Systematic review and meta-analysis of randomized controlled trials evaluating the effect of the level of ligation of inferior mesenteric artery on functional outcomes in rectal cancer surgery.

Background: This systematic review and meta-analysis studied the role of high (HL) versus low (LL) inferior mesenteric artery (IMA) ligation on genitourinary and defecatory dysfunction in patients who had undergone resection for rectal cancer (RC).

Methods: A systematic literature search of four major databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Randomized controlled trials (RCTs) comparing HL and LL of IMA in RC surgery were identified. Those studies that looked at genitourinary or defecatory dysfunction were included. Random-effects modeling to summarize statistics was performed. The risk of bias was assessed using Cochrane's Risk-of-Bias tool 2.

Results: Three RCTs were included. There was clinical heterogeneity with regard to cancer stage and location as well as operative techniques and adjuvant treatments. Functional outcomes (FO) that were reported by at least two studies were International Consultation on Incontinence Questionnaire (ICIQ), International Index for Erectile Function (IIEF), Jorge-Wexner incontinence score (J-W). Difference was observed in ICIQ at 9 months after surgery favoring LL (standard mean difference: - 0.66; 95% confidence intervals (CI): - 0.92, - 0.40; P = 0.37; I 2 = 0%). Difference was also observed in IIEF at 9 months favoring LL (mean difference: 7.43; CI: 1.86, 13.00; P = 0.16; I 2 = 50%).

Conclusions: Although our study has demonstrated the superiority of LL in genitourinary function preservation, these results should be taken with consciousness due to significant heterogeneity between included studies, small sample size, and potential bias. More high-quality studies are needed.

Prospero: CRD4202121099  https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021210998.