Intradiscal oxygen-ozone chemonucleolysis versus microdiscectomy for lumbar disc herniation radiculopathy: a non-inferiority randomized control trial.

Background Context: Low back pain with or without radicular leg pain is an extremely common health condition significantly impacting patient's activities and quality of life. When conservative management fails, epidural injections providing only temporary relief, are frequently utilized. Intradiscal oxygen-ozone may offer an alternative to epidural injections and further reduce the need for microdiscectomy.

Purpose: To compare the non-inferiority treatment status and clinical outcomes of intradiscal oxygen-ozone with microdiscectomy in patients with refractory radicular leg pain due to single-level contained lumbar disc herniations.

Study Design / Setting: Multicenter pilot prospective non-inferiority blocked randomized control trial conducted in three European hospital spine centers.

Patient Sample: Forty-nine patients (mean 40 years of age, 17 females/32 males) with a single-level contained lumbar disc herniation, radicular leg pain for more than six weeks, and resistant to medical management were randomized, 25 to intradiscal oxygen-ozone and 24 to microdiscectomy. 88% (43 of 49) received their assigned treatment and constituted the AS-Treated (AT) population.

Outcome Measures: Primary outcome was overall 6-month improvement over baseline in leg pain. Other validated clinical outcomes, including back numerical rating pain scores (NRS), Roland Morris Disability Index (RMDI) and EQ-5D, were collected at baseline, 1 week, 1-, 3-, and 6-months. Procedural technical outcomes were recorded and adverse events were evaluated at all follow-up intervals.

Methods: Oxygen-ozone treatment performed as outpatient day surgeries, included a one-time intradiscal injection delivered at a concentration of 35±3 μg/cc of oxygen-ozone by a calibrated delivery system. Discectomies performed as open microdiscectomy inpatient surgeries, were without spinal instrumentation, and not as subtotal microdiscectomies. Primary analyses with a non-inferiority margin of -1.94-point difference in 6-month cumulative weighted mean leg pain NRS scores were conducted using As-Treated (AT) and Intent-to-Treat (ITT) populations. In post hoc analyses, differences between treatment groups in improvement over baseline were compared at each follow-up visit, using baseline leg pain as a covariate.

Results: In the primary analysis, the overall 6-month difference between treatment groups in leg pain improvement using the AT population was -0.31 (SE, 0.84) points in favor of microdiscectomy and using the ITT population, the difference was 0.32 (SE, 0.88) points in favor of oxygen-ozone. The difference between oxygen-ozone and microdiscectomy did not exceed the non-inferiority 95% confidence lower limit of treatment difference in either the AT (95% lower limit, -1.72) or ITT (95% lower limit, -1.13) populations. Both treatments resulted in rapid and statistically significant improvements over baseline in leg pain, back pain, RMDI, and EQ-5D that persisted in follow-up. Between group differences were not significant for any outcomes. During 6-month follow-up, 71% (17 of 24) of patients receiving oxygen-ozone, avoided microdiscectomy. The mean procedure time for oxygen-ozone was significantly faster than microdiscectomy by 58 minutes (p<.0010) and the mean discharge time from procedure was significantly shorter for the oxygen-ozone procedure (4.3±2.9 hours vs. 44.2±29.9 hours, p<.001). No major adverse events occurred in either treatment group.

Conclusions: Intradiscal oxygen-ozone chemonucleolysis for single-level lumbar disc herniations unresponsive to medical management, met the non-inferiority criteria to microdiscectomy on 6-month mean leg pain improvement. Both treatment groups achieved similar rapid significant clinical improvements that persisted and overall, 71% undergoing intradiscal oxygen-ozone were able to avoid surgery.