Incidental parathyroidectomy in thyroidectomy and central neck dissection

Background: Although higher thyroidectomy volume has been linked with lower complication rates, its association with incidental parathyroidectomy remains less studied. The volume relationship is even less clear for central neck dissection, where individual parathyroid glands are at greater risk. Methods: Patients undergoing thyroidectomy with or without central neck dissection were evaluated for incidental parathyroidectomy, hypoparathyroidism, and hypocalcemia. Univariate and multivariable analyses were performed using binary logistic regression. Results: Overall, 1,114 thyroidectomies and 396 concurrent central neck dissections were performed across 7 surgeons. Incidental parathyroidectomy occurred in 22.4% of surgeries (range, 16.9%-43.6%), affecting 7.1% of parathyroids at risk (range, 5.8%-14.5%). When stratified by surgeon, lower incidental parathyroidectomy rates were associated with higher thyroidectomy volumes (R-2 = 0.77, P =.008) and higher central neck dissection volumes (R-2 = 0.93, P < .001). On multivariable analysis, low-volume surgeon (odds ratio 2.94, 95% confidence interval 2.06-4.19, P < .001), extrathyroidal extension (odds ratio 3.13, 95% confidence interval 1.24-7.87, P = .016), prophylactic central neck dissection (odds ratio 2.68, 95% confidence interval 1.65-4.35, P <.001), and therapeutic central neck dissection (odds ratio 4.44, 95% confidence interval 1.98-9.96, P < .001) were the most significant factors associated with incidental parathyroidectomy. In addition, incidental parathyroidectomy was associated with a higher likelihood of temporary hypoparathyroidism (odds ratio 2.79, 95% confidence interval 1.45-5.38, P = .002) and permanent hypoparathyroidism (odds ratio 4.62, 95% confidence interval 1.41-5.96, P = .025), but not permanent hypocalcemia (odds ratio 1.27, 95% confidence interval 0.48-3.35, P = .63). Higher lymph node yield in central neck dissection was not associated with higher incidental parathyroidectomy rates (odds ratio 1.13, 95% confidence interval 0.85-8.81, P = .82). Conclusion: Higher surgical volume conferred a lower rate of incidental parathyroidectomy. Nonetheless, greater lymph node yield in central neck dissections did not result in greater parathyroid-related morbidity. Such findings support the value of leveraging surgical volume to both optimize oncologic resection and minimize complication rates. (C) 2020 Elsevier Inc. All rights reserved.