Table 1. Included studies.

No.	Author	Year	Study design	Sample size	Level of evidence
1	Steinsapir et al	2011	Review		3
2	Warner and Eggenberger	2010	Review		3
3	Steinsapir and Goldberg	2005	Review		3
4	Ropposch et al	2013	Retrospective	42	3
5	Agrawal et al	2013	Review		3
6	Yu-Wai-Man and Griffiths	2013	Meta-analysis		1
7	Lee et al	2010	Retrospective	24	3
8	Kubal	2008	Expert opinion		5
9	Lee et al	2004	Retrospective	23	3
10	Yeh and Foroozan	2004	Review		3
11	Holmes and Sires	2004	Prospective	11	2
12	Bodanapally et al	2013	Prospective	12	2
13	Li et al	2014	Prospective	28	2
14	Shi et al	2013	Prospective	54	2
15	Ustymowicz et al	2009	Prospective	72	2
16	Rajiniganth et al	2003	Prospective	44	2
17	Li et al	2008	Prospective	237	2
18	Wang et al	2008	Retrospective	46	3
19	Chen et al	2007	Case series	30	4
20	Yang et al	2006	Case series	12	4
21	Yang et al	2012	Retrospective	96	3
22	Chen et al	2004	Case series	11	4
23	Yang et al	2004	Retrospective	42	3