Infection

Prophylactic antibiotics are not required for patients undergoing first or second time neck exploration. Wound infection should not occur. Infection may occur secondarily in a hematoma. Treatment requires incision and drainage with a prescription of antibiotics. The process of audit should confirm a low incidence of wound infection.

Hematoma

Drains are not required in patients undergoing first or second time neck exploration (1). Hemostasis should be meticulous. Minute bleeding points can be spotted if the wound is filled with saline at the end of the procedure. The incidence of hematomas requiring intervention should be less than 0.5%. Hematomas are readily treated by incision and drainage or, if liquid, by wide bore needle aspiration.

Skin tethering

Despite closing the strap muscles and platysma (some surgeons do not) the subcutaneous tissues and skin may become tethered to the larynx and/or trachea and move uncomfortably with the larynx on swallowing. The incidence of this complication should be very low. Attempts at skin release are not always successful and retethering can occur.

Keloid formation

With an incision in or parallel to a naturally occurring neck skin crease, the wound should heal with an excellent cosmetic result. Some surgeons close platysma and some do not and there are many ways of closing the skin (-clips, sutures, subcuticular sutures, adhesive strips, etc) and one is probably no better than another. If an incision curves down onto the sternum then keloid formation is more likely. Re-excision with or without steroid injection is no guarantee of a better cosmetic result.

Hematoma

This should be a complication of exceedingly low incidence. The blood supply of most parathyroid tumors is well defined and can be seen if the tumor is carefully dissected. The vascular pedicle can be dealt with by diathermy, ligature or metal clips, and these techniques should provide secure hemostasis. The tumors are sometimes fed by branches of the superior and/or inferior thyroid arteries and/or the internal mammary artery and care must be taken to ensure that these branches are securely ligated.

If a hematoma develops the patient should be taken to theatre, the hematoma evacuated and the cause of bleeding dealt with. Expanding hematomas can threaten airway patency and urgency may be required.

Recurrent nerve injury

The recurrent nerve will be vulnerable to injury when dissection and removal of adenomas occurs close to the branches of the inferior thyroid artery. The development of an intraneural hematoma can readily occur through disruption of the fine feeding vessels which run throughout the substance of the nerve. The nerve is especially vulnerable in removal of superior adenomas which “grow” inferiorly and “drop into” the upper posterior mediastinum behind the inferior thyroid artery (2).

Golden rules to help avoid nerve injury are:

(i.

Stay close to the adenoma surface during dissection.

(ii.

Be exceedingly careful if diathermy is used - remember the circumference of thermal injury extends well beyond the points of the forceps, especially if monopolar diathermy is used.

(iii.

Be thoroughly conversant with the course of the nerve and if the adenoma overlies or comes in close proximity be sure that the nerve is seen and preserved throughout mobilization and dissection.

(iv.

Do not sling the nerve on tapes or threads and avoid handling or palpating the nerve.

Superior laryngeal nerve

This will be vulnerable in dissections close to the upper thyroid pole. Adenomas will not be close to the main nerve trunk but the external branch (to the cricothyroid muscle) might be damaged, especially if a superior adenoma is closely applied to the upper thyroid pole or entwined within superior thyroid vessels. Carefully develop the space between the medial surface of the upper pole and the cricothyroid muscle and, if superior thyroid vessels have to be divided to allow access to the adenoma, be sure to divide them individually and on the surface of the thyroid gland and not above the upper pole.

Adenoma/disease not found

Parathyroid surgery should not be undertaken unless a trainee or surgeon is fully conversant with all the potential ,,hiding places,, of the glands (reference). The only localization required before first time exploration is the localization of a parathyroid surgeon (3)! Such a surgeon will successfully identify and remove abnormal tissue in 97% of patients, resulting in eucalcemia. Neck exploration should not be abandoned as negative until all possible ectopic sites have been explored: intrathyroidal adenomas, within the thymus, within the carotid sheath, retro-oesophageal, etc. If no abnormal glands are uncovered think:

(i.

