Otolaryngology Department, Ain-Shams University, Cairo, Egypt.
Swiss Med Wkly. 2011 Nov 8;141:w13299. doi: 10.4414/smw.2011.13299. eCollection 2011.
Intra-operative parathyroid hormone (PTH) levels have successfully been used to assess surgical ablation of parathyroid adenomas, the use of this same test to predict preservation of viable gland has not been widely used.
to test the sensitivity and specificity of intraoperative rapid PTH assay test in predicting permanent postoperative hypoparathyroidism, and applicability to guide the search for inadvertently removed parathyroid glands for possible auto transplantation.
52 patients undergoing total thyroidectomy for non-malignant thyroid diseases were included. Intraoperative rapid PTH assay test was performed. If levels were reduced, or less than 3 parathyroid glands were detected, removed thyroid gland was examined for unintentionally removed parathyroid tissue for possible auto transplantation.
There was a strong correlation between intraoperative rapid PTH assays and those taken 24 hours after surgery, 16 out of 52 patients had reduction of the PTH intraoperatively to levels below 25 pg/ml, of them, 11 patients (who had values between 15-24 pg/ml) recovered to normal PTH levels within 4 weeks, while the 5 patients with intraoperative PTH levels below 15 pg/ml failed to regain normal PTH levels up to 12 weeks postoperatively, even in those patients where parathyroid tissue was auto transplantated. The 4 patients who had parathyroid tissue reimplanted intraoperatively restored some of their parathyroid function as indicated by relative rise of their PTH levels, but did not reach even the low normal levels. (ROC) curve for prediction of early hypoparathyroidism using intraoperative rapid PTH assay was statistically highly significant with optimal cutoff value for predicting early hypocalcaemia level <27 pg/ml, (sensitivity 100%, specificity 68.2%). (ROC) curves for predicting permanent hypoparathyroidism using intraoperative rapid PTH assay or standard PTH assay taken 24 hours after surgery were statistically significant with optimal cutoff value PTH level <12 pg/ml on the intraoperative PTH curve or <15 pg/ml on the postoperative PTH curve (sensitivity 100%, specificity 100%).
Intraoperative PTH assay may allow intraoperative monitoring of parathyroid function, predicting postoperative outcomes, may identify patients at risk of developing postoperative hypoparathyroidism, guiding surgeons to re-examine removed specimens for inadvertently removed parathyroid tissue with possible auto transplantation, or more practically a guide to early replacement therapy to prevent hypocalcaemia, leading to safe and early hospital discharge. Limitations in our study to be reconsidered in further studies, are relative small sample size, inability for randomisation, and the variable values reported for the cut off value of PTH causing hypocalcaemic symptoms needing intervention.
术中甲状旁腺激素 (PTH) 水平已成功用于评估甲状旁腺瘤的手术消融，而使用相同的测试来预测有活力的腺体的保留尚未得到广泛应用。
测试术中快速 PTH 测定预测永久性术后甲状旁腺功能减退的敏感性和特异性，并评估其在指导寻找可能进行自体移植的无意中切除的甲状旁腺组织方面的适用性。
纳入 52 例因非恶性甲状腺疾病行甲状腺全切除术的患者。进行术中快速 PTH 测定。如果水平降低，或检测到少于 3 个甲状旁腺，则检查切除的甲状腺是否存在无意中切除的甲状旁腺组织，以便可能进行自体移植。
术中快速 PTH 测定与术后 24 小时的测定结果之间存在很强的相关性，52 例患者中有 16 例术中 PTH 降低至 25 pg/ml 以下，其中 11 例（PTH 值在 15-24 pg/ml 之间）在 4 周内恢复正常 PTH 水平，而 5 例患者的术中 PTH 水平低于 15 pg/ml，甚至在接受甲状旁腺组织自体移植的患者中，也未能恢复正常 PTH 水平至术后 12 周。4 例术中甲状旁腺组织再植入的患者，其 PTH 水平有所升高，表明部分甲状旁腺功能得到恢复，但仍未达到低正常值。使用术中快速 PTH 测定预测早期甲状旁腺功能减退的 ROC 曲线具有统计学意义，最佳截断值预测早期低钙血症水平<27 pg/ml，（敏感性 100%，特异性 68.2%）。使用术中快速 PTH 测定或术后 24 小时的标准 PTH 测定预测永久性甲状旁腺功能减退的 ROC 曲线具有统计学意义，术中 PTH 曲线的最佳截断值 PTH 水平<12 pg/ml，或术后 PTH 曲线的最佳截断值 PTH 水平<15 pg/ml（敏感性 100%，特异性 100%）。
术中 PTH 测定可用于术中监测甲状旁腺功能，预测术后结果，可识别发生术后甲状旁腺功能减退的风险患者，指导外科医生重新检查切除标本，寻找可能进行自体移植的无意中切除的甲状旁腺组织，或更实际地指导早期替代治疗，以预防低钙血症，从而安全、尽早出院。我们研究中的局限性将在进一步的研究中重新考虑，包括样本量相对较小、无法进行随机化，以及报道的 PTH 截断值导致需要干预的低钙血症症状的可变值。
