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Acs0209 Thyroid And Parathyroid Operations
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Acs0209 Thyroid And Parathyroid Operations Acs0209 Thyroid And Parathyroid Operations Document Transcript

  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 1 9 THYROID AND PARATHYROID OPERATIONS Wen T. Shen, MD, Gregg H. Jossart, MD, FACS, and Orlo H. Clark, MD, FACS Thyroidectomy are placed on the dermis, and subplatysmal flaps are raised, first cephalad to the level of the thyroid cartilage notch operative planning and then caudad to the suprasternal notch. Skin towels and If the patient has had any hoarseness or has undergone a a self-retaining retractor are applied. previous neck operation, indirect or direct (ideally, fiberoptic) laryngoscopy is essential to determine whether the vocal Troubleshooting An incision 1 cm below the cricoid cords are functioning normally. All patients scheduled for cartilage yields an entry point that is precisely over the thyroidectomy should be euthyroid at the time of operation. isthmus of the thyroid gland. The course of the incision Those with hyperthyroidism should be treated with antithy- should conform to the normal skin lines or creases. The roid medication and Lugol’s iodine, and those with hypothy- length of the incision should be modified as necessary for roidism should be taking thyroid hormone supplementation. good exposure. Patients with short, thick necks, low-lying Preanesthetic evaluation should be undertaken as it would be thyroid glands, or large thyroid tumors require longer inci- for any procedure calling for general anesthesia. sions than those with long, thin necks and small tumors. Optimal exposure of the neck is obtained by placing a Patients whose necks do not extend also require longer inci- beanbag or soft roll behind the scapulae and a foam ring sions for adequate exposure. A sterile marking pen should be under the occiput; placement of these devices extends the used to mark the midline of the neck, the level at which the neck and places the thyroid gland in a more anterior position. incision should be made (i.e., 1 cm below the cricoid), and The head must be well supported to prevent postoperative the lateral margins of the incision (which should be at posterior neck pain. The patient is placed in a 20° reverse equal distances from the midline so that the incision will be Trendelenburg position. The skin is prepared with 1% iodine symmetrical). A scalpel should never be used to mark the or chlorhexidine. neck: doing so will leave an unsightly scar in some patients. operative technique To mark the incision site itself, a 2-0 silk tie can be pressed against the neck [see Figure 1]. General Troubleshooting The upper flap is dissected first by placing five straight Thyroid and parathyroid operations should be performed Kelly clamps on the dermis and retracting anteriorly and in a blood-free field so that vital structures can be identified. superiorly. Lateral traction with a vein retractor or an Operating telescopes (magnification: x2.5 or x3.5) are also Army-Navy retractor helps identify the semilunar plane for recommended because they make it easier to identify the dissection. This blood-free plane is deep to the platysma and normal parathyroid glands and the recurrent laryngeal nerve. superficial to the anterior jugular veins. Cephalad dissection If bleeding occurs, pressure should be applied. The vessel can be done quickly with the electrocautery or a scalpel, and should be clamped only if (1) it can be precisely identified or lateral dissection can be done bluntly. The same principles (2) the recurrent laryngeal nerve has been identified and is are applied to dissection of the lower flap. In thin patients, not in close proximity to the vessel. the surgeon must be careful not to dissect through the skin As a rule, dissection should always begin on the side of the from within, especially at the level of the thyroid cartilage. suspected tumor; if there is a problem with the dissection on Step 2: Midline Dissection and Mobilization of Strap Muscles this side, a less than total thyroidectomy can be performed on the contralateral side to prevent complications. There The thyroid gland is exposed via a midline incision through is, however, one exception to this rule: if the tumor is very the superficial layer of deep cervical fascia between the strap extensive, the surgeon will sometimes find it easier to do the muscles. Because the strap muscles are farthest apart just dissection on the “easy” side first to facilitate orientation with above the suprasternal notch, the incision is begun at the respect to the trachea and the esophagus. notch and extended to the thyroid cartilage [see Figure 2]. On the side where the thyroid nodule or the suspected Step 1: Incision and Mobilization of Skin Layers parathyroid adenoma is located, the more superficial sterno- A Kocher transverse incision paralleling the normal skin hyoid muscle is separated from the underlying sternothyroid lines of the neck is made 1 cm below the cricoid cartilage muscle by blunt dissection, which is extended laterally until [see Figure 1]. As a rule, the incision should be about 4 to the ansa cervicalis becomes visible on the lateral edge of the 6 cm long