Predictors of single-gland vs multigland parathyroid disease in primary hyperparathyroidism - A simple and accurate scoring model

Hypothesis: Preoperative clinical, biochemical, and imaging studies could be used to reliably select patients with single-gland primary hyperparathyroidism who could undergo minimally invasive parathyroidectomy and to determine whether additional perioperative testing is necessary. Design: Retrospective analysis. Setting: Tertiary referral center. Patients: A total of 238 patients who underwent neck surgical exploration and parathyroidectomy for primary hyperparathyroidism from January 7, 2002, to December 23, 2004. Main Outcome Measures: Demographic, clinical, biochemical, and imaging factors that predict single-gland vs multigland parathyroid disease, and biochemical cure. Results: Of the 238 patients, 75.2% had a single adenoma, 21.4% had asymmetric 4-gland hyperplasia, and 3.4% had double adenomas. A biochemical cure was achieved in 99.2% of the patients. Preoperative calcium and intact parathyroid hormone levels were significantly higher (P=.03 and.04, respectively) and ultrasound and sestamibi scan results were more likely to be positive (both P <.001) in single-gland primary hyperparathyroidism. A dichotomous scoring model based on preoperative total calcium level (>= 3 mmol/L [>= 12 mg/dL]), intact parathyroid hormone level (>= 2 times the upper limit of normal levels), positive ultrasound and sestarnibi scan results for I enlarged gland, and concordant ultrasound and sestamibi scan findings reliably distinguished single-gland vs multigland cases (P <.001). The positive predictive value of this scoring model to correctly predict single-gland disease was 100% for a total score of 3 or higher. Conclusions: Preoperative biochemical and imaging study results reliably distinguished single-gland vs multigland parathyroid disease in primary hyperparathyroidism. Our findings suggest that patients with a score of 3 or higher can undergo a minimally invasive parathyroidectomy without the routine use of intraoperative parathyroid hormone or additional imaging studies, and those with a score of less than 3 should have additional testing to ensure that multigland disease is not overlooked.