Rnd gaurav (nx power-lite) /certified fixed orthodontic courses by Indian dental academy

NECK
DISSECTION
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


Contents
Introduction
Cervical lymphatics – its drainage
Levels & Sublevels of lymph nodes - their implications
What is neck dissection ?
History of neck dissection
Classifications & Concepts behind classifications
Surgical anatomy

Contents …
Incisions
Description of classical RND
Description of other types of neck dissection
Complications in RND
Clinical controversies :
management of N0 neck
management of N+ neck

Conclusion

Introduction

Surgery is the oldest and the most reliable form of
treatment for oral malignancy.
what is the need for the neck to be treated in oral
malignancy ????


Lymphatic system of head and neck


Patterns of cervical lymphatic metastasis
Lymphatic flow in the neck - consistent pattern - upper neck and
then to the lower neck and superficial to deep.
This orderly lymphatic flow has been demonstrated by the work of
Fisch and Sigel*
*Cervical

lymphatic system as visualized by lymphography  Annals of Otology, Rhinology and

Laryngology 73: 869-872.


Post floor of mouth

Mandibular incisors

Maxillary sinus

Tongue(tip)

Maxillary teeth except 3rd molar

Lower lip (middle)

Mandibular canines,1st & 2nd

& Chin

molars

Ant. floor of mouth

Tongue
Nose, hard palate

SUB-MENTAL

Upper lip

SUB-MANDIBULAR

UPPER DEEP CERVICAL CHAIN OF NODES

RETROPHARYNGEAL

Scalp
Ear
Eyelids

PAROTID NODES

3rd Molars
Tongue (base)
Tonsillar area
Soft palate

UPPER DEEP CERVICAL CHAIN OF NODES

LOWER DEEP CERVICAL CHAIN OF NODES

The regional lymph node groups draining a specific primary site as
first echelon lymph nodes


The first echelon lymph nodes at highest risk from primary tumors in
the oral cavity


Concept of Sentinel Node

Omgo E. Nieweg et al., Annals of Surgical Oncology, 8(6):538–541

“the first lymph node that
receives afferent lymphatic
drainage from a primary
tumor”. - Morton


Risk for nodal metastasis
Various factors
Site
Size
T stage
Location of primary tumour
Histomorphologic characteristics of primary tumor


Risk of nodal metastases increases in relation to location of the
primary tumor


Lymph drainage of tongue, as described by
Jamieson and Dobson


The incidence of lymph node metastasis and survival in relation to the
thickness of the primary lesions for T1 and T2 SCC of the oral tongue and floor
of mouth


The probability of
cervical metastases
(N)
related
to
primary staging (T) in
pts with head & neck
SCC


Memorial Sloan – Kettering Cancer Center leveling system
of cervical lymph nodes


Division of neck levels by sublevels
IA – submental nodes
IB – submandibular nodes
IIA & IIB – together
comprising
the
upper
jugular node
VA –
nodes

Spinal

accessory

VB – Transverse cervical
and supraclavicular nodes

Rationale of sublevels
Suggested by Suen and Goepfert (1997)
Subzones have biological significance independent of
the larger zones in which they lie
Biologic significance for lymphatic drainage depending
on site of tumor
Level I subzones
Lower lip, FOM, ventral tongue – Ia
Other oral cavity subsites – Ib, II, and III


Level II subzones
Oropharynx and nasopharynx – IIb
Oral cavity, larynx and hypopharynx – may not be
necessary to dissect IIb if level IIa is not involved
Level V subzones
Oropharynx, nasopharynx, and cutaneous – Va
• spinal accessory nodes

Thyroid – Vb
• transverse cervical and supraclavicular nodes

Neck Dissection


What is neck dissection?
The term "neck dissection" refers to a surgical
procedure in which the fibro-fatty soft tissue
content of the neck is excised to remove the lymph
nodes that are contained therein*.