and should extend from the anterior border of sternothyroid muscle and on the medial side of the internal one sternocleidomastoid muscle to the anterior border of the jugular vein. The sternothyroid muscle is then dissected other and through the platysma. Five straight Kelly clamps free from the thyroid and the prethyroidal fascia by blunt or DOI 10.2310/7800.S02C09 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 2 Figure 1 The initial incision in a thyroidectomy is made 1 cm below the cricoid cartilage and follows normal skin lines. A sterile marking pen is used to mark the midline of the neck, the level of the incision, and the lateral borders of the incision. A 2-0 silk tie is pressed against the neck to mark the incision site itself. sharp dissection until the middle thyroid vein or veins are Troubleshooting As noted (see above), the strap encountered laterally. These maneuvers provide excellent muscles generally need not be divided; however, if they are exposure; accordingly, we have not found routine division of adherent to the underlying thyroid tumor, the portion of the the strap muscles to be necessary. muscle adhering to the tumor should be sacrificed and removed A 2-0 silk suture can be placed through the thyroid lobe for en bloc with the specimen. Separation of the sternohyoid muscle retraction to facilitate exposure. This stitch should never be from the sternothyroid muscle provides excellent exposure. The placed through the thyroid nodule: doing so could cause middle thyroid veins should be cleaned of adjacent tissues to prevent any injury to the recurrent laryngeal nerve when these seeding of thyroid cancer cells. The thyroid is retracted ante- veins are ligated and divided. It is always safest to mobilize riorly and medially and the carotid sheath laterally; this tissues in a direction parallel to the course of the recurrent retraction places tension on the middle thyroid veins and laryngeal nerve. helps expose the area posterolateral to the thyroid, where the parathyroid glands and the recurrent laryngeal nerves are Step 3: Division of Isthmus situated. The middle thyroid vein is divided to yield better When a thyroid lobectomy is performed, the isthmus of the exposure of the upper lobe of the thyroid [see Figure 3]. thyroid gland is usually divided lateral to the midline with Figure 2 To expose the thyroid, a midline incision is made through the superficial layer of deep cervical fascia between the strap muscles. The incision is begun at the suprasternal notch and extended to the thyroid cartilage. 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 3 Troubleshooting It is essential to avoid injuring the external branch of the superior laryngeal nerve. This nerve is the motor branch of the superior laryngeal nerve and is responsible for tensing the vocal cords; it is also known as the high note nerve or the Amelita Galli-Curci nerve (after the 20th-century opera singer who was reputed to have suffered an injury to this nerve after thyroidectomy). In about 80% of patients, the external branch of the superior laryngeal nerve runs on the surface of the cricothyroid muscle; in about 10%, it runs with the superior pole vessels; and in the remaining 10%, it runs within the cricothyroid muscle. Given that this nerve is usually about the size of a single strand of a spider web, one should generally try to avoid it rather than attempt to identify it. Injury to the external branch of the superior laryngeal nerve occurs in as many as 10% of patients under- going thyroidectomy. The best ways of preventing such inju- ries are (1) to provide gentle traction on the thyroid gland in a caudal and lateral direction during superior dissection and (2) to ligate the superior pole vessels directly on the capsule of the upper pole individually rather than cross-clamp the entire superior pole pedicle. Figure 3 The middle thyroid veins are divided to give better exposure behind the upper lobe of the thyroid. The internal branch of the superior laryngeal nerve pro- vides sensory innervation to the posterior pharynx. Injury to this nerve can result in aspiration. Because the internal branch of the superior laryngeal nerve typically runs cephalad to the Dandy or Colodny clamps at an early point in the dissection thyroid cartilage, it is rarely encountered during a typical thy- to facilitate the subsequent mobilization of the thyroid gland. roidectomy. Care must be taken to avoid injury to this branch The remaining thyroid tissue is oversewn with a 2-0 silk when laryngeal mobilization is performed to relieve tension ligature. To minimize the chance of invasion into the trachea on a tracheal anastomosis after tracheal resection of locally and to prevent the development of a visible mass from com- advanced thyroid cancer. pensatory thyroid hypertrophy, thyroid tissue should not be left anterior to the trachea. Step 5: Identification of Recurrent Laryngeal Nerve and Lower Parathyroid Gland Troubleshooting With larger glands, we divide the isthmus The lower parathyroid gland is usually encountered during first, taking care not to cut across the tumor. This step lateral mobilization of the lower thyroid pole; it is almost always facilitates the lateral dissection by making the gland more located anterior to the recurrent laryngeal nerve and