Background: The Dynesys system remains the most widely implanted posterior non-fusion pedicle screw system. Various study designs used in investigations with good to excellent short- and mid-term results have been reported in the current literature. However, there is a lack of information concerning long-term outcomes following treatment for spinal stenosis with degenerative spondylolisthesis.
Methods: The aim of our study was twofold. Firstly, to assess whether the dynamic stabilization in situ with the Dynesys System without bone grafting provides enough stability to prevent progression of spondylolisthesis and secondarily to maintain significant clinical improvement in a long-term follow-up (FU). Therefore, the consecutive patients due to inclusion criterions underwent interlaminar decompression and stabilization with Dynesys instrumentation. Patients were evaluated clinically and radiologically after a minimum FU of 10 years.
Results: At FU, the mean low back pain (LBP) post-operatively and leg pain (LP) post-operatively on visual analog scale (VAS) and North American Spine Society (NASS) improved significantly (P<0.001) compared to preoperative examination. The mean value of NASS neurogenic symptoms (19.13% and 4.72%) and activity subscores were 23.13% and 10.74% respectively. In plain and functional radiographs the mean listhesis grade in neutral position was 11.11%, 11.8% in reclination and 11.63% in inclination. There were 17 and 8 patients with progressing degenerative osteochondrosis/listhesis at adjacent segments.
Conclusions: Decompression and single and double level dynamic in situ stabilization with the Dynesys System demonstrate good clinical and radiological long-term results in elderly patients.
Keywords: Degenerative spondylolisthesis; Dynesys; North American Spine Society lumbar questionnaire (NASS lumbar questionnaire); adjacent segment degeneration (ASD); finger floor distance (FFD); spinal stenosis; visual analog scale (VAS); walking distance (WD).