Fischer 1976.

Methods	Randomized controlled trial
Participants	Patients with chronic anal fissure
Interventions	Anal stretch (34) versus lateral subcutaneous sphincterotomy (32)
Outcomes	Persistence of the fissure and incontinence to flatus
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	random number table
Blinding of outcome assessment (detection bias) All outcomes	Low risk	physicians examining for recurrence or complications were blinded to patient operative classification
Drop‐outs All outcomes	Low risk	zero