Werner & Ingbar's The Thyroid: A Fundamental & Clinical Text, 9th Edition

70C.Carcinoma of Follicular Epithelium: Surgical Therapy

Robert M. Beazley

A thyroid nodule of uncertain nature is a frequent indication for thyroidectomy. Clinically detectable thyroid nodules are relatively common, with an estimated prevalence in U.S. adults of 2.1% to 4.2% (1,2). Based on 2000 U.S. Bureau of the Census Data, one might predict that 5.8 to 11.7 million Americans harbor clinical thyroid nodules. The American Cancer Society estimates 22,000 new thyroid cancers will be diagnosed in 2003 (3). The clinical challenge, because of the relative rarity of thyroid malignancy, is detecting malignant nodules or those that have a high likelihood of malignancy. Overall, 5% to 10% of thyroid nodules presenting for surgical consultation will ultimately be determined to be cancerous.

EVALUATION OF PATIENTS WITH THYROID NODULES

Initial evaluation of a patient with a thyroid nodule consists of a thorough history and physical. A number of aspects of the patient's history are important in the workup of a suspected malignant nodule. Age is significant in that nodules in the young (under 14 years of age) and old (over 65 years) are more likely to be malignant than those in intervening age groups. Sex is of interest in that although thyroid nodules are more common in females, nodules in males are more likely to be malignant. A family history of multinodular goiter might tend to predict a benign lesion, whereas documented thyroid cancer in a first-degree relative increases the likelihood of a malignant nodule. A history of pain suggests inflammation and may be indicative of thyroiditis. Sudden rapid appearance of a nodule is commonly associated with hemorrhage into a preexisting colloid nodule. A diffuse goiter with signs of metabolic hyperactivity suggests Graves' disease. If hyperactivity is associated with multinodular goiter, one must consider Plummer's syndrome. Goiter patients presenting with atrial fibrillation or heart failure should also be evaluated for a hyperfunctioning thyroid nodule. Rapid enlargement of a long-standing goiter, particularly in an elderly patient, may predict thyroid malignancy. Past history of external radiation exposure in childhood significantly increases the likelihood that a thyroid nodule is cancerous or that subclinical cancer may be located elsewhere in the thyroid gland. Although in the distant past external beam radiation therapy was used in the head and neck region for a variety of dermatologic and lymphatic conditions, it is seldom used today. The most recent internal radiation experience occurred following exposure of a large population after the Chernobyl accident, resulting in an epidemic of pediatric thyroid cancer. Cowden's disease, characterized by multiple cutaneous facial papules and oral papillomatosis, may be associated with toxic and nontoxic goiters, thyroid adenomas, and a high incidence of follicular carcinomas. Pendred's syndrome is an autosomal-recessive disorder presenting with deafness, hypothyroidism, and goiter. Patients with a family history of multiple endocrine neoplasia type 1 or familial hyperparathyroidism may be at risk for developing carcinoma of follicular cell origin. Papillary thyroid cancer is recognized as the third most common malignancy associated with Gardner's syndrome after colon and ampullary carcinoma. It is multifocal, more aggressive, and appears one third of the time before the diagnosis of Gardner's is established. Papillary thyroid cancer is reported to occur at more than 100 times the expected incidence in females under 35 years of age with Gardner's syndrome (4). Patients who have had thyroid cancer in the past treated by lobectomy are at increased risk for having recurrence in the thyroid remnant.

Physical Examination

Patients presenting with a multinodular goiter have a lower incidence of malignancy than individuals presenting with a solitary nodule. Those presenting with a solitary nodule and cervical lymphadenopathy, particularly involving the lower jugular chain, should be considered as having thyroid malignancy until proven otherwise. Clinical presentation with bilateral cervical adenopathy and rapid thyroid enlargement is suspect for lymphoma, especially if there is a history of Hashimoto's disease. Hard nodules, which are adherent or fixed to surrounding tissues are highly suggestive of malignancy. Patients presenting with a solitary thyroid nodule and fracture or bone pain should also be suspected of harboring a thyroid malignancy. Patients with thyroid nodules may present with signs of cervicothoracic venous obstruction, particularly if the lesion is in the mediastinum, so-called Pemberton's sign. Dysphagia and dyspnea may accompany large goiters occurring in the neck or those with a significant mediastinal component. Likewise, recurrent nerve palsy with hoarseness and Horner's syndrome from cervical sympathetic involvement may occasionally accompany large benign multinodular goiters, although these signs are more likely to be predictors of malignancy.

