Study of the ascending lumbar and iliolumbar veins: surgical anatomy, clinical implications and review of the literature.

The surgical anatomy (geometrical features, metric relations, and drainage pattern) of the ascending lumbar vein (ALV) and iliolumbar vein (ILV) is clinically important. Notwithstanding, the available literature comprises but a small number of studies and a limited number of specimens involved. The present study constitutes a detailed description and classification of the drainage pattern of both these veins. The detailed anatomy of ALV and ILV was examined in both sides in 59 embalmed adult human cadavers of Caucasian origin. Cases with anatomical variations (9 cadavers) of the inferior vena cava (IVC), common iliac vein (CIV), external iliac vein (EIV) and internal iliac vein (IIV) were excluded from subsequent study and analysis. In the remaining 50 cadavers (100 sides) two main drainage types of the lower end of ALV were found. In Type I (54%, 54/100) the ALV presented the same pattern in both sides. In Type II, the ALV differed in pattern from one side to the other (46%, 46/100). Four subtypes were recorded for each Type. An ALV-ILV common trunk occurred in 15% (15/100). The percentage of variations of ALV was 34% and ILV 91%. The number of variations of the two veins differed significantly (p<0.001). No statistically significant difference was found relating to side or gender. Thorough knowledge of the surgical anatomy of ALV and ILV prevents injury, bleeding and further complication of many operations in the retroperitoneal space and pelvis. Awareness of the geometrical features of ALV and ILV helps avoiding or aids early recognition of a misplacement of a vascular catheter into the ALV during femoral vein catheterizations.