The anatomy of the inferior mesenteric artery: a systematic review with meta-analysis

This evidence-based systematic review with meta-analysis aims to synthesize the inferior mesenteric artery (IMA) variants including their origin level, branching patterns, and morphometric characteristics.

The study adhered to the latest guidelines. Four online databases were used for the systematic review, and studies that reported the prevalence of IMA variants were considered eligible for inclusion. A statistical meta-analysis was conducted using R programming software with a random-effects model to calculate the pooled prevalence of the variants.

Twenty-three (23) studies were included in this analysis. The IMA typically originated at the 3rd lumbar vertebra (L3) level, occurring in 70.16% of cases. The most common branching pattern of the IMA was bifurcated, indicating a pooled prevalence of 63.89%. This predominant pattern involved the IMA bifurcating into the left colic artery (LCA) and a common trunk for both the superior rectal artery (SRA) and the sigmoid artery (SA), with a pooled prevalence of 46.09%. The IMA trifurcation and tetrafurcation had pooled prevalences of 27.35% and 11.62%, respectively. The diameter of the IMA had a pooled mean of 41.41 mm, and the distance from the IMA's origin to the LCA had a pooled mean of 40.67 mm.

This review of existing literature delineates the IMA levels of origin, branching patterns, and morphometric characteristics. A comprehensive understanding of the surgical anatomy of this vessel is imperative during colorectal cancer procedures. Consequently, surgeons operating in this anatomical region must possess an in-depth knowledge of typical and variant anatomical structures.