Neck Dissection - Level 2-4

Considerations

• • Anatomy

    • C1 vs C2 transverse process and SAN

      • • 1997: Transverse process of the atlas (C1)--an important surgical landmark of the upper neck

          • The transverse process of the atlas is an important surgical landmark for the neurovascular bundle (spinal accessory nerve), which is located anteriorly

  • Marginal mandibular nerve (MMN)

    • See section on identifying and preserving the MMN from the SMG excision page

    • YouTube (5:23): Lateral dissection of the neck cadaver, excellent display of external carotid artery system

  • YouTube (14:23): Anatomical dissection - Superficial neck by Dr. Snow (USC anatomist)

  • YouTube (15:12): Anatomical dissection - Deep neck by Dr. Snow (USC anatomist)

• Types and terminology

  • 1991 Selective Neck Dissection classification

    • supraomohyoid neck dissection (levels I, II, III)

    • lateral neck dissection (levels II, III, IV)

    • anterior compartment neck dissection (VI)

    • posterolateral neck dissection (levels II, III, IV, V)

  • 2002 revised classification omits the descriptive name and includes only the levels removed 

  • "Extended" neck dissection refers to any additional lymph node groups or non-lymphatic structures, which should be listed in parenthesis 

• Indications for levels

  • Oral cavity primary with N0-1 neck metastasis 

    • Levels I, II, and III

    • Some advocate adding level IV

    • Some advocate including level IIB only if level IIA contains gross disease 

  • Oropharyngeal, hypopharyngeal, or laryngeal primary

    • Levels II, III, and IV

    • Some advocate including level IIB only if level IIA contains gross disease 

  • Primary involving midline structure of the lower anterior neck - thyroid gland, hypopharynx, cervical trachea, cervical esophagus, and subglottic larynx

    • Level VI

  • Cutaneous primary involving posterior scalp and / or upper posterolateral neck

    • Levels II, III, IV, and V including subocciptal and postauricular nodes 

  • Cutaneous primary involving preauricular, anterior scalp, or temporal region

    • Levels II, III, and Va including parotid and facial nodes

• Incisions

  • Single transverse in natural crease 

  • Hockey stick 

Preparation

• • Mark the incision

  • Infiltrate with local vasoconstriction agent 

    • Dr. Fong - 1:100,000 Epinephrine

  • Place nerve monitoring electrodes (Dr. Fong)

    • Dr. G and Dr. W do NOT use the NIM

  • Sterile prep and drape 

Procedure

• • Unilateral hockey stick incision vs bilateral apron incision (Guru/Wang)

  • Dr. Fong prefers straight linear incision along a neck crease

  • Ensure incision is two finger breadths below the lower border of mandible

• Hash mark

• Raise subplatysmal flaps

  • KEY: watch out for the MMN

    • Fong technique to ID and preserve the MMN

      • Be wary within the 1 cm radius, anterior and inferior to the angle of the mandible, for the MMN usually lies here and is easy to miss given its small caliber

      • Beginning at the level of the inferior edge of the SMG, dissect anteriorly through the fascia just anterior to the EJV toward the SMG layer by layer remembering the old adage "only cut what you can see through" 

        • Avoid spreading; Simply let your fine dissector glide through the tissue, inspect the fascia, divide with bipolar 

        • If you suspect the MMN lies between your tines, gently squeeze with the bipolar forceps or apply the nerve stimulator probe

  • Posteriorly, no longer platysma. Therefore keep dissection just superficial to the EJ vein and GAN

• ID greater auricular nerve and external jugular vein, which help guide plane of dissection

• ID the lower border of the submandibular gland to help you identify the posterior belly of the digastric

• Follow the posterior belly to the SCM towards the mastoid

  • The digastric is your friend; Nothing to hurt if you stay along the digastric

• Incise SCM fascia just anterior to the EJ vein

  • Then "unwrap" fascia anteriorly to the SAN (cephalic landmark) and to the level of the omohyoid (caudal landmark)

  • You will see the SCM branch of the occipital artery just superficial to the SAN

  • Also, C1/2 transverse process will be palpable at level of SAN (Depending on the attending, they will say C1 or C2)

    • Dr. Wang: C1

    • Drs. Guru/Fong: C2

• Follow the SAN to the IJ

  • 90% of time, SAN will be superficial to the IJ, but be careful not to perforate IJ since there are times when SAN is deep to the IJ

