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Posterolateral Neck Dissection

last modified on: Tue, 01/09/2024 - 16:31

See also: Case Example Posterolateral Neck Dissection; Case example 2 Posterolateral Neck Dissection; Posterolateral neck dissection variant of trapezius innervation

Return to: Cervical Lymphadenectomy- General Considerations; Selective Neck Dissection; Radical Neck Dissection and Minor Modifications; Sentinel Lymph Node Biopsy

GENERAL CONSIDERATIONS

  1. Historical perspective - in addition to treatment of clinically apparent metastases, before use of sentinel lymph node biopsy: 
    1. Elective treatment of the N0 neck at significant risk for regional metastasis due to primary malignant skin tumors located posterior to a coronal plane through the external auditory canals
    2. Elective lymphadenectomy (for cN0 disease) for melanoma has been supplanted by sentinel lymph node biopsy
  2. Contemporary indications
    1. Treatment of N+ neck disease in the posterior neck
      1. Most commonly due to primary malignant skin tumors located posterior to a coronal plane through the external auditory canals
      2. Expanded use of SLN bx has altered the stage distribution of melanoma - most N+ disease is now identified by a SLN bx rather than clinical exam.
  3. Contraindications
    1. Extensive disease by clinical or radiographic evaluation (ie, involvement of deep neck muscles, carotid artery, vertebrae)
    2. Disseminated disease
  4. Rationale for Posterolateral Neck Dissection
    1. Lesions of the posterior scalp and pinna drain lymphatic fluid into two main groups
      1. Suboccipital lymph nodes: three subgroups
        1. Superficial occipital nodes: located close to cutaneous branch of the occipital artery and greater occipital nerve at the insertion of the trapezius muscle to the superior nuchal line
        2. Deep occipital nodes: located beneath the superficial layer of the deep cervical fascia
        3. One lymph node found along the splenius segment of the occipital artery
      2. Retroauricular lymph nodes
        1. Located on or behind the mastoid process
    2. These lymph nodes are not typically included in the standard radical or modified radical neck dissection
    3. Suboccipital and retroauricular lymph nodes drain primarily into the spinal accessory lymph node chain and secondarily into Level II

PREOPERATIVE PREPARATION

  1. Additional Preoperative Evaluations
    1. CT scan of neck
  2. Consent Inclusions
    1. Similar to modified radical neck dissection (see Radical neck dissection protocol)
    2. Potential paresthesia or anesthesia of the scalp 
    3. A study out of MD Anderson reviewed 49 posterolateral neck dissections (the majority of which were performed for melanoma) noting a 29% rate of complications including wound dehiscence/infection, seroma, partial flap necrosis, hematoma, or cellulitis, all of which responded to conservative therapy, and none of which were life threatening.  Of 44 patients in whom the nerve was not intentionally sacrificed, only 2 (4%) were reported with measurable or subjective postoperative CN XI weakness.

NURSING CONSIDERATIONS

  1. Same as modified radical neck dissection (see Radical neck dissection protocol) except
    1. Vacuum beanbag is placed on the operating table prior to patient transfer.  
    2. Patient positioned in lateral position after intubation. Consider placement of an axillary roll in the contralateral axillary area if needed with care to attend to potential pressure points.
    3. Mayfield headrest supports head.  See example of positioning for unilateral dissection: Case Example Posterolateral Neck Dissection
    4. If bilateral posterolateral neck dissections are required, the patient is placed in the prone position.
    5. Preparation with 10% providone iodine should include the primary site, entire posterior neck, ipsilateral neck and shoulder, and upper back.

ANESTHESIA CONSIDERATIONS

  1. Same as modified radical neck dissection (see Radical neck dissection protocol) except: endotracheal tube must be secured well to prevent accidental extubation during position changes. Access to the tube may be limited during the procedure if it is brought out of the mouth opposite the side of the dissection. We therefore now most commonly have the oral tube come out the right side of the mouth when a right sided dissection (left side down) procedure is done.

