Background: A recent study of focused minimally invasive parathyroidectomy (FPTX) in sporadic primary hyperparathyroidism (pHPT) using intraoperative parathyroid hormone (ioPTH) measurements shows that inadequate ioPTH drop and multiglandular disease are more commonly found when a first gland<200 mg is resected. Our aim was to study if a resected gland that weighed <200 mg was associated with an increased persistence rate after FPTX.
Methods: This is a cohort study of FPTX for pHPT performed in the period 1998-2013. FPTX was performed in patients with pHPT where Sestamibi and Ultrasound imaging localized single-gland disease, only one gland was excised and the weight recorded. IoPTH was not used routinely. Two groups were composed according to the weight of the resected gland: Group A<200 mg and Group B≥200 mg. Persistent or recurrent disease was defined if it occurred within, or after 6 months. The primary outcome measure was the rate of persisting pHPT.
Results: A total of 3,511 parathyroidectomies were performed, and a total 1,745 FPTX (1,347 female) met inclusion criteria. There were 245 and 1,500 patients in groups A and B, respectively. The rate of persistent pHPT was higher in Group A, 6.1 versus 2.0% (p<0.001). Findings at re-operative surgery showed that the ipsilateral gland was diseased in 47% (7/15) of persistent cases in group A.
Conclusion: The risk of persistent disease after MIP was higher if the resected gland weighed ≤200 mg, and this corroborates the findings of a recent study. A heightened awareness of the possibility of multigland disease should be raised, and ioPTH monitoring, identification of the ipsilateral gland or bilateral exploration may be advisable in such cases.