gms | German Medical Science

Objective: Dynamic devices for stabilization of lumbar degenerative instability are becoming more popular. But it is unclear, whether the use of a posterior dynamic device influences the re-OP rate compared to fusion. Therefore we investigated the re-OP rate at one single centre in a retrospective-consecutive style.

Methods: From 04/2006–12/2010 n=346 were treated using a posterior dynamic fixateur interne for degenerative lumbar instability. In n=48 patients implant-related re-OPs were performed up to 06/2011 (m=20; f=28). Median age 67 yrs. (39–78 yrs.). Median interval from first posterior dynamic stabilization to first re-OP at the dynamic device or at an adjacent level was n=14 months (range: 3–41 months). In n=9/48 patients indication for posterior dynamic stabilization was adjacent level disease due to prior instrumentation. Data-collection was performed in a retrospective-consecutive style using digital patient folder, pre- and postop CT/MR-imaging, and with telephone-interview for those, who didn't take part in a follow-up program or who chose another institution for further therapy.

Results: In n=48 (13.9%) patients of n=346 patients in total, re-OPs were done at the implanted dynamic device or at an adjacent segment. In n=48 patients n=83 motion segments (range 1–3) were instrumented at the time of first dynamic stabilization procedure. n=18 pats mono-segmental, n=25 bi-segmental and n=5 tri-segmental. Indications for re-OP within or adjacent to the stabilized segments were: n = 2 (0.6 %) spondylodiscitis n=1 (0.3%) osteoporotic fracture cranial to the hardware, n=10 (2.9%) screw-loosening, n=5 (1.4%) persistent/new low back pain, n=5 (1.4%) symptomatic protrusion/stenosis within the stabilized segment – therefrom n = 2 with additional screw-loosening, n=25 (7.2%) symptomatic degeneration in crania/caudal adjacent segment – therefrom n=4 with additional screw-loosening. N=9 patients after posterior dynamic stabilization due to ALD n=6/9 (66.7%) developed further symptomatic degeneration in an adjacent segment and in n=3/9 patients screw loosening was observed.

Conclusions: The “overall” re-OP rate of 13.9% using a dynamic posterior fixateur interne is low in relation to the observation period and the total number of observed patients – particularly a low re-OP rate due to symptomatic degeneration within an adjacent segment of 7.2% is remarkable. Posterior dynamic stabilization can be considered to be at least equivalent or superior to fusion procedure for a well selected collective.