D. C. Cron1, S. Kapeles1, S. Kwon1, P. Kirk1, E. Andraska1, B. McNeish1, D. T. Hughes1 1University Of Michigan,Surgery,Ann Arbor, MI, USA
Introduction: Cure rates for hyperparathyroidism with parathyroidectomy are typically 95%; however, studies analyzing risk factors for operative failure and persistent hyperparathyroidism are limited. This study sought to identify predictors of operative failure in parathyroidectomy for primary hyperparathyroidism.
Methods: This is a retrospective review of 2084 adult patients with primary hyperparathyroidism who underwent initial parathyroidectomy at a single center from 1999-2012. Parathyroidectomy included both directed-approach (59%) and bilateral explorations (41%). The following data were collected: age, sex, perioperative lab values, imaging results, thyroid pathology, intraoperative data including parathyroid hormone (IOPTH) levels, and number of excised glands. Biochemical cure was defined as both an IOPTH decrease of ≥50% from the baseline and a level in the normal range (<75pg/ml). Operative failure (persistent disease) was defined by two or more postop serum calcium measurements ≥10.2mg/dL or a single calcium ≥11.0mg/dL when no other data available. Univariate logistic regression and backwards-stepwise multivariate logistic regression were used to identify significant predictors of operative failure.
Results: Operative failure was identified in 65 patients (3%), with 35% having reoperative parathyroidectomy as a result. Significant predictors of failure on univariate analysis included: failure to meet IOPTH criteria, lower excised gland weight (< median of 600mg), multiple glands excised, bilateral exploration, lower preop PTH, higher preop calcium, and higher final IOPTH. A correct pre-op sestamibi was protective (Fig. A). Preop ultrasound localization was not associated with operative success. Predictors retained in the multivariate model included: IOPTH criteria met (OR=0.2, CI 0.1-0.3, P<0.01), low gland weight (OR=4.2, CI 2.0-9.0, P<0.01), high preop calcium (OR=1.9, CI 1.3-2.8), and low preop PTH (OR=0.99 CI 0.99-1.0, P=0.03). The C-statistic for this model was 0.80 (Fig. B).
Conclusion: Operative failure of parathyroidectomy for primary hyperparathyroidism is rare; however, failure to meet IOPTH criteria, low preoperative PTH levels, high preoperative calcium levels, and low gland weight are risk factors for persistent disease.
