The Effect of Lordosis on Clinical Outcome After Spinal Fusion for One-level Degenerative Spondylolysthesis

Degenerative spondylolisthesis is a common spinal degenerative disease. It is defined as the slippage of one vertebrae on the vertebrae bellow. In the process of spinal ageing and spinal joint degeneration, the spine becomes subjected to degenerative development that results in joint instability, shifting of vertebrae and can be responsible for a progressive kyphosis of the lumbar spine and sagittal imbalance with forward inclination of the trunk and chronic low back pain development. To address these changes and restore stability, lumbar spinal fusion has been developed and is nowadays a common procedure for unstable degenerative spine disorders. In the past several years, studies that highlight the importance of sagittal balance analysis with the restoration of adequate lumbar lordosis, have emerged. However, it remains a challenge to determine the correct amount of lumbar lordosis that is required for each patient to maintain optimal post-fusion sagittal balance. Additionally, the relationship between pelvic incidence (PI) and impact of LL correction has been highlighted in literature. The position of fused vertebrae is of paramount importance, as sagittal alignment should be done with minimizing muscle work during posture. Failure to reach proper sagittal balance can result in compensatory mechanisms such as increased pelvic tilt (PT), cervical and thoracic segment hyperextension, and knee flexion. These compensatory mechanisms have adverse effects such as chronic pain, disability and muscle fatigue. With this study the investigators aim to analyze long-term clinical and spinopelvic radiographic parameter outcomes of patients who underwent a one-level spinal fusion procedure for single level degenerative spondylolisthesis disease at a single institution.