BackgroundSpondylolisthesis is characterized by the slipping of one vertebra, compared with the underlying one, due to structural and degenerative changes. Its origin is multifactorial which includes disc degeneration, facet joint anatomic orientation, iliolumbar configuration, and ligament hyperlaxity. The most common operative treatment is decompression and may require an individualized surgical plan. However, only decompression may progress the slippage which can result in pain or recurrence of neurological complaints. Therefore, lumbar fusion and fixation are considered appropriate to stabilise the spine and prevent delayed deterioration. The aim of our study was to find out the outcome of posterior decompression, with reduction and fixation of lumbosacral spondylolisthesis by Oswestry Disability Index (ODI) to improve further our results.MethodsThis study was conducted from July 2013 to February 2017 including 94 patients with lumbosacral spondylolisthesis. The Meyerding classification was used to grade the extent of vertebral slippage. The assessment was done using the ODI.ResultsThere were 50 (53.19%) males and 54 (46.80%) females with a mean age of 44 years ± 10.49 SD. Backache was present in all patients and claudication in 85 (90.42%) patients. There were 10 (10.63%) patients with spondylolisthesis at L3-L4, 36 (38.29%) at L5-S1 and 48 patients (51.06%) at L4-L5 level. In 48 patients with L4-L5 level, 38 (79.16%) were in grade II while six (12.5%) were in grade III. According to the preoperative ODI score, 38 patients were placed in moderate disability, 42 patients were severely disabled while four patients were disabled.Good outcome was achieved in a total of 79 (84.04%) patients. In 40 (42.55%) patients, with complete reduction, the good outcome achieved in 35 (83.33%) while in 22 (23.40%) patients there was no reduction and a good outcome was achieved in 17 (77.27%) patients. In 38 (40.42%) patients with moderate disability, 32 (84.04%) patients had a good outcome. Post-operative cerebrospinal fluid (CSF) leak occurred in five (5.31%) and wound infection in seven (7.44%) patients while there was no mortality.ConclusionReduction with decompression can have a good outcome in spondylolisthesis, and ODI should be used as a predictor of outcome. It also shows that proper decompression is required and not a complete reduction.