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

Table 1

Critical appraisal of the studies.

Articles	Years	Validity							Relevance
		Study design	Number of patients	Randomization	Similarity treatment & control	Blinding	Comparable treatment	Intention to treat	Determinant	Measurement of outcome	Level of evidence
Xiang and Feng [6]	2015	Retrospective study (case-control)	151	−	+	−	+	−	+	+	4
Sim and Tan [1]	2013	Randomized single-blind clinical trial	67	+	+	+	+	−	+	+	2
Samalavicius et al. [9]	2012	Prospective study (case series follow-up)	10	−	+	−	−	−	−	+	4
Sutherland et al. [10]	2009	Prospective study (case series follow-up)	49	−	+	−	−	−	−	+	4