Methylene Blue Effectiveness as Local Analgesic after Anorectal Surgery: A Literature Review.

Background: Methylene blue (MB) has been found to have unique analgesic property through temporary disruption of sensory nerve conduction. In anorectal surgery, MB is widely used as a biologic stain but the analgesic effect has never been studied. Thus, a literature review completed with critical appraisal is required to find out its efficacy.