Israel Medical Association Journal

Background: Direct aspiration from suspected pathological tissue and rapid parathyroid hormone analysis may offer a reliable, cost effective alternative to currently used “gold standard” tests.

Objectives: To validate the accuracy of intraoperative measurements of parathyroid hormone levels in parathyroid adenomas.

Methods: A prospective study included 22 patients diagnosed with primary hyperparathyroidism who underwent parathyroidectomy due to an adenoma or hyperplasia. Aspirations of tissues extracted from three adjacent areas (the pathological parathyroid, thyroid, and muscle tissues) were sent for rapid parathyroid hormone analysis. The assay values of these tissue aspirates were compared to the results of the pathology report based on frozen section analysis and the final pathology report.

Results: All assay results were significantly higher for parathyroid tissue 16,800 to 1,097,986 pmol/L (median 26,600), than for either thyroid 1.7 to 415 pmol/L (median 6.5), P < 0.001, or muscle tissue 1.1 to 1230 pmol/L, (median 11.3), P < 0.001. All tissues showing high parathyroid assay values were also verified by pathology examinations: 7 had adenomas and 15 had a differential diagnosis of adenoma or hyperplasia. The frozen section identified all but one (false negative). Rapid intraoperative parathyroid levels > 1500 predicted parathyroid tissue with a 99% level of confidence, while levels between 1000 and 1500 predicted it with 95% confidence. The intraoperative parathyroid hormone assay showed > 70% decrease in 15/21 cases.

Conclusions: Rapid intraoperative parathyroid hormone analysis is a reliable and precise technique, equally accurate for frozen section analysis in predicting with high certainty intraoperative parathyroid tissue.

Background: Four-dimensional parathyroid computed tomography (4DCT) is a relatively new parathyroid imaging technique that provides functional and highly detailed anatomic information about parathyroid tumors.

Objective: To assess the accuracy of 4DCT for the preoperative localization of parathyroid adenomas (PTAs) in patients with biochemically confirmed primary hyperparathyroidism (PHPT) and a history of failed surgery or unsuccessful localization using ^99mTc-sestamibi scanning and ultrasonography.

Methods: Between January 2013 and January 2015, 55 patients with PHPT underwent 4DCT at Hillel Yaffe Medical Center, Hadera, Israel. An initial unenhanced scan was followed by an IV contrast injection of nonionic contrast material (120 ml of at 4 ml/s). Scanning was repeated 25, 60, and 90 seconds after the initiation of IV contrast administration. An experienced radiologist blinded to the earlier imaging results reviewed the 4DCT for the presence and location (quadrant) of the suspected PTAs. At the time of the study, 28 patients had undergone surgical exploration following 4DCT and we compared their scans with the surgical findings.

Results: 4DCT accurately localized 96% (27/28) of abnormal glands, all of which were hypervascular and showed characteristic rapid enhancement on 4DCT that could be distinguished from Level II lymph nodes. Surgery found hypovascular cystic PTA in one patient who produced a negative 4DCT scan. All patients had solitary PTAs. The scan at 90 seconds provided no additional information and was abandoned during the study.

Conclusions: 4DCT accurately localized hypervascular parathyroid lesions and distinguished them from other tissues. A three-phase scanning protocol may suffice.

Background: Hypocalcaemia following thyroid and parathyroid surgery is a well-recognized potential complication.

Objectives: To determine the utility of intraoperative quick parathormone assay in predicting severe hypocalcemia development following parathyroidectomy for a single-gland adenoma causing primary hyperparathyroidism.

Methods: A retrospective cohort study was performed. IO-QPTH[1] values were measured at time 0 (T0) before incision, and 10 (T10) and 30 minutes (T30) following excision of the hyperfunctioning gland. Percent decrease in IO-QPTH at 10 minutes (T10), maximum percent decrease of IO-QPTH value, and lowest actual IO-QPTH value obtained at surgery were used to determine any correlation with the development of postoperative hypocalcemia requiring treatment.

