Dynamic stabilization for degenerative spondylolisthesis: evaluation of radiographic and clinical outcomes

To evaluate the dynamic stabilization system in degenerative lumbar spondylolisthesis.

This retrospective study included 38 patients (mean age 63.7 years) with one- or two-level lumbar spinal stenosis who underwent laminectomy and Dynesys (Zimmer Spine, Minneapolis) stabilization. Pre-operatively, 24 had degenerative spondylolisthesis while the other 14 did not. Radiographic and clinical evaluations were analyzed with a mean follow-up of 41.4±6.9 (30-58) months.

The mean range of motion (ROM) at the index level was significantly reduced post-operation (10.0±3.3° to 2.7±1.5°, P<0.001). Screw loosening occurred in 13.3% of levels, 21.1% of patients, and 4.6% of screws. There were no differences between patients with and without spondylolisthesis in ROM and screw loosening. Overall, the mean Visual Analogue Scale (VAS) of back and leg pain improved significantly (6.0±3.2 to 1.9±2.6 and 7.4±2.6 to 2.5±2.9, both P<0.001, respectively), and the Oswestry Disability Index (ODI) also improved significantly (50.6±19.5 to 27.3±24.9, P<0.001) after the operation. Moreover, there were no differences between the groups of spondylolisthesis and non-spondylolisthesis, or among the patients with and without screw loosening.

There is significant clinical improvement after laminectomy and dynamic stabilization with Dynesys for lumbar spinal stenosis. While there was restriction (<3°) in segmental ROM, Dynesys provides similar radiographic stability and clinical effects regardless of pre-operative spondylolisthesis.