Lateral decubitus anterior exposure of the L4-5 disc maintains safety compared with supine positioning.

Background: Anterior retroperitoneal lumbar spinal exposure has traditionally been performed in the supine position (SUP) to access the L4-L5 and L5-S1 disc spaces where lateral approaches may be unsafe. However, advancements in lateral single position surgery have resulted in advocacy for anterior L4-5 disc access in the lateral decubitus position (LAT). While L5-S1 access in the lateral position is well-described, no series of L4-5 anterior access in the lateral position has been published. The study aims to evaluate the safety of anterior lumbar exposure at the L4-5 disc level in the LAT compared to the SUP.

Methods: A multi-center retrospective study of patients who underwent anterior retroperitoneal lumbar exposure involving the L4-5 disc level were classified according to patient positioning: (I) LAT or (II) SUP.

Results: One hundred and forty patients were included, of which 65 LAT and 75 SUP patients. Two hundred and thirty-eight anterior levels were exposed, including 113 levels performed in lateral and 125 levels in supine. Mean anterior levels fused was similar (1.74 vs. 1.67 levels, P=0.37). Significantly more LAT patients underwent additional lateral lumbar interbody fusion (LLIF) (21.50% vs. 0.00%, P<0.001). A larger proportion of LAT patients underwent surgery for spinal deformity (21.50% vs. 6.70%, P=0.01) and planned staged procedures (21.50% vs. 6.70%, P=0.01). Intraoperative complication rates were similar (3.10% vs. 4.00%, P=0.77), including similar vascular injury rates (1.50% vs. 0.00%, P=0.28) and no visceral injury. Postoperative complications (15.40% vs. 38.70%, P=0.002) were significantly lower in the LAT group, however major complications (6.20% vs. 13.30%, P=0.16) were similar between groups. Fewer LAT patients experienced postoperative ileus (0.00% vs. 6.70%, P=0.03). The rate of reoperation within 30 days (3.10% vs. 6.70%, P=0.33) and 90 days (3.10% vs. 10.70%, P=0.09) were similar between groups.

Conclusions: Anterior lumbar spinal exposure of the L4-5 disc in the LAT is safe compared to supine exposure, despite higher case complexity in the lateral position.