Analysis of Factors Contributing to Postoperative Spinal Instability after Lumbar Decompression for Spinal Stenosis

method and level. Results: Female patients, normal lordotic angle, and asymmetrical paraspinal muscle volume were factors more significantly associated with spondylolisthesis (p-value=0.026, 0.015, <0.01). Statistical results indicated that patients with facet tropism were more likely to have segmental angulation (p-value=0.046). Facet tropism and asymmetry of paraspinal muscle volume were predisposing factors to spinal instability (p-value=0.012, <0.01). Conclusion: Facet joint tropism and asymmetry of paraspinal muscle volume are the most important factors associated with spinal instability; therefore, careful follow-up after decompressive laminectomy in affected patients is necessary.