Evaluation

Fine-needle aspiration biopsy (FNAB) is the key to characterizing the nature of thyroid nodules. However, the inability to distinguish between benign follicular lesions and follicular carcinoma remains the major shortcoming of this technique. As a result, most patients with the diagnosis of follicular lesion are advised to have surgery. Ultimately, only 15% to 20% of follicular lesions will be found to be malignant. Intraoperative frozen section determination of malignancy may be difficult and can be impossible with follicular carcinomas. Several studies have concluded that both the increased operative time and pathology charges do not support routine frozen section analysis, especially if FNAB is malignant or benign (5,6). Frozen section may be helpful in FNAB classified as suspicious (7). Frequently the surgeon must wait for permanent section to obtain the diagnosis. The false-positive rate for FNAB is in the 1% range, whereas the false-negative rate is about 5%, probably resulting from sampling error or misinterpretation.

Ultrasonography (US) is especially useful in the management of thyroid nodules because it is noninvasive and may be quickly performed in the outpatient setting. Thyroid US allows discrimination between cystic, mixed, and solid nodules, as well as evaluation of regional nodal beds. A recent study from M.D. Anderson Cancer Center documented lymph node metastases by preoperative US in 34% of thyroid cancer patients felt to be node negative by physical examination (8). US is extremely helpful in accurately directing FNAB. Additionally, US may be repeated so that existing nodules (FNAB negative) may be monitored for future size change. Simple cysts smaller than 4 cm, which are nearly always benign, may be managed by aspiration or tetracycline sclerosis, thus avoiding surgery. US allows lesions located on the edge of a cystic nodule to be accurately sampled by FNAB.

Owing to the widespread acceptance and utilization of FNAB, traditional nuclear thyroid scans are performed much less frequently. They are useful for evaluating hot nodules, in the workup of Plummer's disease, and with goiters suspected of having mediastinal extension. In the past few years, positron emission tomography (PET) has become available in many centers. A recent paper by Kresnik et al reported a group of 24 patients with follicular cytology in whom preoperative PET accurately predicted cancer in 9. All remaining 15 patients had benign lesions (9). Other reports have similarly suggested potential usefulness for PET in evaluating thyroid nodules. This new modality may aid in discriminating benign follicular lesions from malignant lesions, allowing more selective surgical management of the “follicular lesion.”

Preoperative computed tomography (CT) can be helpful in determining the extent of disease and involvement of adjacent tissue and lymph nodes. Preoperative awareness of tracheal deviation or compression is especially important from an anesthesia standpoint. One must ensure that intravenous contrast media is not used during CT studies because the high iodine load of the contrast will interfere with pre- and postoperative isotopic scanning.

Routine chest x-rays that include the neck can show tracheal deviation, intrathoracic extension, and pulmonary metastases. Occasionally, fine calcifications are seen within the thyroid gland, which may be associated with papillary or medullary thyroid carcinomas.

PREOPERATIVE PREPARATION

Preoperative preparation for thyroidectomy is not especially involved and does not differ from that for any other major surgical procedure. Cardiopulmonary function needs to be assessed, and problems like chronic lung disease, asthma, and cardiac instability addressed prospectively. Any hyperthyroid state should be treated as necessary us beta-blockers, antithyroid drugs, and iodine depending on time constraints. Anticoagulants and aspirin should be stopped approximately 1 week prior to the planned procedure. Laryngoscopy should be considered in those patients manifesting or complaining of voice changes as well as patients undergoing reoperative surgery.

Preoperative patient counseling should include a discussion of the conduct of surgery, essentially what patients will experience from the time they enter the hospital until the time they leave. Additionally, patients should be told what they may expect at home in the way of recovery and when to return to work. Patients with “follicular lesions or suspicious” FNAB diagnosis should be reassured that they may not necessarily have cancer, although many are quite anxious because they are convinced they already have it. A 1 in 5 or less risk for cancer may be quoted for these anxious patients. Additionally, one must alert them to the fact that frozen section may not be helpful and that a reoperation might be necessary when the permanent section report is obtained. At this juncture many patients will request that if there is a question or ambiguity at the time of frozen section that a total thyroidectomy be performed rather than chancing the necessity of a second procedure.

