Midterm outcome of posterior decompression and Dynesys stabilization for lumbar degenerative disease

English Keywords:Lumbar vertebrae  Degenerative disease  Dynamic stabilization  Dynesys  Adjacent segment degeneration.

English Abstract:

  【Abstract】 Objectives: To evaluate the midterm clinical and radiographic outcomes of posterior decompression and Dynesys stabilization in the treatment of lumbar degenerative disease. Methods: From July 2008 to May 2010, 59 patients suffering from lumbar degenerative disease underwent lumbar spine stabilization with Dynesys were retrospectively analyzed. Clinical outcomes were evaluated by using Oswestry disability index(ODI) and visual analogue scale(VAS). Radiographic evaluations included the mean range of motion(ROM) and the disc height of stabilized segments and the ROM of upper adjacent segments under lumbar neutral, flexion and extension X-ray. The occurrence of radiographic and symptoms due to adjacent segment degeneration(ASD) was evaluated. Results: 55 patients completed the follow-up more than four years. The mean follow-up was 54 months(48-70 months). The ODI score significantly improved at 3 months[(24.1±5.7)%] and the final follow-up[(15.9±6.3)%] compared with the preoperative score[(56.3±16.4)%, P<0.05]. The VAS score significantly decreased at 3 months(2.9±1.5) and the final follow-up(1.4±0.5) compared with the preoperative score(6.7±2.7, P<0.05). The ROM of surgical segments decreased from (7.6±2.5)° to (4.5±2.8)° at 3 months postoperatively and to (4.9±2.3)° at the final follow-up(P<0.05). The disc height of surgical segments increased significantly at 3 months postoperatively(13.4±2.6mm) compared with the preoperative(12.3±2.7mm)(P<0.05), and finally decreased(12.1±3.2mm) to the preoperative value(P>0.05). The ROM of the upper segment increased significantly from (8.1±3.0)° to (9.3±3.2)° at 3 months postoperatively and to (10.0±2.9)° at the final follow-up(P<0.05). 7 cases were noted with radiographic ASDs(12.7%) at the final follow-up. 1 patient received a revision operation due to the symptomatic ASD. Conclusions: Posterior decompression and Dynesys placement can improve the clinical outcomes for lumbar degenerative disease at midterm follow-up. Dynesys partially preserves the ROM of diseased segments, but the incidence of ASD should be considered at midterm follow- up.