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Thyroid and Parathyroid Glands

Cernea CR, Dias FL, Fliss D, Lima RA, Myers EN, Wei WI (eds): Pearls and Pitfalls in Head and Neck Surgery. Basel, Karger, 2012, pp 24–25

DOI: 10.1159/000337469

1.12 Reoperative Parathyroidectomy

Alfred Simental

Otolaryngology Head Neck Surgery, Loma Linda University, Loma Linda, Calif., USA

P E A R L S

• Confirm initial diagnosis.

• Maximize localization techniques.

• Read previous operative and pathology reports.

• Work in previously undissected field first, lateral to medial, where scarring is least and probability of finding affected gland is highest.

• Develop an organized dissection pattern and understand ectopic locations.

• Identify and remove concomitant thyroid pathology.

P I T F A L L S

• Failing to recognize improper diagnosis.

• Risk of permanent hypocalcemia and vocal cord paralysis is greatly increased in reoperative surgery.

• Removing normal parathyroid glands.

• Pharyngoesophageal injury.

• Failure to preoperatively recognize concomitant pathology.

Introduction

Hyperparathyroidism is surgically cured on initial exploration in more than 90-95% of cases in experienced hands. However, uncontrolled hyperparathyroidism after unsuccessful explorations may result in severe osteoporosis, fatigue, depression, nephrolithiasis, renal failure, hypertension, and increased cardiovascular risk. This necessitates consideration for re-exploration and surgical correction of the hyperparathyroid state, especially in younger patients.

Re-exploration for hyperparathyroidism is complicated by previous scarring, a higher incidence of tumors in ectopic locations, multigland hyperplasia, and may be associated with recurrence of parathyroid carcinoma. Ectopic parathyroid locations include thymus, thyroid, carotid sheath, retroesophageal, superior mediastinum, tracheoesophageal groove, submandibular, and posterior mediastinum [1, 2].

Patients and physicians should understand that reoperative surgery has inherently increased risks. Reoperation in a scarred field increases the risk of injury to the recurrent laryngeal and superior laryngeal nerves, resulting in subsequent dysphonia. In addition, the incidence of either postoperative hypoparathyroidism or persistent hyperparathyroidism is increased and may approach 10% [3]. Localization studies may aid in identifying ectopic and hyperfunctioning glands, while reducing the morbidity of re-exploration [4].

Practical Tips

Before embarking on reoperative surgery, the initial diagnosis of hyperparathyroidism should be confirmed ruling out medications, dietary contributions, or any secondary reason to have hypercalcemia, especially benign familial hypocalciuric hypercalcemia. Endocrinology evaluation can confirm the diagnosis and determine whether medical management may be effective. Re-exploration should be delayed at least 6-9months to allow inflammation to subside and increase the efficacy of repeat imaging studies.

The previous operative and pathological reports should be reviewed to determine previous sites of exploration, pathological confirmation of removed tissues, and other intraoperative findings. In situations of unilateral exploration, the unexplored side is utilized unless localization studies suggest the initial side is active.

Imaging studies should be repeated, including sestamibi imaging to look for new or ectopic activity [5] and ultrasound to determine presence of thyroid nodules and paratracheal masses, which may represent enlarged parathyroid glands or concomitant thyroid pathology. CT or MRI may also be considered to evaluate the mediastinal and retroesophageal regions that may not be visualized by ultrasound [6]. Selective venous sampling by interventional radiology may help determine laterality and possibly venous outflow location of the most active gland [7]. Internal jugular vein sampling is also helpful.

Intraoperative parathyroid hormone monitoring should be employed to determine adequacy of resection and prevent hypoparathyroidism, beginning with a preincision 'defined baseline level' [8, 9]. Postresection intraoperative parathyroid hormone levels drawn at 10 min should be at least reduced by 50% unless the level is within the normal range. A draw at 15 min should continue to reveal a drop of 25-30%, as an additional half-life has occurred.

Localization studies should direct exploration. The reoperative strategy should routinely begin by exposing the carotid artery, then work from lateral to medial towards the cricoid cartilage. The recurrent laryngeal nerve should be identified early, either just inferior to the cricoid cartilage or lower in the lateral paratracheal region where scarring is least. Once the carotid and recurrent nerve are dissected, exploration of the paratracheal region, retropharyngeal, retrothyroid, and superior mediastinum should be systematically undertaken. Any intrathyroidal lesions should prompt thyroidectomy as these may represent intrathyroidal parathyroid glands, especially in the face of unsuccessful exploration. Early exploration of the superior mediastinum with resection of thymus should be considered after the routine areas have been explored [10].

Conclusion

Reoperative surgery for hyperparathyroidism is associated with increased incidence of complications including vocal cord paralysis, permanent hypoparathyroidism, and persistent hypercalcemia. The use of nuclear medicine imaging, ultrasound and high resolution CT/MRI may aid in surgical planning. However, knoWIedge of potential ectopic locations and a well-planned surgical approach from lateral to medial are critical in ensuring adequate resection, which may be verified by intraoperative parathyroid hormone monitoring.

References

1 Phitayakorn R, McHenry CR: Incidence and location of ectopic abnormal parathyroid glands. Am J Surg 2006;191:418–423.

2 Shen W, Duren M, Morita E, et al: Reoperation for persistent or recurrent primary hyperparathyroidism. Arch Surg 1996; 131: 861-869.

3 Allendorf J, Digorgi M, Spanknebel K, et al: 1112 consecutive bilateral neck explorations for primary hyperparathyroism. World J Surg 2007;31:2075–2080.

4 Rodriguez JM, Tezelman S, Siperstein AE, et al: Localization procedures in patients with persistent or recurrent hyperparathyroidism. Arch Surg 1994;129:870–875.

5 Chen CC, Skarulis MC, Fraker DL, et al: Technetium-99m-sestamibi imaging before reoperation for primary hyperparathyroidism. J Nucl Med 1995;36:2186–2191.

6 Rodgers SE, Hunter GJ, Hamberg LM, et al: Improved preoperative planning for directed parathyroidectomy with 4-dimensional computed tomography. Surgery 2006;140:932–940.

7 Ogilvie CM, Brown PL, Matson M, et al: Selective parathyroid venous sampling in patients with complicated hyperparathyroidism. Eur J Endocrinol 2006;155:813–821.

8 Riss P, Kaczirek K, Heinz G, et al: A ‘defined baseline’ in PTH monitoring increases surgical success in patients with multiple gland disease. Surgery 2007;142:398–404.

9 Richards ML, Thompson GB, Farley DR, et al: Reoperative parathyroidectomy in 228 patients during the era of minimal-access surgery and intraoperative parathyroid hormone monitoring. Am J Surg 2008;196:937–943.

10 Powell AC, Alexander HR, Chang R, et al: Reoperation for parathyroid adenoma: a contemporary experience. Surgery 2009;146:1144–1155.

Alfred A. Simental Jr., MD, FACS

Chair Loma Linda University

Otolaryngology Head Neck Surgery

11234 Anderson St., Suite 2586

Loma Linda, CA 92354 (USA)

E-Mail asimenta@llu.edu