Randomized clinical trial comparing scan-directed unilateral versus bilateral cervical exploration for primary hyperparathyroidism due to solitary adenoma

Background: It was shown in a previous retrospective study that scan-directed unilateral cervical exploration for primary hyperparathyroidism (HPT) can be carried out without an increase in the incidence of persistent or recurrent hypercalcaemia. This randomized clinical trial was conducted to test the hypothesis that focused unilateral operation leaves the patient no more vulnerable to persistent HPT than standard bilateral neck exploration. Methods: Patients with HPT routinely underwent preoperative dual-isotope subtraction scintigraphy in an attempt to localize the presumed solitary parathyroid adenoma. Individuals with a positive scan (one residual focus of activity following subtraction) were deemed suitable for focused unilateral cervical exploration. At operation, if a single tumour was identified at the site suggested by the scan, the patient was randomized to unilateral or bilateral neck exploration. Results: Between April 1998 and December 2003, 190 patients underwent first-time cervical exploration for HPT. Of these, 100 qualified for randomization. Fifty-four patients were randomized to unilateral neck exploration and 46 to bilateral operation. All 100 patients were cured following operation, as assessed by return of the serum calcium level to normal. Two patients randomized to bilateral exploration were found to have an unsuspected additional enlarged parathyroid on the contralateral side. Conclusion: Scan-directed unilateral cervical exploration for HPT does not significantly increase the incidence of persistent hypercalcaemia compared with standard bilateral operation.