* K Harish - Review Neck dissections: radical to conservative, World
Journal of Surgical Oncology 2005, 3:21

Historical Perspective


In 1906 paper
“Exicision of cancer of the

head and neck ”

Gold standard procedure :

“Radical Neck dissection”
Dr George Crile (1864-1943 )


In 1951 paper
“Neck Dissection”

“Routine prophylactic RND was
impracticle”

www.indiandentalacademy.com Martin
Dr. Hayes

(1892-1977 )

1880 – Kocher –proposed removal of nodal metastasis
1906 – George Crile –RND
1933 & 1941 – Blair and Martin popularised RND
1953 – Pietrantoni - recommended sparing SAN
1967 - Bocca and Pignataro described FND
1975- Bocca established oncologic safety of FND compared to
RND
1980- Ballantyne –concept of selective neck dissection
1989, 1991, and 1994 – Medina, Robbins and Byers respectively
proposed classifications of neck dissections

Concepts behind classification of neck
dissection
Based on 4 concepts
RND: the standard basic procedure - against which all
other modifications are compared
preservation of any non- lymphatic structures : MRND
that preserves one or more gps or levels of LN`s : SND
removal of additional LN groups or non lymphatic
structures relative to the RND – Extended neck
dissection

MEDINA CLASSIFICATION(1989)
Comprehensive neck dissection
1.
2.

Radical neck dissection (RND)
Modified radical neck dissection (MRND)
•
•
•

MRND I – Preserves spinal accessory nerve.
MRND II – preserves Spinal accessory and internal jugular vein
but sacrifices sternocleidomastoid muscle.
MRND III –preserves all- SAN, sternocleidomastoid muscle and
internal jugular vein

Selective neck dissection (SND)
•
•
•
•
•

Supraomohyoid neck dissection – I, II, III
Jugular neck dissection – II, III, IV
Anterior triangle neck dissection – I, II, III, IV
Central compartment neck dissection – VI
Posterolateral neck dissection – II, III, IV

Spiro’s classification
Radical (4 or 5 node levels resected)
Conventional radical neck dissection
Modified radical neck dissection
Extended radical neck dissection

Selective (3 node levels resected)
SOHND
Jugular dissection (Levels II-IV)
Any other 3 node levels resected

Limited (no more than 2 node levels resected)
Paratracheal node dissection
Mediastinal node dissection
Any other 1 or 2 node levels resected

AAO-HNS CLASSIFICATION *
1991

Classification

2001 Classification

* Neck dissection classification update-Revisions proposed by the American
Head and Neck Society and the American Academy of Otolaryngology-Head and
Neck Surgery.

Surgical Anatomy
‘Anatomy is a language,
As dead as can be,
It killed the ancient medics,
And now it’s killing me’


Fascial layers of the neck
Superficial cervical fascia
Deep cervical fascia
Superficial layer
• SCM, strap muscles, trapezius

Middle or Visceral Layer
• Thyroid
• Trachea
• esophagus

Deep layer (also prevertebral fascia)
• Vertebral muscles
• Phrenic nerve

Triangles of neck


Imp structures in posterior triangle


Submandibular space


Facial artery and submandibular gland


Platysma
Origin – fascia overlying the pectoralis major and
deltoid muscle
Insertion – 1) depressor muscles of the corner of the
mouth,
2) the mandible, and
3) the SMAS layer of the face
Function – 1) wrinkles the the neck
2) depresses the corner of the mouth
3) increases the diameter of the neck
4) assists in venous return

Surgical considerations
Absent in the
midline of the neck
& posteriorly in
part of post
triangle

Does platysma
supplies skin or skin
supplies platysma ?

Omohyoid muscle
Origin – upper border of the scapula
Insertion – 1) via the intermediate tendon onto the
clavicle and first rib
2) hyoid bone lateral to the sternohyoid m
Blood supply – Inferior thyroid a.
Function – 1) depress the hyoid
2) tense the deep cervical fascia


Absent in 10% of
individuals
Landmark demarcating
level III from IV
Inferior belly lies
superficial to
The brachial plexus
Phrenic nerve
Transverse cervical
vessels
Superior belly lies
superficial to
IJV

Trapezius muscle
Origin –
1) medial 1/3 of
sup. nuchal line
2) ext occipital
protub
3) ligamentum nuchae
4) spinous pr of C7
& T1-T12
Insertion –
1) lat 1/3 of the clavicle
2) acromion pr
3) spine of the scapula

Function – elevate and rotate the scapula and stabilize
the shoulder
Posterior limit of Level V neck dissection
Denervation results in shoulder drop and winged scapula


Digastric Muscle
Origin – digastric fossa of the mandible (at the
symphyseal border
Insertion – 1) hyoid bone via the intermediate tendon
2) mastoid process
Function – 1) elevate the hyoid bone
2) depress the mandible (assists lateral
pterygoid)