Clearly the major operative risks of bleeding, infection, nerve injury, and hypoparathyroidism must be discussed in detail, including treatments for these various complications. This discussion should take place with the patient and a family member or friend because the accompanying person will hear and retain more of the explanation than the patient. It is useful to use diagrams and illustrative materials during this portion of the interview. Written material, which the patient may take home, can also be of great help.

THYROIDECTOMY

Thyroid surgical procedures generally follow a series of technical steps, which are invariably the same with every procedure. First is that of anatomic exposure; second, identification of structures to be preserved (i.e., nerves, parathyroid glands); and lastly, excision of pathologic tissues. As patients undergoing thyroid surgery are frequently young women, cosmetic considerations related to the incision are a major concern. A symmetric “collar” incision utilizing a visible skin crease or in the plane of Langer's skin lines offers the best option for a pleasing cosmetic result. The incision should be located on the anterior neck approximately one finger breadth above the clavicular heads. The majority of thyroidectomies can be performed through a skin incision of 6 to 8 cm. Skin flaps are raised under the plane of the platysma muscle, cephalad, caudally, and laterally. The sternohyoid and sternothyroid muscles are liberally divided vertically along the median raphe from the sternal notch to the superior portion of the thyroid cartilage. In most cases transection of these muscles is not required for exposure, but doing so will enhance exposure, particularly of the upper thyroid pole region. If surgical division is elected, the muscles should be divided cephalad because the ansa cervicalis innervation takes place toward the caudal portion of the muscles. The functional morbidity of dividing, denervating, or even excising the sternohyoid or sternothyroid muscles is relatively minimal. Muscle found to be adherent to underlying tumor nodules should be divided and allowed to remain on the resection specimen. Exposure continues by dissecting the overlying strap muscles off the anterior capsular surface of the thyroid gland.

The thyroid gland is invested by the deep layer of cervical fascia, which forms a “filmy” capsule over the gland projecting into the thyroid substance, dividing the gland into irregularly shaped and sized lobules. The capsule provides a plane of surgical dissection between the gland and the strap muscles, which are retracted laterally as the capsular dissection progresses over the surface of the gland. The superficial surface of the gland is covered with multiple veins of varying size and numerous small lymphatic vessels. Early in this lateral dissection, a middle thyroid vein or veins are encountered, which upon ligation and division allows more lateral and dorsal capsular dissection with additional mobilization and exposure of the gland. At this juncture, the carotid artery will be visualized laterally and the tracheoesophageal groove medially (Fig. 70C.1).

FIGURE 70C.1. Anatomy on medial rotation of the thyroid gland. A: Recurrent laryngeal nerve. B: Superior laryngeal nerve. C: Inferior thyroid artery. D: Superior thyroid artery. E: Superior parathyroid gland. F: Trachea. G: Carotid artery. H: Cricothyroid muscle.

Exposure is enhanced at this point by dissection of the upper pole of the thyroid lobe and ligation of the superior thyroid artery (first branch of the external carotid) and the superior thyroid veins, which may be multiple. Lateral and caudal retraction of the thyroid lobe permits visualization of the superior pole vessels and helps to identify the relative avascular “medial cricothyroid space” (between upper pole and cricothyroid muscle), facilitating individual ligation of the vascular structures on the surface of the thyroid capsule. In this region the surgeon must be aware of the external branch of superior laryngeal nerve, which innervates the cricothyroid muscle and is a tensor of the vocal cord responsible for the timbre or pitch of the voice. This nerve is especially important in individuals who are singers or public speakers. Identification of the nerve may be difficult with large goiters or fibrosis associated with radiation or Hashimoto's disease. Approximately 50% of the time the nerve courses more than a centimeter superior to the site of vessel ligation and hugs the larynx medially, and is thus not

likely to be injured. Fifty percent of the time the course of the nerve is such that injury may occur if ligation of the superior pole vessels is not immediately performed on the thyroid capsule (10). It is not possible to estimate the frequency of inadvertent injury to the superior laryngeal nerve, because the ensuing morbidity may be subtle and laryngoscopic findings minimal. However, one might speculate that such injury could account for the occasional ill-defined dysphonia and dysphagia complaints manifested following thyroidectomy. The surgeon must be diligent in ensuring that the nerve does not traverse close to the gland prior to ligating the superior pole vessels.