Could the diagnosis be incorrect? (see below)

(ii.

Could the patient have primary parathyroid hyperplasia? - consider biopsy of one of the apparently normal glands.

(iii.

How many glands can be confidently identified? - mark them with a silver clip and/or suture to aid subsequent localization by radiology or surgery.

(iv.

If only one gland is missing this should help in focusing or directing appropriate exploration in that quadrant of the neck.

The surgeon should be leaving the neck after a negative exploration having confidence that the tumor must be truly ectopic (e.g. within the chest) (4).

Persistent/recurrent disease

The criteria of Muller (5) for true recurrent disease will not be fulfilled in today's practice because they required:

(i.

Biopsy confirmation of all four glands (not done today)

(ii.

Removal of all abnormal tissue

(iii.

Achievement of normal calcium for one year after surgery

(iv.

Identification of abnormal pathology at the site of a previously normal gland

Most disease is persistent disease.

Wrong diagnosis/persistent disease

If hypercalcemia persists after first exploration then the diagnosis of primary hyperparathyroidism has to be reconfirmed by establishing (a) positive or confirmatory markers such as inappropriately high PTH, hypercalciuria, hypophosphataemia, etc, and (b) negative markers - be sure to have excluded familial hypocalciuric hypercalcemia and occult malignancy or other causes of hypercalcemia.

If a diagnosis of persistent primary hyperparathyroidism is confirmed then be sure that the patient warrants re-exploration with its attendant increased morbidity. For example, you might not wish to re-explore the neck of an 85 year old woman with cerebro-vascular disease and mild asymptomatic hypercalcemia. You would want to re-explore a 35 year old man with a serum calcium of 3.00 mmol/l who continues to produce renal calculi. If the diagnosis is confirmed and re-exploration is warranted then localization should be carried out before surgery. The operation note should be reviewed to see if the localization coincides with a likely uncovered adenoma. For example - if three normal glands had been found but the left inferior gland had not been seen and Sestimibi and MRI scans suggest a mediastinal gland in the upper left quadrant, then exploration should be directed initially in this area. The adenoma is likely to be in the upper horn of the left thymic lobe.

The histopathology and frozen section reports pertaining to the first exploration must be reviewed. Frozen section errors “allow” premature and in approprite cessation of exploration. Failure to recognize hyperplasia on frozen section, for example, leads to inadequate resection. A false call of an adenoma instead of hyperplasia “allows” three hyperplastic glands to remain in situ (6). More appropriate surgery would have been 3_ gland resection. Surgical errors “allow” multiple adenomas to be left in situ because the condition is not known about or because not all glands were visualized. A danger of scan directed unilateral neck exploration is that in 10% of patients the existence of hyperplasia and/or double or multiple adenomas will not be recognized by preoperative scans or by the surgeon only opening one compartment of the neck (7).

Hypocalcemia

An aggressive biopsy policy leads to a higher incidence of postoperative hypocalcemia (8). Currently most surgeons remove only the abnormal gland(s) and at most might take a sliver biopsy of one of the other glands. The other glands can, of course, be inadvertently bruised or devascularized, thereby leading to hypocalcemia.

Further contributions to the incidence and severity of hypocalcemia include the atrophy of residual glands in the face of a single hyperfunctioning adenoma (especially if there has been longstanding and significant hypercalcemia), so called hungry bone syndrome and previous parathyroid or thyroid surgery. It may need treating with vitamin D and/or calcium supplements. Very rarely a patient may need vitamin D and calcium supplements in the long term especially after reoperative parathyroid surgery or after resection of multiple gland disease (9).

