Navigating the mesentery: part II. Vascular abnormalities and a review of the literature.

Aim: Vascular abnormalities present advantages and/or disadvantages for the patient undergoing surgery. The aims of this study were to define, classify and demonstrate the courses, and to assess the clinical value, of arterial and venous abnormalities in the central mesentery.

Method: We conducted a review of the anatomy of 340 patients planned for enrolment in the 'Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic MDCT Angiography' trial, 312 of whom were submitted to surgery. Vascular abnormalities were analysed in context with surgical notes and images. A meta-analysis of the literature was performed.

Results: Arterial Abnormalities were found in 28 (8.2%) of the 340 patients and were classified into the following three groups based on anticipated surgical difficulty: group 1, accessory or replaced arteries to solid organs [14 (4.1%)]; group 2, arterial shunts [11 (3.2%)] between the coeliac trunk and the superior mesenteric artery, which resulted in bleeding in three patients; and group 3, common stem abnormalities [3 (0.9%)]. Two groups of superior mesenteric vein abnormalities were noted. The first included morphological abnormalities in a single vein [4 (1.2%)]: aneurysm [1 (0.3%)]; and ring variants of principal tributaries [3 (0.9%)]. The second included double superior mesenteric vein trunks [31 (9.1%)]: genuine bifid [10 (2.9%)]; and pseudo bifid [21 (6.2%)]. The meta-analysis revealed 26 articles, including 10 series of anatomical dissections or angiographies [1970 cases with 205 (10.4%) arterial abnormalities] and 16 case reports, none of which described a clinical or surgical setting.

Conclusion: Vascular abnormalities occur frequently. Arterial abnormalities are a hazard when inadvertent injury occurs during surgery. Preoperative knowledge of a bifid superior mesenteric vein is useful.