Posterior belly is
superficial to:
•
•
•
•

ECA
Hypoglossal nerve
ICA
IJV

Anterior belly
• Landmark for
identification of
mylohyoid for
dissection of the
submandibular
triangle

Marginal Mandibular Nerve
Should be preserved
Most commonly injuredat level 1b
Can be found:
1 cm ant & inf to angle of
mandible
At the mandibular notch
Deep to fascia of the submand
gland (superficial layer of deep
cervical fascia)
Superficial to adventitia of the facial vein

More than one branch often present

Spinal accessory nerve
After emerging from jugular foramen, crosses the IJV
Occipital artery crosses the nerve
Descends obliquely in level II (forms Level IIa and IIb
Penetrates the deep surface of the SCM
Exits posterior surface of SCM deep to Erb’s point
Traverses the posterior triangle ensheathed by the
superficial cervical fascia and lies on the levator
scapulae
Enters the trapezius approx. 5 cm above the clavicle

CN XI – Relationship with the IJV


Hypoglossal Nerve


Venous system


Thoracic Duct
Conveys lymph from the entire body back to the blood
Exceptions:
Right side of head and neck, RUE, right lung right heart
and portion of the liver

Begins at the cisterna chyli
Enters posterior mediastinum between the azygous
vein and thoracic aorta
Courses to the left into the neck anterior to the
vertebral artery and vein
Enters the junction of the left subclavian and the IJV

Anatomy of the vascularization of neck skin
Kambic and Sirca 1967 stated that arterial supply is
in a vertical direction.
descending branches: facial and occipital artery
ascending branches: transverse
supraclavicular arterial branches .


cervical

and

The vasculature can be summarized into
upper neck region - anterior to the angle of mandible –
branches of facial and submental arteries.
upper lateral neck - the area between ramus of mandible and the
sternocleidomastoid muscleOccipital and external auricular branches of external carotid
.
Lower half of neck –
The transverse cervical artery and suprascapular artery
Large platysma-cutaneous branches and branches of superior
thyroid supply the front middle portion of the neck.


Incisions
Incisions classified into
Vertical
Horizontal

The incisions used for neck dissections are
Tri-radiate incision and its modification
Hayes martin double ‘Y’ incision
McFee incision
Apron flap incision


Basic needs of an incision are
Good exposure of the neck and primary disease
Ensure viability of the skin flaps. Avoid acute angles
Protect carotid artery even in the cases of wound
infection
Facilitate reconstruction
Adapt to the condition of patient esp after
radiotherapy
It should be cosmetically acceptable


Differences between incisions
Transverse incision

Vertical incision

Have cosmetic advantage as they
follow natural skin folds of the
skin

Disadvantages because they
intersect to the natural skin folds
of the skin and the vascular
supply of the neck

Recovery of scar tissue in these
folds are rapid and successful

They tend to contract along their
long axis – leads to deformity and
restricted action.

Easy to modify


Tri-radiate incision and its modifications
Advantages
Incision
provides
good
exposure to surgical site.

Disadvantages
Flap necrosis is high due to
disruption of vasculature of
skin flaps
Occurrence of flap separation
at the trifurcation site.
Carotid exposure/rupture


Modification of Tri-radiate incision

Schobinger (1957)
Cramer & Culf (1969)
Conley (1970)


Schobinger (1957)
Schobinger
suggested
that
vertical
limb
instead
of
being
straight
should
be
curved posteriorly in
order to avoid lying
directly
over
the
carotids.


Conley (1970)
Suggested a posteriorly
curving vertical incision
rather than a horizontal
incision
The incision starts from
the submental region
and ends by running
downwards along the
anterior border of the
trapezius to the level of
clavicle gently curving
posteriorly.

Hayes Martin Incision
Paired ‘Y’ incision.
the
submandibular
component is met by a
vertical limb which below
becomes continuous with
an inverted ‘Y’ in the
supraclavicular region.
Disadv :
Cyanosis of the skin flaps
Flap necrosis and
carotid exposure


McFee Incision
Avoids a vertical limb.
Two horizontal incisions
are
used
one
in
submandibular region
and other in the
supraclavicular region.


