Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom improvement
RCT 4-armed trial	160 people with chronic anal fissure	Mean time to complete pain relief (pain assessed daily using visual analogue scale) 5.7 days (40 people) with open lateral internal sphincterotomy 15.6 days (40 people) with topical glyceryl trinitrate	P <0.001	Effect size not calculated	lateral internal sphincterotomy