Colorectal resection via natural orifice specimen extraction versus conventional laparoscopic extraction: a meta-analysis with meta-regression

Background Studies have shown differences in postoperative outcomes between two minimally invasive extraction methods for colorectal lesions-natural orifice specimen extraction surgery (NOSES) and conventional laparoscopic surgery (CLS). The aim of this study was to discover the major differences in NOSES and CLS to refine current practice. Methods Electronic databases were searched for articles comparing NOSES and CLS from inception till March 2020. Weighted mean differences (WMD) and odds ratio (OR) were estimated for continuous and dichotomous outcomes, respectively. Summary statistics were calculated using the DerSimonian and Laird random effects. Results Twenty-one studies (15 on malignant disease, 4 on benign disease, 2 on both) were included in this meta-analysis, totalling 2378 patients (1079 NOSE, 1299 CLS). NOSE was associated with decreased: intraoperative bleeding (WMD: - 10.652 ml; 95% CI: - 18.818 ml to - 2.482 ml;p < 0.001), pain score (WMD: - 1.520; 95% CI - 1.965 to - 1.076;p < 0.001), time to flatus (WMD: - 0.306 days; 95% CI: - 0.526 to - 0.085 days;p < 0.001), length of hospital stay (WMD: - 1.048 days; 95% CI: - 1.488 to - 0.609 days;p < 0.001), and total morbidity (OR: 0.548; 95% CI: 0.387 to 0.777;p = 0.001). Subgroup analyses showed significant differences between malignant and benign lesions for intraoperative bleeding (p = 0.011) and pain score (p = 0.010). Meta-regression analyses showed an association between the American Society of Anaesthesiologists (ASA) physical status classification III with pain (p = 0.03) and ASA III with time to flatus (p = 0.04). Conclusions This meta-analysis and meta-regression demonstrated that NOSES had better postoperative outcomes compared to CLS. More comprehensive reviews should be conducted on the long-term outcomes specific to the extraction site to better inform clinical practice.