Ghai 2015.

Methods	Placebo‐controlled trial Source: public tertiary care hospital Country: India
Participants	69 patients randomised (Group 1 = 35, Group 2 = 34); Diagnosis: clinical assessment with evidence of disc herniation in the magnetic resonance imaging (MRI) Mean age (SD): Group 1 = 45.9 years (13.3), Group 2 = 44.7 years (10.5); Duration of symptoms: chronic (> 12 weeks)
Interventions	Group 1: epidural injection of methylprednisolone acetate (80 mg, 2 mL) plus lidocaine (6 mL, 0.5%) Group 2: epidural injections of lidocaine (8 mL, 0.5%)
Outcomes	Pain intensity: overall pain (NRS) Disability: ODI Pain relief: at least 50% of reduction in NRS Adverse events: proportion of patients experiencing adverse events Follow‐ups: 3, 6, and 12 months
Notes	Epidural approach: interlaminar under fluoroscopic guidance. Additional injections were done when increased levels of pain were reported with deteriorating relief lower than 50%. Anaesthetist's experience: not specified Co‐interventions: all patients received conservative management including analgesics (adjuvant; pregabalin, amitriptyline, opioid, or non‐opioid) and/or exercise programme.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Patients were randomized (block of six, software: Random‐Randomizer)".
Allocation concealment (selection bias)	Low risk	"Randomization codes were placed in sealed opaque envelopes and opened at the time of injection by an independent anaesthesiologist not involved in the study."
Blinding of participants (performance bias)	Low risk	Patients were blinded to the interventions (placebo‐controlled trial using epidural approach in both groups).
Blinding of personnel/care providers (performance bias) All outcomes	Low risk	"Patients, investigators including outcome assessor, and care providers were unaware of randomisation and group allocation."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐report outcomes with patients blinded to the treatment allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	8/69 = 11% at short‐term; 13/69 = 19% at intermediate and 13/69 = 19% at long‐term. Loss to follow‐up was below the proposed threshold.
Intention‐to‐treat analysis (attrition bias)	Low risk	"The primary and secondary effectiveness analyses were performed on the intention‐to‐treat (ITT) population, defined as patients who received at least one injection and have one post‐procedure assessment. We analysed all patients according to the group to which they were allocated."
Selective reporting (reporting bias)	Low risk	(CTRI/2014/04/004572). Any discrepancies were identified between protocol and publication.
Group similarity at baseline (selection bias)	Low risk	Both groups were similar with respect to pre‐procedure demographic and clinical characteristics (Table 1).
Co‐interventions (performance bias)	Low risk	"All patients received conservative management including analgesics (adjuvant; pregabalin, mitriptyline, opioid, or non‐opioid) and/or exercise program during the study. Dose titration of analgesics was done as per patient requirement. Job attendance continued. All patients were encouraged to engage in physical activities. No additional occupation/physical therapy or any other interventions were offered beyond the protocol."
Compliance (performance bias)	Low risk	Compliance in both groups 100%.
Timing of outcome assessment (detection bias)	Low risk	"A blinded investigator followed the patients at 2 weeks, one, 2, 3, 6, 9, and 12 months post‐intervention."
Other bias	Low risk	Funding was not reported, but the authors reported no conflict of interest.