The effect of symptom duration on the outcomes of lumbar discectomy for radicular pain secondary to lumbar disc herniation: a systematic review and meta-analysis

Abstract

Background Low back pain, often resulting from degenerative disc disease, affects up to 80% of the population at some point in their lives. The impact of preoperative radicular pain duration on discectomy outcomes remains inconclusive. We aim to compare the outcomes of lumbar discectomy for patients with different symptom durations to determine the optimal timing of surgery. Methods Medline, Embase, and Central databases were searched for studies comparing the outcomes of discectomy in patients with different durations of radicular pain secondary to lumbar disc herniation. Cutoffs at three months (very early), six months (early), and after 12 months (delayed) were selected based on pilot searches for symptom durations comparisons. Mean differences (MD) and standardised mean differerences (SMD) were calculated using the inverse-variance method, and risk ratios (RR) were calculated using the Mantel-Haenszel method. Results 29 studies with a total of 23,550 patients were included in this study. No statistically significant differences were found in the postoperative improvement in back pain, Oswestry Disability Index (ODI) or one-year reoperation rate for all of the cutoffs used (three months, six months, and 12 months). Sensitivity analyses found significant improvement in leg pain for symptom durations of < 12 months compared to > 12 months (SMD = 0.26, 95%CI: 0.11; 0.41, p = 0.02), which equates to a score of 1 point on the Visual Analogue Scale (VAS). Existing studies suffer from high risk of bias, inconsistent outcome measures, and varied timepoint assessment postoperatively. Conclusions There is low quality evidence suggesting that discectomy within 12 months of symptom onset can improve postoperative leg pain. There was no significant effect of symptom duration on postoperative back pain, disability, quality of life and reoperation risk. As a precaution, we recommend surgeons to operate within 12 months of symptom onset after a trial of nonoperative management has failed. We recommend the collection of discectomy outcomes in national registry programmes for detailed assessment of factors affecting postoperative outcomes.