POSTERIOR STABILIZATION FOR LUMBOSACRAL INSTABILITY

Abstract

Background: Lumbar and lumbosacral instability involving the L3–L4, L4–L5, and L5–S1 levels is a major cause of chronic low back pain, radiculopathy, and functional impairment. Posterior stabilization using pedicle screw–rod constructs, with or without interbody fusion, is considered the gold standard for restoring segmental stability, alleviating pain, and promoting fusion. This study evaluates the clinical and radiological outcomes of posterior stabilization in 100 patients with instability at L3–L4, L4–L5, and L5–S1, with a primary focus on the lumbosacral junction.

Materials and Methods: A prospective observational study was conducted on 100 patients with symptomatic instability at L3–L4, L4–L5, or L5–S1 due to degenerative spondylolisthesis, post-traumatic instability, or post-laminectomy changes. All patients underwent posterior stabilization using pedicle screw–rod constructs; 65 patients also received interbody fusion. Clinical outcomes were assessed using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) preoperatively and at 3, 6, and 12 months postoperatively. Radiological assessment included fusion status, segmental disc height, and segmental lordotic angle at the involved level at 12 months. Complications were documented. Statistical analysis was performed using paired t-tests, with p < 0.05 considered significant.

Results: The mean age was 52.4 ± 11.6 years, with 62% males. VAS improved from 7.6 ± 1.1 preoperatively to 2.1 ± 0.9 at 12 months (p < 0.001), and ODI improved from 62.5 ± 9.8% to 18.4 ± 7.3% (p < 0.001). Solid fusion was achieved in 92% of patients. Mean disc height and segmental lordosis at the affected levels (L3–L4, L4–L5, or L5–S1) showed significant improvement at 12 months. Complications were minimal, including superficial wound infection (6%), transient neuropraxia (3%), and hardware failure (1%). No permanent neurological deficits were observed.

Conclusion: Posterior stabilization with pedicle screw–rod constructs is an effective and safe intervention for lumbar instability at L3–L4, L4–L5, and L5–S1, resulting in significant pain relief, functional improvement, high fusion rates, and restoration of segmental alignment. The procedure demonstrates a low complication profile and is effective across a range of etiologies. Long-term studies are recommended to evaluate durability, adjacent segment effects, and outcomes of minimally invasive approaches.