[Pedicular dynamic stabilization system. Functional outcomes and implant-related complications for the treatment of degenerative lumbar disc disease with a minimum follow-up of 4 years].

INTRODUCTION The Dynesys(®) system is a non-fusion pedicular dynamic stabilization system. The aim of our study is to evaluate the clinical outcomes in patients with degenerative disc disease and/or stenosis, and to measure the prevalence of screw loosening and breakage after 4 years of follow up. MATERIAL AND METHODS All patients who underwent surgery with Dynesys(®) system in 2008 were reviewed. The surgery was performed in cases of low back pain of more than 6 months duration and a positive MRI for degenerative disc disease and/or stenosis. RESULTS A total of 22 patients (11 females, 11 males) with a mean age of 44.40 ± 11 years were included, 20 patients (91%) underwent Dynesys(®) without any associated decompression maneuver. The evaluation of back and leg pain (0-10mm) showed a mean decrease of 2.4 ± 2.06 mm (P=.0001). The preoperative value of the Oswestry disability index was 52.36 ± 16.56% (severe functional limitation). After surgery, this value was 34.27 ± 17.87% (moderate functional limitation) (P=.001) with a decrease of 18.09 ± 16.03% (P=.001). A total of 4 (18%) patients showed signs of loosening screws. One patient (4.5%) had a screw breakage. CONCLUSIONS Surgery with Dynesys(®) shows favorable long term clinical results, however the range of improvement in our series is lower than those reported in other studies. Comparative studies between Dynesys(®) and decompression need to be performed in order to isolate the benefit of the dynamic stabilization system. Implant-related complications are not uncommon.