Anatomical Variations of the Venous Drainage from the Left Adrenal Gland: An Anatomical Study

Background For radiologists, the venous drainage of adrenal glands is a key to the technique of selective adrenal venous sampling. For endocrine surgeons, it is key to adrenalectomy for carcinoma and pheochromocytoma. This study aims to demonstrate direct anastomosis between the left adrenal vein, the diaphragmatic circulation and the azygos system. Anatomical textbooks only offer very little information concerning the left adrenal vein (LAV) and its potential anastomosis with the reno-lumbo-azygo trunk (RLAT) and the diaphragmatic circulation. Methods Between November 2014 and October 2015 in the LADAF (French Alps Anatomy Laboratory), we dissected 44 formalin-fixed adult cadavers. Results We found no direct anastomosis between the left adrenal vein and the reno-azygo-lumbar trunk and two anastomoses (4.5%) between the adrenal capsular vein and azygos system. A lumbo-azygo trunk has been found 38 times (86.3%), drained 35 times (79.5%) into the left renal vein and 3 times (6.8%) into the left genital vein. An inferior phrenic vein ending into an adrenal vein was highlighted in all cases, 6 times (13.7%) in a double adrenal vein and 38 times (86.3%) in a single one. Conclusions No connections have been found between left adrenal vein and the RLAT, and frequency of the IPV is discordant with the literature. However, our findings concerning the capsular vessels’ anastomosis with the azygos system, inferior diaphragmatic flow and double adrenal vein could have two clinical applications: Firstly, the ligation of the adrenal vein solely is not enough to entirely interrupt the adrenal vein drainage, and secondly, sampling of hormones in the LAV could be underestimated because of the risk of dilution.