Surgical Anatomy of the Mesopancreas in Obese Patients: A Retrospective Study

Introduction The mesopancreas is described as a triangle formed by the superior mesenteric vein, celiac axis (CA), and superior mesenteric artery (SMA). It is the most likely site of residual cancer and local recurrence after surgical resection, making it the key site of the current radical resection of pancreatic head cancer. The surgical anatomy of the mesopancreas triangle has not been studied in detail. Furthermore, to the best of our knowledge, no information is available on the impact of obesity on the anatomy of the mesopancreas triangle. Methods Between January 2016 and August 2016, 200 consecutive triple-phase computed tomography scans of the abdomen were performed and included in this retrospective study aiming to define the anatomical relation of the left renal vein (LRV) to the root of the SMA and focusing on the relevance of the LRV as a landmark to guidance for the dissection of the mesopancreas. Furthermore, by studying six surgically relevant anatomical parameters namely the thickness of the areolar tissue separating the LRV from the root of the SMA, IVC from the root of the SMA, the left adrenal vein (LAV) from the root of the SMA, splenic vein from the aorta, and CA from the SMA at two levels, we investigated the impact of obesity on the mesopancreas anatomy. Results The mean distance from the upper border of the LRV to the root of the SMA (LRV-SMA distance) was 2.3 ± 5.4 mm. There was no correlation between this distance and patient's age (r = -0.02), height (r = -0.07), BMI (r = -0.01), visceral fat area (r = -0.04), or abdominal circumference (r = -0.02). There was no correlation between the distance from the IVC to the root of the SMA, and patient's age (r = 0.01), height (r = 0.11), BMI (r = 0.15), or abdominal circumference (r = 0.00). However, there was a negligible correlation between the IVC-SMA distance and patient's visceral fat area (r = 0.15, p = 0.036). Conclusion In the current study, the LRV was reliably identified in more than 99% of the studied patients, and in 96% of patients, the LRV crosses anterior to the aorta at the level of the second lumbar vertebra, making it easily accessible following mobilization of the duodenum and the head of the pancreas. The relationship between the LRV and SMA remains unchanged following Kocherization. Most importantly, we demonstrated that the LRV-SMA distance does not correlate with patient's age, height, BMI, visceral fat area, or abdominal circumference. This makes the LRV a reliable landmark in both obese and non-obese patients.