Impact of concurrent thyroid pathology on surgical intervention for primary hyperparathyroidism

Objectives: Minimally-Invasive Parathyroidectomy (MIP) is the gold standard treatment of primary hyperparathyroidism in single-gland disease with adequate pre-operative localization. The study aim was to evaluate the effect of concomitant thyroid pathology on the accuracy of pre-operative localization for primary hyperparathyroidism and impact on the surgical approach.

Methods: A retrospective cohort analysis of patients undergoing surgical intervention for parathyroid disease in a tertiary referral center from 1999 to June 2014 was conducted.

Results: Of 429 parathyroidectomies performed on 424 patients, coexistent thyroid pathology was identified in 68 patients (16%). The sensitivity of pre-operative localization of parathyroid pathology in these patients was considerably lower than in patients without concurrent thyroid disease: ultrasonography 55% vs 63%, ^99mTc-sestamibi scintigraphy 50% vs 60% and CT 47% vs 49%. Single-gland disease was present in 58 patients (85%), but correctly identified on pre-operative imaging in only 43%. Of these 58 patients, 45 (66%) required Bilateral Neck Exploration (BNE), with MIP in 23 (34%) with a conversion rate of 13%. All conversions resulted from intra-operative identification of thyroid disease. Of the remaining open procedures, 40 (88%) were conducted with simultaneous thyroid lobectomy/total thyroidectomy, 2 (4%) due to multi-nodular goitre, and 3 to thyroiditis and thyroid nodules/cysts. The biochemical cure rate was 100%. In 84 months median follow-up, no patient experienced persistent or recurrent hypercalcemia, or required re-intervention.

Conclusion: Concurrent thyroid pathology reduces the sensitivity of pre-operative localization of parathyroid pathology and results in higher rates of open parathyroidectomy in single-gland disease.