Celiac-Mesenteric Anastomosis (Arc of Bühler): Original Evidence and Proposed Classification System

Background: The Arc of Bühler (AoB) is a persistent embryonic ventral anastomosis between the celiac trunk (CeT) and superior mesenteric artery (SMA). Despite its clinical importance in hepatopancreatobiliary surgery, its global prevalence is inconsistent and its configurations are poorly systematized. This study aims to establish a global pooled prevalence and propose a clinically actionable, embryologically anchored classification system.

Materials and Methods: We analyzed 375 contrast-enhanced CT examinations from a single center, defining the AoB as a distinct, direct vertical collateral channel between the celiac and mesenteric systems. Concurrently, a systematic review and meta-analysis of the global literature (PubMed, Scopus, Web of Science; through April 2026) was conducted. Pooled prevalence was calculated using random-effects models. To capture structural diversity, a morphological analysis was performed on 120 total cases pooled from our cohort and published case reports/series.

Results: In our original cohort, AoB prevalence was 2.93% (11/375). The meta-analysis of 16 studies (4,799 patients) yielded a pooled prevalence of 1.71% (95% CI: 0.93–2.68). Substantial heterogeneity was observed (I2=76.4%), primarily driven by variations in imaging modalities across historical studies. Morphological analysis revealed that 14.2% of variants could not be accommodated by existing systems. Based on the specific origin and termination points of the anastomosis, we propose a four-tier classification: Type I (trunk-to-trunk), Type II (trunk-to-branch), Type III (branch-to-branch), and Type IV (variant-associated, involving replaced/accessory hepatic arteries). Type Ia (direct CeT–SMA) was the most frequent configuration (55.0%).

Conclusions: The AoB is a critical collateral pathway with highly diverse morphology. Our proposed classification encompasses previously unorganized variants, particularly Type IV complex cases. Preoperative identification via CT angiography is essential to mitigate risks of ischemic complications during pancreaticoduodenectomy and liver transplantation.