Abstract
BACKGROUND: Lumbar degenerative spondylolisthesis is a common spinal condition characterized by the anterior slippage of a vertebra over the one below due to degenerative changes. It often leads to chronic low back pain, radiculopathy, and spinal stenosis. Surgical intervention is typically considered when conservative treatments fail, with posterior lumbar fusion (PLF) and posterior lumbar interbody fusion (PLIF) being two widely used techniques. OBJECTIVE: To compare the clinical and radiological outcomes along with complication rates, among patients who underwent PLF and PLIF for lumbar degenerative spondylolisthesis. METHODOLOGY: This prospective cohort study was conducted on 100 patients with lumbar spondylolisthesis who underwent either PLF (n=50) or PLIF (n=50). Preoperative clinical features, including low back pain, radicular symptoms, and neurologic deficits, were recorded. Postoperative outcomes at six months included low back pain, Oswestry Disability Index (ODI), radiological fusion (Bridwell grade), infection, hardware failure, and reoperation. Categorical data were compared using Chi-square tests and logistic regression was applied to determine independent associations. RESULTS: Postoperative low back pain was reported by 18 (36.0%) patients in the PLIF group compared to 42 (84.0%) patients in the PLF group (p < 0.001). PLIF patients showed superior functional outcomes with more achieving minimal disability on the ODI (80% vs. 52%, p = 0.007) and better radiological fusion (Grade 1 fusion in 60% vs. 24%, p < 0.001). Reoperation was significantly more frequent in the PLF group (24% vs. 4%, p = 0.004). Multivariate logistic regression confirmed PLIF as an independent predictor of improved outcomes. CONCLUSION: PLIF demonstrated superior clinical and radiological outcomes with fewer reoperations compared to PLF at six-month follow-up. These findings support the preference for PLIF in selected cases of lumbar spondylolisthesis.