An initial experience with radioguided parathyroid surgery

Contemporary Management of Primary Hyperparathyroidism

Primary hyperparathyroidism can be asymptomatic or symptomatic, as well as classic, normocalcemic, or normohormonal. It is important to rule out other causes of hypercalcemia or hyperparathyroidism. Preoperative localization with imaging is necessary for a minimally invasive approach and can be helpful even if planning 4-gland exploration. There are a variety of intraoperative techniques that can assist with localization as well as confirming success. Standard of care remains surgical resection of affected glands. However, there are less invasive management strategies that can be considered for poor surgical candidates.

What is the link between nonlocalizing sestamibi scans, multigland disease, and persistent hypercalcemia? A study of 401 consecutive patients undergoing parathyroidectomy

BACKGROUND

We hypothesized that nonlocalizing sestamibi scans would correlate with multigland disease and persistent primary hyperparathyroidism.

METHODS

We reviewed records for 401 consecutive patients who underwent parathyroidectomy from 1999 to 2004. Gender, age, preoperative imaging, surgical findings, gland weight and volume, and 6-month calcium levels (Ca) were examined.

RESULTS

We identified 289 women and 112 men, 297 of whom had a preoperative sestamibi scan localized to a single gland (localized group; LG). Ninety-six percent of the LG were found to have single-gland disease, and 4% had multigland disease (MGD). In the nonlocalized group (NLG), 76% had single-gland disease and 24% MGD. Mean gland weight was greater in the LG than in the NLG (1128 mg vs 699 mg; P < .05). Mean gland volume was larger in the LG (1.34 cc vs 0.89 cc; P < .05). A localizing sestamibi scan had a positive predictive value (PPV) of 96% and a likelihood ratio of 2.29 for predicting "curative" intraoperative parathyroid hormone drop after removal of a single abnormal gland. Patients were stratified into normocalcemic (NCa) and hypercalcemic (HCa) groups based on 6-month postoperative serum calcium data (n = 328). HCa incidence at 6 months did not differ significantly between the LG (5%) and NLG (3%). A localizing scan had a PPV of 95% for normocalcemia at 6 months. A nonlocalizing scan had a PPV of 21% for HCa at 6 months.

CONCLUSIONS

Nonlocalizing sestamibi scans were more common in primary hyperparathyroidism with MGD and were associated with smaller-volume abnormal glands found at operation. Preoperative sestamibi scan-results did not predict HCa at 6 months.

A systematic review of the diagnosis and treatment of primary hyperparathyroidism from 1995 to 2003

OBJECTIVE

To systematically review the current preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism.

STUDY DESIGN

A systematic literature review.

RESULTS

Of the 20,225 cases of primary hyperparathyroidism reported, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and parathyroid carcinomas (CAR) occurred in 88.90%, 5.74%, 4.14%, and 0.74% of cases respectively. Tc 99m -sestamibi and ultrasound were 88.44% and 78.55% sensitive, respectively, for SA, 44.46% and 34.86% for MGHD, and 29.95% and 16.20% for DA, respectively. Postoperative normocalcemia was achieved in 96.66%, 95.25%, and 97.69% of patients offered minimally invasive radio-guided parathyroidectomy (MIRP), unilateral, and bilateral neck exploration (BNE). Intraoperative PTH assays (IOPTH) were helpful in approximately 60% of bilateral neck exploration conversion (BNEC) surgeries.

CONCLUSION

The overall prevalence of multiple gland disease (MGD and DA) was lower than often suggested by conventional wisdom. Furthermore, preoperative imaging was less accurate than it is often perceived for accurately imaging MGD. MIRP and UNE were more successful in achieving normocalcemia than is typically quoted. IOPTH was a helpful but not "fool-proof" adjunct in parathyroid exploration surgery.

SIGNIFICANCE

These results support a greater role for the treatment of primary hyperparathyroidism using less invasive approaches. EMB rating: B-3.

Minimally invasive radioguided parathyroidectomy using intraoperative sestamibi localization

This article presents the authors' technique of minimally invasive radio guided parathyroidectomy (MIRP) with intra-operative use of the hand-held gamma probe for primary HPT caused by a solitary adenoma. It points out how this approach varies from that of others who perform MIRP. It also illustrates ways to troubleshoot common problems with the technique in inexperienced hands. The goal is to present an understandable and systematic approach to MIRP for surgeons who do not currently use this technique. This article is not intended to replace formalized training, which is essential to master the technique.

