Plate 189

There are two major indications for radical neck dissection. The first is for the removal of palpable metastatic cervical lymph nodes, and the second is for the removal of presumed occult metastatic disease in the neck. The latter indication has been termed “prophylactic neck dissection.” “Elective neck dissection” better describes this operation, since it is not intended to prevent metastasis but to remove occult metastatic lymph nodes.

Before radical neck dissection is performed, the surgeon must have assurance that the primary lesion can be controlled either by simultaneous en bloc removal with the radical neck dissection or by radiation therapy. However, curative radiation for cervical metastases must be confined to a single node or small group of nodes, because patients cannot tolerate radical surgery plus radiation therapy to the entire neck. Node fixation, invasion of adjacent tissues, bilateral or contralateral, and distant metastases are relative contraindications to this procedure. In general, radical dissection of the cervical lymph nodes in a patient who is a reasonable surgical risk remains the preferred treatment for metastatic disease of the neck.

The usual patient with metastatic cancer in the neck from an unknown primary source should be treated as if the primary tumor were controlled. If surgical treatment of the cervical metastasis is deferred until the primary neoplasm becomes obvious, the opportunity to control the neck disease is sometimes lost.

The patient's general medical status should be assessed and corrective measures instituted for any treatable abnormalities. Intraoral ulcerations represent a potential source of pathogenic material. The liberal preoperative use of nonirritating solutions (e.g., diluted hydrogen peroxide) can significantly reduce the danger of postoperative infection.

Only rarely will primary cancers of the hypopharynx, cervical esophagus, larynx, and so forth produce respiratory obstruction or interference with alimentation significantly enough to require preoperative tracheostomy or insertion of a feeding tube.

The major consideration is a free airway. The equipment should allow free movement of the head and easy access to the endotracheal tube.

The choice of anesthetic agents varies. Consideration must be given to the individual needs of the patient and to the need for cautery. General endotracheal anesthesia is preferred.

Complications at surgery are the carotid sinus syndrome, pneumothorax, and air embolus. The carotid sinus syndrome, consisting of hypotension, bradycardia, and cardiac irregularity, can usually be corrected by infiltrating the carotid sinus with a local anesthetic agent. Intravenous atropine sulfate will usually control the syndrome if the local anesthetic fails. Pneumothorax may result from injury of the apical pleura. It is treated with a closed-tube thoracostomy through the second intercostal space anteriorly.

The patient is placed in a dorsal recumbent position. The head of the table is somewhat elevated to lessen the blood pressure, particularly the venous pressure, in the head and neck and thus reduce blood loss. The bend of the neck should be placed on the hinge of the headpiece so that the head may be either flexed or extended as needed. A small sandbag should be placed under the shoulders so that the head and neck are extended while the chin remains on a plane horizontal with the shoulders.

The patient's hair should be completely covered by a snug gauze cap to avoid contamination of the operative field. Once the patient has been correctly positioned on the table, the skin is prepared routinely. The preparation should include a large portion of the face on the side of the dissection, the neck from the midline posteriorly to the sternocleidomastoid muscle of the opposite side of the neck, and the anterior chest wall down to the nipple. The entire field of dissection is outlined with sterile towels secured by either skin staples or sutures. A large sheet about the head and neck area completes the draping.

Radical neck dissection is described and illustrated. Radical neck dissection refers to the removal of all ipsilateral cervical lymph node groups extending from the inferior border of the mandible superiorly to the clavicle inferiorly and from the lateral border of the sternohyoid muscle, hyoid bone, and contralateral anterior belly of the digastric muscle anteriorly to the anterior border of the trapezius muscle posteriorly. Today most surgeons employ a modified radical neck dissection or functional neck dissection.

Modified radical neck dissection is defined as the excision of all lymph nodes routinely removed in a radical neck dissection with preservation of one or more nonlymphatic structures (spinal accesory nerve, internal jugular vein, and strenocleidomastoid muscle).

The surgeon stands on the side of the proposed dissection. Many types of incision have been used. The incision illustrated allows maximum anatomic visualization, whereas many surgeons prefer two nearly parallel, oblique incisions with an intervening skin bridge that is broadly based at both ends. The most useful incision is a modification of the double trifurcate incision (Figure 1), in which the angles of the skin flaps are obtuse and connected by a short vertical incision. Some prefer to make only the upper transverse incision with a single vertical extension that proceeds to the sternocleidomastoid muscle edge and then takes a lazy-S posterior course to the clavicle, as shown by the dashed line in Figure 1. The upper arm of the double Y extends from the mastoid process to just below the midline of the mandible. The lower arm extends from the trapezius in a gentle curve to the midline of the neck. This incision allows the greatest exposure of the neck area while producing a good cosmetic result. Creation of the skin flaps includes the platysma muscle (Figure 2). In most instances, if the skin flaps are developed without inclusion of the platysma muscle, poor wound healing and uncomfortable scarring with fixation of the skin to the deep neck structures will result. The two lateral skin flaps are turned back, the posterior flap is extended as far as the anterior edge of the trapezius muscle, and the anterolateral flap is extended to expose the strap muscles covering the thyroid gland. In developing the superior skin flap, care must be taken to preserve the mandibular marginal branch of the facial nerve (Figure 2). This branch of the facial nerve innervates the lower lip. In the majority of cases the nerve can be identified as it crosses over the external maxillary artery and the anterior facial vein beneath the platysma muscle. Usually, it lies parallel to the lower border of the mandible. Occasionally, the nerve will lie much higher, and it may not be visualized during the neck dissection. As suggested by others, a useful maneuver to preserve this nerve is to identify the external maxillary artery and the anterior facial vein at least 1 cm below the lower border of the mandible (Figure 2). After identification, the nerve is retracted and covered by securing the upper end of the vascular stump to the platysma muscle. If obvious or strongly suspected tumor is present in this area, the branches of this nerve are sacrificed voluntarily. The inferior skin flap should be reflected down to expose the superior aspect of the clavicle.

Once the four skin flaps have been created, the inferior limits are outlined. The sternocleidomastoid muscle is severed just above its insertion into the clavicle and the sternum (Figure 3). The dissection is then shifted to the posterior cervical triangle. Using both sharp and blunt dissection, the surgeon exposes the anterior border of the trapezius muscle (Figure 4).

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