Locchi Fabrizio, Cavalli Tiziana, Giudici Francesco, Brandi Maria Luisa, Tonelli Francesco
Departement of Surgery and Translational Medicine, AOUC Hospital, University of Florence, Florence, Italy.
Endocr J. 2014;61(3):239-47. doi: 10.1507/endocrj.ej13-0446. Epub 2013 Dec 8.
Some published criteria for intraoperative monitoring of PTH serum concentrations may cause misleading results, since the timing of samples measured between the pre-incision and pre-excision phase of surgery is often unrecorded. In our opinion this information is critical, as the time of an intermediate sample during surgical manipulation may represent the "true" beginning of the PTH decay. We modified the usual criterion of monitoring (cut-off at 10 minutes after clamping) proposing a further check at manipulation in case the primary check at clamping produces an apparently negative result. On the basis of a mathematical model, false negative curves were simulated by means of a time shift. This shift was assumed to be the interval between manipulation and clamping. Analysing the decay curve, we used the 50% cut-off at 10 minutes after the supposed "true" origin (clamping or manipulation). Using a rapid immunochemiluminometric assay (ICMA), data were collected from 22 patients successfully operated for parathyroid adenoma. The check at clamping correctly diagnosed 13 patients. Among the 9 false negative cases, 6 were correctly diagnosed considering the manipulation as the baseline value. In the remaining 3 patients, diagnosis required prolonged observation of the curves. In case the iPTH decay does not follow the expected curve, it can be useful to check the decay normalising to a pre-excision value. The advantages of our criterion are both the prompt recognition of false negative results and the construction of a "true" decay curve for each patient, supporting the surgeon during the excision of hyperfunctioning parathyroid tissue.
一些已发表的术中监测血清甲状旁腺激素（PTH）浓度的标准可能会导致误导性结果，因为手术切口前和切除前阶段所测样本的时间往往未记录。我们认为该信息至关重要，因为手术操作过程中中间样本的时间可能代表PTH下降的“真正”开始。我们修改了通常的监测标准（钳夹后10分钟为临界值），建议在钳夹时的初步检查结果为明显阴性的情况下，在操作时进行进一步检查。基于一个数学模型，通过时间偏移模拟假阴性曲线。该偏移被假定为操作与钳夹之间的间隔。分析下降曲线时，我们在假定的“真正”起始点（钳夹或操作）后10分钟使用50%临界值。使用快速免疫化学发光分析法（ICMA），收集了22例成功接受甲状旁腺腺瘤手术患者的数据。钳夹时的检查正确诊断了13例患者。在9例假阴性病例中，将操作视为基线值时，有6例被正确诊断。在其余3例患者中，诊断需要对曲线进行长时间观察。如果iPTH下降未遵循预期曲线，将下降值归一化为切除前值进行检查可能会有帮助。我们标准的优点在于既能迅速识别假阴性结果，又能为每位患者构建“真正”的下降曲线，在切除功能亢进的甲状旁腺组织时为外科医生提供支持。