• Identify hypoglossal nerve

  • typically comes out between IJ and carotid

• Now should do level IIa/b then you can relieve the person retracting at the head of the bed

• Level IIb

  • Skeletonize the SAN

  • Wang - use Bovie to excise fibrofatty tissue from the deep cervical muscles

    • use dissection when you get close to SAN

    • Then use Allis clamp and sweep the tissue under the SAN

  • Fong - use Shaw blade

    • Bluntly dissect with the tonsil at the lateral border of the IJ to the floor 

    • Sharply dissect with the Shaw blade at the medial border of the SCM starting at the superior edge of the SAN where it enters the deep surface of the SCM until you join the dissected pocket lateral to the IJ superiorly 

      • Sharply excise the fibrofatty tissue with the Shaw off the floor until you are able to pass the specimen under the SAN 

• Level IIa

  • With level IIb (if you did it), dissect away from the posterior belly, IJ, SAN, and hypoglossal nerve

  • When adequately away and you do not need a retractor at head of bed, you can start dissecting the fascia from the floor of the neck

• Level III-IV

  • Continue to unwrap the fascia of the SCM to the posterior border of the SCM

  • Skeletonize the cephalic edge of the omohyoid

    • Do level IV

      • Use tonsil clamp and bluntly dissect free level IV starting from IJ , then come across at the level of the clavicles

        • Should see transverse cervical artery / vein, possibly phrenic nerve

        • On the left side, you may see thoracic duct, ligate this with clips

  • Then finish your level III

  • Do not continue past the posterior border of the SCM unless you identify the posterior emerging SAN

  • Identify cervical rootlets, then start coming forward along the floor of the neck staying at the level of the cervical rootlets

  • Dissect to the carotid, sharply dissect at areas of tension

    • You'll see phrenic inferiorly coursing lateral to medial on the anterior scalene muscles

    • Identify the vagus nerve within the carotid sheath between the great vessels

  • "Unwrap" the specimen off the carotid sheath and carry anteriorly

    • Superficially, you should see ansa cervicalis 

  • Carry forward to the lateral border of strap muscles

  • Excise the specimen while keeping it oriented 

• Label the specimen

  • Dr. Fong, divide the specimen into anatomic levels and send each level as a separate specimen

• Valsalva to check for chyle leaks and / or bleeding

• Irrigation, warm saline or water 

• 10 french flat drains, closed suction; 10 Blake (round) closed fully fluted suction drain (Dr. Fong)

  • Trim the drain and the length of the tubing

  • Secure with 2-0 Silk (Wang), 2-0 Nylon (Fong, Guru)

    • Tie an air knot at the skin directly beneath where the white internal drain connects to the external plastic tubing

    • Then tie a surgeon's knot around the external plastic tubing where it connects the white internal drain

• Layered closure

  • 2 layers (Dr. Fong, Guru)

    • 3-0 Polysorb platysma and deep dermis 

    • 5-0 Biosin subcuticular running (Dr. Fong); 5-0 Fast gut simple running (Dr. Guru)

  • 3 layers (Dr. Wang)

    • 3-0 Polysorb platysma

    • 4-0 Polysorb deep dermis 

    • 5-0 Fast gut simple running 

• Dressing 

  • • Dr. Fong: Mastisol / Benzoin, steri-strips in parallel with the incision, Telfa or folded gauze, Tegaderm 

    • Dr. Wang: Bacitracin alone

Sample operative report

An incision was planned from the submental area down into a low transverse skin crease and then back to the post auricular area near the mastoid process to include the old scar. A total of 7 ml of epinephrine 1:100,000 solution was then infiltrated into the proposed incision line. The neck was then prepped and draped in standard fashion.

The skin was then incised through skin and subcutaneous tissue and platysma muscle. A subplatysmal flap was then raised a superiorly to expose level 2. The inferior edge of the submandibular gland was identified and the fascia overlying the gland was then elevated off of the gland. The flap was then elevated to the inferior aspect of the mandible. The marginal branch of the facial nerve was preserved. The soft tissue posterior and inferior to the gland was dissected away from the gland and the posterior belly of the digastric muscle. The posterior belly of the digastric was then traced posteriorly and the spinal accessory nerve was identified running over the internal jugular vein at the level of C2 transverse process.