The usefulness of radio-guided surgery in secondary hyperparathyroidism

Recent reports have shown that radio-guided surgery with an intraoperative gamma probe (IGP) is useful for identifying parathyroid adenomas. The aim of this study was to evaluate the usefulness of IGP mapping in patients with secondary hyperparathyroidism. Seven patients with secondary hyperparathyroidism underwent technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) scintigraphy immediately before undergoing surgical resection of all parathyroid tissues. We compared the sensitivity of Tc-99m MIBI scintigraphy alone with that of the combination of Tc-99m MIBI scintigraphy and IGP mapping. The sensitivity of the combination of Tc-99m MIBI scintigraphy and IGP mapping was 100% (28 of 28 lesions) and was significantly higher than that of Tc-99m MIBI scintigraphy alone (71.4%, 20 of 28 lesions). The combination of the Tc-99m MIBI scintigraphy and IGP mapping has increased sensitivity for identifying parathyroid lesions during parathyroidectomy in patients with secondary hyperparathyroidism.

Sestamibi scanning and minimally invasive radioguided parathyroidectomy without intraoperative parathyroid hormone measurement

OBJECTIVE

To evaluate the results of a large series of patients undergoing minimally invasive radioguided parathyroidectomy (MIRP) in which routine use of the intraoperative parathyroid hormone assay was not used, and to investigate characteristics between patients who had positive preoperative parathyroid scans versus those with negative scans.

SUMMARY BACKGROUND DATA

The technique of parathyroidectomy has traditionally involved bilateral exploration of the neck under general endotracheal anesthesia. Parathyroid imaging using technetium-99m sestamibi (MIBI) has evolved and can localize the adenomas in 80% to 90% of patients. The MIRP technique combines parathyroid scintigraphy with a hand-held gamma detector used intraoperatively to guide the surgeon to the adenoma in patients with positive MIBI scans. Central to this technique or other unilateral approaches is a positive MIBI scan.

METHODS

One hundred seventy-three patients with primary hyperparathyroidism operated on by a single surgeon between January 1998 and July 2002 were included. One hundred twelve patients underwent the MIRP procedure and by definition had a positive preoperative parathyroid scan. The technique involved injecting 20 mCi MIBI 1 hour before the surgical procedure in patients who preoperatively had positive MIBI imaging. Patients had the choice of general or MAC anesthesia. Using an incision of less than 4 cm, the dissection to the adenoma was guided by the Navigator 11-mm probe. These 112 patients and 4 additional patients who for various reasons did not have the MIRP procedure yet had positive MIBI scans were compared to 57 patients who had clearly negative MIBI parathyroid imaging.

RESULTS

Follow-up data were available for 108 of 112 patients who underwent MIRP. No patients had persistent hypercalcemia. The long-term success rate for the MIRP group was 98%. Fifty-two percent of the MIRP procedures were performed using MAC anesthesia. Overall, gland weight and serum PTH were related to the probability of a positive MIBI scan. Multiple logistic regression revealed that females were more likely to exhibit positive scans than were males for any fixed serum PTH level. For females, there was a significant relationship between increasing serum parathyroid hormone and a positive MIBI scan. Conversely, in males, the relationship between scan positivity and serum parathyroid hormone was weaker.

CONCLUSIONS

The MIRP technique without routine intraoperative serum parathyroid hormone measurement resulted in an excellent cure rate for primary hyperparathyroidism. As the MIRP technique as well as other techniques for unilateral cervical exploration are predicated on a positive parathyroid scan, the possible effect of gender on the sensitivity of MIBI scintigraphy for the detection of parathyroid adenomas warrants further investigation.

Improving the yield of preoperative parathyroid localization: technetium Tc 99m-sestamibi imaging after thyroid suppression

BACKGROUND

Preoperative localization is essential for successful directed, minimally invasive or reoperative parathyroidectomy. Standard technetium Tc 99m-sestamibi imaging is the most sensitive modality for localization. We reviewed our experience with (99m)Tc-sestamibi imaging and specifically investigated the effect of thyroid suppression on repeat imaging of patients who had initially nonlocalizing scans.

METHODS

. The records of patients who underwent (99m)Tc-sestamibi imaging during evaluation for primary hyperparathyroidism were reviewed. A subset of patients with initially nonlocalizing scans underwent thyroid suppression with either thyroxin or liothyronine and then had their scans repeated.

RESULTS

Ninety-nine patients with primary hyperparathyroidism underwent (99m)Tc-sestamibi imaging followed by parathyroidectomy (initial operation, 78; reoperation, 21). Successful parathyroid localization was obtained on standard imaging in 67 patients. Fourteen of 32 patients who had nonlocalizing (99m)Tc-sestamibi imaging studies underwent an additional scan after thyroid suppression. In 10 of 14 patients (71%), repeat (99m)Tc-sestamibi imaging after thyroid suppression successfully localized abnormal parathyroid tissue.

CONCLUSIONS

Thyroid suppression may improve the yield of (99m)Tc-sestamibi imaging in patients with hyperparathyroidism who have an initially nonlocalizing study. This diagnostic strategy may be helpful in patients motivated to undergo a directed, minimally invasive operation, as well as in the evaluation of patients for reoperative parathyroidectomy.