Inadvertent parathyroidectomy: incidence, risk factors, and outcomes

Parathyroid glands are ≤5 mm, often subcapsular or intrathyroidal, and obscured by lymph nodes, making preservation a challenge. The purpose of this study was to determine the incidence of inadvertent parathyroidectomy (IP) and whether it contributes to hypoparathyroidism after thyroidectomy.

A retrospective review of all thyroidectomies by a single surgeon from January 2010 to August 2014 was completed to determine the rate of IP and permanent hypoparathyroidism. Medical records were assessed for demographics, extent of thyroidectomy, central compartment neck dissection, thyroid gland weight, parathyroid autotransplantation, reoperation, pathology, postoperative calcium levels, and number of parathyroid glands removed.

A total of 386 patients underwent thyroidectomy. Mean age was 52 y, and 327 (85%) patients were women. There were 25 (7%) patients who underwent reoperation, 40 (10%) who underwent central compartment neck dissection, and 128 (33%) who underwent parathyroid autotransplantation. IP occurred in 78 (20%) patients. Permanent hypoparathyroidism occurred in 7 (2.7%) of 258 patients after total or completion thyroidectomy, four (6.7%) with IP compared with three (1.5%) without IP (P = 0.033). Logistic regression analysis revealed that female gender (odds ratio = 2.768, P = 0.040), central compartment neck dissection (odds ratio = 9.584, P = 0.001), and thyroid gland weight (odds ratio = 0.994, P = 0.022) were independent factors associated with IP.

IP, which occurred in 20% of patients undergoing thyroidectomy, is a potentially remediable factor associated with a higher rate of hypoparathyroidism. Central compartment neck dissection is an independent risk factor for IP.