The effect of retroaortic left renal vein on lumbar osteophytes formation.

Purpose: Assess whether a Retroaortic left renal vein (RLRV) affects vertebral osteophyte formation in the lumbar spine, compared to normal anatomy left renal vein.

Methods: We conducted a retrospective case-control study. Computed tomography (CT) scans of individuals with a RLRV (study group) were compared to age- and gender-matched normal anatomy CT scans (control group). L1 to L4 vertebral levels were appreciated for: left renal vein level, osteophyte presence and the aorta-vertebral distance (AVD) at the left renal vein level. Univariate analyses were conducted using Chi-square test and Fisher's test for categorical variables, and Student's t-test for continuous variables. Logistic regression was used for multivariate analyses.

Results: A total of 240 patients were included in the study - equally distributed between the study and control groups. Normal anatomy left renal veins traversed the spine only at the L1 and L2 levels. RLRVs traversed the spine in all L1-L4 levels, mostly at the L3 and L2. Osteophyte prevalence at the level of left renal vein was significantly higher in the study group, compared with the control group [OR 2.54, P = 0.01]. Mean AVD was greater in the study group [9.2 mm ±3.6 mm Vs. 3.5 mm ± 2.6 mm, P < 0.001]. Increased AVD was found to be associated with a higher chance of osteophyte presence at the level of the left renal vein [OR 1.282, P = 0.025].

Conclusions: Osteophytes are more prevalent at the level of the RLRV variant compared to the normal anatomy. Furthermore, the RLRV is characterized by a lower lumbar level compared to the normal anatomy.

Clinical Relevance Statement: This anatomic variation could assist in further understanding of osteophyte formation.