Romano 2009.

Methods	Randomised, double‐blind, cross‐over (4 weeks each treatment, with 1 week washout)
Participants	Chronic low back pain of at least 6 months' duration, due to disc prolapse, lumbar spondylosis, and/or spinal stenosis. Pain intensity > 40/100 mm N = 42, age 18 to 75 years Results reported according to LANSS score (non‐neuropathic <12; neuropathic ≥12)
Interventions	Celecoxib 3 to 6 mg/kg/day Pregabalin 1 mg/kg/day for 1 week than 2 to 4 mg/kg/day Treatment groups: celecoxib alone, pregabalin alone, celecoxib + pregabalin
Outcomes	Self‐reported VAS (0 to 100 mm) Withdrawals, adverse events
Notes	Oxford Quality Score: R = 2, DB = 1, W = 1. Total = 4/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly assigned to pre‐ordered sequence based on consecutive recruitment order
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blind, but method not stated
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	Data on 36 completers of 42
Selective reporting (reporting bias)	Low risk	No problems detected
Size	High risk	36 completers (16 with neuropathic pain according to LANSS criteria)