Atlas of General Surgical Techniques (Courtney M. Townsend Jr., B. Mark Evers)

STEP 5: PEARLS AND PITFALLS

Posterior belly of the digastric muscle is considered the “resident’s friend”; there are no important structures lateral to it, and the contents of the carotid sheath are deep to it. This is a very important landmark.

The omohyoid muscle lies lateral to the carotid sheath, brachial plexus, and phrenic nerve. It is also considered the “resident’s friend” and is a very important landmark.

The skin flaps in a previously irradiated patient should be raised sharply, or a Shaw knife should be used to decrease chance of skin necrosis.

The marginal mandibular nerve is most commonly injured where it courses near the angle of the mandible.

If there is a question intraoperatively as to whether the tumor can be dissected off of the carotid artery, proximal and distal control of the vessel should be obtained and vessel loops placed before dissection of the area in question.

INTRAOPERATIVE COMPLICATIONS

“Button hole” of posterior skin flap

Injury to brachial plexus (sensory and motor deficits in upper extremity) and cranial nerves: marginal mandibular (weakness in lower lip), hypoglossal (weakness/atrophy hemitongue), vagus (aspiration, dysphonia), phrenic (elevated hemidiaphragm, respiratory compromise), and spinal accessory (shoulder droop, chronic pain)

Injury to cervical sympathetic chain (Horner syndrome)

Chyle leak: If this occurs, the thoracic duct is ligated and fibrin glue and Gelfoam are placed over the repair. Loupe magnification is helpful in this situation.

Laceration of the IJV: Small laceration of the vein can typically be repaired with a vascular suture of 6-0 nylon. If the laceration is too large to repair, the vein is sacrificed. This causes a problem in the case of bilateral neck dissections only if the contralateral IJV must be sacrificed because of tumor. If laceration of the vein occurs at the skull base, bleeding can be stopped by packing the area with Gelfoam and applying pressure or suturing the stump to the digastric muscle. If laceration occurs near the thoracic inlet, the assistance of a thoracic surgeon may be necessary to control the bleeding, and an air embolus may occur.

Injury to the subclavian vein

Air embolus through open cervical veins is rare (“gurgle” heard via precordial stethoscope and blood pressure drops). If this occurs, the patient is immediately placed in the left lateral position and the central line is aspirated. If a central line is not present, one should be immediately placed. If there is no time, direct left ventricular puncture should be attempted.

SELECTED REFERENCES

1. Eibling DE: Neck dissections. In Myers EN (ed): Operative Otolaryngology Head and Neck Surgery. Philadelphia, Saunders, 1997, pp 676-718.

2. Peters GE, Price JC, Johns ME: Cervical lymphadenectomy. In Johns ME, Price JC, Mattox DE (eds): Atlas of Head and Neck Surgery. Philadelphia, BC Decker, 1990, pp 378-411.

3. Crile G: Excision of cancer of the head and neck with special reference to the plan of dissection based on 132 operations. JAMA 1906; 47:1780.

4. Head and neck sites. In Greene FL, Page DL, Fleming ID, et al (eds): AJCC Cancer Staging Manual, 6th ed. New York, Springer, 2002, pp 17-22.

5. Martin H, Del VB, Ehrlich H, Cahan WG: Neck dissection. Cancer 1951; 4:441.

C H A P T E R 3

PARATHYROIDECTOMY

B. Mark Evers

STEP 1: SURGICAL ANATOMY

A comprehensive understanding of the anatomy of the neck is critical (see Figure 1-1). In addition, a thorough knowledge of the embryology and development of the parathyroid glands is important to understand where in the neck or mediastinum the parathyroid gland may lie, based on normal embryologic descent of the superior and inferior glands.

Whereas bilateral neck explorations are still being performed for hyperparathyroidism, more endocrine surgeons are choosing to localize the abnormal gland before surgery as a result of improvements in imaging techniques over the past decade. Several noninvasive preoperative localization modalities are available including Technetium-99m sestamibi scintigraphy, ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and most recently, four-dimensional CT and positron emission tomography. These studies have been used with great success for parathyroid localization preoperatively. This allows for more directed operation and a smaller incision. Figure 3-1 illustrates an abnormally enlarged right inferior parathyroid gland.

FIGURE 3–1

42

STEP 2: PREOPERATIVE CONSIDERATIONS

Criteria for surgical referral, as noted by the National Institutes of Health workshop in 2002, include: serum calcium concentration greater than 1 mg/dL above the upper limits of normal, 24-hour urinary calcium greater than 400 mg, creatinine clearance reduced by greater than 30% in comparison with age-matched subjects, bone density greater than

2 standard deviations below peak bone mass, all individuals with hyperparathyroidism and age younger than 50 years, and patients for whom medical surveillance is either undesirable or impossible. In addition, all patients who are symptomatic from their hypercalcemia should be referred for surgical management.

Preoperative localization is imperative before primary exploration if unilateral exploration is desired. As noted previously, this can be accomplished by one of several noninvasive techniques.

STEP 3: OPERATIVE STEPS

1. INCISION

Proper positioning of the patient is critical for adequate exposure. This is normally accomplished by hyperextension of the neck using a rolled sheet between the shoulder blades. The head is supported with a foam rubber doughnut-shaped ring. In addition, the patient is usually placed in the semierect (semi-Fowler) position (Figure 3-2).

Incision

FIGURE 3–2

MC

If unilateral dissection is planned, the incision can be smaller than required for bilateral exploration. The incision extends through the subcutaneous tissue, and the platysma muscle is divided using electrocautery (Figure 3-3). Flaps are then mobilized superiorly and inferiorly using the cautery, as well as blunt dissection, just deep to the platysma muscle (Figures 3-4 and 3-5). The flaps do not need to be extended superiorly and inferiorly as one would do for a thyroid resection, but only enough to allow adequate exposure and placement of retraction.

FIGURE 3–4

FIGURE 3–3

FIGURE 3–5

2. DISSECTION

A self-retaining retractor is used to retract the skin flaps. The dissection then proceeds in the midline raphe, which provides a bloodless plane for the separation of the strap muscles (Figure 3-6).

As noted in Figure 3-7, the parathyroid adenoma has been localized preoperatively to the right inferior location. In this situation the right inferior pole of the thyroid gland is identified and this portion of the gland is gently mobilized.

FIGURE 3–6

Right inferior pole of thyroid gland

FIGURE 3–7

The parathyroid adenoma is now mobilized, with care taken to preserve the recurrent laryngeal nerve and minimize manipulation of the tumor during ligation of the end artery (Figure 3-8).

If the adenoma is adherent to the thyroid gland, a pledget of gauze is effective in gently teasing the adenoma away from the thyroid (Figure 3-9).

Once the parathyroid adenoma is mobilized, care is taken to ensure that the vascular supply is isolated and secured with either clips or ties, and the gland is then completely excised (Figure 3-10). If a unilateral exploration had been undertaken with preoperative localization, then many endocrine surgeons will obtain a rapid parathyroid hormone (PTH) assay to confirm the adequacy of resection.

Right recurrent laryngeal nerve

Right inferior thyroid gland

FIGURE 3–8

FIGURE 3–9

FIGURE 3–10