Complications and informed consent

The operating surgeon should have audit figures from his or her own practice which provide details on various end points, both “happy” - e.g. restoration of normocalcemia with no complication, and “sad” - e.g. high rate of recurrent nerve injury. The surgeon's figures must be bench marked against other national or international figures. It is becoming possible to calculate acceptable standards. Surgeons falling below a certain level of performance must stop and examine possible reasons for this, e.g. high rate of reoperative surgery. Inadequate technical performance must not be excluded as a possible cause. The higher the volume of patients then the more secure is the data on performance and, for this reason alone, there may be justification for rationalizing the provision of surgery for this rather rare condition. A poor performance is more readily spotted in a surgeon performing five parathyroid procedures per year rather than five surgeons performing one each year.

Armed with local performance data and a knowledge of other external standards the surgeon should inform patients of possible complications. The threshold of disclosure will vary from country to country and from patient to patient. A five page information booklet might be expected in some cultures. A legal system might expect that any complication occurring at a rate of 1% or more must be discussed. An elderly patient might say “I trust you doctor, I don’t understand these things, do what you have to do and what will be will be.” In whichever setting be sure to write in the notes exactly what you have said.

Complications can be particularly hard end points which are easily measured, e.g. persistent hypercalcemia. Others are softer, e.g. the definition of a wound infection (Is it a red wound? Does there have to be pus? Does there have to be a positive microbiology culture?).

Symptom relief may be obvious and dramatic, for example, following excision of a 10 gram adenoma in a patient with hypercalcemic crisis. For the majority of patients with primary hyperparathyroidism, however, symptoms may be vague and only tenuously linked to a mild degree of hypercalcemia. The causative link is more difficult to establish in the elderly when bone pains, lassitude and mental change may occur as part of the “normal” aging process. An elderly patient may not notice that his ejection fraction has improved by 10% or that his cognitive function has improved by 15%! These functions can be measured and used to “justify” surgical intervention but be sure to remember they do not necessarily convert into tangible feelings of better health in the patient. You must, therefore, carefully describe the expected benefits. A dissatisfied patient is a rarely measured end point and yet it is the most important and disastrous complication. As well as a technically excellent outcome be sure that communication skills are both good and objective and based on your own results.

References

1.

Kristoffersson A, Sandzen B, Jarhult J. Drainage in uncomplicated thyroid and parathyroid surgery. Br J Surg. (1986);73:121–124. [PubMed: 3947901]

2.

Sinclair I S R. The risk to the recurrent laryngeal nerves in thyroid and parathyroid surgery. JR Coll Surg Edinb. (1994);39:253–257. [PubMed: 7807461]

3.

Hewin D F, Brammar T J, Kabala J, Farndon J R. Role of preoperative localization in the management of primary hyperparathyroidism. Br J Surg. (1997);84:1377–1380. [PubMed: 9361592]

4.

Rothmund M. A parathyroid adenoma cannot be found during neck exploration of a patient with presumed primary hyperparathyroidism. Br J Surg. (1999);86:725–726. [PubMed: 10383569]

5.

Muller H. True recurrence of hyperparathyroidism: proposed criteria for recurrence. Br J Surg. (1975);62:556–559. [PubMed: 1174787]

6.

Thompson N W, Sandelin K. Primary hyperparathyroidism caused by multiple gland disease (hyperplasia) long-term results in familial and sporadic cases. Acta Chir Aust. (1994);26 (S112):44–47.

7.

Szabo E, Lundgren E, Juhlin C, Ljunghall S, Akerstrom G, Rastad J. Double parathyroid adenoma, a clinically nondistinct entity of primary hyperparathyroidism. World J Surg. (1998);22:708–713. [PubMed: 9606286]

8.

Kaplan E L, Bartlett S, Sugimoto J, Fredland A. Relation of postoperative hypocalcemia to operative techniques: Deleterious effect of excessive use of parathyroid biopsy. Surgery. (1982);92:827–834. [PubMed: 7135203]

9.

Wong W K, Wong N A C S, Farndon J R. Early postoperative plasma calcium concentration as a predictor of the need for calcium supplement after parathyroidectomy. Br J Surg. (1996);83:532–534. [PubMed: 8665252]