Do Good Clinical Radiographs Correlate with Functional Outcomes in Lumbar Spine Surgery in Nigeria: A Retrospective Single Centre Cohort Study

Abstract

Background: The relationship between radiographic success and functional improvement following lumbar spine surgery remains a subject of ongoing debate. While plain radiographs are routinely used to assess fusion and alignment in clinical practice, their correlation with patient-reported functional outcomes is not well established, particularly in resource-limited settings. Methods: A retrospective cohort study of 302 consecutive patients who underwent lumbar surgery (discectomy, fusion with or without instrumentation) at the National Orthopaedic Hospital Dala, Kano, from January 2019 to December 2025 was conducted. Radiographic parameters assessed included fusion status (presence of continuous bridging trabecular bone, absence of lucency, and <3° motion on flexion-extension views), lumbar lordosis, segmental lordosis, and sagittal balance. Functional outcomes were measured using the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for back and leg pain at 12-month follow-up. Correlation between radiographic parameters and functional outcomes was assessed using Spearman's correlation coefficient. Results: Radiographic fusion was achieved in 268 patients (88.7%). A positive but weak correlation was observed between radiographic fusion and improvement in VAS for back pain (r=0.255, p=0.02), while no significant correlation was found with ODI improvement (r=0.112, p=0.18). Restoration of lumbar lordosis correlated weakly with ODI improvement (r=0.218, p=0.04). Notably, 18 patients (6.0%) with radiographic non-union reported satisfactory functional outcomes (ODI improvement ≥15 points), while 22 patients (7.3%) with solid radiographic fusion reported poor functional outcomes (ODI improvement <5 points). Conclusions: Good clinical radiographs show only a weak to moderate correlation with functional outcomes after lumbar spine surgery. Radiographic fusion does not guarantee functional success, nor does non-union uniformly predict failure. Functional outcomes are influenced by multiple factors beyond radiographic parameters, including patient expectations, psychosocial factors, and residual pain. Surgeons should therefore avoid over-reliance on plain radiographs as the sole measure of surgical success.