Long-term outcomes of Dynesys stabilization in lumbar disc herniation

English Keywords:Lumbar disc herniation  Dynesys  Dynamic stabilization  Adjacent segment degeneration

English Abstract:

  【Abstract】 Objectives: To retrospectively study the long-term clinical and radiographic outcomes of lumbar discectomy Dynesys stabilization system in lumbar disc herniation. Methods: From July 2008 to July 2012, 84 patients with lumbar disc herniation were treated by the lumbar discectomy with Dynesys system, including 61 cases with complete follow-up data. There were 38 males and 23 females, whose mean age was 46.3±11.5 years old (range, 31-58 years). The mean follow-up was 74±14 months(60-108 months). Clinical outcomes were evaluated by using Oswestry disability index(ODI) and visual analogue scale(VAS). Radiographic evaluation included the disc height and range of motion(ROM) in lumbar neutral, flexion and extension X-ray. The above indicators were evaluated before surgery, at 3 months and the final follow-up. The change of intervertebral disc signal was defined by MRI, and disc degeneration was classified according to the Pfirrmann grade classification. Results: The ODI score and VAS score significantly improved at 3 months and the final follow-up compared with the preoperative scores(P<0.05). No disc herniation recurred in all cases. The disc height of surgical segments increased at 3 months follow-up(12.3±2.3mm) when compared with that before surgery(11.8±1.8mm)(P>0.05) and decreased at the final follow-up(10.1±1.7mm) when compared with that before surgery(P<0.05). The ROM of surgical segments decreased from 8.1°±2.8° to 5.3°±1.8° at 3 months follow-up and to 3.6°±1.9° at the final follow-up(P<0.05). The ROM of the upper segments increased significantly from 8.5°±3.0° to 10.3°±3.8° at 3 months follow-up and to 11.4°±3.7° at the final follow-up(P<0.05). 12 segments were noted as radiographic ASDs(19.7%) at the final follow-up. 1 segment was noted as the symptomatic adjacent segment degeneration. There was significant change of Pfirrmann grade between preoperation and final follow-up in both groups(P<0.05). There were 2 cases of screws broken. No other complication was found, such as screw loosen. Conclusions: Dynesys stabilization system can obtain the satisfactory clinical outcomes. The stability of the surgical segment can be maintained and partially preserve the ROM of diseased segments after intervertebral disc resection for lumbar degenerative disease in long term follow-up.