inferior mobile. to the point where the inferior thyroid artery crosses the recurrent laryngeal nerve [see Figure 6]. The carotid sheath is Step 4: Mobilization of Thyroid Gland and Identification of retracted laterally, and the thyroid gland is retracted anteri- Upper Parathyroid Gland orly and medially. This retraction puts tension on the inferior Once the isthmus has been divided, dissection is continued thyroid artery and consequently on the recurrent laryngeal superiorly, laterally, and posteriorly with a small peanut nerve, thereby facilitating identification of the nerve. The sponge on a clamp. The superior thyroid artery and veins are recurrent laryngeal nerve is situated more medially on the left identified by retracting the thyroid inferiorly and medially. (running in the tracheoesophageal groove) and more obliquely The tissues lateral to the upper lobe of the thyroid and on the right. Dissection should proceed cephalad along the lateral edge of the thyroid gland. Fatty and lymphatic tissues medial to the carotid sheath can be mobilized caudal to the immediately adjacent to the thyroid gland are swept from it cricothyroid muscle; the recurrent laryngeal nerve enters the with a peanut clamp, and small vessels are ligated. No tissue cricothyroid muscle at the level of the cricoid cartilage, first should be transected in this area until one is sure that it is not passing through Berry’s ligament [see Figure 4]. The superior the recurrent laryngeal nerve. pole vessels are individually identified, skeletonized, double- or triple-clamped, ligated, and divided low on the thyroid Troubleshooting The upper parathyroid glands are usu- gland [see Figure 5]. To prevent injury to the external branch ally situated on each side of the thyroid gland at the level of the superior laryngeal nerve as it traverses the anterior where the recurrent laryngeal nerve enters the cricothyroid surface of the cricothyroid muscle, the superior pole vessels muscle [see Figure 6]. Because the recurrent laryngeal nerve are divided and ligated close to the thyroid surface. The enters the cricothyroid muscle at the level of the cricoid carti- tissues posterior and lateral to the superior pole that have lage, the area cephalad to the cricoid cartilage is relatively safe, not already been mobilized can now be easily swept by blunt though care should be taken to avoid injury to the external dissection away from the thyroid gland medially and anteri- branch of the superior laryngeal nerve (see above). orly and away from the carotid sheath laterally. The upper The right and left recurrent laryngeal nerves must be parathyroid gland is often identified at this time at the level preserved during every thyroid operation. Although both of the cricoid cartilage. nerves enter at the posterior medial position of the larynx in 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 4 Figure 4 The recurrent laryngeal nerve enters the cricothyroid muscle at the level of the cricoid cartilage, first passing through Berry’s ligament. the cricothyroid muscle, their courses vary considerably. The on the right. The left recurrent laryngeal nerve almost always right recurrent laryngeal nerve takes a more oblique course runs in the tracheoesophageal groove because of its deeper than the left recurrent laryngeal nerve does and may pass origin within the thorax as it loops around the ductus arterio- either anterior or posterior to the inferior thyroid artery. In sus. Either recurrent laryngeal nerve may branch before enter- about 0.5% of the population, the right recurrent laryngeal ing the larynx; the left nerve is more likely to do this. Such nerve is in fact nonrecurrent and may enter the thyroid from branching is important to recognize because the motor fibers a superior or lateral direction. On rare occasions, both a of the recurrent laryngeal nerve are usually located within the recurrent and a nonrecurrent laryngeal nerve may be present most medial branch. Figure 5 The superior pole vessels should be individually identified and ligated low on the thyroid gland to minimize the chances of injury to the external branch of the superior laryngeal nerve. 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 5 Figure 6 The upper parathyroid glands are usually situated on either side of the thyroid at the level where the recurrent laryngeal nerve enters the cricothyroid muscle. The lower parathyroid glands are usually anterior to the recurrent laryngeal nerve and inferior to where the inferior thyroid artery crosses this nerve. In identifying the recurrent laryngeal nerves, it is helpful to with minimal manipulation and with its remaining blood supply remember that they are supplied by a small vascular plexus preserved. and that a tiny vas nervi runs parallel to and directly on In patients who have large thyroid tumors or thyroiditis or each nerve [see Figures 4 and 6]. In young people, the artery who have previously undergone a neck operation, extensive usually is readily distinguished from the recurrent laryngeal scarring is often present. For some of these patients, it is nerve; however, in older persons with arteriosclerosis, the preferable to identify the recurrent laryngeal nerve via a white-appearing artery may be mistaken for a nerve, and thus medial approach by dividing the