Database	Period of Search	Search Strategy
Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Wiley)	Issue 1, 2013	#1 MeSH descriptor Cholecystectomy, Laparoscopic explode all trees #2 (laparoscop* OR coelioscop* OR celioscop* OR peritoneoscop*) AND cholecystectom* #3 (#1 OR #2) #4 MeSH descriptor Pneumoperitoneum, Artificial explode all trees #5 MeSH descriptor Insufflation explode all trees #6 MeSH descriptor Abdominal Wall explode all trees #7 pneumoperitoneum OR insufflation OR "abdominal wall lift" OR gasless #8 (#4 OR #5 OR #6 OR #7) #9 (#3 AND #8)
MEDLINE (PubMed)	1987 to February 2013	(laparoscop* OR coelioscop* OR celioscop* OR peritoneoscop*) AND (cholecystectom* OR cholecystectomy, laparoscopic[MeSH]) AND (pneumoperitoneum OR Pneumoperitoneum, Artificial[MeSH] OR insufflation OR insufflation[MeSH] OR "abdominal wall lift" OR Abdominal Wall[MeSH] OR gasless) AND ((randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized [tiab] OR placebo [tiab] OR drug therapy [sh] OR randomly [tiab] OR trial [tiab] OR groups [tiab]) AND humans [mh])
EMBASE (Ovid SP)	1987 to February 2013	1 exp CROSSOVER PROCEDURE/ 2 exp DOUBLE BLIND PROCEDURE/ 3 exp SINGLE BLIND PROCEDURE/ 4 exp RANDOMIZED CONTROLLED TRIAL/ 5 (((RANDOM* or FACTORIAL* or CROSSOVER* or CROSS) and OVER*) or PLACEBO* or (DOUBL* and BLIND*) or (SINGL* and BLIND*) or ASSIGN* or ALLOCAT* or VOLUNTEER*).af. 6 1 or 2 or 3 or 4 or 5 7 (laparoscop* or coelioscop* or celioscop* or peritoneoscop*).af. 8 "cholecystectom*".af. 9 8 and 7 10 exp Cholecystectomy/ 11 exp Laparoscopic Surgery/ 12 11 and 10 13 9 or 12 14 (pneumoperitoneum or insufflation or "abdominal wall lift" or gasless).af. 15 exp Pneumoperitoneum/ 16 exp Abdominal Wall/ 17 16 or 15 or 14 18 6 and 13 and 17
Science Citation Index Expanded (Web of Knowledge)	1987 to February 2013	#1 TS=(laparoscop* OR coelioscop* OR celioscop* OR peritoneoscop*) #2 TS=(cholecystectom*) #3 TS=(pneumoperitoneum OR insufflation OR "abdominal wall lift" OR gasless) #4 TS=(random* OR blind* OR placebo* OR meta‐analysis) #5 #4 AND #3 AND #2 AND #1