Risk Assessment of Lumbar Segmental Artery Injury During Lateral Transpsoas Approach in the Patients With Lumbar Scoliosis.

STUDY DESIGN A retrospective study using 27 contrast-enhanced multi-planar computed tomography scans of subjects with lumbar scoliosis. OBJECTIVE To assess the risk of injury of lumbar segmental arteries during transpsoas approach in patients with lumbar scoliosis. SUMMARY OF BACKGROUND DATA Although lumbar interbody fusion using big intervertebral cage through transpsoas approach has a big advantage to correct coronal and sagittal deformity in patients with spinal deformity, the risk for injury of lumbar segmental artery is always concerned. METHODS The abdominal-contrast enhanced multi-planar computed tomography scans of 27 subjects with lumbar scoliosis with over 15° of Cobb angle were retrospectively reviewed. The coronal views through the posterior one third of the intervertebral discs were reviewed. The cranio-caudal intervals of the adjacent segmental arteries at each intervertebral level were measured. The recommended working space for the lateral transpsoas approach using extreme lateral interbody fusion retractor is 24 mm in the cranio-caudal direction. The cutoff value for an intersegmental Cobb angle that would estimate a cranio-caudal interval of less than 24 mm was determined using a receiver operating characteristic curve. RESULTS The average interval between the cranio-caudal lumbar segmental arteries on the concave side was significantly shorter than that on the convex side (29.9 vs. 33.6 mm, P < 0.05). The differences in the intervals between the convex and concave sides were correlated with the corresponding intersegmental Cobb angle (r = 0.65, P < 0.05). Receiver operating characteristic curve analysis revealed that cutoff value for the best prediction of an interval less than 24 mm was 14.5°, with a specificity of 94.3% and sensitivity of 71.4%. CONCLUSION This study demonstrated that female patients with lumbar scoliosis with an intersegmental Cobb angle higher than 14.5° would be at high risk for potential injury to the lumbar artery during a transpsoas approach for extreme lateral interbody fusion from the concave side. LEVEL OF EVIDENCE 4.