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Neck Dissections:Classifications, Indications,

and

Techniques

Dr Kuljinder Sodhi


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INTRODUCTION

Status of the cervical lymph nodes

is important prognostic factor in SCCA of

the upper aerodigestive tract

Cure rates drop in half when there is

regional lymph node involvement


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SURGICAL ANATOMY

Fascial layers ofthe neckSuperficial cervical fascia

Deep cervical fascia

Superficial layer

SCM, strap muscles,trapezius

Middle or Visceral

LayerThyroid,Trachea,esophagus

Deep layer (alsoprevertebral fascia)

Vertebral musclesPhrenic nerve


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Muscles of the neck

Sternocleidomastoid Muscle

medial third of clavicle(clavicular

head), manubrium (sternal head)

Insertionmastoid process

Nerve supplyspinal accessory

Blood supply1) occipital a. or direct from ECA

2) superior thyroid a.

3) transverse cervical a.

Function turns head toward opposite side

and tilts head toward theipsilateral shoulder


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Omohyoid muscle

Originupper border of the scapula

Insertion1) via the intermediate tendon

onto the clavicle and first rib

2) hyoid bone lateral to the sternohyoidmuscle

Blood supplyInferior thyroid a.Function

1) depress the hyoid

2) tense the deep cervical fascia

Surgical considerations

Absent in 10% of individuals

Landmark demarcating level III from IV

Inferior belly lies superficial to Thebrachial plexus, Phrenic nerve,transverse cervical vessels

Superior belly lies superficial to IJV


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TRAPEZIUS

Origin

1) medial 1/3 of the sup. Nuchal line

2) external occipital protuberance

3) ligamentum nuchae

4) spinous process of C7 and T1-T12

Insertion1) lateral 1/3 of the clavicle

2) acromion process

3) spine of the scapula

Functionelevate and rotate the scapula and

stabilize the shoulder Surgical considerations

Posterior limit of Level V neck dissection

Denervation results in shoulder drop and winged scapula


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DIGASTRIC MUSCLE

Origindigastric fossa of the mandible

Insertion

1) hyoid bone via the intermediate tendon

2) mastoid process

Function1) elevate the hyoid bone

2) depress the mandible (assistslateral pterygoid)

Surgical considerations

Residents friend

Posterior belly is superficial to:

ECA, Hypoglossal nerve, ICA, IJV

Anterior bellyLandmark for identification of mylohyoid

for dissection of the submandibulartriangle


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MARGINAL MANDIBULAR NERVE

Should be preserved in

neck dissections

Most commonly injury

dissection level Ib

Can be found:

1cm anterior and inferior

to angle of mandible

Deep to fascia of thesubmandibular gland

Superficial to adventitia of

the facial vein


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SPINAL ACCESSORY N.Originates in the spinal nucleus

Passes through two foramen

Foramen Magnumenters the skullposterior to the vertebral artery

Jugular Foramenexits the skullwith CN IX,X and the IJV

Occipital artery crosses the nerveDescends obliquely in level II

(forms Level IIa and IIb)

Penetrates the deep surface of theSCM Exits posterior surface ofSCM deep to Erbs point

Traverses the posterior triangleensheathed by the superficialcervical fascia and lies on thelevator scapulae

Enters the trapezius approx. 5 cmabove the clavicle


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PHRENIC NERVE

Sole nerve supply to thediaphragm

Supplied by nerve rootsC3-5

Runs obliquely towardmidline on the anteriorsurface of anteriorscalene

Covered by prevertebralfascia

Lies posterior and lateral tothe carotid sheath


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HYPOGLOSSAL N.Motor nerve to the tongue

Cell bodies are in the Hypoglossalnucleus of the Medulla oblongata

Exits the skull via the hypoglossalcanal

Lies deep to the IJV, ICA, CN IX, X,

and XICurves 90 degrees and passes

between the IJV and ICA

Extends upward along hyoglossusmuscle and into the genioglossus

to the tip of the tongue Iatrogenic injury Most common site

- floor of the submandibulartriangle, just deep to the duct


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STAGING OF THE NECK

N classification AJCC (1997)