Mobilization of the upper pole permits the thyroid lobe to be retracted medially, exposing the tracheoesophageal groove and providing visualization of the posterior thyroid capsule. At this point parathyroid tissue lying on the posterior surface of the thyroid near the inferior thyroid artery may become visible. The inferior thyroid artery may be localized laterally, coursing medially toward the thyroid lobe. As the recurrent nerve crosses the inferior thyroid artery at an acute angle in its course to the cricothyroid membrane, careful dissection of the vessel can be helpful in localizing the nerve with minimal undue trauma. The recent availability of intraoperative neuromonitoring of vocal cord muscle responsiveness has provided an aid in early nerve identification, especially in conditions of fibrosis and scarring, thus preserving nerves and saving time (11). Another successful anatomic approach to nerve identification is the tubercle of Zuckerkandl. The tubercle is a thickening on the posterior thyroid surface, which is a remnant of the fusion of the lateral thyroid anlage and ultimobranchial body to the median thyroid analage. The recurrent nerve lies in a “fissure” in the tubercle between the lateral and posterior surfaces of the thyroid or trachea. Gentle “unroofing” of the overlying tubercle from the nerve is a safe and effective technique of nerve identification and exposure (12).

Terminally the nerve may vary in size from a few millimeters to 3 to 4 mm in some cases. It usually is a bright white color with distinguishing “racing stripes”—vaso nervorum—running on the surface. Frequently the nerve branches prior to entering the cricothyroid membrane, occasionally caudal to the junction with the inferior thyroid artery, which if unrecognized may put one or both nerve branches at risk. With large goiters, nodules, or fibrosis the nerve may be adherent or incorporated into the thyroid capsule in the lower pole region and mistaken for a vascular structure, with disastrous outcome. The current standard of care is to identify and dissect the nerve before thyroid resection while leaving the surrounding connective tissue and attachments to the trachea intact, basically atraumatically unroofing the nerve in order to preserve its blood supply. Some difficulty may be encountered in the area of the posterior suspensory ligament (ligament of Berry), which attaches the thyroid lobe to the side of the cricoid cartilage as well as the first and second tracheal rings and the esophagus. This firm fibrous attachment to the laryngoskeleton is responsible for the movement of the thyroid gland experienced during swallowing. The recurrent nerve can pass deep to the ligament of Berry or between the ligament and its lateral fascial leaf. This is a sticky area where identification and dissection may be difficult, especially with cancer and fibrosis from radiation or Hashimoto's disease.

It is nearly impossible to perform thyroid surgery without encountering and having to deal with the parathyroid glands. Eighty percent of the time the upper parathyroids will be found within a 1 cm radius of the junction of the inferior thyroid artery and the recurrent laryngeal nerve. Embryologically, the lower parathyroid develops and descends with the thymus, separating to remain near the lower pole of the thyroid as the thymus continues descending into the mediastinum. However, the lower parathyroid gland may be found within the thyroid gland, the thymus, or anywhere from the angle of the mandible to the deep mediastinum, including the pericardium and even the heart. Once the parathyroid glands are identified, they may need to be dissected from the thyroid capsule, using great care to preserve their delicate blood supply, generally end arterial branches of the inferior thyroid artery. Inadvertent devascularization dictates parathyroid autotransplantation into the adjacent sternocleidomastoid muscle. A postoperative serum (parathyroid hormone) PTH level may be useful in clinical management and patient counseling if postoperative hypocalcemia is experienced.

Veins accompanying the inferior thyroid artery are ligated on the capsule of the thyroid, carefully avoiding branches of the recurrent laryngeal nerve. Careful attention should be practiced in controlling the small branch of the inferior thyroid artery and accompanying vein within Berry's ligament. This branch is usually quite close to the nerve and if torn nearly always appears to retract under the nerve, necessitating control by local pressure and hemostatics. Point suture ligation under loup magnification may be required to control bleeding and avoid nerve injury.