OPERATIVE PROCEDURE

  1. Pertinent Anatomy
    1. Identify the pinna, posterior midline of neck, clavicle, and posterior border of sternocleidomastoid muscle.
    2. Due to potential loss of perspective once the patient is positioned and draped, we have found it useful to place a 2-0 silk suture at the midline posterior neck before draping to maintain orientation to the posterior midline.
  2. Incisions
    1. For unilateral dissections, a vertical limb originating from the primary resection site is designed midway between the posterior midline and mastoid. The incision is then carried into the lateral and, if needed, the anterior neck via a cervical skin crease.
    2. For bilateral dissections, an inverted U-shaped flap is designed to incorporate the primary resection site. The descending limbs can be brought into the anterolateral neck as needed.
  3. Skin Flap Elevation
    1. Thin subcutaneous flaps are elevated. Care is taken to preserve the hair follicles of the scalp.
    2. Limits of elevation
      1. Superior limit is inferior nuchal line
      2. Inferior limit may be the clavicle - the value in dissecting lower level V and level IV may be questioned (see Diaz et al 1996)
      3. Anterior limit is posterior border of SCM muscle, postauricular sulcus
      4. Posterior limit is posterior midline of the neck
  4. Dissection
    1. Insertion of the trapezius muscle is separated from the nuchal line and C1-4.
    2. The superficial occipital node-bearing tissue can be dissected off the underlying splenius capitus muscle. The cutaneous branch of the occipital artery is ligated as it passes through the fascia of the splenius capitus muscle. Note that suboccipital nodes lie along the occipital artery as it courses across the skull base after exiting under the splenius capitus. see Case example 2 Posterolateral Neck Dissection: The splenius capitus muscle is may be retracted anteriorly to track the occipital artery to remove underlying nodes. We have not routinely found this reported step to be useful in identifying additional nodes; we have also not seen any additional morbidity from this step in the procedure. 
    3. The retroauricular node-bearing tissue is dissected away from the mastoid and over the superior portion of the SCM muscle.
    4. The posterior aspect of the SCM muscle is identified and defined. The spinal accessory nerve is identified exiting the SCM muscle approximately 1 cm superior to Erb's point. The SCM muscle is retracted anteriorly allowing identification of the entrance of the spinal accessory nerve into the SCM muscle and the internal jugular vein. The spinal accessory nerve is followed from the SCM muscle to the trapezius. If adherent to nodal disease, the nerve is sacrificed and removed.
    5. The remaining soft tissue between the trapezius, posterior border of the SCM muscle, and clavicle is removed as in a radical or modified radical neck dissection. The superior portion of the trapezius is resected at the C4 level and removed with the specimen.
    6. The specimen is inspected, labeled, and divided into lymph node groups. Individual lymph node groups are sent separately to pathology.
  5. Closure
    1. Skin flaps are closed in two layers
      1. Subcutaneous layer with 3-0 vicryl
      2. Skin with surgical clips, 4-0 or 5-0 nylon
  6. Drains
    1. At least two fully perforated, 10 mm Jackson-Pratt drains are placed
      1. Along the posterior midline into the occipital area
      2. Anteriorly under the SCM muscle into Level II
      3. Drains are attached to Varidyne pumps set for continuous suction at 125 cm H2O. Suction is initiated immediately following drain placement to prevent clotting of the drain.
  7. Dressing
    1. Bacitracin ointment to skin incision

POSTOPERATIVE CARE

  1. Same as for modified radical neck dissection (see Modified Radical neck dissection protocol)
  2. If the spinal accessory nerve is sacrificed, postoperative shoulder physical therapy is initiated on postoperative day 3 to reduce the likelihood of developing adhesive capsulitis

REFERENCES

de Langen AJ, Vermey A. Posterolateral neck dissection. Head Neck. 1988;10:252-256.

Goepfert H, Jesse RH, Ballantyne AJ. Posterolateral neck dissection. Arch Otolaryngol. 1980;106:618-620.

Rochlin DB. Posterolateral neck dissection for malignant neoplasms. Surg Gynecol Obstet. 1962;115:369-373.

Diaz EM Jr, Austin JR, Burke LI, Goepfert H.  The posterolateral neck dissection. Technique and results.Arch Otolaryngol Head Neck Surg. 1996 May;122(5):477-80.

Robbins KT, Samant S and Ronen O: Chapter 121 "Neck Dissection" in Cummings Otolaryngology Head & Neck Surgery pp. 1718-1719 (posterolateral neck dissection) 2010 Mosby Elsevier Philadelphia