Comparative Study of Corticosteroid Injection in the Caudal Epidural Space Under Fluoroscopy Guidance With or Without Ozone Injection in Lumbo-Sacral Radiculopathy: A Single-Blind Clinical Trial

To compare the efficacy of fluoroscopic-guided caudal epidural steroid injections with and without ozone therapy in reducing pain and improving functional outcomes in patients with lumbosacral radiculopathy caused by lumbar disc protrusion

A single-center, single-blind, parallel-group randomised controlled trial with 40 patients randomly assigned into two equal groups. The study will compare the efficacy of caudal epidural steroid injections with and without ozone therapy. Outcome assessment will be blinded to ensure unbiased results

A single-center, single-blind trial at Imam Khomeini Hospital, Tehran, Iran, using fluoroscopic guidance. Participants will be monitored for safety, with treatment allocation blinded to participants and outcome assessors

Inclusion Criteria: Patients aged 18–70 years with lumbosacral radiculopathy due to disc protrusion (L4-L5 or L5-S1) and symptoms persisting >3 months. Exclusion Criteria: History of spinal surgeries, severe systemic diseases, uncontrolled diabetes, infections, pregnancy, or cauda equina syndrome

Group A: Caudal epidural steroid injection (8 mg dexamethasone, 5 mL lidocaine 1%, 3 mL normal saline). Group B: Same steroid injection as Group A + 5 mL ozone gas (10 µg/cc). Procedure: All injections under fluoroscopic guidance to ensure accuracy. The study compares the efficacy of steroid injections with and without ozone therapy for lumbosacral radiculopathy

Pain Intensity: Measured using the Visual Analog Scale (VAS), ranging from 0 (no pain) to 10 (worst pain). Functional Disability: Assessed with the Oswestry Disability Index (ODI), scored as a percentage (higher scores = greater disability). Timing of Measurements: At baseline, one month, and six months post-treatment

Forty patients meeting the inclusion criteria will be randomly assigned into two groups of 20 patients each using a computer-generated randomization list. Group A will receive a caudal epidural steroid injection, while Group B will receive the same injection plus ozone therapy. The participants and the physician assessing outcomes will be blinded to the type of procedure, though the operator performing the injections will be aware of the treatment administered.

In our randomized controlled trial comparing fluoroscopic-guided caudal epidural steroid injections with or without ozone therapy, we implemented blinding in specific groups to minimize bias. Below is a detailed description of the blinding process and its application to various roles involved in the study. 1. Participants (Patients) – Blinded ✅ The patients were unaware of which treatment they received (steroid injection alone or steroid + ozone injection). Since the injections were performed under the same procedural conditions for both groups, no distinguishing factors indicated the treatment assignment. 2. Principal Investigator – Not Blinded ❌ The principal investigator was involved in study design and oversight but was not blinded to treatment allocation. Given the need for procedural oversight and protocol adherence, they had access to treatment assignment information. 3. Healthcare Providers (Care Providers/Interventionists) – Not Blinded ❌ The physician performing the injections was aware of the treatment allocation since they had to prepare and administer the correct mixture. Due to the nature of the intervention (i.e., the inclusion of ozone gas in one group), it was not possible to blind the care provider. 4. Data Collectors – Blinded ✅ All data collectors, including those responsible for recording patient-reported pain scores and functional disability assessments, were blinded to the treatment assignment. This ensured that subjective measures such as the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI) were not influenced by knowledge of group allocation. 5. Outcome Assessors – Blinded ✅ The physician assessing clinical outcomes (pain and disability scores) was blinded to the treatment groups. Outcome assessments were conducted at baseline, 1 month, and 6 months post-procedure without knowledge of whether the patient received steroids alone or steroids plus ozone. 6. Data Analysts – Blinded (Unclear, Needs Clarification) ❓ The data analyst responsible for statistical analyses may or may not have been blinded. If blinding was applied, the dataset would have been coded in a way that concealed treatment allocation. If unblinded, this may have introduced potential bias in the interpretation of results. 7. Data Safety and Monitoring Board (DSMB) – Not Applicable ❌ The study did not include an independent Data Safety and Monitoring Board (DSMB), as it was a relatively small-scale clinical trial without external oversight. 8. Manuscript Writers – Not Blinded ❌ The authors of the manuscript had access to full study data and treatment allocation, which allowed for an informed discussion of results and clinical implications. Summary of Blinding Implementation Group Blinding Status Rationale Participants (Patients) ✅ Blinded Ensured unbiased patient-reported outcomes (VAS, ODI). Principal Investigator ❌ Not Blinded Required for study design and oversight. Care Providers (Interventionists) ❌ Not Blinded Needed to prepare and administer treatment. Data Collectors ✅ Blinded Ensured unbiased data collection of patient responses. Outcome Assessors ✅ Blinded Prevented bias in evaluating clinical outcomes. Data Analysts ❓ Unclear Should ideally be blinded to prevent bias in analysis. DSMB ❌ Not Applicable No external monitoring board was used. Manuscript Writers ❌ Not Blinded Required access to complete data for reporting. How Blinding Was Achieved Randomization: Patients were randomly assigned to two treatment groups using a computer-generated randomization list. Standardized Procedures: Both groups underwent identical procedural steps, making it difficult for patients to distinguish between treatments. Separate Roles: The care provider (interventionist) was separate from the outcome assessor, ensuring the assessment process remained unbiased. Blinded Data Collection: The individuals collecting VAS and ODI scores were unaware of treatment allocation. Potential Data Analysis Blinding: If implemented, treatment codes were masked until the final statistical analysis was completed.