Having identified and exposed the recurrent nerve and controlled the vascular supply, one is ready to resect the lobe. The status of the parathyroid glands should be reevaluated to ensure that the glands have a satisfactory blood supply. If in doubt, a devascularized gland should be removed, minced into 1 to 2 mm pieces, and transplanted into the ipsilateral sternocleidomastoid muscle. At this point, resection of the lobe is performed by retracting the thyroid lobe medially and elevating it from the underlying trachea. This fibrous pretracheal plane is easily dissected with electrocautery or the scalpel. The pyramidal lobe, a cephalad extension from the isthmus or medial aspect of the thyroid lobe, lying on the anterior surface of the cricoid cartilage and the larynx is dissected and included with the specimen. Failure to excise the pyramidal lobe is a recognized cause of “incomplete” total thyroidectomy. Any nodal tissues associated with the isthmus and the pyramidal lobe should also be resected. At times, particularly with papillary thyroid cancer, an enlarged pretracheal node in this area will contain metastatic disease. This node has been dubbed the delphian node after the Oracle of Delphi, who was able to predict what the future held.

EXTENT OF THYROIDECTOMY

If a total thyroidectomy is planned, the contralateral lobe is removed using the same extracapsular technique and maneuvers as described above. If the planned operation is a lobectomy, the isthmus is divided at the junction with the contralateral lobe, the cut edge being suture ligated. The other surgical option at this point is a near-total thyroidectomy, in which varying amounts of contralateral thyroid tissue are left in place, usually requiring intraglandular resection as opposed to the extracapsular approach described above.

No clear consensus exists of the definition of the extent of thyroidectomy. Bliss et al have proposed a classification of extent of thyroidectomy as follows (12). Partial thyroidectomy is defined as removal of neoplasm with a margin of normal thyroid tissue. Subtotal thyroidectomy is described as bilateral excision of more than 50% of each lobe, including the isthmus, whereas a lobectomy or hemithyroidectomy is a total extracapsular excision, including the isthmus. Total thyroidectomy is the extracapsular removal of both lobes and the isthmus (Fig. 70C.2). Bliss et al define near-total thyroidectomy as the extracapsular removal of one lobe and up to 90% of the contralateral lobe, leaving behind approximately 1 g of thyroid tissue (12).

FIGURE 70C.2. Thyroidectomy procedures. A: Bilateral subtotal thyroidectomy. B: Total lobectomy and isthmusectomy. C: Total thyroidectomy.

Considerable debate continues in the literature concerning the appropriate surgical procedure for thyroid carcinoma of follicular epithelium. The controversy is between two ideologies, that of management by lobectomy or by total thyroidectomy. Arguments for lobectomy include the fact that overall survival appears uninfluenced by the extent of surgical resection in low-risk patients. A number of prognostic systems have been proposed for defining risk level in thyroid malignancy (13,14,15). Although there are some individual differences between the prognostic systems, all use patient age, size of tumor, extent of disease, and metastases. Low-risk female patients, of age less than 50, with well-differentiated tumors without tumor extension outside the thyroid gland, and without metastases, are predicted to have an excellent prognosis with either lobectomy or total thyroidectomy. The majority of patients with thyroid carcinomas of follicular epithelium fall into this favorable category. On the other hand, patients deemed to be high risk have been found to do equally poorly with either limited or total thyroidectomy. Additional recognized advantages of lobectomy are decreased morbidity from nerve injury, negligible hypoparathyroidism, no absolute need for thyroid replacement therapy, and the lack of potential risks from adjuvant 131I treatment.

The advantages of total thyroidectomy include the ability to remove occult multicentric disease, present in over 30% of cases, thus reducing remnant recurrences; the ability to postoperatively scan patients for residual thyroid-bred tissue and distant disease, and to treat if necessary with radioactive iodine; and the ability to monitor for tumor recurrence with serum thyroglobulin levels following removal of all thyroid tissue.

At Boston University School of Medicine we have favored the more aggressive regimen of total thyroidectomy for all but minimal lesions (i.e., < 1 cm well-differentiated without capsular invasion) in patients under 40 years of age, thereby accepting the studies of Mazzaferri and others that document both decreased local recurrence and improved survival with combined total thyroidectomy and 131I therapy (16,17,18).

