Evaluation of the learning curve for intraoperative neural monitoring of the recurrent laryngeal nerves in thyroid surgery.

Abstract

Intraoperative neuromonitoring facilitates identification of the recurrent laryngeal nerves (RLN) and allows for predicting their postoperative function. Nevertheless, the outcome of thyroid surgery monitoring is affected by both the experience of the operator and his mastering of the technique. The aim of the study was the assessment of the learning curve for intraoperative RLN neuromonitoring. The prospective analysis included 100 consecutive thyroid operations performed by a single surgeon during implementation of RLN neuromonitoring in a district surgical ward in Staszów. RLN neuromonitoring was performed in keeping with the recommendations of the International Neural Monitoring Study Group using a C2 NerveMonitor (Inomed, Germany). The outcomes of initial 50 procedures (group I: 08/2012-07/2013) were compared with the results of subsequent 50 operations (group II: 08/2013-07/2014). The evaluation included demographic and intraoperative data along with predictive value of the method and complications. In group II as compared to group I, a significant reduction of operative time was noted (102.1 ± 19.4 vs 109.9 ± 19; p = 0.045), along with an increased percentage of identified RLNs (99% vs 89.2%; p = 0.006), a decreased percentage of correction-requiring technical errors (8% vs 24%; p = 0.029), an improved negative predictive (99% vs 89.3%; p < 0.001) and positive value (75% vs 55.6%; p < 0.001), as well as a decreased percentage of RLN injuries (3% vs 14%; p = 0.006). Mastering the technique of intraoperative RLN neuromonitoring in thyroid surgery requires the surgeon to perform independently approximately 50 monitored procedures, what allows for achieving the predictive value of the method that is comparable to outcomes published by referral centers.