Intraoperative determination of PTH concentrations in fine needle tissue aspirates to identify parathyroid tissue during parathyroidectomy.

BACKGROUND: Exact tissue identification during parathyroidectomy is essential to successfully cure hyperparathyroidism. PTH level determination from tissue aspirates has been advocated as a "biochemical frozen section" for parathyroid tissue identification. We investigated the sensitivity and specificity of this method in a large cohort of consecutive patients who underwent parathyroidectomy in a tertiary referral center. METHODS: PTH levels of 359 tissue aspirates were measured intraoperatively in 223 consecutive patients from March 2006 to December 2008. Suspected parathyroid and control tissues were aspirated with a standardized technique immediately after their excision. Samples were processed for quick-PTH assay with peripheral blood samples before and after excision. PTH levels from tissue aspirates were correlated with pathological diagnosis. The Mann-Whitney test was used to determine statistical significance (P < 0.05). RESULTS: A total of 255 parathyroid (196 adenoma, 30 hyperplasia, 4 carcinoma, 25 normal parathyroid) and 104 nonparathyroid tissue (88 thyroid, 16 lymph node, thymus, or fat) aspirates were compared. A highly significant difference was found between PTH levels of parathyroid (8,120 +/- 2,711 pg/ml; interquartile range (IQR): 4,949-9,075) and nonparathyroid (0.8 +/- 9.29 pg/ml; IQR: 0.4-1.4) tissue aspirates (P < 0.005). This test is 100% sensitive and 100% specific to identify parathyroid tissue for values >84 pg/ml. Furthermore, PTH levels of pathological parathyroid aspirates (8,169 +/- 2,597; IQR: 5,634-9,109) were higher than that of normal parathyroid aspirates (4,130 +/- 2,952; IQR: 2,569-8,284; P = 0.0011). CONCLUSIONS: PTH level determination from tissue aspirates is a highly reliable, quick, and simple method to differentiate parathyroid and nonparathyroid tissues during parathyroidectomy. This method can obviate frozen sections in patients undergoing surgery for hyperparathyroidism.

[Surgery of primary hyperparathyroidism]. / A primer hyperparathyreosis sebészi kezelése.

Surgery of primary hyperparathyroidism. Primary hyperparathyroidism is usually caused by a single parathyroid adenoma, rarely by multiple adenomas or hyperplasia and in 1-2% of cases by carcinoma. The definitive cure of the disease can be achieved only by surgical means. Unfortunately, only 10% of expected cases based on the number of population are diagnosed in Hungary. The main reason is that the disease has no specific symptoms and it causes only a few cases present with clinical entities such as nephrolithiasis, osteoporosis-osteopenia, pancreatitis, hypertension, peptic ulcer disease, depression, etc. The clue to the diagnosis of primary hyperparathyroidism is usually the laboratory result of hypercalcemia and in order to this aim the measurement of serum Ca would be an obligatory part of routine laboratory investigation in Hungary. The diagnosis of primary hyperparathyroidism rests on the laboratory confirmation of increased serum calcium and inappropriately elevated intact parathyroid hormone concentrations. If surgical intervention is planned, cervical ultrasonography and parathyroid-scintigraphy are indicated for the exact localization of hyperfunctioning parathyroid gland(s). CT and/or MRI are usually not necessary, except in cases of previous neck operation. The operation must be performed by surgeon skilled in parathyroid surgery. The surgical success can be assessed intraoperatively by the use of a gamma probe or by intraoperative measurement of parathyroid hormone concentrations in the serum or in the removed tissue(s). Support of these procedures is recommended. Although many recent publications deal with the minimal invasive methods of parathyroidectomy, the cost-effectiveness of these newer techniques are controversial.

[New intraoperative diagnostic methods parathyroid surgery. Adenoma localization by gamma probe]. / Uj, intraoperatív diagnosztikus módszerek a mellékpajzsmirigy-sebészetben: gamma-szondás adenoma-lokalizáció.

INTRODUCTION: The key to heal primary hyperparathyroidism is to find the hyper functioning parathyroid gland(s). Promoting this the perioperative isotope guided localization technique is worldwide used in the last years. AIM: Authors use this method since February, 2000. They present their experiences. METHODS: At 122 patients undergoing parathyroidectomy in last 5 years with diagnosis of primary hyperparathyroidism perioperative sestamibi scanning by gamma probe was taken to localize the adenoma. Tc-99m-sestamibi was administered 90-150 minutes before starting anesthesia. The distribution of activity was measured before operation percutaneously on the neck and during operation directly at explored parathyroid regions. Finally the removed specimens were ex vivo scanned. RESULTS: Because of the thyroid lobes also accumulate sestamibi the localizability of adenomas depended on direction of scanning. Important factor is the correct timing of isotope administration in order to achieve domination of parathyroid activity in time of measurement. Localization of adenomas by percutaneous measurement was correct in 36.1% of cases and by perioperative direct scanning in 66.4%. Furthermore, ex vivo scan of removed adenomas showed impressively high activity in all cases. CONCLUSIONS: In their experience sestamibi scanning lightens the operation only in a part of cases but probably it will be the most important method of localization if isotope selectively accumulating in parathyroid gland could be found. For the moment the greatest profit of this method is that the ex vivo measurement indicates the success of operation with great probability.