An inferior skin/subplatysmal flap was then raised down to the level of the clavicle. The fascia overlying the sternocleidomastoid muscle was then divided with a 15 blade, and the fascia was then dissected off the anterior and medial aspects of the muscle. The spinal accessory nerve was identified superiorly in the anterior muscle and traced superiorly toward the IJV. The hypoglossal nerve was also dissected out and away, dissected toward the skull base as well. The dissection of the SCM away from the soft tissue continued until approximately 3-4 cm of soft tissue were exposed posterior to the posterior aspect of the internal jugular vein. The spinal accessory nerve was freed up from its surrounding soft tissue attachments so that it was freely mobile, and the level 2B area was then dissected away from the sternocleidomastoid muscle and the deep floor of the neck fascia, and the fat and lymph nodes were then located under the nerve and onto the internal jugular vein. The fat and soft tissue were then divided from superiorly to inferiorly 3-4 cm posterior to the posterior edge of the internal jugular vein. The cervical plexus rootlets were identified and preserved. The omohyoid muscle was retracted inferiorly and the soft tissue in level IV was mobilized and brought superiorly. The transverse cervical artery and vein were identified and preserved, and the specimen was then rotated onto the carotid sheath contents. The specimen was then dissected away from the internal jugular vein, the common carotid artery, vagus nerve, and internal jugular vein, and the specimen was rotated medially so that the final attachments to the strap muscle fascia was then divided and specimen was removed. The phrenic nerve was identified and preserved. The specimen was then divided in levels 2, 3, and 4.

The wound was then inspected for hemostasis. No bleeding was encountered. No evidence of leak from an accessory duct/thoracic duct was identified with Valsalva maneuver. The wound was then Irrigated with copious amounts of Bacitracin irrigation. A round Blake drain was then placed into the wound deep in the posterior triangle and then brought out through the anterior triangle superiorly. The drain was secured to the skin using 3-0 Nylon. The skin flaps were then reapproximated. The incision was closed in two layers; The subcutaneous layer was closed using buried 3-0 Polysorb. The skin was closed using subcuticular running 5-0 Biosyn. The wound was then dressed with steri-strips, Mastisol, gauze, and Tegaderm.

The patient was returned to the anesthesiologist for further management and was subsequently transferred to PAR in stable condition. Final needle and sponge counts were correct. No complications were encountered.

Post-op

• • CPT codes 

    • 38724 - Cervical lymphadenectomy (modified radical neck dissection)

    • 37600 - Ligation; external carotid artery

  • Wound care

    • If present, remove outer dressing in 2 days 

    • Apply Bacitracin until sutures removed / skin healed 

    • Avoid direct water until 2 days after drains removed 

    • Drain removal permitted once output appears appropriate (serous) with appropriate volume (down-trending, less than 30 ml / 24 hours) 

  • Medications

    • Analgesic 

    • Colace 

    • Bacitracin 

  • Follow up

    • RTC ~ POD 5 for wound check and drain removal 

    • RTC ~ POD 14 for repeat wound check

  • Complications 

    • SAN injury

    • 2005: Shoulder disability after different selective neck dissections (levels II-IV versus levels II-V): a comparative study

      • • Dissection of level 5 increases shoulder morbidity

    • 2007: The spinal accessory nerve in head and neck surgery

      • • Subclinical spinal accessory nerve impairment can be observed even after selective neck dissections (levels II-IV) due to routine clearance of sublevel IIB

  • Chyle leak (see full page for more details)

• • • • Octreotide SQ 100 ug TID 

      • Low fat diet 

      • Regular diet challenge 

      • Do not remove drain until clearly no chyle

Pearls & Pitfalls

• • Pitfalls

    • Neck incision too small

    • Violate the deep cervical fascia, ending up deep to the carotid (and other vitals structures - phrenic, brachial plexus) 

    • Nerve hook on the SAN

    • Injure the IJV at its superior or inferior aspects 

  • Pearls

    • Level 4

      • Stay above the deep plane of the deep cervical fascia (stay gray, avoid red); The John Connolly technique involves a finger sweep anterior to the anterior scalene muscle and ligation of a large bulk of tissue 

High-Yield

• • What is the blood supply to the SCM? 

    • Upper --> Occipital a. (see SCM branch of the occiptal a.) 

    • Middle --> STA, ECA, or both

    • Lower --> Suprascapular a. 

Links

• YouTube (15:39): Surgical Pearls for Neck Dissection – Management of the N0 Neck

  • YouTube Level 2-5 SND from Dr. Chaplin, New Zealand with narration 

  • YouTube Level 2-4 SND high quality video with text but no narration 

• eMedicine article: Neck Dissection Classification

• eMedicine artticle: Management of the N0 Neck