Introduction
The posterolateral neck dissection is an operation that is typically used in the management of cutaneous cancers of the posterior scalp, auricle, or upper neck. It is done either electively, to stage the clinically node-negative neck, or therapeutically, to treat the node-positive neck. In contemporary practice, this operation is most often used to treat a clinically node-negative neck that has been found to have microscopically positive nodal disease in one or more of the regional nodal basins. The posterolateral neck dissection is an extended neck dissection that is often combined with a comprehensive or selective neck dissection. A description of this operation was first published in 1962. More recently, however, in 1980, Drs. Goepfert, Jesse, and Ballantyne of the M.D. Anderson Cancer Center wrote a definitive description of this procedure and their results with it. Typically this operation involves the removal of the lymph nodes in the postauricular, suboccipital, spinal accessory, and jugular lymph node basins ( Fig. 71.1 ). In experienced hands, this operation provides excellent oncologic, functional, and cosmetic results.
Key Operative Learning Points
- 1.
The spinal accessory nerve must be identified on the anterior and posterior border of the sternocleidomastoid muscle (SCM) and traced in its entirety to prevent inadvertent injury to this structure.
- 2.
During the procedure, fibroadipose node-bearing tissue is removed from the inferolateral portion of the neck where the trapezius and clavicle meet. Extreme caution must be exercised in this region to avoid injury to inferolateral branches of the brachial plexus and the terminal aspect of the spinal accessory nerve.
Preoperative Period
History
- 1.
Personal history of skin cancer: The majority of patients undergoing posterolateral neck dissection have skin cancer as the primary indication for the procedure ( Fig.71.2 ); therefore, a history of prior skin cancers is useful in treatment planning. This includes histologic type, location, and previous treatment (history of surgery or radiation treatment for skin cancer).
Fig. 71.2
Given the location, this scalp melanoma may require posterolateral neck dissection for gross disease or positive sentinel lymph node biopsy.
- 2.
History of sun exposure
- 3.
Family history of skin cancer
- 4.
Occupational history: This operation, when performed without complication, can lead to decreased shoulder function for up to 18 months following surgery. Typically this is manifested by a decreased range of motion and strength on shoulder abduction, which, with intervention by a trained physical therapist, can be improved greatly with anticipated return to baseline.
Physical Examination
- 1.
Skin
- a.
Visual evaluation and palpation of the extent of the primary tumor
- 1)
Include examination of the skin of the head and neck, especially the scalp, and auricle.
- 1)
- a.
- 2.
Neck
- a.
Inspect and palpate the postauricular, suboccipital, spinal accessory, and jugular nodal basins.
- 1)
Note the number and size of each involved node and use as part of the clinical staging.
- 2)
Assess the extent of nodal burden and involvement of regional structures.
- 1)
- a.
- 3.
Nerve function: Evaluate and document preoperative function of the spinal accessory nerve and brachial plexus, because these nerves will be at risk for injury during the dissection.
Imaging
- 1.
Axial computed tomography (CT) scan with contrast
- a.
Define the location and extent of the primary cancer.
- b.
Assess regional lymph node metastases.
- a.
- 2.
Magnetic resonance imaging (MRI) or positron emission tomography (PET)/CT
- a.
Systemic imaging may be indicated based on the histology and clinical stage of the disease.
- 1)
For patients with melanoma or Merkel cell carcinoma with thick primary tumors or extensive lymph node metastasis, a PET/CT and brain MRI or brain MRI with CT scan of the head and neck, chest, and abdomen should be ordered for a complete metastatic evaluation.
- 1)
- a.
Fine-Needle Aspiration Biopsy
- 1.
Fine-needle aspiration (FNA) is indicated for patients found to have palpable lymph node metastasis if the results will change the management of the patient’s problem.
- a.
If the presence of histologically confirmed lymph node metastasis is part of the inclusion criteria for a protocol of neoadjuvant systemic therapy, and FNA should be obtained
- a.
- 2.
Use to confirm or rule out the presence of regional lymph node metastasis to facilitate treatment planning in cases where the finding of lymph node metastasis is indeterminate by cross-sectional imaging criteria.
Indications
- 1.
The treatment of occult and clinically node-positive metastasis to the neck from a cutaneous malignancy involving the skin of the posterior scalp, auricle, and upper neck
- 2.
The treatment of microscopically positive disease in the lymphatic basin after sentinel lymph node biopsy for cutaneous malignancy
Contraindications
- 1.
