Minimally invasive parathyroid surgery, the Norman 20% rule: is it valid?

The 20 per cent rule proposed by Norman established a guideline using radioactivity in the minimally invasive radioguided parathyroidectomy (MIRP) technique to localize and confirm removal of an abnormal parathyroid gland in patients with primary hyperparathyroidism. If radioactivity in the resected gland was at least 20 per cent of excision site/background radioactivity, the 20 per cent rule was satisfied. Patients meeting these criteria underwent unilateral MIRP without intraoperative parathyroid hormone assay or intraoperative frozen section. The study aim was to independently evaluate the 20 per cent rule in MIRP patients with primary hyperparathyroidism. Using the University of Louisville Parathyroid Database from January 1, 1999 to December 31, 2007, 216 MIRP patients with complete radioguided and postoperative management data were identified. The average percentage of ex vivo parathyroid gland radioactivity compared with excision site/background radioactivity was 107 per cent with a range from 14 to 388 per cent. For 99 per cent (196/198) radioactivity recorded from the excised gland was at least 20 per cent of radioactivity recorded from the excision site. Normocalcemia was documented in 98.5 per cent (195/198) at 12 month follow-up. Our data supports the 20 per cent rule in that in 99 per cent of MIRP patients the resected gland radioactivity was at least 20 per cent of excision site radioactivity allowing localization and confirmation of an overactive gland without intraoperative parathyroid hormone monitoring or tissue analysis.

Parathyroidectomy in the elderly population: does age really matter?

OBJECTIVES/HYPOTHESIS: Compare parathyroidectomy patients based on age, including demographics, outcomes, and complications. STUDY DESIGN: Retrospective review. METHODS: Prospective parathyroidectomy database covering 1998 to 2007 was reviewed retrospectively. RESULTS: A total of 687 patients underwent parathyroidectomy, including 247 (36%) >65 years old. Discharge was more often on day of surgery in younger patients (42.5% vs. 29.2%, P = .007) and >23 hours for older patients (24.7% vs. 12.3%, P < .0001). Older patients stayed longer in the recovery room (134 vs. 107 minutes, P = .005). Despite postoperative normocalcemia, older patients tended to have persistently elevated parathyroid hormone (PTH) (10.5% vs. 6.4%, P = .07), whereas younger patients had normal PTH (81.6% vs. 70%, P = .0007). PTH levels were low-abnormal (56-110) in younger patients (47% vs. 29%, P = .046), but high-abnormal (>220) in older patients (16.6% vs. 9.55%, P = .009). Overall complication rates were low (6%-8%), with >93% in either group having no major complications. There was no difference in timing or types of complications, except elderly patients were more likely to have cardiac complications (2.83% vs. 0.45%, P = .022). CONCLUSIONS: Nearly 700 parathyroidectomies were performed at our institution over 10 years. Elderly patients comprised one third of this population. They were likely to have longer hospital and recovery room stays, and postoperative normocalcemia with elevated PTH, which may actually be a normal finding for these patients, but it warrants further study. The rate, timing, and types of complications were similar between age groups, although elderly patients had more cardiac complications. When properly indicated, parathyroidectomy remains a safe and effective option for management of hyperparathyroidism in elderly patients.

Intra-operative parathyroid identification using methylene blue in parathyroid surgery.

The objective of this study was to determine the value of intra-operative methylene blue (MB) during parathyroid surgery. We did a retrospective study of 473 patients after initial exploration for previously untreated symptomatic primary hyperparathyroidism. Procedural and post procedural data were collected on four groups of patients: minimally invasive parathyroidectomy with MB (n = 147), and without MB (n = 205), bilateral parathyroid exploration with intra-operative parathormone assay with MB (n = 56), and without MB (n = 65). Length of surgery was shorter for patients explored with MB (P = 0.026). For the minimally invasive parathyroidectomy group, the difference between the MB and non-MB groups was seven minutes. Twelve minutes was the difference between the MB and non-MB intra-operative parathormone assay groups. Length of stay, local complications, and correction of hypercalcemia after parathyroidectomy were not significantly affected by the use of MB. Systemic complications were lower in the MB groups. Aside from a statistically significant, but quantitatively minimal decrease in the length of surgery, no consistent benefit was identified with the use of MB for intra-operative parathyroid identification.

Advantages of a targeted approach in minimally invasive radioguided parathyroidectomy surgery for primary hyperparathyroidism.

OBJECTIVE: In a large series of patients, we associated the need for preoperative parathyroid hormone (PTH) and calcium levels as a vital component in our approach to the radioguided minimally invasive parathyroidectomy (MIRP) procedure. Our objective was to determine whether these preoperative levels indeed complemented the procedure. Our study also included a postoperative assessment of excised gland volume and length of operation. STUDY DESIGN: This was a prospective cohort study. METHODS: : One hundred seventy-three patients with primary hyperparathyroidism enrolled in our radioguided MIRP protocol. Patients were divided into groups based on the results of sestamibi scans. Comparisons were made between these results and the assessed preoperative PTH and calcium levels and the postoperative excised gland volume and length of operation. RESULTS: PTH and calcium levels did not statistically relate with the likelihood of having a "positive," "equivocal," or "negative" sestamibi scan, but the volume of excised gland was significantly different among the three groups (P < .01). There was no significant difference between positive and equivocal scans (P = .40). Operative time was significantly different between positive and equivocal scans (P < .01), positive and negative scans (P < .01), and equivocal and negative scans (P < .01). CONCLUSIONS: Routine preoperative PTH and calcium levels are necessary for the biologic diagnosis of hyperparathyroidism, but they do not appear to relate to the outcome of a sestamibi scan and therefore do not complement the radioguided MIRP procedure. Because the size of the affected gland, however, did correlate with a positive sestamibi scan, we conclude that as the volume of the gland increases, so does the likelihood of a successfully chosen minimally invasive surgical approach.

Three-year financial analysis of minimally invasive radio-guided parathyroidectomy.

Minimally invasive radio-guided parathyroidectomy (MIRP) has had a high success rate in correcting hypercalcemia, along with a low morbidity rate and high patient satisfaction. Our study was conducted in an attempt to analyze the cost-effectiveness of MIRP in patients treated for primary hyperparathyroidism. We conducted a retrospective study of the total charges of three groups of patients undergoing surgery for previously untreated hyperparathyroidism in a single health care system. The three study groups included patients undergoing traditional bilateral neck exploration, MIRP, and neck exploration guided by intraoperative parathormone (PTH) assay. Charges were stratified into preoperative, intraoperative, and postoperative categories. The average total charge was $8,512 for MIRP, $12,723 for traditional neck exploration, and $13,011 for bilateral neck exploration with PTH assay. The decreased charge for MIRP was due to reduced operating room time, anesthesia costs, length of hospitalization, and an avoidance of the use of intraoperative tissue analysis and PTH assay. There was a greater than $4,000 savings with MIRP as compared with the more extensive neck exploration. These savings more than compensate for the cost of technology (preoperative sestamibi scan and intraoperative gamma probe) necessary to perform radio-guided parathyroidectomy.