Background: Minimally invasive radioguided parathyroidectomy (MIRP) combines technetium sestamibi scan, intraoperative gamma probe, methylene blue dye, and measurement of circulating parathyroid hormone (PTH) levels.
Study design: All patients presented with biochemically proved primary hyperparathyroidism. A technetium sestamibi scan was performed preoperatively. Technetium sestamibi and methylene blue dye (7.5 mg/kg) were administered IV on the day of operation. Operative dissection was directed by the gamma probe. Blood samples for PTH assay were obtained before and after excision of an abnormal gland. When an appropriate decrease in the PTH assay was obtained, the exploration was concluded. Persistent PTH elevation instigated further neck exploration.
Results: Thirty-six consecutive patients were explored for untreated primary hyperparathyroidism and three for recurrent hyperparathyroidism. Hypercalcemia was corrected in all 39 patients. A single adenoma was found in 32 of 36 patients with untreated primary hyperparathyroidism, and a single abnormal gland was identified in all of those with recurrent hyperparathyroidism. Persistently elevated PTH prompted further exploration in two patients, identifying a second abnormal gland in one and hyperplasia in the other. Minor local complications occurred in 8% (3 of 39) of the patients. Forty-four percent (16 of 36) of the patients were discharged on the day of operation and 83% (30 of 36) within 23 hours after the initial neck exploration for primary hyperparathyroidism. Comparison of charges for MIRP with charges for "standard" neck exploration revealed lower costs with MIRP because of decreased duration of the operation, anesthesia, and hospital stay, and elimination of intraoperative histologic analysis.
Conclusions: MIRP is a safe and effective procedure, resulting in the correction of hypercalcemia in all patients. The combination of intraoperative gamma probe and methylene blue dye allows rapid identification of the abnormal gland with minimal dissection through a small incision. PTH assay after excision provides biochemical confirmation that the abnormal gland has been removed. Most patients undergoing MIRP can be treated on an outpatient basis. Low postoperative complications, a small incision, and rapid return to normal activities resulted in very high patient acceptance of the procedure.