Radionuclide scanning in parathyroid diseases

Minimally invasive, radioguided surgery for primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism affects 1 in 700 individuals in the United States. A single adenoma is responsible in over 85% of cases. Surgery remains the most effective treatment. This study was designed to assess the feasibility of minimally invasive radioguided parathyroidectomy (MIRP) with confirmation of excision by ex vivo radioactivity alone.

METHODS

Seventy-five consecutive patients with primary hyperparathyroidism were prospectively studied. Following sestamibi scan, patients underwent unilateral neck exploration guided by a handheld gamma probe, which was also used to measure ex vivo radioactivity of excised tissue.

RESULTS

The sestamibi scan was positive in 88% of the patients. A small incision (mean, 3.2+/-0.3 cm) was sufficient. Ectopic gland sites were localized in five patients with positive scans and single adenomas. Mean operative time was 48 minutes (range, 15-125 minutes), with shorter procedures after the initial 20 cases (mean, 24 vs. 72 minutes; P < .01). Radioguided parathyroidectomy was successful in 97%, with a mean follow-up of 11 months (range, 1-26 months). As noted previously, adenomatous parathyroid glands contained more than 20% of the background radioactivity.

CONCLUSIONS

MIRP is a feasible alternative to bilateral dissection with the advantages of guided dissection and rapid confirmation, and may become the procedure of choice for primary hyperparathyroidism.

[Radioguided surgery for primary hyperparathyroidism. Experience in 75 cases]

STUDY AIM

To report feasibility and efficacy of radioguided mini invasive hyperparathyroidism surgery.

PATIENTS AND METHOD

From November 1998 to August 2000, 75 patients with primary hyperparathyroidism have been operated on by radioguided surgery within 90 to 180 minutes following i.v. injection of a diagnostic dose of MIBI and after parathyroid scanning with planar and oblique views. Exclusion criteria were thyroid pathology requiring surgery and suspicion of multiple endocrine neoplasia. A 20% step-up between the background noise and tissue uptake was the diagnostic threshold for parathyroid hyperfunctioning tissue.

RESULTS

A 20% step-up was observed in only 17% of cases overall; all cured, but two. Various angles of application of the probe can result in significant discrepancies of recorded uptake for the same spot. These results demonstrate a physiological step-up between the ipsilateral unaffected upper and lower quadrants of the neck (range: -17 to -8%), because of the proximity of supraortic vessels (upper neck-upper mediastinal gradient: -44 to -30%). Therefore, significant ratios are meaningful only between either the symmetrical left and right controlateral quadrants respectively, and not between the upper and the lower ipsilateral quadrants. Eleven per cent (8/75) of preoperative scannings were non-contributory, and probe detection was contributory in 3/8 cases only.

CONCLUSION

Benefit of the technique is limited in routine, but it can be helpful in redo cases if the offending gland is not located in close surroundings of tissues physiologically taking up the radiopharmaceutical (salivary glands, great vessels and heart).

An initial experience with radioguided parathyroid surgery

BACKGROUND

Recent reports have shown the effectiveness of preoperative parathyroid scintiscanning as an aid to parathyroidectomy. Less attention has been paid to limitations of this approach based on patient characteristics.

METHODS

All patients evaluated for primary hyperparathyroidism by an endocrine surgeon from December 1, 1998, through October 31, 1999, were retrospectively reviewed. Data were gathered to determine which patients were candidates for the radioguided approach, the effectiveness of this approach, and the reasons why some patients were not candidates for this approach.

RESULTS

Thirty-three patients were evaluated. Based on history, 4 patients were not candidates for a radioguided approach. Of the remaining 29 patients, 19 had positive sestamibi scans (65.5%) and successful radioguided operations. The 10 patients (34.5%) with negative scans had successful standard parathyroidectomy.

CONCLUSION

Although radioguided parathyroid surgery is an effective surgical approach, only 57.6% of patients in this series could have a radioguided operation. Standard four-gland exploration will continue to be needed for many patients.

Radio-guided surgery in recurrent renal hyperparathyroidism: report of a case

BACKGROUND

It has been demonstrated that radio-guided surgery offers several advantages in treating primary hyperparathyroidism. Even if it is considered less helpful in renal hyperparathyroidism, it could be of tremendous advantage in the treatment of persistent or recurrent secondary hyperparathyroidism.