Advantages

Disadvantages

Excellent cosmetic result (McFee
1960, McNeil 1978)

Exposure is not good (Hetter 1972)

No ↓ in vascularity in the centre of
the flap (Ariyan 1986)

Not suitable for bilat simultaneous
neck dissection (Chandler and Ponzoli
1969)

No angle intersection in incision
(McFee 1960)

Operating period is long (McFee 1960)

Post - op wound recovery - rapid
(McFee)

Posterior triangle dissection is
difficult (Maran et al 1989, White et
al 1993)

Suitable in necks receiving
radiotherapy & in peripheral vascular
ds (Maran et al 1989)

Working under the bridge flap difficult

Recovery of flap excellent due to
wide bipedicled flaps (Stella & Brown
1970, Daniel & McFee 1987)

In short neck it might be difficult to
distinguish between the front tip of
the incision from that of the
tracheostomy.


Apron flaps
Described by Latyschevsky & Freund
1960.
Only a horizontal incision from mastoid
gently curving inferiorly upto upper
border of the thyroid.
Advantages
Carotid artery is well protected
Protects the descending arterial
supply
Disadvantages
Damage to the ascending arterial and
venous supply
Venous congestion and oedema might
develop at the bottom corner


Hockey stick incision
Lahey et al (1940)
Modified for RND by Eckert
& Byars 1952.
It has a longitudinal and
transverse incision
B/L hockey stick incision
allows the deglovement of
the whole neck.

Radical neck dissection


RND… Indications
Current indications for classical RND
N3 disease
Multiple gross metastases involving multiple levels.
Recurrent metastatic disease in a previously irradiated
neck.
Grossly apparent extranodal spread with invasion of
the spinal accessory nerve &/or IJV at the base of the
skull
Involvement of accessory chain lymph nodes by
metastatic disease.

Contraindications
Neck dissection is contraindicated in disease beyond
the superficial or deep cervical fascia. These include:
Poor surgical candidate.
Rampant distant metastasis.
Significant bilat neck disease.
Base of skull disease.
Mediastinal or infraclavicular disease.
Unresectable or uncontrollable primary disease.
Extension into deep vital structures of neck.

The sequence of neck dissection
as described by Hayes Martin


Incision

Dissection of post t’gle begins
at ant border of trapezius


Radical neck dissection predominantly from behind forward
makes use of the anatomical fact that the IJV does not
have posterior branches


Dissection of post t’gle medially →
exposure of brachial plexus, phrenic
n. & cut roots of cervical plexus

SCM dissected off & retracted to
expose the carotid sheath & IJV


IJV ligated & divided after
common carotid & vagus n
exposed & retracted medially

Dissection proceeds along the
carotid sheath upto skull base


Surgical field
following RND


Two suction drains inserted


Final closure

Bilateral RND
Not often performed
Loss of both SCMs → difficulty in
lifting head, esthetics
Loss of both XI Ns → doubling the disability
Indications :
Primary at base of the tongue/floor of the mouth at
midline
When metastatic nodes develop on contralat side of the
neck after nodal clearance on ipsilat side

Most often carried out as two separate operative
procedures, separated in time (4 weeks)

Complications of ligating bilat IJVs simultaneously

Always try to preserve one of the IJVs
An attempt at preservation of the vein made on the
1st side dissected leaves the second available for
another attempt, should the 1st be unsuccessful.

Functional Neck Dissection
The versions which have been described are
RND — XI N
RND — XI N, IJV & SCM
RND — XI N, IJV, SCM & nodes of the post triangle
Resections corresponding to above two but in addition
IJV is removed

Common to all versions : removal of deep jugular
chain of nodes + subm’lar gland & its assoc nodes


Rationale…
It is the length of the nerve bw its emergence from
the jugular foramen & its disappearance into SCM
which is its most sensitive segmentin patological
terms, b’se of its proximity to deep jugular nodes
higher in the neck


Operative
steps in the
functional
neck
dissection


Rationale of FND
The most controversial factor:
whether or not the post triangle with its nodes can be
left undisturbed without compromising the
pathological basis of resection???
Lindberg (1972) – overall incidence of nodes in post
triangle… 2%
Feind (1972) – a very low overall incidence of post
triangle metastases
• When positive nodes were present in post t’gle multiple positive
nodes were also present elsewhere in the neck.


Supraomohyoid neck dissection

•Cancers of oral cavity that are N0 clinically
•Discrete N1 lesions can also be treated

Jugular neck dissection


Posterolateral neck dissection


Extended radical neck dissection


CLINICAL CONTROVERSIES


“Should we treat No neck or not ?”


