Lumbosacral arthrodesis using pedicular screws and ringed rods.

Sixty-one patients who had lumbar instability and chronic low back pain or deformity from nontraumatic lumbar pathologies were studied. In all of them a posterior lumbosacral fusion with CUN (Clinic of the University of Navarre) pedicle rod fixation was used. The mean follow-up period was 36 months (range 26-46 months). The consolidation rate was evaluated according to plain and functional radiographs, and a clinical evaluation was made using an analogue pain scale. The rate of fusion was 93.5%. Neurological complications occurred in 3.3%. The incidence of screw failure was 2.3% of all the screws. No other implant failure occurred. The patients rated their clinical results as 'excellent' in 33.8% of the cases, 'good' in 42.2%, 'fair' in 16.9% and 'poor' in 6.7%. CUN instrumentation is a versatile internal fixation system that has been shown to provide satisfactory stability. Furthermore, the clinical results are comparable to those reported in studies in which the most common hardwares were used.