BACKGROUND AND OBJECTIVES: This study examined the impact of anterior lumbar interbody fusion (ALIF) on coronal alignment, before and after the placement of posterior instrumentation, and the changes in coronal alignment based on patient positions in adult spinal deformity surgery. METHODS: A total of 65 consecutive adult spinal deformity patients with scoliosis presenting with a main curve cobb angle ≥20° undergoing thoraco-lumbar fusion with 1-2 levels of ALIF performed at L5-S1 or L4-S1 were retrospectively reviewed. L4 tilt, L5 tilt, and fractional curve (FC) cobb angle were measured to assess coronal alignment. Preoperative computed tomography and intraoperative supine x rays were compared with assess radiographic correction with ALIF alone, and preoperative and postoperative computed tomography were compared to evaluate ALIF with posterior spinal fusion. RESULTS: Of 65 patients, 17 underwent a L5-S1 ALIF, while 48 underwent L4-S1 ALIF. Significant differences in coronal alignment, including L4 tilt, L5 tilt, and FC, were found when comparing preoperative supine radiographs with intraoperative supine radiographs taken after ALIF alone. The proportions of ALIF correction (the ratio of correction after ALIF to ALIF + posterior spinal fusion) were 58% and 56% for L4 tilt, 69% and 63% for L5 tilt, and 56% and 59% for FC in L5-S1 and L4-S1 cases, respectively. The flexibility of FC demonstrated a significant negative correlation with the change in FC (postoperative supine FC−preoperative supine FC, r = −0.56, P < .001). Notably, the coronal parameters measured on initial postoperative standing radiographs were comparable with those observed in the supine radiographs taken after ALIF alone. CONCLUSION: The radiographic correction in L4 tilt, L5 tilt, and FC after ALIF alone were similar to the ultimate radiographic correction we achieve even after the addition of posterior fixation. For patients presenting with adult degenerative scoliosis and rigid FC in the setting of coronal malalignment, ALIF can be an effective procedure to help correct coronal alignment.
Bansal et al. (Mon,) studied this question.