Studies of Patterns of cervical lymph node metastasis –
Jatin P Shah

Distribution of nodal
metastasis in
therapeutic
neck dissections

% of patients with
pathologically
proven metastasis
at that level

Treatment options for the No neck
Elective surgery
Elective radiotherapy
Elective neck investigation (CT or MRI)
‘Wait & watch’


Selective neck dissection (N0 neck)
Organ

Nodal clearance

Oral cavity

I, II, III

Tongue

I, II, III, IV

Hypopharynx, larynx, oropharynx

II, III, IV

Some laryngeal and hypopharyngeal lesions
where IIB is not removed

IIA, III, IV

Laryngeal, hypopharyngeal extending below
glottis

II, III, IV, VI

Thyroid, hypopharynx, cervical trachea, cervical
esophagus, sub-glottic larynx

VI,

Cutaneous carcinoma of posterior scalp and
upper neck

II – V, Post auricular,
Suboccipital

Cutaneous malignancy from pre-auricular,
anterior scalp and temporal region

II, III, VA, parotid, facial,
external jugular nodes

Cutaneous malignancy of anterior or lateral face I, II, III

Pros and cons for elective neck dissection (END)
For END
Low morbidity & mortality

Against END
Results in a large no of unnecessary surgical
procedures & is assoc with inevitable
morbidity

Cure rate for neck dissection is ↓ed if gland
Cure rates are no lower if the surgeon waits for
enlargement occurs or multiple nodes
the neck to convert from N0 to N1
appear
Impossible to provide follow-up necessary
to detect the earlier conversion of a neck
from N0 to N1

Careful clinical follow-up will allow detection
of the earliest conversion from N0 to N1

Allowing the neck metastases to develop
increases the incidence of distant
metastasis

END removes the barrier to the spread of
disease and also has a detrimental
immunological effect

If neck has been entered to remove the
primary it is better to perform an incontinuity resection

Radiation is as effective as neck dissection in
N0 neck

High incidence of occult metastatic disease

Vandenbrouk et al.,1980 (Cancer 46: 386-90) & Fakih
1989 (Am J Surg 158: 309-13)
NO benefit from elective surgery to the clinically N0 neck

Elective neck irradiation could eradicate > 90%
subclinical ds in neck
Pointon et al., 1990 & Dearnaley et al,. 1991
Elective neck irradiation may prolong survival by
reducing subsequent local recurrent metastatic ds.

Indications for elective neck treatment
Chance of subclinical neck ds > 20- 25 %
Vigilant follow – up not possible
Clinical evaluation of the neck- difficult
Surgery is being performed for access or
reconstruction
Imaging suggests possible occult nodal spread

When the primary tumor is being treated with radiotherapy (eg., T1 lat tongue border/floor of the mouth)
The elective Rx to the neck should be with radiotherapy
to the 1st echelon nodes or whole neck
Where midline extn occurs – Rx should be bilateral

When the primary tumor is being treated with surgery
(eg., larger T2/ T3 lat tongue border)
Surgery should be carried out on the basis that:
It provides further info for clinical staging
Nodes in the area cleared to give access to vessels for
reconstr purposes
Local recurrence rates ↓
Survival enhanced

Van den Berkel et al. (1999), Outcome of observing the
No neck using ultrasonic- guided cytology for follow- up
Arch Otolaryngol Head Neck Surg 125:153-6

After transoral excision follow-up for bw 1-4 yrs using
palpation & US – FNAC
14 pts (18%) had occult node metastases & subsequent
neck failure.
9/14 were detected within 7 mos & of these, 6 were
not palpable
10/14 were successfully salvaged but 4 died
Conclusion: the high salvage rate (71%) indicated that
a strict follow-up using US – FNAC enables early
detection of recurrence in the high- risk No neck &
justifies a policy of wait & watch.