isthmus with Colodny the nerve may be injured as a result of the misidentification. clamps and ligating and dividing the superior thyroid vessels. Lateral traction on the carotid sheath and medial and anterior By carefully dissecting the thyroid away from the trachea, one traction on the thyroid gland place tension on the inferior can identify the recurrent laryngeal nerve at the point where thyroid artery; this maneuver often helps identify the recur- its position is most consistent (i.e., at its entrance into the rent laryngeal nerve where it courses lateral to the midportion larynx immediately posterior to the cricothyroid muscle). of the thyroid gland. One should, however, be careful not to The most difficult dissection in a thyroidectomy is in the devascularize the inferior parathyroid glands by dividing the area of Berry’s ligament, which is situated at the posterior lateral vascular attachments. To remove the thyroid lobe, it portion of the thyroid gland just caudal to the cricoid carti- is best to divide the vessels directly on the thyroid capsule lage [see Figure 4]. A small branch of the inferior thyroid to preserve the blood supply to the parathyroid glands. It is artery traverses the ligament, as do one or more veins from usually safest to identify the recurrent laryngeal nerve low in the thyroid gland. If bleeding occurs during this part of the the neck and then to follow it to the site where it enters the cricothyroid muscle through Berry’s ligament. The recurrent dissection, it should be controlled by applying pressure with laryngeal nerves can usually be palpated through the sur- a gauze pad. Nothing should be clamped in this area until the rounding tissue in the neck; they feel like taut ligatures of recurrent laryngeal nerve is identified. In some patients (about approximately 2-0 gauge. 15%), the peduncle of Zuckerkandl, a small protuberance of Parathyroid glands should be swept from the thyroid gland thyroid tissue on the right, tends to obscure the recurrent on as broad a vascular pedicle as possible to prevent devas- laryngeal nerve at the level of Berry’s ligament. cularization. When it is unclear whether a parathyroid gland Step 6: Mobilization of Pyramidal Lobe can be saved on its own vascular pedicle, the gland should undergo a biopsy to confirm that it is parathyroid and then The pyramidal lobe is found in about 80% of patients. It be autotransplanted in multiple 1x1 mm pieces into separate extends in a cephalad direction, often through the notch in pockets in the sternocleidomastoid muscle; the muscle pocket the thyroid cartilage to the hyoid bone. One or more lymph should be marked with a clip or stitch in case removal subse- nodes are frequently found just cephalad to the isthmus of quently proves necessary. At times, it is preferable to clip the the thyroid gland over the cricothyroid membrane (so-called blood vessels running from the thyroid to the parathyroid glands Delphian nodes) [see Figure 7]. The pyramidal lobe is mobilized rather than to clamp and tie them. Clipping not only marks the by retracting it caudally and by dissecting immediately adja- parathyroid gland (which is useful if another operation subse- cent to it in a cephalad direction. Small vessels are coagulated quently becomes necessary) but also enables the gland to remain or ligated. 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 6 Figure 7 Delphian lymph nodes may be found just cephalad to the isthmus over the cricothyroid membrane. Step 7: Thyroid Resection prevent tension on the anastomosis, the trachea should be Once the parathyroid glands have been carefully swept or mobilized before resection, the recurrent laryngeal nerves dissected from the thyroid gland and the recurrent nerve has should be preserved and mobilized from the trachea, and the been identified, the thyroid lobe can be quickly resected. For mylohyoid fascia and muscles should be divided above the a total thyroidectomy, the same steps are repeated on the thyroid cartilage to drop the cartilage. Special care must be other side. taken to not injure the internal branch of the superior laryn- geal nerve during this dissection, given that this nerve courses Troubleshooting The thyroid lobe or gland should be from lateral to medial just above the lateral aspect of the carefully examined after removal. If a parathyroid gland is thyroid cartilage. After resection, the trachea is reapproxi- identified, a biopsy should be performed to confirm that it is mated with 3-0 polyglyconate sutures. One or two Penrose parathyroid, and the gland should be autotransplanted. In a drains should be left near the resection site to allow air to exit. thyroid operation, every parathyroid gland should be treated The drains are removed after several days, when there is no as if it is the last one, and at least one parathyroid gland more evidence of air leakage. should be definitively identified. As a rule, a biopsy should If the esophagus is invaded by tumor, the muscular wall of not be performed on a normal parathyroid gland during a the esophagus can be resected along with the tumor, with the thyroid operation unless the gland has been devascularized inner mucosa left in place (unless it too is involved with and autotransplantation is planned. tumor). Step 8: Closure Neck Dissection