588. EFFICACY OF INTRAOPERATIVE RECURRENT LARYNGEAL NERVE MONITORING DURING MINIMALLY INVASIVE ESOPHAGECTOMY FOR ESOPHAGEAL CANCER: A NATIONWIDE INPATIENT COHORT STUDY

Abstract Background Lymphadenectomy around the recurrent laryngeal nerve (RLN) is an essential part of curative surgery for esophageal cancer. The rate of lymph node metastasis around the RLN is extremely high, and postoperative RLN palsy could lead to a poor prognosis in patients with esophageal cancer. Although several single-center studies have shown that intraoperative nerve monitoring (IONM) can avoid RLN palsy, this has not been confirmed in a large-scale multicenter study. This study was performed to evaluate whether intraoperative nerve monitoring IONM can reduce postoperative RLN palsy during minimally invasive esophagectomy (MIE) for esophageal cancer using a national database. Methods We retrieved data of patients with esophageal cancer who underwent MIE involving thoracoscopic or robotic esophagectomy with IONM (502 patients) and without IONM (4,353 patients) at 348 hospitals from April 2020 to March 2022 from the Diagnosis Procedure Combination database in Japan. We compared the frequency of postoperative RLN palsy and respiratory complications between the IONM (+) group and IONM (−) group using propensity score-matching (PSM) analysis. The propensity score was estimated using multivariable logistic regression models including age, sex, Body Mass Index, Brinkman index, Activities of Daily Living, comorbidities at admission, clinical TNM classification, approach of MIE, and hospital case volume with reference to previous studies of IONM. Results After PSM, the standardized bias was <10% for all covariates, which indicated improved balance in the covariates between the matched pairs. With 1-to-1 matching, 501 pairs (1,002 cases) were created between the IONM (+) and (−) groups. The postoperative RLN palsy rate was significantly lower in the IONM (+) than (−) group (odds ratio, 0.24; 95% confidence interval [CI], 0.13–0.46). The respiratory complication rate was also significantly lower in the IONM (+) than (−) group (odds ratio, 0.66; 95% CI, 0.45–0.97). The anesthesia time was significantly longer in the IONM (+) group (regression coefficient, 60.1 minutes; 95% CI, 44.2–76.9). The length of postoperative hospitalization tended to be shorter in the IONM (+) than (−) group (regression coefficient, −1.39 days; 95% CI, −3.91 to 1.14). Conclusion This nationwide cohort study showed that IONM during MIE for esophageal cancer can reduce postoperative RLN palsy and respiratory complications.