Effects Of Surgical Positioning On L4-L5 Accessibility And Lumbar Lordosis In Lateral Transpsoas Lumbar Interbody Fusion: A Comparison Of Prone And Lateral Decubitus In Asymptomatic Adults

BACKGROUND: Lateral interbody fusion (LIF) is traditionally performed in lateral decubitus on a breaking surgical table to improve L4-L5 access. Prone transpsoas (PTP) LIF may improve sagittal alignment and facilitate single-position circumferential procedures; but may require manipulation of the iliac crest for L4-L5 accessibility.METHODS: Healthy adult volunteers (n = 41) were positioned as if for surgery in right-lateral decubitus on a radiolucent breaking table, and also prone on a Jackson style surgical frame atop a custom PTP bolster. Iliac crest distance from the L5 superior endplate, and coronal and sagittal plane alignments were measured from fluororadiographs obtained in each of 5 positions: standard lateral decubitus (LD), prone-hips and spine neutral (PR NN), prone-hips neutral and spine coronally bent (PR-NCB), prone-hips extended and spine neutral (PR-EN), and prone hips extended and spine coronally bent (PR-ECB).RESULTS: L4-L5 accessibility was lowest in prone neutral and improved in all augmented positional configurations: PR-NN<>PR-ENLD, P = 0.0480). Coronal angulations were greatest in LD, and statistically different from both prone neutral (LD>PR-NN, P < 0.0001) and prone coronally & nbsp;bent (LD>PR-NCB, P < 0.0001). Lordosis was greatest in extended prone positions and lowest in lateral decubitus: PR-EN>PR-ECB>PR-NCB<>PR-NN>LD. All prone positions showed significantly greater lordosis than lateral decubitus (P < 0.001).CONCLUSIONS: Compared with lateral decubitus, prone positioning provides equivalent or better L4-L5 LIF access around the iliac crest when a positioner is used that enables coronal bending, and improved positional lordosis, which may facilitate segmental correction and achievement of surgical alignment goals