Iliolumbar vein: a challenge for the exposure of the L4-5 disc in the anterior approach to the lumbar spine.

PURPOSE: Anterior lumbar spine arthrodesis has been increasingly prescribed. In order to obtain better exposure of the intervertebral discs, it is necessary to identify vascular structures depending on the level to be approached. Systematic ligation of the iliolumbar vein has been suggested for access to the L4-L5 level, which may be technically challenging. The goal of the present study was to determine a safe limit for separating the iliolumbar vein safely without the need for its ligation. METHODS: In total, 2284 patients involving the topography of the iliolumbar vein were included. If this vein was up to 5 mm distant from the inferior border of the L4-L5 intervertebral disc, its ligature was performed. In cases that the distance was greater than 5 mm, only the retraction was performed without ligature. RESULTS: A total of 115 ligatures were necessary (5% of cases). Among the 2169 cases with no ligature, bleeding due to ruptures occurred during traction in only 55 patients (3% of cases). The time taken for ligation ranged from five minutes to thirty-two minutes, with an average of 18.3 min per ligature. In cases in which ligatures were needed (distance less than 5 mm), there was loosening of the ligatures leading to bleeding in 23 cases (20% of ligatures). CONCLUSIONS: Systematic ligature is not necessary for accessing the anterior route to the L4-L5 level, leading to a reduction in the time of surgery and avoiding serious vascular injuries that can occur.