Does L5-S1 Anterior Lumbar Interbody Fusion Improve Sagittal Alignment or Fusion Rates in Long Segment Fusion for Adult Spinal Deformity?

Study Design: Retrospective cohort study. Objectives: To assess whether the addition of L5-S1 anterior lumbar interbody fusion (ALIF) improves global sagittal alignment and fusion rates in patients undergoing multilevel spinal deformity surgery. Methods: Two-year radiographic outcomes, including lumbar lordosis, pelvic incidence, pelvic tilt, and T1 pelvic angle; hardware complications; and nonunion/pseudarthrosis rates were compared between patients who underwent lumbosacral fusion at 4 or more vertebral levels with and without L5-S1 ALIF between November 2003 and September 2016. Results: A total of 51 patients who underwent fusion involving a mean of 11.1 levels with minimum 2-year postoperative radiographic follow-up data were included. Patients who underwent L5-S1 ALIF did not have significant improvement in global sagittal alignment parameters and demonstrated a trend toward a higher rate of nonunion and hardware failure. Conclusions: L5-S1 ALIF did not confer significant benefit in terms of global sagittal alignment and fusion rates in patients undergoing multilevel lumbosacral fusion. Given these results and that L5-S1 ALIF is associated with increased surgical morbidity, surgeons should be judicious in including L5-S1 ALIF in large multilevel constructs.