for Nodal Metastases Lymph nodes The sternothyroid muscles are approximated with 4-0 in the central neck (medial to the carotid sheath) are absorbable sutures, and a small opening is left in the midline frequently involved in patients with papillary, medullary, and at the suprasternal notch to make any bleeding that occurs Hürthle cell cancer. These nodes should be removed without more evident and to allow the blood to exit. The sternohyoid injury to the parathyroid glands or the recurrent laryngeal muscles are reapproximated in a similar fashion, as is the nerves. In most patients it is relatively easy to remove all platysma. The skin is then closed with butterfly clips, which tissue between the carotid sheath and the trachea. In some are hemostatic and inexpensive and permit precise alignment patients with extensive lymphadenopathy, it is necessary of the skin edges. If these clips are not available, the skin can to remove the parathyroids, perform biopsies on them to be closed with a subcuticular stitch and Steri-Strips instead. confirm that they are in fact parathyroid, and autotransplant A sterile pressure dressing is applied. them into the sternocleidomastoid muscle. Special Concerns When lymph nodes are palpable in the lateral neck, a Invasion of Trachea or Esophagus On rare occasions, modified neck dissection is performed through a lateral exten- thyroid or parathyroid cancers may invade the trachea or the sion of the Kocher collar incision to the anterior margin of esophagus. As much as 5 cm of the trachea can be resected the trapezius (a MacFee incision). The jugular vein, the safely without impairment of the patient’s voice. If the inva- spinal accessory nerve, the phrenic nerve, the vagus nerve, the sion is not extensive and is confined to the anterior portion cervical sympathetic nerves, and the sternocleidomastoid of the trachea, a small section of the trachea that contains the muscle are preserved unless they are directly adherent to or tumor should be excised, and a tracheostomy may be placed invaded by tumor. at the site of resection. If the invasion is more extensive or In patients with medullary thyroid cancer, a meticulous occurs in the lateral or posterior portion of the trachea, a and thorough central neck dissection is necessary. When a segment of the trachea measuring several centimeters long is primary medullary tumor is larger than 1 cm or the central resected, and the remaining segments are reanastomosed. To neck nodes are obviously involved, these patients will also 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 7 benefit from an ipsilateral functional neck dissection (with outcome evaluation preservation of the aforementioned structures). During the dis- The duration of a typical thyroid operation is 1 to 3 hours, section, all fibrofatty lymph node tissues should be removed depending on the size and invasiveness of the tumor, its vascu- from the level of the clavicle to the level of the hyoid bone. larity, and the location of the parathyroid glands. Postopera- The deep dissection plane is developed anterior to the scale- tively, the patient is kept in a low Fowler position with the head nus anterior, the brachial plexus, and the scalenus medius. and shoulders elevated 10° to 20° for 6 to 12 hours to maintain The phrenic nerve runs obliquely on the scalenus anterior. negative pressure in the veins. The patient typically resumes The cervical sensory nerves can usually be preserved unless eating within 3 to 4 hours, and an antiemetic is ordered as there is extensive tumor involvement. needed (many patients experience postoperative nausea and emesis). Median Sternotomy A median sternotomy is rarely The serum calcium level is measured approximately 5 to 8 necessary for removal of the thyroid gland, because the blood hours after operation in patients who have undergone bilat- supply to the thyroid gland, the thymus, and the lower para- eral exploration; no tests are required in those who have thyroid glands originates primarily from the inferior thyroid undergone a unilateral operation. On the first morning after arteries in the neck. Metastatic lymph nodes frequently extend total or completion thyroidectomy, the serum calcium and inferiorly in the tracheoesophageal groove into the superior serum phosphate levels are measured. If the patient is still mediastinum; these nodes can almost always be removed hospitalized on postoperative day 2, these tests may be through a cervical incision without any need for a sternotomy. repeated. Oral calcium supplements are given if the serum On rare occasions, metastatic nodes spread to the aortic pul- calcium concentration is below 7.5 mg/dL or if the patient monary window and can be identified preoperatively on com- experiences perioral or finger numbness or tingling. A low puted tomography (CT) or magnetic resonance imaging serum phosphate level (< 2.5 mg/dL) usually is a sign of (MRI). If a median sternotomy proves necessary, the sternum so-called bone hunger and suggests that there is little reason should be divided to the level of the third intercostal space to be concerned about permanent hypoparathyroidism, and then laterally on one side at the space between the third whereas a high level (> 4.5 mg/dL) should prompt concern and fourth ribs. Median sternotomy