Table 1.

Studies Included in Meta-analysis

Article	Level of Evidence	Treatment Group	Mean ± SD (Range)	Male %/Female %	Follow-up (months)
Roux 2017(43)	4	1	45.24 ± 16.75	59/41	>12
		2	42.91 ± 16.85	54/46	>12
Sousa 2017(44)	4	1	N/A	N/A	>12
		2			>12
Nahm 2017(45)	4	2	59 ± 16	41/59	24–60
Capretta 2016(36)	4	1	69 (54–88)	53/47	N/A
		2	57.25 (53–62)	50/50	N/A
van Zon(24), Kraaijenga(16), Smulders(33)	1	0	52.5 ± 12.5 (26–67)	58/42	-
		1			>12
		2			>12
(Simultaneous)	1	0	47.7 ± 15.9 (18–70)	42/58	>12
		2			>12
Zhang 2015(34)	3	0	63 ± 13 (20–81)	42/58	-
		2			24
Ramos-Miguel 2015(46)	4	1	51 ± 13	40/60	N/A
		2			N/A
Harkonen 2015(35)	4	1	41 (19–58)	40/60	12–168
		2			12
Potts 2014(47)	4	1	45.8 ± 8.6 (38–58)	50/50	>24
		2			6
Perreau 2014(48)	4	1	55.3 ± 15.2	51/49	105.3 ± 70.9
		2		43/57	69.8 ± 44.5
Bonnard 2013	4	2	44.3 ± 11.3 (31–58)	17/83	7–74
Olze 2012(49)	4	0	50.3 ± 14.5 (18–71)	27/73	-
		1			>6
		2			>6
Tyler 2009(37)	4	1	55.7 ± 15.5 (18–89)	48/52	>12
		2	52.8 ± 15.6 (20–81)	50/50	>12
Noble 2008(50)	4	1	60.6 ± 15.1	51/49	N/A
		2	64.3 ± 15.5	43/57	N/A

Pre-implant, unilateral CI, and bilateral CI are abbreviated as treatment groups 0, 1, and 2, respectively.