Table 1. Characteristics of included studies.

Studies	Year	Country	Study type	No.patients LN/ON	BMI LN/ON	ASA	Level of evidence*	Matching factors	Quality scores #	Variables
Seshadri	2001	Canada	Prospective	10/10	NA	N	3	1,2,5,6,7,8	6	1,2,4
Gill	2001	USA	Retrospective	10/10	35.9/23.8	3	3	1,2,3,4,7,8	6	1,2,4,5,6
Binsaleh	2006	Canada	Retrospective	6/6	29/26	3	3	1,2,3,4,5	6	1,2,3,4,5
Desai	2007	India	Retrospective	13/14	26.3	N	4	1,2,3,5,7	5	1,2,3,4,6
Verhoest	2012	France	Retrospective	21/19	25/23	3	3	1,2,3,6,7,8	6	1,2,4,5,6,7
Eng(Unilateral)	2013	USA	Retrospective	24/12	NA	N	3	1,2,3,5,6,7,8	7	1,2,3,4,7
Eng(Bilateral)	2013	USA	Retrospective	34/6	NA	N	3	1,2,3,5,6,7,8	7	1,2,3,4,7

Matching factors:1,age; 2,gender; 3,body mass index; 4,American Society of Anesthesiology score; 5,operative side; 6,preoperative dialysis; 7,Indication for surgery; 8, kidney size; 9, previous pelvic/abdominal surgery; Variables:1,operative time; 2,length of hospital stay; 3, specimen weight; 4,overall complications; 5,estimated blood loss; 6, Analgesic requirement; 7, Transfusion. BMI: Body Mass Index, NA: data not available.

*Level of evidence: according to criteria by the Centre for Evidence-Based Medicine[28].

^# Quality scores: according to criteria by the Newcastle-Ottawa Scale[29].