Evaluation of lordosis recovery after lumbar arthrodesis and its clinical impact

BACKGROUND: Posterior lumbar arthrodesis has become a widely used therapeutic option to correct sagittal imbalances in patients suffering from degenerative lumbar conditions. However, in western Africa, there is no study have reported long-term outcome of posterior lumbar arthrodesis. The aim of this study was to investigate the relationship between the restoration of adequate lordosis and the patient’s postoperative quality of life. METHOD: The study was retrospective. From January 2012 to December 2019, 80 patients who underwent posterior lumbar arthrodesis for lumbar degenerative diseases were included with a mean follow-up of 43.2 months. Mean age was 50.8 years (SD = 12.2). Preoperative and postoperative patients’ symptoms were assessed by the visual analog scale (VAS), Oswestry Disability Index (ODI), and 12-item Short Form (SF-12). Pre- and post-operative radiographic evaluation included lumbar lordosis measured (LLm), pelvic incidence (PI), sacral slope (SS), and pelvic stilt (PS). Theoretical lumbar lordosis (LLt) was defined by the following: LL = 0.54 × PI + 27.6. Data analysis was done using the statistical software “R.” The risk of error was 5% (p < 0.05). RESULT: The mean pelvic incidence was 57.23°. There was no statistically significant difference between preoperative and postoperative lumbar lordosis (p = 0.2567). There was no statistical difference between preoperative and postoperative PI-LL (p = 0.179). There was a statistically significant difference between the pre and postoperative clinical scores (p < 0.001). Statistical analysis showed a correlation between recovery of lumbar lordosis and improvement in physical component of SF-12 (PCS) (p < 0.05) and lumbar and radicular VAS (p < 0.05) for the subgroup of narrow lumbar spine. There was a statistical relationship between the restoration of lumbar lordosis and improvement in PCS (p = 0.004) and VAS (p = 0.003) for the subgroup of isthmic lysis spondylolisthesis. DISCUSSION: The root decompression performed in most patients could explain the clinical improvement regardless of recovery of lordosis. The failure to consider spinal parameters and sagittal balance of patients in the surgery could explain no restoration of lumbar lordosis. Our study had limitations inherent to its retrospective character such as the classic selection bias. CONCLUSION: Satisfactory correction of spinopelvic alignment may improve long-term clinical signs.