Spondylolisthesis at L4/5 but Fixation of L4, L5 and S1 Reduces the Rate of Adjacent Segment Degeneration

Abstract

Study background: Adjacent segment disease (ASD) is a common phenomenon seen in patients who have undergone prior lumbar fusion surgery is characterized by degeneration and/or stenosis. Treatment for ASD includes extension of the fusion with a posterior approach, with direct decompression of the neural elements when indicated. Methods: 54 patients of spondylolisthesis involving L4/5 level were included in this study that were operated from January 2012 to December 2020 in Bangabandhu Sheikh Mujib Medical University and few private hospital in Dhaka who failed to respond in conservative treatment. 30 patients were male and 24 were female. patients were evaluated by clinical finding (low back pain, sensory, motor and jerks) VAS score, ODI score, JOA score, modified Macnab’s criteria, claudication distance, X-ray lumbosacral spine AP and lateral view, MRI of lumbosacral spine, CT scan of lumbosacral spine. P value of less than 0.05 was level significance. Results: Mean (± SD) age of the patients was 56.29 ± 8.13 with highest age being 68 years and lowest being 41 years. 40 were male and 24 were female. Preoperative VAS score (for both back pain and leg pain) was 6.86 ± 0.65 which significantly reduced to 1.04 ± 0.19 36 months after operation. Out of 64 patients, 62 patients showed interbody fusion with good trabecular marking. Postoperative MRI of lumbosacral spine at 36 months showed 48 patients out of 64 had no desiccation of L3/4 disc, 9 had mild disc desiccation and 7 developed desiccation of L3/4 disc. Final outcome was determined by Modified Macnab’s criteria. Excellent result found in 39 patients, good result found in 22 patients and fair result found in 3 patients. Conclusion: Fixation of L4, L5 along with S1 in single level PLIF or TLIF in L4/5 level significantly reduce the rate of disc degeneration at L5/S1 level with slight degeneration at L3/4 level.