Bischoff 2014.

Study characteristics
Methods	RCT, DB, PC, parallel group, single application, 12‐week duration. Pain assessment twice daily in 3 days before treatment and clinical visits at 1, 2, 3 months.
Participants	Persistent pain after inguinal herniorrhaphy score ≥ 5/10 for > 6 months Exclusion: bilateral groin pain, allergy to any component of treatment, comorbidity that might interfere with treatment or assessment N = 46 M = 42, F = 4 Mean age: 54 years Baseline pain on movement: 5.5/10 (range 3 to 7)
Interventions	(1) Capsaicin patch 8%, n = 24 (23 treated) (2) Placebo patch, n = 22 Topical local anaesthetic (EMLA; lidocaine + prilocaine) applied for 60 min, then patch applied to groin area for 60 min Cool packs applied to skin for 45 to 60 min after patch removal and cleansing Stable (≥ 4 weeks) analgesic medication continued without change
Outcomes	SPID ‐ difference between groups at 4, 8, 12 weeks AEs Withdrawals
Notes	Oxford Quality Score: R2, DB2, W1. Total = 5/5 Study terminated early due to expiry of placebo patch
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"computer‐generated randomization list"
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	"placebo patches were identical in appearance and composition (in regard to vehicle substances)". 70% of capsaicin participants and 80% of placebo participants correctly guessed assignment
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Imputation unclear
Size	High risk	< 50 participants per treatment arm