provides excellent expo- about possible permanent hypoparathyroidism. sure of the upper anterior mediastinum and the lower neck. The surgical clips are removed on postoperative day 1, and Steri-Strips are applied to prevent tension on the healing wound. complications Patients usually are discharged on the first day; they are given a The following are the most significant complications of prescription for thyroid hormone (L-thyroxine, 0.1 to 0.2 mg/ thyroidectomy. day orally) if the procedure was more extensive than a thyroid lobectomy, and are instructed to take calcium tablets for any 1. Injury to the recurrent laryngeal nerve. Bilateral injury to the tingling or muscle cramps. Patients with papillary, follicular, recurrent laryngeal nerves may result in vocal cord paresis or Hürthle cell cancer should receive enough L-thyroxine to and stridor and may necessitate tracheostomy. keep their serum levels of thyroid-stimulating hormone (TSH) 2. Hypoparathyroidism. This complication may arise as the below 0.1 mIU/mL. The Steri-Strips are removed on day 10, result of removal of, injury to, or devascularization of the the pathology is reviewed, and further management is discussed parathyroid glands. As noted [see Operative Technique, in the light of the pathology findings. In patients with thyroid above], we recommend leaving parathyroid glands on their cancer, values for serum calcium, TSH, and thyroglobulin are own vascular pedicle; however, if one is concerned about obtained; in patients with coexisting hyperparathyroidism, values possible devascularization of a parathyroid, biopsy should be for serum calcium, phosphorus, and parathyroid hormone performed on the gland to confirm its identity, and it should (PTH) are obtained. then be cut into multiple 1x1 mm pieces and autotrans- Most patients can return to work or full activity within 1 week. planted into separate pockets in the sternocleidomastoid Patients with benign lesions who have undergone hemithyroid- muscle. ectomy may or may not require thyroid hormone; those with 3. Bleeding. Postoperative bleeding in the neck can be life- multinodular goiter, thyroiditis, or occult papillary cancer typi- threatening because of airway compromise. Any postopera- cally do, whereas those with follicular adenoma typically do not. tive respiratory distress is due to neck hematoma until proven Patients who have undergone total or near-total thyroidectomy otherwise. Most bleeding occurs within four hours of opera- will require thyroid hormone. Patients with papillary or follicular tion, and virtually all episodes occur within 24 hours unless cancer who have undergone total or near-total thyroidectomy the patient is taking anticoagulant medications. appear to benefit from radioactive iodine scanning and therapy. 4. Injury to the external branch of the superior laryngeal (It is necessary to discontinue L-thyroxine for 6 to 8 weeks and nerve [see Operative Technique, above]. L-triiodothyronine for 2 weeks before scanning.) Those consid- 5. Infection. This complication is quite rare after thyroidec- ered to be at low risk (age < 45 years, tumor confined to the tomy. If acute pharyngitis is present preoperatively, the thyroid and not invasive, and tumor diameter < 4 cm) may operation should be rescheduled. receive radioactive iodine on an outpatient basis in a dose of 6. Seroma. Most seromas are small and resorb spontane- approximately 30 mCi. Those who are considered to be at high ously; for some, aspiration is necessary. risk should receive approximately 100 to 150 mCi. Long-term 7. Keloid. Keloid formation after thyroidectomy is most (20-year) mortality is about 4% in low-risk patients and about common in African-American patients and in patients with 40% in high-risk patients. Serum thyroglobulin levels should be a history of keloids. determined before and after discontinuance of thyroid hormone; 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 8 such levels are very sensitive indicators of persistent thyroid tracheoesophageal groove, but care must be taken to not disease after total thyroidectomy. injure the recurrent laryngeal nerve, which is frequently encountered early in the course of the dissection. Upon lateral retraction of the jugular vein and the carotid sheath Parathyroidectomy and medial retraction of the strap muscles, the recurrent operative planning laryngeal nerve can usually be identified when the tracheo- esophageal groove is exposed. The preparation for parathyroidectomy is similar to that for thyroidectomy. Patients who have profound hypercalcemia Step 2 : Parathyroid Exploration and Resection Ex- (serum calcium g12.5 mg/dL) or mild to moderate renal ploration for the parathyroid adenoma is undertaken on the failure should be vigorously hydrated and given furosemide basis of the results of the preoperative localization studies. if needed before operation. On rare occasions, patients with The upper parathyroid glands are usually found at the level refractory hypercalcemia will require additional treatment with of the ligament of Berry, posterior to the recurrent laryngeal bisphosphonates or calcitonin. Any electrolyte abnormalities nerve. The lower glands are usually found anterior to the (e.g., hypokalemia) should be corrected. recurrent laryngeal nerve and caudal to the