Single-Position Prone Lateral Interbody Fusion Improves Segmental Lordosis in Lumbar Spondylolisthesis

Objective: Single-position surgery in prone position is a novel technique for lateral interbody fusion with pedicle screw fixation. We performed a radiographic comparison of patients treated for spondylolisthesis using the prone lateral (PL) transpsoas approach versus the traditional dual position (DP) approach (lateral decubitus then prone).

Methods: Thirty consecutive patients with spondylolisthesis were treated using the PL approach (n = 15) versus the dual position approach (n = 15). Radiographic factors in the groups were retrospectively compared.

Results: The groups were similar for age, sex, body mass index, and implant size, but there were more 15° (vs. 10°) cages inserted in the dual position group. Radiographically the groups had similar baseline spinopelvic parameters, lumbar lordosis (LL), segmental lordosis, anterolisthesis, and disc height (P > 0.05). Postoperatively the PL group demonstrated a larger improvement in segmental lordosis (5.1° vs. 2.5°, P = 0.02), but not overall LL (6.3° vs. 3.1°, P = 0.14). Both groups had similar improvements in pelvic tilt, disc height, and spondylolisthesis reduction (P > 0.05). The mean relative distance of the implant from the posterior edge of the vertebral body was greater in the PL group (26% vs. 17%, P < 0.001) indicating a tendency for more anterior cage placement. However, there was no significant correlation between the relative cage position and the increase in segmental lordosis (P = 0.35), so this result alone did not explain the relative increase in lordosis seen.

Conclusions: This is the first study to our knowledge to demonstrate an improvement in segmental lordosis for patients with single-level spondylolisthesis using the PL approach.