DYNESYS STABILIZATION IN DEGENERATIVE LUMBAR SPONDYLOLISTHESIS: 4 YEARS FOLLOW-UP

Abstract

In spinal stenosis with degenerative spondylolisthesis, decompression and fusion is widely recommended. However, the main drawback of fusion remains pain at the bone donor site. A novel dynamic transpedicular system (Dynesys™) was introduced to stabilize the spine without adding bone graft for fusion. Two years results reported earlier were excellent.

Objective: To test whether dynamic stabilization in situ can maintain enough stability to prevent progression of spondylolisthesis in long term follow-up.

Methods: 26 consecutive patients (mean age 71 years) with lumbar spinal stenosis and degenerative spondylolisthesis underwent interlaminar decompression and stabilization with Dynesys™. Patients were re-evaluated clinically and with plain and functional radiographs after a minimum follow-up time of 4 years.

Results: A total of 20 patients could be evaluated. Pain on VAS as well as walking distance improved significantly (p< 0.01) at 2 years and remained unchanged at 4 years follow-up. Radiographically spondylolisthesis did not progress and the motion segments remained stable. Implant failure in terms of screw- loosening (3 patients) or breakage (1 patient) seen after 2 years did not increase. Progressive degeneration at an adjacent level was seen in 35% of the patients at 2 years and in 39% at 4 years. Overall, patient satisfaction remained high as 95% would undergo the same procedure again.

Conclusions: In elderly patients with spinal stenosis and degenerative spondylolisthesis, decompression and dynamic stabilization leads to sustained excellent clinical and radiological results. It maintains enough stability to prevent progression of spondylolisthesis. Since no bone grafting is necessary, donor site morbidity is eliminated. The degenerative disease however is progressive and degeneration at adjacent motion segments remains a problem.