The effect of anterior longitudinal ligament resection on lordosis correction during minimally invasive lateral lumbar interbody fusion: Biomechanical and radiographic feasibility of an integrated spacer/plate interbody reconstruction device

Abstract Background Lateral lumbar interbody fusion is powerful for correcting degenerative conditions, but sagittal correction remains limited by anterior longitudinal ligament tethering. Although lordosis has been restored via ligament release, biomechanical consequences remain unknown. Investigators examined radiographic and biomechanical of ligament release for restoration of lumbar lordosis. Methods Six fresh-frozen human cadaveric spines (L3–S1) were tested: (Miller et al., 1988) intact; (Battie et al., 1995) 8 mm spacer with intact anterior longitudinal ligament; (Cho et al., 2013) 8 mm spacer without intact ligament following ligament resection; (Galbusera et al., 2013) 13 mm lateral lumbar interbody fusion; (Goldstein et al., 2001) integrated 13 mm spacer. Focal lordosis and range of motion were assessed by applying pure moments in flexion-extension, lateral bending, and axial rotation. Findings Cadaveric radiographs showed significant improvement in lordosis correction following ligament resection ( P < 0.05). The 8 mm spacer with ligament construct provided greatest stability relative to intact ( P > 0.05) but did little to restore lordosis. Ligament release significantly destabilized the spine relative to intact in all modes and 8 mm with ligament in lateral bending and axial rotation ( P < 0.05). Integrated lateral lumbar interbody fusion following ligament resection did not significantly differ from intact or from 8 mm with ligament in all testing modes ( P > 0.05). Interpretation Lordosis corrected by lateral lumbar interbody fusion can be improved by anterior longitudinal ligament resection, but significant construct instability and potential implant migration/dislodgment may result. This study shows that an added integrated lateral fixation system can significantly improve construct stability. Long-term multicenter studies are needed.