350. CONTINUOUS INTRAOPERATIVE NERVE MONITORING TO REDUCE THE LEFT RECURRENT LARYNGEAL NERVE PARALYSIS IN TRANSMEDIASTINAL ESOPHAGECTOMY

Abstract Introduction Transmediastinal esophagectomy (TME) is a curative option for esophageal cancer, and can achieve total mediastinal lymph node dissection (LND) with transcervical and transhiatal procedures. With the transcervical procedure, the upper mediastinal LND is highly associated with the risk of causing recurrent laryngeal nerve paralysis (RLNP). Continuous intraoperative nerve monitoring (CIONM) can visualize the risk procedure in real time, which may result in reducing postoperative RLNP. The aim of this study was to clarify the usefulness of CIONM in reducing postoperative left RLNP with TME. Material and methods A total of 227 patients who underwent TME for esophageal cancer (EC) or esophagogastric junction cancer (EGJC) between October 2017 and July 2022 at our institution were included in this study. Patients who did not undergo the upper and middle mediastinal LND (33 patients) and could not undergo CIONM (34 patients) were excluded from these 227 patients. Finally, we analyzed data on 160 patients. The clinicopathological data were reviewed from the medical record database of our institution. Results The technical implementation rate of CIONM was 87.4%. The diagnostic performance for RLNP with amplitude<100μV (LOS: loss of signal) at the end of transcervical procedure was as follows (sensitivity: 83.3%, specificity: 90.7%, positive diagnostic value: 88.8%). In the univariate analysis, the frequency of left RLNP was significantly higher in male, patients with primary tumor located at the upper thoracic esophagus, and patients with LOS (p<0.001, respectively). Moreover, the multivariate analysis identified patients with tumor located at the upper thoracic esophagus and patients with LOS (p<0.001) as independent risk factors for left RLNP. Conclusion In the present study, we showed the significant association between amplitude LOS and left RLNP. CIONM could contribute to reducing left RLNP by not only paying attention to amplitude reduction during surgery, but also learning the risk procedure that may cause nerve damage after surgery.