Certainty assessment Certainty
Number of
studies 		Outcome Study design Risk of
bias 		Inconsistency Indirectness Imprecision Other
considerations
2 Postoperative pain Randomized clinical trials Not serious Seriousa Not serious Not Serious None Moderate
2 Postoperative pain Non-randomized clinical studies Not serious Seriousa Not serious Not Serious None Moderate

aPresence of clinical and methodological heterogeneity.
GRADE = grading of recommendations assessment, development, and evaluation.