METHODS

We report a case of recurrent secondary hyperparathyroidism treated by the use of radio-guided surgery. The preoperative assessment consisting of ultrasonography, magnetic resonance imaging, and 99mTc-sestamibi scintigraphy identified a parathyroid in the upper mediastinum. The patient underwent a radio-guided neck re-exploration that allowed a rapid localization and excision of the ectopic gland, which was located in the anterosuperior mediastinum, in front of the trachea, between the innominant and the left common carotid artery.

RESULTS

The operative time was 45 minutes. The patient was discharged on the first postoperative day. A decrease in serum calcium and parathyroid hormone was observed subsequently. A follow-up of 6 months did not show any recurrence.

CONCLUSIONS

The case reported indicates that radio-guided surgery can help surgeons detect parathyroid tissue in selected cases of renal hyperparathyroidism.

Direct, minimally invasive adenomectomy for primary hyperparathyroidism: An alternative to conventional neck exploration?

OBJECTIVE

To evaluate the feasibility and efficacy of a direct, minimally invasive adenomectomy (MIA) as an alternative to conventional neck exploration (CNE) in patients with primary hyperparathyroidism.

SUMMARY BACKGROUND DATA

Because primary hyperparathyroidism is caused by a solitary adenoma in 85% to 90% of patients, a direct adenomectomy through a mini-incision would theoretically suffice whenever an adenoma is correctly localized on preoperative imaging. If effective, a less invasive method could spare the patient an unnecessary bilateral neck exploration, thus saving time and rendering future surgical procedures in the neck less problematic.

METHODS

Between October 1994 and October 1998, 110 consecutive patients with biochemically proven primary hyperparathyroidism who were to undergo surgery were enrolled in this study. Ultrasound and spiral CT were routinely performed as standard preoperative imaging modalities in the first series of 65 patients. In the second series of 45 patients, ultrasound was performed as the sole initial modality; it was supplemented by CT only in case of inconclusive test results. If test results were unequivocal (one adenoma), the patient was offered MIA. CNE was performed if the results were equivocal or if multiglandular disease was suspected.

RESULTS

Overall, 84 patients were selected for MIA and 26 for CNE. In the first series, 2 MIA procedures (2/51) were converted to CNE because of negative perioperative findings. All 65 procedures resulted in normocalcemia. In the second series, all but five (4/33 MIAs, 1/12 CNEs) resulted in normocalcemia. A reexploration (CNE) was performed in three patients, resulting in normocalcemia after resection of a second or third adenoma. Two patients are still awaiting reexploration. In both series together, 78 of the 110 patients were successfully treated with MIA and spared CNE.

CONCLUSION

MIA is a safe and effective alternative to CNE that may replace CNE in approximately two thirds of all patients.

Correlation of parathyroid scanning and anatomy in 261 unselected patients with sporadic primary hyperparathyroidism

BACKGROUND

Despite abundant literature on parathyroid scanning with technetium 99m-labeled cationic complexes, comprehensive clinical reports that unequivocally correlate scanning findings with the anatomy of parathyroid glands in extensive and homogeneous cohorts of patients are lacking.

METHODS

We analyzed the records of patients with sporadic primary hyperparathyroidism who had had a preoperative scan with either 99mTc-labeled sestamibi or 99mTc-labeled tetrofosmin at our institution and who were cured after a bilateral surgical neck exploration procedure.

RESULTS

In 261 patients, 710 normal and 347 abnormal glands (1494 +/- 2626 mg), including 15 glands within the mediastinum, were identified. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of scanning were 82%, 98%, 91%, 94%, and 94%, respectively, in 197 patients with uniglandular disease and 53%, 98%, 98%, 60%, and 72%, respectively, in 64 patients with multiglandular disease. False-positive uptakes were encountered in 17 patients (7%), 3 false-positive uptakes being within the mediastinum. If the unilateral approach had been followed, guidance with preoperative scanning would have significantly increased the number of effective unilateral neck exploration procedures (164 patients (63%) vs 78 patients (30%); P < .001). One abnormal gland would also have been neglected in 28 patients (11%).

CONCLUSIONS

Preoperative scanning would limit neck exploration procedures in two thirds of patients with sporadic primary hyperparathyroidism but may also increase the risk of failure in the most challenging cases.