Microdiscectomy compared with transforaminal epidural steroid injection for persistent radicular pain caused by prolapsed intervertebral disc: the NERVES RCT

Abstract

Background Sciatica is a common condition reported to affect > 3% of the UK population at any time and is most often caused by a prolapsed intervertebral disc. Currently, there is no uniformly adopted treatment strategy. Invasive treatments, such as surgery (i.e. microdiscectomy) and transforaminal epidural steroid injection, are often reserved for failed conservative treatment. Objective To compare the clinical effectiveness and cost-effectiveness of microdiscectomy with transforaminal epidural steroid injection for the management of radicular pain secondary to lumbar prolapsed intervertebral disc for non-emergency presentation of sciatica of < 12 months’ duration. Interventions Patients were randomised to either (1) microdiscectomy or (2) transforaminal epidural steroid injection. Design A pragmatic, multicentre, randomised prospective trial comparing microdiscectomy with transforaminal epidural steroid injection for sciatica due to prolapsed intervertebral disc with < 1 year symptom duration. Setting NHS services providing secondary spinal surgical care within the UK. Participants A total of 163 participants (aged 16–65 years) were recruited from 11 UK NHS outpatient clinics. Main outcome measures The primary outcome was participant-completed Oswestry Disability Questionnaire score at 18 weeks post randomisation. Secondary outcomes were visual analogue scores for leg pain and back pain; modified Roland–Morris score (for sciatica), Core Outcome Measures Index score and participant satisfaction at 12-weekly intervals. Cost-effectiveness and quality of life were assessed using the EuroQol-5 Dimensions, five-level version; Hospital Episode Statistics data; medication usage; and self-reported cost data at 12-weekly intervals. Adverse event data were collected. The economic outcome was incremental cost per quality-adjusted life-year gained from the perspective of the NHS in England. Results Eighty-three participants were allocated to transforaminal epidural steroid injection and 80 participants were allocated to microdiscectomy, using an online randomisation system. At week 18, Oswestry Disability Questionnaire scores had decreased, relative to baseline, by 26.7 points in the microdiscectomy group and by 24.5 points in the transforaminal epidural steroid injection. The difference between the treatments was not statistically significant (estimated treatment effect –4.25 points, 95% confidence interval –11.09 to 2.59 points). Nor were there significant differences between treatments in any of the secondary outcomes: Oswestry Disability Questionnaire scores, visual analogue scores for leg pain and back pain, modified Roland–Morris score and Core Outcome Measures Index score up to 54 weeks. There were four (3.8%) serious adverse events in the microdiscectomy group, including one nerve palsy (foot drop), and none in the transforaminal epidural steroid injection group. Compared with transforaminal epidural steroid injection, microdiscectomy had an incremental cost-effectiveness ratio of £38,737 per quality-adjusted life-year gained and a probability of 0.17 of being cost-effective at a willingness to pay threshold of £20,000 per quality-adjusted life-year. Limitations Primary outcome data was invalid or incomplete for 24% of participants. Sensitivity analyses demonstrated robustness to assumptions made regarding missing data. Eighteen per cent of participants in the transforaminal epidural steroid injection group subsequently received microdiscectomy prior to their primary outcome assessment. Conclusions To the best of our knowledge, the NErve Root Block VErsus Surgery trial is the first trial to evaluate the comparative clinical effectiveness and cost-effectiveness of microdiscectomy and transforaminal epidural steroid injection. No statistically significant difference was found between the two treatments for the primary outcome. It is unlikely that microdiscectomy is cost-effective compared with transforaminal epidural steroid injection at a threshold of £20,000 per quality-adjusted life-year for sciatica secondary to prolapsed intervertebral disc. Future work These results will lead to further studies in the streamlining and earlier management of discogenic sciatica. Trial registration Current Controlled Trials ISRCTN04820368 and EudraCT 2014-002751-25. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 24. See the NIHR Journals Library website for further project information.

Predictors of outcome in sciatica patients following an epidural steroid injection: the POiSE prospective observational cohort study protocol

“…A recent randomised controlled trial compared surgical microdiscectomy with TFESI (transforaminal ESI) in patients with disc-related sciatica pain with symptom duration of up to 12 months. 15 No significant difference was found for pain or disability outcomes, and the trial team recommended that TFESI should be considered as a first invasive treatment option. With the need to reduce low-value healthcare, 16 it would be helpful to be able to better identify patients who have a reasonable chance of benefiting from ESI.…”

“…Anecdotally, we know clinicians use the “flip of a coin” analogy, that is, explaining to patients that they have a “50:50” chance of improvement from an ESI. A recent randomised controlled trial compared surgical microdiscectomy with TFESI (transforaminal ESI) in patients with disc-related sciatica pain with symptom duration of up to 12 months 15. No significant difference was found for pain or disability outcomes, and the trial team recommended that TFESI should be considered as a first invasive treatment option.…”

Percutaneous Spinal Interventions for Chronic Pain Management

“…In a large cohort of patients that were randomized to either receive epidural steroid injections or not, as well as randomized to either undergo discectomy or not, a significantly greater percentage (41%) of those in the surgical group that received epidural steroid injection crossed over to the nonsurgical group, compared to those in the surgical group that had not undergone steroid injection (19%), acknowledging that the baseline preference for surgery was higher in the nonsteroid group. 40 Another study randomized 163 patients with radicular low back pain due to disc herniation to receive epidural steroid injection or microdiscectomy, and found no significant difference between the two treatment modalities in terms of pain reduction or disability reduction 41 These interventions are not without downside. The inclusion of steroid into an epidural injection can also introduce the systemic effects of steroid to the body, even without it being administered intravascularly.…”

What’s New in Spine Surgery

“…Several recent studies have examined options for the management of lumbar disc herniation. In a randomized controlled trial, Wilby et al compared microdiscectomy with transforaminal epidural corticosteroid injection in patients with persistent radicular pain for <1 year secondary to disc herniation 12 . The authors found that there were no significant differences in pain scores between the epidural injection group and the surgery group, although 18% of the injection group underwent a surgical procedure prior to the completion of the study.…”