Occasionally, patients with thyroid cancer require reoperation, either a completion procedure to remove a thyroid remnant or a procedure to excise recurrent local disease. Reoperative thyroid surgery presents a number of technical challenges, which in some instances are best managed by an experienced endocrine surgeon. In the hands of such an individual, surgery can be performed successfully with minimal morbidity (19).

LYMPH NODE DISSECTION

Patients with known thyroid malignancy or who have suspicious appearing tracheoesophageal (TE) nodes should have a lymph node dissection. At a minimum, dissection should include all the nodes on the epsilateral TE groove and a bilateral dissection if the contralateral nodes are grossly suspicious or the opposite thyroid lobe appears to contain multicentric disease. Nodes anterior to the trachea, above the isthmus and under the sternal notch, also should be removed. Nodal resection carried out between both carotid vessels and from the sternal notch to the thyroid cartilage constitute what is known as a central compartment resection and are indicated in patients with high-grade lesions or larger tumors, as well as in men over 40 and women over 50. The use of sentinel lymph node techniques have been proposed to identify drainage nodes and aid in sampling, particularly if lymph nodes are clinically not involved (20).

Patients with suspicious or enlarged nodes in the lateral neck or with biopsy-proven metastatic disease are candidates for a modified neck dissection, which would include lymph nodes in levels III, IV, and V, preserving the jugular vein, sternocleidomastoid muscle, and accessory nerve.

Individuals with clinically negative lateral lymph nodes who have positive central nodes may be treated with 131I in observation. In most instances, subclinical disease will be adequately successfully controlled by 131I and TSH suppression. Postoperative monitoring with clinical examination, cervical ultrasound evaluation of the neck, and serum thyroid-binding globulins should be used.

COMPLICATIONS OF THYROIDECTOMY

In general, complications of thyroidectomy may be related to disease type, size of the gland, degree of technical difficulty (i.e., reoperative surgery), surgical training, and volume of surgical work (21). Three major complications need to be highlighted in any preoperative discussion with the patient: postoperative recurrent nerve dysfunction, hypoparathyroidism, and bleeding complications, which may occur during or following thyroidectomy. Permanent unilateral recurrent nerve palsy is perhaps the most disabling. Bilateral nerve palsy, although rare, even of a transient nature, on the other hand, may be life threatening. Such an injury may become immediately apparent with the patient developing significant stridor within minutes or hours following extubation. Reintubation or possibly immediate tracheotomy may be required to save the patient's life.

Identification and dissection of the recurrent laryngeal nerve does not increase the risk for either transient or permanent nerve palsy; indeed, it has been found to decrease the incidence of these complications. Ideally, the nerve should be exposed over its entire course from the jugular angle to insertion into the cricothyroid membrane while leaving surrounding supporting connective tissues intact to minimize the risk for devascularization. When the nerve is visualized to be intact, any ensuing palsy will be almost uniformly transient. The nerve is most commonly injured at the junction with the inferior thyroid artery and the ligament of Berry or near the inferior pole of the thyroid. About 60% of the time, extralaryngeal branching occurs near the inferior thyroid artery or the ligament of Berry, significantly increasing the risk for nerve damage. In the majority of cases, the most ventral nerve branch innervates the intrinsic laryngeal muscles. Obviously, the anterior location of the ventral branch makes it vulnerable to suture injuries when less than a lobectomy is performed. Failure to recognize adherence of the nerve to an enlarged lower pole nodule or the occurrence of an aberrant nonrecurring laryngeal nerve (1%) are other causes of nerve injury. Permanent nerve palsy is cited in the literature to occur from 0% to 2.1%, with the average of approximately 0.5% to 1%. Temporary palsy varies from 2.9% to over 10% (12).

