper a browser - then you can read any document on it
  3. Simple uploading - no need to register. Just enter your email, title of document and select the file, we do the rest. Once the document is ready for you, you will receive automatic email from us.

Previous 10

Next 10