Retrospective patient outcome evaluation after semi-rigid stabilization without fusion for degenerative lumbar instability

Late infections after dynamic stabilization of the lumbar spine with Dynesys

INTRODUCTION

Dynamic stabilization of the spine was developed as an alternative to rigid fusion in chronic back pain to reduce the risk of adjacent segment degeneration. Dynamic neutralization system (Dynesys, Zimmer CH) is one of the most popular systems available, but some midterm studies show revision rates as high as 30 %. Some late infectious complications in our patients prompted us to review them systematically. Propionibacterium recently has been shown to cause subtle infections of prosthetic material.

MATERIALS AND METHODS

Here, we report on a consecutive series of 50 Dynesys implants. In a median follow-up of 51 months (range 0-91), we identified 12 infectious and 11 non-infectious complications necessitating reoperation or removal of the implant in 17 patients.

RESULTS

Material infections occurred after a median of 52 months (2-77) and were due to Propionibacterium alone (n = 4) or in combination (n = 3) in seven out of 11 patients. Clinical presentation combines new or increasing pain associated with signs of screw loosening on conventional X-rays; however, as many as 73.5 % of patients present some degree of screw loosening without being at all symptomatic of infection.

CONCLUSION

The high rate of late infections with low-grade germs and the frequency of screw loosening signs made us suspect a lack of integration at the bone-screw interface. Surgeons should be suspicious if the patient presents a combination of new or increasing pain and signs of screw loosening, and aggressive revision is recommended in these cases.

Efficacy and safety of dynamic stabilization for patients with degenerative disc, spinal stenosis and low back pain: a systematic review of randomized controlled clinical trials

STUDY DESIGN: Systematic review of the literature. OBJECTIVE: To perform a systematic review of the literature to organize, critical appraisal and select the best evidence available about the efficacy and safety of non-fusion fixation and its potential use for patients with degenerative disc, spinal stenosis and low back pain. SUMMARY OF BACKGROUND DATA: Recent reports have increased debate about the role of dynamic stabilization in the treatment of chronic back pain associated with lumbar disc degeneration and spinal stenosis. We conducted a systematic review of randomized trials through a more sensitivity search strategy and rigorous criteria applied for the type of studies. METHODS: An electronic search was made in the databases of the Cochrane Central Register of Controlled Trials, Medline, Embase, and Latin American and Caribbean Health Sciences (Lilacs) extended to November 31, 2008, with no linguistic restrictions. RESULTS: One randomized controlled trial that fulfilled the inclusion criteria described above was included in this review. CONCLUSION: The data included in this review show that the use of non-fusion stabilization could be a suitable alternative to another therapies in well selected patients with spinal stenosis and degenerative disc disease. This review highlighted the need for continued research into the use of non-fusion stabilization in the treatment of spinal disorders. There is an urgency need to conduct randomized clinical trials. Long-term efficacy should be evaluated.