The second feared adverse result of thyroidectomy is temporary or permanent hypoparathyroidism. Obviously this is only a consideration in bilateral procedures or patients having central neck dissection for cancer. Careful identification and ligation of the terminal branches of the inferior thyroid artery with preservation of vascular pedicles, especially to the inferior parathyroid gland, and liberal employment of autotransplantation of damaged or devascularized glands will minimize this difficult complication. Transient hypocalcaemia, frequently asymptomatic, may be related to intraoperative manipulation, vitamin D deficiency, or hypomagnesemia and may be observed in up to 7.3% of patients. If a patient is symptomatic, treatment with calcium and 1,25-dihydroxy vitamin D is indicated. On the other hand, in the asymptomatic individual one might argue for expectant observation. However, in this day of outpatient or short-stay surgery, the clinician does not have the luxury of additional observation days. Therefore, many patients, asymptomatic or otherwise, will get outpatient calcium supplementation. A postoperative serum PTH determination may reassure the physician enough to follow an outpatient observation course.

Bleeding or hematoma is an infrequent but potentially serious complication of thyroidectomy. The signs of postoperative bleeding can be respiratory distress, pain, pressure, and dysphagia, with symptoms sometimes appearing 4 to 18 hours after wound closure. Meticulous hemostasis is the best technique to avoid hematoma, and wound drainage should not to be used routinely. Although drainage will not prevent hemorrhage, it can alert the staff to the occurrence of postoperative bleeding. If a hematoma is not visible, but the patient complains of pain out of proportion to the operation, US of the neck may reveal a developing hematoma and lessen treatment delay. Some surgeons have used fibrin glue application to the thyroid resection bed as an adjunct to hemostasis, particularly in patients with large glands or a bleeding disorder such as low platelets. Other rare complications include pneumothorax, pneumomediastinum, and wound infection. With large glands, Hashimoto's disease, or cancer, injury to the sympathetic nerves, esophagus, and trachea are possibilities that must be avoided.

THYROID SURGERY IN THE ELDERLY

When thyroid problems occur in the elderly, the risk for malignancy is higher and the end results are generally poorer. Questions often are raised as to the patient's ability to tolerate thyroid surgery based on age and concomitant diseases. A recent study evaluated morbidity following thyroidectomy in patients 75 years of age and over and concluded that it was no greater than in patients under the age of 75 years (22). These results were obtained in the face of comorbidity rates of 80%, including essential hypertension (52.7%), coronary arteriosclerosis (30.9%), cardiac arrhythmias (21.8%), diabetes (5.5%), Parkinson's disease (9.1%), and chronic obstructive pulmonary disease (12.7%). Forty-two percent of individuals had two or more comorbidity's in the elderly group. When the two groups were compared, no statistical differences were documented in postoperative course or morbidity. As expected, in the elderly population there were more reinterventions and an increased occurrence of large goiters with associated mechanical symptoms, substernal thyroid tumors, and cancer, particularly of the undifferentiated variety. Fortunately, even the frail elderly tolerate modern anesthesia and expert thyroid surgery quite well if the procedure is an elective one. The aim should be to manage these patients electively rather than on an emergency basis.

NEW DIMENSIONS

The future holds a number of technological changes that will impact thyroid surgery. The first is the increased use of the harmonic scalpel, which employs US to simultaneously cut and coagulate tissue. Recently it was documented in a large series to reduce operative time by at least 30 minutes for the standard thyroidectomy (23).

Increased use of intraoperative neuromonitoring has decreased operative time while lowering the morbidity of both transient and permanent nerve palsy. High-risk groups for postoperative palsy are the reoperative patient and those undergoing extended surgeries for nodular disease, Hashimoto's disease, and cancer. Nerve monitoring facilitates earlier, easier, and less traumatic identification of the recurrent laryngeal nerve and allows the surgeon to reassure those patients who may be hoarse following surgery that electrical continuity exists with an excellent possibility of full voice recovery (24).

Finally, video-assisted surgery has found a role in nearly every surgical specialty. With evolution of advanced video operative skills, reports have appeared showing that video-assisted thyroid lobectomy leads to better cosmetic outcome and is associated with less postoperative pain and reduces postoperative hospital stays when compared with standard open lobectomy. Bellantone et al concluded thatt could be “a valid alternative to conventional surgery in patients with small solitary nodular thyroid lesions” (25). At this time the operation appears best suited to those patients with solitary nodules smaller than 3 cm, cysts, and small toxic nodules. This area is currently developing and may expand when surgical robotics become more widely available.

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