Rauck 2013b

Methods	Randomised, double‐blind, placebo‐controlled, parallel‐group, not enriched. Both LOCF and BOCF imputation methods used in analyses Itrathecal drug delivery system implanted and filled with saline until randomisation. Fixed dose of gabapentin (1 mg, 6 mg or 30 mg/d) or placebo for 22 days, followed by 7‐day taper
Participants	Chronic intractable pain below neck for ≥ 1 year (86% classified as neuropathic or mixed). N = 170, mean age 50 years, 58% women. PI at randomisation 7.5/10, initial average daily pain ≥ 5/10
Interventions	Gabapentin injection 1 mg, 6 mg, 30 mg daily, n = 42, 41, 43 respectively Placebo (saline) injection, n = 44
Outcomes	Pain intensity reduction Adverse events Withdrawals
Notes	Oxford Quality Score: R = 1, DB = 2, W = 1, Total = 4
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Low risk	"coded drug syringe labels, stored in sealed, sequentially numbered randomization envelopes". Pharmacist took next sequential envelope, prepared assigned drug, and attached coded label before sending to clinic
Blinding (performance bias and detection bias) All outcomes	Low risk	Both treatments were clear liquids. Saline (placebo) "seemed identical to gabapentin"
Incomplete outcome data (attrition bias) Efficacy	Low risk	BOCF analysis reported alongside LOCF
Size Efficacy	High risk	< 50 participants per treatment group
Study duration Efficacy	High risk	22 days
Outcomes reported	Unclear risk	≥ 30% reduction in pain