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 5.7 days (40 people) with open lateral internal sphincterotomy 2.7 days (40 people) with botulinum toxin Absolute results not reported	Reported as not significant P value not reported		Not significant
RCT	40 people with chronic anal fissure	Pain score day 7 with lateral internal sphincterotomy with botulinum toxin	P = 0.041	Effect size not calculated	lateral internal sphincterotomy