Long-term outcome of lumbar disc herniation surgery and its associated factors

English Keywords:Disc herniation  Discectomy  Long-term follow-up  Clinical outcome  Predictive factor

English Abstract:

  【Abstract】　Objectives: To evaluate the long-term outcome of surgical treatment for lumbar disc herniation and to investigate its associated factors.　Methods: 125 cases suffering from lumbar disc herniation and undergoing discectomy at Ruijin Hospital from February 1996 to December 2002 were included in this study. All patients had single segment involved. The patients′ gender, age, body mass index, disease course, clinical symptom, signs and the type of disc herniation were recorded. The postoperative recurrent disc herniation was also documented. The patients′ functional conditions were reviewed by Oswestry disability index(ODI) pre- and postoperatively. Low back pain/leg pain was evaluated by visual analog scale(VAS). Stauffer-Coventry′s(SC) evaluation criteria was used in determining the patient′s overall efficacy. Preoperative and final follow-up′s VAS and ODI were analyzed by means of Univariate analysis. Considering overall clinical results as the variable outcome, the relationship between the outcome and 14 related factors such as age, gender, BMI, smoking, history of lumbar sprain, duration, preoperative VAS of low back pain/leg pain, preoperative ODI, SLR, muscle strength, sensation, segment and type of disc herniation were processed by univariate analysis. The association between variable outcome and 14 related factors was analyzed by means of multivariate logistical regression of the full model with all prognostic variables included and the model with the variables selected by the stepwise procedure. Results: The average follow-up was 109 months. The overall excellent/good/fair/poor rate was 32%, 35.2%, 23.2% and 9.6% respectively, and the recurrence rate was 8%. ODI decreased from (72.23±25.72)% preoperatively to (15.64±17.52)% at final follow-up, which had significant difference(P<0.05); VAS of low back pain decreased from 5.44±3.43 preoperatively to 2.12±2.32 at final follow-up, and VAS of leg pain decreased from 7.34±3.72 to 1.42±2.74. There were significant differences in low back pain and leg pain VAS between pre- and postoperatively(P<0.05). In the full-model logistic analysis for overall efficacy,　history of lumbar sprain and preoperative abnormal sensory were negative predictors while type of herniation was a positive predictor. In the stepwise regression model, smoking(OR=4.48; 95%CI 1.51-13.34), preoperative history of lumbar sprain(OR=6.50; 95%CI 2.21-19.10) and sensory(OR=9.01; 95%CI 1.75-46.46) were negative predictors and type of herniation(OR=0.027; 95%CI 0.005-0.145) was a positive predictor of overall efficacy. Conclusions: Discectomy can significantly improve the patient′s low back and leg pain as well as patient′s functional outcomes.　History of lumbar sprain, smoking, sensory and type of lumbar disc herniation are the most-related predictors.