LAUSR

BACKGROUND To compare left and right vascular anatomy at L5-S1 disc space and validate anatomical feasibility of right oblique approach for L5-S1 oblique lumbar interbody fusion (OLIF). METHODS Axial T2 MR images at L5-S1 disc level were used to study 274 subjects (164 females, 110 males; average age of 62.97 years). Distance from the center of L5-S1 disc to the medial wall of the left or right vessel was measured. According to vessel position, three groups were established: medial, middle, and lateral. To describe morphologic configuration, vessel type and the presence of perivascular adipose tissue (PVAT) around vessels were identified on both sides. RESULTS Vessels on the left L5-S1 disc space were located at 12.47 mm from the midline and most (209 subjects, 76.3%) subjects were included in the medial or middle group. On the right side, vessels were located more laterally (16.93 mm, p = 0.000) and most (248 subjects, 90.5%) subjects were included in the middle or lateral group. On the left side, vessels were mostly veins (260 subjects; 94.9%) and 139 (50.7%) subjects had the presence of PVAT. On the right side, vessels were mostly arteries (213 subjects; 77.7%) and 242 subjects (88.3%) showed the presence of PVAT. CONCLUSIONS Vessels on right side of L5-S1 disc were located more laterally and most vessels on the right side were arteries accompanying PVAT that might minimize vessel manipulation. These results indicate that the right side of L5-S1 disc could provide a feasible access for OLIF at L5-S1.