point where the The gold standard operation for primary hyperparathyroidism recurrent laryngeal nerve crosses the inferior thyroid artery. remains bilateral neck exploration; however, the excellent The thyroid gland can be retracted medially and anteriorly results of preoperative imaging with sestamibi scanning and with a peanut sponge. Palpation for the adenoma may be ultrasonography, coupled with the availability of rapid intra- carried out to complement visual inspection. Once the ade- operative PTH assays, have made unilateral focused exploration noma is identified and carefully dissected free of surrounding feasible for well-localized parathyroid adenomas. Preoperative tissues, its vascular pedicle is clipped and the specimen exam- localizing studies are essential when reoperation for persistent or ined ex vivo. If intraoperative PTH monitoring is employed, recurrent hyperparathyroidism is indicated. We do not believe postexcision values are obtained 5 and 10 minutes after spec- that using the gamma probe is any better than preoperative imen removal and compared with preexcision values. At this sestamibi scanning for either first-time surgery or reoperation. point, the remaining parathyroid gland on the ipsilateral side All patients requiring reoperation should undergo direct or of the neck can be identified. If the intraoperative PTH level indirect laryngoscopy before operation for evaluation of vocal does not drop by an appropriate amount, or if other intraop- cord function. erative findings raise any questions regarding the diagnosis of a single adenoma, then the contralateral side of the neck operative technique should be explored. Unilateral Exploration Step 3: Closure The lateral border of the strap muscle Step 1: Lateral Approach between Sternocleidomas- is approximated to the medial border of the sternocleidomas- toid and Strap Muscles For a well-localized parathyroid toid muscle with one or two interrupted absorbable sutures. adenoma, we usually perform unilateral exploration via a The platysma muscle is reapproximated with interrupted lateral approach; this approach is also useful for reoperation. absorbable sutures, and the skin is closed with either buried A 2 to 3 cm incision is made overlying a naturally occurring interrupted subdermal sutures or a continuous subcuticular skin crease approximately 1 cm below the cricoid cartilage suture. and lateral to the midline. The incision should overlie the lateral border of the strap muscles and may extend onto the Bilateral Exploration anterior surface of the sternocleidomastoid muscle for a dis- Steps 1 through 4 Steps 1, 2, 3, and 4 of a bilateral tance of up to 0.5 cm. Dissection is continued down through exploration for parathyroidectomy are virtually identical to the platysma muscle until the medial border of the sterno- steps 1, 2, 4, and 5 of a thyroidectomy [see Thyroidectomy, cleidomastoid muscle is encountered. The medial border of Operative Technique, above], and the same troubleshooting the sternocleidomastoid muscle is mobilized for a few centi- considerations apply. meters superiorly and inferiorly. The avascular space between the medial border of the sternocleidomastoid muscle and the Troubleshooting. About 85% of people have four parathy- lateral border of the strap muscles is developed. The internal roid glands, and in about 85% of these persons, the parathyroids jugular vein becomes apparent at this point. Deep and medial are situated on the posterior lateral capsule of the thyroid. to this vein lies the carotid sheath. The internal jugular vein Normal parathyroid glands measure about 3x3x4 mm and are and the carotid sheath are retracted laterally, and the lateral light brown in color. The upper parathyroid glands are more border of the strap muscles is retracted medially. We do not posterior (i.e., dorsal) and more constant in position (at the level routinely divide the omohyoid muscle, which will traverse the of the cricoid cartilage) than the lower parathyroid glands, which space that is developed; the muscle can simply be retracted typically are more anteriorly placed (on the posterior-lateral out of the path of the dissection. The recurrent laryngeal surface of the thyroid gland). In most patients, both the upper nerve is frequently identified at this point within the tracheo- and the lower parathyroid glands are supplied by small branches esophageal groove. The lateral border of the thyroid gland is of the inferior and superior thyroid arteries. About 15% of identified, and the dissection of the parathyroid adenoma can parathyroid glands are situated within the thymus, and about commence. 1% are intrathyroidal. Other abnormal sites for the parathyroid glands are (1) the carotid sheath, (2) the anterior and posterior Troubleshooting. The lateral approach affords easy mediastinum, and (3) anterior to the carotid bulb or along the access to the lateral border of the thyroid gland and the pharynx (undescended parathyroids). 07/08
