Normalization of 2-Week Postoperative Parathyroid Hormone Values in Patients with Primary Hyperparathyroidism: Four-gland exploration compared to focused-approach surgery

Background Elevation of parathyroid hormone (PTH) levels is commonly seen in patients with primary hyperparathyroidism (PHPT) who have undergone parathyroidectomy. This study evaluates differences in 2-week postoperative PTH levels in patients having focusedapproach surgery versus four-gland exploration. Methods Over 6 years, patients at Rhode Island Hospital (RIH) and the Cleveland Clinic (CCF) who had PHPT and underwent localization studies suggestive of single adenoma were analyzed. At RIH patients underwent focused-approach surgery, and at CCF routine four-gland exploration was performed. Postoperative calcium supplementation was routine at RIH and selective at CCF. Results There were 308 patients at RIH and 370 at CCF. They were similar in age (59.2±13.0 years at RIH and 60.4±12.9 years at CCF), and sex (76.9 and 80.0% female at RIH and CCF, respectively). The mean preoperative serum calcium measured 10.9±0.7 mg/dl at RIH and 11.1±0.7 mg/dl at CCF (P<0.001). Preoperative PTH values were similar, measuring 143.8±104.8 pg/ml in the focused-approach group (RIH) and 157.6±150.3 pg/ml in the four-gland exploration group (CCF). Preoperative 25-hydroxyvitamin D (vitamin D-25) levels were 24.1 ±12.0 ng/ml at RIH and 27.4±10.6 ng/ml at CCF; and the prevalence of vitamin D-25 deficiency (level<20 ng/ml) was 43.9% at RIH and 27% at CCF (P = 0.017). The proportion of patients whose intraoperative PTH value droppedby ≥50% prior to completion of surgery was 95.0% at RIH and 95.5% at CCF. The total gland weight resected per patient was 942 mg at RIH versus 1,394 mg at CCF (P = 0.003). The 2-week postoperative serum PTH was >65 pg/ml in 18.8% at RIH and in 38.7% at CCF (P<0.001). The 2-week postoperative serum calcium values dropped to 9.2±0.6 mg/dl at RIH and to 9.5±0.8 mg/ dl at CCF (P<0.001). The incidence of multigland disease was 5.8% at RIH and 21.9% at CCF (P <0.001). Conclusions Among patients with PHPT who underwent a localizing study indicating unilateral disease, a significantproportion had eucalcemic PTH elevation 2 weeks after parathyroidectomy. The elevation was more frequent in the four-gland exploration group and correlated most strongly with greater adenoma mass.