Anterior Lumbar Interbody Fusion for Lumbosacral Junction in Steep Sacral Slope

Abstract

Retrospective study of surgical technique and clinical outcome. To examine the technique and outcomes of anterior lumbar interbody fusion (ALIF) surgery for a lumbosacral junction in a steep sacral slope. There are no studies on the outcome and technical pitfalls on ALIF surgery for a lumbosacral junction in a steep sacral slope. Six female patients (mean age of 55.67 y; range, 42 to 69) who had a steep sacral slope underwent ALIF surgery for degenerative (2 patients) and spondylolytic (4 patients) spondylolisthesis. The average follow-up duration was 29.33 months (range, 27 to 33 mo). The following parameters were used to assess the outcomes: slip angle, slip percentage, sacral inclination, lumbosacral angle, sacral slope, and distance from the upper margin of the pubis symphysis to the sacral plane. The level of pain was measured using the visual analog pain scale score. The function was assessed using the Oswestry Disability Index (ODI) score. Satisfaction surveys were also carried out. Statistical analysis was performed using a Friedman test. A P value <0.05 was considered significant. The mean sacral inclination, lumbosacral angle, sacral slope, and distance from the upper margin of the pubis symphysis to the sacral plane were 37.34 degrees (range, 28.55 to 48.92 degrees), 12.20 degrees (range, 5.09 to 16.5 degrees), 40.70 degrees (range, 30.54 to 49.98 degrees), and 22.06 cm (range, 16.13 to 29.72 cm), respectively. The mean correction of slip percentage and slip angle was 35.46%, and 9.3 degrees, respectively. The mean visual analog pain scale score decreased from 8.5 (back pain) and 7.3 (leg pain) to 1.8 (back pain) and 1.8 (leg pain) after surgery (P=0.001). The mean ODI scores also reflected the improved status (ODI of 64.7 before surgery to 8.5 after surgery; P=0.001). The patient's satisfaction was relatively high. All the patients had radiographically solid fusion at the latest follow-up. There were no significant complications encountered in this study. In selected cases, a steep sacral slope may not be an absolute contraindication of ALIF. Moreover, the C-arm-guided reduction and cage insertion method is a reliable way of treating spondylolisthesis in those with a steep sacral slope.