Learning curve characteristics of Mckeown-type minimally invasive esophagectomy and effects of the para-recurrent laryngeal nerve lymphadenectomy on efficacy

Abstract

Objective To explore the learning curve characteristics of Mckeown-type minimally invasive esophagectomy and effects of the para-recurrent laryngeal nerve lymphadenectomy on efficacy. Methods The retrospective cohort study was conducted. The clinicopathological data of 163 patients with esophageal squamous cell carcinoma (ESCC) who underwent Mckeown-type minimally invasive esophagectomy in the Affiliated Tumor Hospital of Xinjiang Medical University between January 2011 and December 2015 were collected. According to the para-recurrent laryngeal nerve lymphadenectomy in the different learning curve stages (early, medium and later stages), 49 patients who didn′t undergo right para-recurrent laryngeal nerve lymphadenectomy were allocated into the group A, 65 who underwent para-recurrent laryngeal nerve lymphadenectomy were allocated into the group B, and 49 underwent bilateral para-recurrent laryngeal nerve lymphadenectomy were allocated into the group C. Observation indicators: (1) comparisons of intra- and post-operative recovery among groups; (2) comparisons of follow-up and survival among groups; (3) correlation analysis between operation time or volume of intraoperative blood loss and cases of learning curve of Mckeown-type minimally invasive esophagectomy. Follow-up using outpatient examination and telephone interview was performed to detect postoperative survival up to April 2017. Measurement data with normal distribution were represented as ±s. Comparison among groups was analyzed using the ANOVA, and pairwise comparison was done using the independent-sample t test. Measurement data with skewed distribution were described as M (range), and comparison of count data was done using the chi-square test. The survival time was calculated by the Kaplan-Meier method, and Log-rank test was used for survival analysis.Correlation analysis was done by Spearman rank correlation. Results (1) Comparisons of intra- and post-operative recovery among groups: patients in the 3 groups underwent successful Mckeown-type minimally invasive esophagectomy of ESCC, without conversion to open surgery. The operation time, total number of lymph node dissected, number of thoracic lymph node dissected and volume of intraoperative blood loss were respectively (395±94)minutes, 14.7±6.9, 9.6±5.4, (175±100)mL in the group A and (329±67)minutes, 20.4±9.1, 11.4±7.3, (117±49)mL in the group B and (301±51)minutes, 25.8±11.0, 14.8±10.1, (115±50)mL in the group C, with statistically significant differences in above indicators among groups (F=21.962, 1.992, 5.775, 12.744, P 0.05). There were statistically significant differences in total number of lymph node dissected and number of thoracic lymph node dissected between group B and group C (t=2.751, 3.245, P 0.05). Number of lymph node dissected at right and left para-recurrent laryngeal nerve were respectively 0, 0 in the group A and 1.9±1.8, 0 in the group B and 2.6±2.1, 1.1±0.8 in the group C. Of 35 patients with unilateral recurrent laryngeal nerve were treated with symptomatic and supportive treatment of neuro nutrition, 18 encountered permanent hoarseness and 17 recovered well. Patients with anastomotic fistula and pneumonia were improved by sufficient drainage and antibiotic therapy. (2) Comparisons of follow-up and survival among groups: 149 of 163 patients were followed up for 17-65 months, with a median time of 32 months, including 43 in the group A, 61 in the group B and 45 in the group C. Survival time of patients who received follow-up was recpectively (31.3±2.6)months, (32.2±1.6)months and (25.5±2.5)months in group A, B and C, with no statistically significant differences (χ2=4.412, P>0.05). (3) Correlation analysis between operation time or volume of intraoperative blood loss and cases of learning curve of Mckeown-type minimally invasive esophagectomy: results of correlation analysis showed that there was a significant negative correlation between operation time or volume of intraoperative blood loss and cases of learning curve of Mckeown-type minimally invasive esophagectomy (r=-0.632, -0.451, P<0.05), showing a decreasing trend in operation time and volume of intraoperative blood loss with increasing surgical cases. Conclusions The operation time and volume of intraoperative blood loss are gradually declining with learning curve process of Mckeown-type minimally invasive esophagectomy. Para-recurrent laryngeal nerve lymphadenectomy cannot increase the incidence of recurrent laryngeal nerve injury, with more completely lymphadenectomy. Key words: Esophageal neoplasms; Radical resection; Minimally invasive surgery; Thoracoscopy; Laparoscopy; Lymphadenectomy; Recurrent laryngeal nerve; Learning curve