Consistent for all mucosal sites except the

nasopharynxThyroid and nasopharynx have different

staging based on tumor behavior and

prognosis


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NODAL STAGE

NX: Regional lymph nodes cannot beassessed

N0: No regional lymph nodemetastasis

N1: Metastasis in a single ipsilaterallymph node, < 3

N2a: Metastasis in a single ipsilaterallymph node 3 to 6 cm

N2b: Metastasis in multiple ipsilateral

lymph nodes, none more than 6 cm

N2c: Metastasis in bilateral orcontralateral nodes < 6cm

N3: Metastasis in a lymph node morethan 6 cm in greatest dimension


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LYMPH NODE LEVELS


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Contralateral metastasis is found in the

supraglottis, the base of the tongue, and the

posterior pharyngeal wall palate.

Bilateral metastasis is found in the nasopharynx,the base of the tongue, the soft palate, the floor

of mouth, and the supraglottis.

Multiple cervical metastases (adenocarcinoma)

occur with thyroid carcinoma, breast carcinoma,

and nasopharyngeal carcinoma.


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Nodal metastasis


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Classification of Neck

Dissections

Academys classification

1) Radical neck dissection (RND)

2) Modified radical neck dissection (MRND)3) Selective neck dissection (SND)

Supra-omohyoid type

Lateral typePosterolateral type

Anterior compartment type

4) Extended radical neck dissection


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Medina classification (1989)

Comprehensive neck dissection

Radical neck dissection

Modified radical neck dissection

Type I (XI preserved)

Type II (XI, IJV preserved)

Type III (XI, IJV, and SCM preserved)

Selective neck dissection (previously

described)


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RADICAL NECK DISSECTION

All lymph nodes in Levels

I-V including spinal

accessory nerve (SAN),

SCM, and IJV

Indications

Extensive cervical

involvement or matted

lymph nodes with gross

extracapsular spread andinvasion into the SAN,

IJV, or SCM


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Modified Radical Neck

Dissection (MRND)

Excision of same lymph node bearing

regions as RND with preservation of one

or more nonlymphatic structures (SAN,

SCM, IJV)

Type I: Preservation of SAN

Type II: Preservation of SAN and IJV

Type III: Preservation of SAN, IJV, and

SCM


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TYPE I TYPE II

TYPE III


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MRND Type I

Indications

Clinically obvious lymph node metastases

SAN not involved by tumor

Rationale

RND vs MRND Type I:

Actuarial 5-year survival and neck failure rates

for RND (63% and 12%) not statistically differentcompared to MRND I (71% and 12%)(Andersen)

No difference in pattern of neck failure


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MRND Type II

Indications

Rarely planned

Intraoperative tumor found adherent to theSCM, but not IJV and SAN


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MRND III

Rationale

Suarez (1963) surgery specimens of

larynx and hypopharynxlymph nodes do not share

the same adventitia as adjacent BVs

Sharpe (1981) showed ) 0% involvement of the SCM in

98 RND specimens despite 73 have nodal metastases

Survival approximates MRND Type I assuming IJV,

and SCM not involved

Neck dissection of choice for N0 neck

TYPE


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Selective Neck Dissections

Cervical lymphadenectomy with

preservation of one or more lymph node

groups

Four common subtypes:

Supraomohyoid neck dissection

Posterolateral neck dissection

Lateral neck dissection

Anterior neck dissection


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SND: Supraomohyoid type

Indications

Oral cavity carcinoma with N0 neck

Subsites - Lips, buccal mucosa, upper and lower

alveolar ridges, retromolar trigone, hard palate, and

anterior 2/3s of the tongue and FOM

Medina recommends SOHND with T2-T4NO

or TXN1 (palpable node is


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Bilateral SOHND

Anterior tongue

Oral tongue and

FOM that approach

the midline Adjuvant XRT given

to patients with

> 2positive nodes +/-ECS.