  • © 2008 BC Decker Inc ACS Surgery: Principles and Practice 2 HEAD AND NECK 9 THYROID AND PARATHYROID OPERATIONS — 9 The upper parathyroid glands are usually lateral to the have been located and no abnormal parathyroid tissue has recurrent laryngeal nerve at the level of Berry’s ligament; their been identified. The carotid sheath and the area posterior position makes them generally easier to preserve during thyroid- to the carotid, as well as the retroesophageal area, should ectomy and easier to find during both parathyroid and thyroid also be explored. In rare cases, there may be an undescended surgery. When the upper parathyroids are not found at this site, parathyroid tumor anterior to the carotid bulb. they often can be found in the tracheoesophageal groove or in Although we do not recommend routine biopsy of more than the posterior mediastinum along the esophagus. The lower para- one normal-appearing parathyroid gland, we do recommend thyroid glands are almost always situated anterior to the recur- biopsy (not removal) and marking of all normal parathyroid rent laryngeal nerves and caudal to the point where the recurrent glands that have been identified when no abnormal parathyroid laryngeal nerve crosses the inferior thyroid artery; they may be tissue can be found. When four normal parathyroid glands surrounded by lymph nodes. When the lower parathyroids are are found in the neck, the fifth (abnormal) parathyroid gland is not found at this site, they usually can be found in the anterior usually in the mediastinum. Median sternotomy is not indicated mediastinum (typically in the thymus or the thymic fat). during initial operation unless the patient’s calcium concentra- tion is severely elevated; instead, the operation should be termi- Step 5: Parathyroid Resection Abnormal parathyroid nated, the patient should undergo repeat imaging studies, and glands are removed in the manner previously described referral to an endocrine surgery center should be considered. (see above). In about 80% of patients with primary hyper- The surgeon’s responsibilities are to make sure during the parathyroidism, one parathyroid gland is abnormal; in about initial operation that the elusive parathyroid adenoma is not 15%, all glands are abnormal (diffuse hyperplasia); and in removable through the cervical incision and to minimize about 5%, two or three glands are abnormal and one or two complications. The risk of permanent hypoparathyroidism or injury to the recurrent laryngeal nerve should be less than normal. Parathyroid cancer occurs in about 1% of patients with 2%. primary hyperparathyroidism. About 50% of patients with parathyroid cancer have a palpable tumor, and most exhibit Step 6: Closure Closure is essentially the same for profound hypercalcemia (serum calcium g14.0 mg/dL). parathyroidectomy as for thyroidectomy. Troubleshooting. In some patients, parathyroid tumors complications and hyperplastic parathyroid glands are difficult to find. If The complications of parathyroidectomy are similar to this is the case, the first step is to explore the sites where those of thyroidectomy but occur less often. Patients with a parathyroids are usually located, near the posterolateral very high preoperative serum alkaline phosphatase level and surface of the thyroid gland. (About 80% of parathyroid osteitis fibrosa cystica are prone to profound hypocalcemia glands are situated within 1 cm of the point where the inferior after parathyroidectomy. In these patients, both serum thyroid artery crosses the recurrent laryngeal nerve.) When a calcium and serum phosphorus levels are low. In contrast, lower gland is missing from the usual location, it is likely to patients with true hypoparathyroidism exhibit low serum be found in the thymus; this possibility can be confirmed by calcium levels but high serum phosphorus levels. mobilizing the thymus from the anterior-superior mediasti- num. If an upper parathyroid gland cannot be located, one outcome evaluation should look not only far behind the thyroid gland superiorly Outcome considerations are essentially the same as for but also in a paraesophageal position down into the posterior thyroidectomy. The patient should have a normal voice mediastinum. A thyroid lobectomy or thyroidotomy can be and be normocalcemic. The overall complication rate and done on the side where fewer than two parathyroid glands recurrence rate should be less than 2%. Recommended Reading Arici C, Cheah WK, Ituarte PH, et al. Can Clark OH. Endocrine surgery of the thyroid thyroidectomy. Surg Oncol Clin N Am localization studies be used to direct focused and parathyroid glands. Philadelphia: WB 2008;17:121–44. parathyroid operations? Surgery 2001;129: Saunders Co; 2003. Palazzo FF, Delbridge LW. Minimal-access/mini- 720–9. Lee JA, Inabnet WB 3rd. The surgeon’s arma- mally invasive parathyroidectomy for primary Bliss RD, Gauger PG, Delbridge LW. Surgeon’s mentarium to the surgical treatment of hyperparathyroidism. Surg Clin North Am approach to the thyroid gland: surgical primary hyperparathyroidism. J Surg Oncol 2004;84:717–34. 2005;89:130–5. anatomy and the importance of technique. Lennquist S. Thyroidectomy. In: Clark OH, World J Surg 2000;24:891–7. Duh Q-Y, Kebebew E, editors. Textbook of Cady B, Rossi R: Surgery of thyroid gland. endocrine surgery. 2nd ed. Philadelphia: WB In: Cady B, Rossi R, editors. Surgery of the Acknowledgment Saunders Co; 2005. p. 828. thyroid and parathyroid glands. Philadelphia: Miller MC, Spiegel JR. Identification and moni- WB Saunders Co; 1991. toring of the recurrent laryngeal nerve during Figures 1 through 7 Tom Moore. 07/08