Single palpable mets in one side of the
neck < 3 cm in dia (N1)
Treatment of such nodes: Surgery
All 5 levels may be involved & should be dissected
Therefore, minimum operation that should be
performed: MRND
Unless otherwise indicated, SCM muscle & IJV should
be sacrificed.
Role of radiotherapy- controvercial.
Less efficient than surgery... represents a less
preferred option unless the primary site is also being
treated with radiotherapy.
The classic eg. is Ca nasopharynx

Bilateral & Contralateral Nodes (N2c)
Common primary sites involved: tongue base,
supraglottic larynx & hypopharynx
Prognosis depends on: size, no of nodes & +nce/-nce
of extracapsular spread; rather than pure laterality
Rx often worthwhile – if B/l nodes are either N1/N2a
Post- op radiotherapy
Pts with extensive tongue- base tumor & B/l cervical
lymphadenopathy: inoperable
Pts with B/l nodes where one side is fixed are usually
incurable

Treatment of Contralat N0 Neck in early SCC of
Tongue: Elective Neck Dissection v/s Observation
Young Chang Lim, Laryngoscope, 116:461–465, 2006

ipsilat elective neck management is necessary during
initial treatment of stages I and II for Ca tongue.
study suggests… contralat occult lymph node
metastasis was unlikely in early tongue SCC, and there
was no survival benefit for pts who underwent elective
neck dissection rather than “observation.”
Thus, observation of contral N0 neck for the
treatment of early oral tongue cancer may not be
harmful.

Complications
‘If anything can go wrong, it will.’
Murphy’s law


Classification of complications
Major and minor
Early, intermediate & late
Local & systemic
General & specific


Immediate local complications
Bleeding
Airway obstruction
Incresed intracranial pressure
Carotid sinus syndrome
Nerve injury


Increased intra – cranial pressure
Assoc with IJV ligation
Signs & symptoms:
Restlessness from headache
Slowing of the pulse
A rise in BP
Gross swelling & cyanosis of the face
How to ↓ risk of raised ICP ??
No dressing around the neck
DO NOT allow the pt to hyperextend the neck
Sit the pt up as soon as possible after surgery

Intermediate local complications
Chylous fistula
Seroma
Skull – base syndrome
Wound infection
Failure of skin healing
Carotid artery rupture
Flap failure
Fistula formation


Clinical assessment of flap vitality


Late complications
Recurrence
Primary
Nodal
Distant

Parotid tail hypertrophy
Lymphoedema
Hypertrophic scar
Contractures


Indications for postoperative radiation therapy to
the neck

1.

Gross residual disease following neck dissection

2.

Multiple positive lymph nodes in the neck

3.

Extracapsular extension by metastatic diseae

4.

Perivascular or perineural invasion by tumor

5.

Other ominous findings such as tumor emboli in
lymphatics, cranial nerve invasion, or extension of
disease to the base of the skull.

Conclusion
Thorough knowledge of surgical anatomy & lymphatic
system
Decision of how to manage the neck in cases of SCC of
head & neck region, should be based on a sound &
logical comprehensive treatment plan
Bilat IJV dissection should be avoided
Post – 0p care is also of utmost importace
Radiotherapy, chemotheray or ‘wait & watch’ policy
do have their roles in managing the neck

References
Stell and Maran’s Head and Surgery, 4/ed
Color atlas of operzative techniques in head and neck surgery- Jatin P.
Shah (1990)
Oral Cancer - Jatin P. Shah
Charles W. Cummings, John M. Fredrickson, Lee A. Harker, Charles J.
Krause, David E. Schurller. Neck Dissection. Otolaryngology- Head and
neck surgery. Vol. II, 2nd edition. 1993: 1649-1672.
Ian A. McGregor, Frances M. McGregor. Neck dissection. Cancer of the
face and mouth – Pathology and management for surgeons. Churchill
Livingstone.1986: 282- 320.
Ian T. Jackson. Inrtra oral tumour and cervical lymphadenectomy.
Grabb & Smith’s Plastic Surgery. Sherrel J. Aston, Robert W. Beasley,
Charles H. M. Thorne. 5th edition. Lippincott- Raven . 1997 : 439 –452.


Aydin Acar, Gürsel Dursun, Ömer Aydin,Yücel Akbaş. J incision in
neck dissections. The journal of Laryngology and otology. 1998:
112: 55 - 60.
Susumu Omura, Hiroki Bukawa, Ryoichi Kawabe, Shinjiro Aoki,
Kiyohide Fujita. Comparision between hockey stick and reverse
hockey stick incision: gently curved single linear neck incisions
for oral cancer. Int. J. Oral Maxillofac
Vandenbrouk et al., (Cancer 46: 386-90)


Thank you…

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