Results: Percent decrease in IO-QPTH at 10 minutes, maximum percent decrease in IO-QPTH and lowest IO-QPTH value did not correlate with the lowest postoperative calcium levels measured 18 hours after surgery (r = 0.017, P = 0.860 r = 0.018, P = 0.850 and r = 0.002, P = 0.985 respectively). For the purposes of our analysis, patients were subdivided into three groups. Group 1 comprised 68 patients with normal calcium levels (serum Ca 8.6¨C10.3 mg/dl) Group 2 had 28 patients with hypocalcemia (8.1¨C8.6 mg/dl) Group 3 included 12 patients with severe hypocalcemia (calcium level ¡Ü 8.0 mg/dl) requiring calcium supplementation due to symptoms of hypocalcemia. There was no difference between the three groups in the lowest IO-QPTH value (P = 0.378), percent decrease in IO-QPTH (P = 0.305) and maximum percent decrease in IO-QPTH (P = 0.142).

Conclusions: IO-QPTH evaluation was not useful in predicting the group of patients susceptible to develop severe postoperative hypocalcemia.  

[1] IO-QPTH = intraoperative quick parathormone

Objective: To evaluate the contribution of the sestamibi-SPECT (MIBI) localization, cervical ultrasonography, and intraoperative rapid turbo intact parathormone assay in minimal invasive parathyroidectomy.

Methods: Between August 1999 and March 2004, 146 consecutive hyperthyroid patients were treated using the MIBI and ultrasound for preoperative localization and iPTH[1] measurements for intraoperative assessment.

Results: Parathyroid adenoma was detected in 106 patients, primary hyperplasia in 16, secondary hyperplasia in 16, tertiary hyperplasia in 5 and parathyroid carcinoma in 1 patient. Minimal invasive exploration of the neck was performed in 84 of the 106 patients (79.2%) with an adenoma, and in 17 of them this procedure was performed under local cervical block anesthesia in awake patients. Adenoma was correctly diagnosed by MIBI scan in 74% of the patients, and by ultrasound in 61%. The addition of ultrasonography to MIBI increased the accuracy of adenoma detection to 83%. In 2 of the 146 patients (1.4%) iPTH could not be significantly reduced during the initial surgical procedure. Minimal invasive surgery with minimal morbidity, and avoiding bilateral neck exploration, was achieved in 79.2% of patients with a primary solitary adenoma.

Background: Among the various new technologies in the field of parathyroid surgery are intraoperative quick parathormone measurements.

Objectives: To evaluate the contribution of QPTH[1] measurements during parathyroidectomy to the achievement of higher success rates. 

Methods: QPTH assay using Immulite Turbo Intact PTH[2] was measured in 32 patients undergoing parathyroidectomy: 30 for primary and 2 for secondary hyperparathyroidism.  QPTH levels were measured at time 0 minutes (before incision) and at 10, 20, and 30 minutes after excision of the hyperfunctioning gland.  Only a drop of 60% or more from the 0’ level was considered to be a positive result.

Results: The mean QPTH level at time 0’ for PHPT[3] patients was 38.12 ± 25.15 pmol/L (range 9.1–118 pmol/L).  At 10 minutes post-excision of the hyperfunctioning gland (or glands), QPTH dropped by a mean of 73.80% to 9.89 ± 18.78 pmol/L. 

Conclusions: Intraoperative QPTH level measurement is helpful in parathyroid surgery.  A drop of 60% or more from 0’ level indicates a successful procedure, and further exploration should be avoided.

Background: Technetium-99m sestamibi scintigraphy has become one of the most popular techniques for localization of the parathyroid gland after failure of primary neck exploration.

Objective: To examine the efficacy of sestamibi with the hand-held gamma ray detecting probe for the identification of parathyroid adenomas during revision parathyroidectomy.

Methods: We reviewed six cases of probe-assisted neck exploration for parathyroid lesions following unsuccessful primary exploration.

Results: In all cases, the pathologic glands were successfully detected and removed.

Conclusions: With careful planning, a gamma ray detecting probe can be used optimally at 2–3 hours after technetium-99m sestamibi injection. The probe is efficient, easy and convenient to use.