S

N

D:

L

at

e

r

a

l


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SND: Lateral Type

En bloc removal of the

jugular lymph nodes

including Levels II-IV

Indications

N0 neck in

carcinomas of the

oropharynx,hypopharynx, supraglottis, and

larynx


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SND: Posterolateral Type

En bloc excision of lymph bearing tissues in

Levels II-V

Indications

Cutaneous malignancies

Melanoma

Squamous cell carcinoma

Merkel cell carcinoma

Soft tissue sarcomas of the scalp and neck


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SND: Anterior Compartment

En bloc removal of lymph structures in Level VI Perithyroidal nodes

Pretracheal nodes

Precricoid nodes (Delphian)

Paratracheal nodes along recurrent nerves Limits of the dissection are the hyoid

bone,suprasternal notch and carotid sheaths

Indications

Selected cases of thyroid carcinoma

Parathyroid carcinoma Subglottic carcinoma

Laryngeal carcinoma with subglottic extension

CA of the cervical esophagus


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Extended Neck Dissection

Any previous dissection which includes removal of one ormore additional lymph node groups and/or non-lymphaticstructures.

Usually performed with N+ necks in MRND or RNDwhen metastases invade structures usually preserved

Examples:Resection of the hypoglossal nerve, resection ofdigastric muscle, Carotid artery resection,

dissection of mediastinal nodes and central compartmentfor subglottic involvement, and removal ofretropharyngeal lymph nodes for tumors originating inthe pharyngeal walls.


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Incisions


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Apron incision Half apron


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Conleys Double-Y


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H incision Macfee


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Y incision Modified schobinger

Schobinger


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StepsFlap raising

Make the skin incision throughthe platysma and elevate the

flap in the subplatysmal plane.

Traction with the surgeon's

fingers and countertraction by

the assistant with skin hooks

Elevate the posterior flap

toward the trapezius muscle.

Identify and preserve the

marginal mandibular nerve at

the superior aspect of the flap.


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The contents of the submentaltriangle are then elevated fromthe inferior border of the mandibleand the opposite digastric muscleoff of the mylohyoid muscle

Dissection in the proper plane allowsfor an en bloc elevation of thecontents into the submandibulartriangle and to the posterior borderof the mylohyoid muscle.

Retraction of the mylohyoid muscleanteriorly allows for identificationof the submandibular duct, whichis ligated and divided

The dissected contents of sublevelsIA and IB are then elevated overthe digastric muscle in continuitywith the nondissected portion ofthe neck


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The contents dissected from level I areelevated caudally to visualize thesuperior internal jugular vein..

Identification of the SAN can beperformed anterior or posterior to theSCM.

If the SAN can be preserved,dissection is then continued from nearto IJV towards the trapezius muscle,dividing the SCM. If the SCM is goingto be preserved, the SAN must becarefully dissected by identifying thenerve both anterior and posterior tothe SCM.

A posterior to anterior dissection isthen performed beginning at theanterior border of the trapeziusmuscle, preserving the phrenic nerveand the brachial plexus, located deepto this fascia.

The SAN must then be freed from thesoft tissues of the posterior triangleand can be carefully retracted awayfrom the region of dissection with avessel loop or nerve hook. Dissectionis continued to the posterior border ofthe SCM.


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.

At this point, the posterior triangle contents,with or without the SAN and SCM, have beenelevated to the lateral aspect of the IJV. If theSCM is being resected, transection isperformed below the mastoid tip and abovethe clavicle as in a RND.

The nodes along IJV can usually be removeden bloc with the remainder of the dissectionin a posteroanterior fashion, sharply incisingthe fascia of the jugular vein with a scalpelblade using a feather-light touch. If the IJVrequires sacrifice due to metastatic nodalinvolvement or tumor thrombosis, the vein isligated and divided superiorly and inferiorlyfollowing identification and preservation of thevagus nerve.

Dissection is continued anteriorly, elevatingthe fascia and soft tissues up to theinfrahyoid strap muscles and the hyoid-digastric junction.

Preservation of a fascial layer superficial tothe carotid artery is usually possible, andexposure of the carotid artery should bediscouraged unless necessary.

Suction drains are strategically placed and alayered closure is performed.


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Complications Intraop.CxHemorrhage

Nerve damage

Thoracic duct injury

Pneumothorax

Post op. Cx

Hematoma

Wound infection

Skin flap loss

Salivary fistula

Chylous fistula 500 mlFacial edema

Carotid artery rupture


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THANK YOU

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