Surgical management of primary hyperparathyroidism: the case for giving up quick intraoperative PTH assay in favor of routine PTH measurement the morning after.

OBJECTIVE: To analyze the utility of quick intraoperative parathyroid hormone (PTH) measurement in the surgical management of primary hyperparathyroidism. BACKGROUND DATA: The use of intraoperative PTH monitoring is well established in the surgery of primary hyperparathyroidism. However, some false-negative predictions lead to unnecessary explorations; furthermore, surgeons are becoming increasingly dependent on hormone measurement for intraoperative decisions, which raises concerns about the cost-effectiveness of the method. METHODS: A retrospective analysis of 268 neck explorations performed for primary hyperparathyroidism using intraoperative PTH monitoring from April 2001 to February 2003 was done. We used the criterion of "biologic recovery" of hyperfunctioning tissue, defined as a more than 50% decrease in PTH level from baseline value at 5 minutes after excision to predict the outcome of successful parathyroidectomy documented by normal postoperative serum calcium level. Additionally, we also sampled PTH at 10 minutes, 30 minutes, and the morning after surgery to compare the predictive value of delayed sampling. Patients were classified according to the prediction being concordant or discordant with the outcome. The data were analyzed using a 2 x 2 table construct for each of the sampling times, therefore providing sequential sensitivity, specificity, positive and negative predictive values, and overall accuracy of the predictions. RESULTS: Concordance or overall accuracy of prediction (true positives and negatives) was obtained in 229 cases (85.4%), and discordance or failure of prediction (false positives and negatives) was obtained in 34 cases (12.7%) at T5. On analyzing the iPTH prediction at T10, T30, and D1 among the group of 33 false negatives, we found that 28 (10.4%) patients reached the concordance at 30 minutes, while by the first day 32 patients (12.3%) had achieved concordance. Thus, there was a progressive increase in sensitivity and overall accuracy, but more importantly, in the negative predictive value reaching 88.9% on the day after surgery. CONCLUSIONS: The method of sampling PTH intraoperatively at 5 minutes has a high positive predictive value (99.5%) but a low negative predictive value (19.5%), which can lead to unnecessary explorations and a delay in the operative procedure. The negative predictive value increases substantially at 30 minutes and is best on the day after surgery. We suggest giving up the intraoperative measurement of PTH to adopt the first day postoperative measurement of PTH as a predictor of successful parathyroidectomy.

Unilateral surgery for hyperparathyroidism: indications, limits, and late results--new philosophy or expensive selection without improvement of surgical results?

We assessed the "late" results after unilateral parathyroidectomy (PTX) performed for selected indications. From October 1998 throughout March 2001 we operated on 454 patients for hyperparathyroidism (HPT). A positive unifocal (99m)tc-MIBI scan was required for the unilateral approach to be used. Intact parathormone (PTH) measurements were done intraoperatively. Postoperative calcium and PTH serum levels of unilaterally operated patients were checked. Follow-up has been 16.2 months (range 6-40 months). Of the 454 patients, 336 (74.0%) were not eligible for the unilateral approach; and 125 (27.5%) of the 454 patients had renal HPT. Among the 329 patients with primary HPT, 125 (38.0%) were excluded for well established reasons, and in 77 other cases (23.5%) preoperative imaging results did not allow the unilateral approach. Altogether, 126 patients (38.3%) with primary HPT were selected for the unilateral approach. Of the 126 unilateral operations, 8 (6.3%) had to be converted to a bilateral procedure. Among the 118 patients with a unilateral approach, 3 patients have been reoperated for overlooked contralateral disease, and 13 dropped out of the study. A total of 102 postoperative calcium and PTH serum late levels are known: 90 (88.2%) patients had normal levels; 10 (9.8%) had a high PTH level, and 2 (1.9%) had high ionized calcium levels. The failure rate in selected cases was 4.2% (5/118) (three were reoperated, and two had a supranormal postoperative ionized Ca level). Even with stringent indications, the late results of unilateral surgery (95.8% cure rate) barely matched those of conventional bilateral surgery (97.6% cure rate). The economic impact of such a surgical strategy should be clarified.