Disseminated metastases: This operation is contraindicated in patients for whom the procedure would provide neither prolonged survival nor significant palliation.
- 2.
Patients with extensive lymph node metastasis: Those with involvement of the deep muscles of the neck, vertebrae, or carotid artery are advised to consider systemic therapy options that could help to decrease the risk of distant metastatic cancer and potentially make the locoregional disease burden more manageable by resection.
- 3.
Medical comorbidities with increased risk for general anesthesia: Patients deemed to be medically at high risk for general anesthesia who have microscopic lymph node metastasis can be often be managed successfully with radiation therapy alone.
Operative Period
Anesthesia
General
- •
Place the endotracheal tube and secure it at the oral commissure contralateral to the side of the neck that is being dissected.
- •
Use a paralytic agent throughout the procedure. This prevents excess stimulation of motor nerves by electrical dissection. Even in the presence of paralyzing agents, these motor nerves are readily identified by reliable anatomic landmarks and the stimulation provided by electrical dissection.
Positioning
Supine
- •
Place the patient in the supine position with the ipsilateral upper extremity tucked at the patient’s side and the operating table turned at a 90-degree angle such that the side of the dissection is facing out.
- •
Place a roll under the patient’s shoulders to extend the neck and turn the head toward the anesthesiologist.
- •
When bilateral posterolateral neck dissection is performed, consider placing the patient in the prone position. This occurred in only 3 of 55 patients reported in a large series, making this a rare position for this operation.
Perioperative Antibiotic Prophylaxis
First-generation cephalosporin
Monitoring
None necessary
Instruments and Equipment to Have Available
- 1.
Major head and neck soft tissue set
- 2.
Bipolar electrocautery
- 3.
Two half-inch Penrose drains to be used for retraction
Key Anatomic Landmarks
- 1.
Erb’s point (punctum nervosum): Located on the posterior border of the SCM midway between its attachments to the mastoid process, sternum, and clavicle. Cutaneous branches of the cervical plexus (C5 and C6 roots) emerge at Erb’s point from behind the posterior border of the SCM. The four cutaneous nerves of the cervical plexus are the lesser occipital nerve, great auricular nerve, transverse cervical nerve, and supraclavicular nerve. The spinal accessory nerve exits the SCM muscle approximately 1 cm superior to Erb’s point.
- 2.
The spinal accessory nerve: After exiting the skull base, it most often passes anteriorly to the jugular vein and enters, and innervates, the SCM and exits the SCM at the posterior margin of the muscle. It then courses inferolaterally through the posterior triangle and passes under the trapezius muscle that it innervates.
- 3.
Trapezius muscle: The upper fibers of the trapezius originate from the spinous processes of C1 to C7, the external occipital protuberance, the medial third of the superior nuchal line of the occipital bone, and the ligamentum nuchae. Inferiorly the fibers travel downward and laterally and insert into the posterior border of the lateral third of the clavicle.
Prerequisite Skills
- •
Neck dissection levels 1 through 5
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Selective neck dissection
- •
Radical neck dissection
- •
Posterolateral neck anatomy
Operative Risks
- 1.
Nerve injury: Significant risk to the accessory nerve. Other nerves are at risk, including the brachial plexus and phrenic nerve.
- 2.
Possible disinsertion of the SCM muscle from the mastoid during dissection
- 3.
Chylous fistula
- 4.
Superficial loss of the most distal (superior) aspects of the skin flap
Surgical Technique
- •
Draping:
- •
Neck, shoulder, and upper chest are sterilely prepped.
- •
Using towels, square off the operative field, including exposure of the posterior neck to the nuchal line, the clavicle, the anterior neck to the midline, and the superior aspect of the auricle.
- •
The ear or scalp should be included in the operative field based on the location of the primary.
- •
- •
Incision
- •
The incision is designed to provide optimal visual access to facilitate the removal of all the nodal groups to be dissected while preserving vital structures and cosmesis.
- •
The location of the primary tumor and incisions used for prior procedures such as a lymph node biopsy may dictate the design of the incision.
- •
I prefer an S -shaped incision in which a horizontal limb is oriented along the occiput from the midline to the postauricular region, where it then descends vertically just anterior to the anterior border of the trapezius to a lower cervical skin crease, which the incision should follow horizontally anterior to the anterior border of the SCM ( Fig.71.3 ).
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