Table 1 The characteristics of included studies in current meta-analysis

Giovannini et al. 1995 [8]

12

R

S

No

Cahn et al. 1996 [9]

8

R

M

No

Bhutani et al. 1997 [10]

10

p

S

Yes

Faigel et al. 1997 [11]

12

P

S

Yes

Chang et al. 1997 [23]

11

P

S

No

Bentz et al. 1998 [24]

13

P

S

Yes

Voss et al. 2000 [12]

12

P

S

No

Gress et al. 2001 [13]

11

p

S

No

Ylagan et al. 2002 [14]

10

R

S

No

Harewood 2002 [15]

13

P

M

Yes

Raut et al. 2003 [16]

13

P

S

No

Afify et al. 2003 [17]

11

R

S

Yes

Agarwal et al. 2004 [18]

11

R

S

No

Ryozawa et al. 2005 [19]

9

R

M

Yes

Eloubeidi et al. 2007 [20]

13

P

S

No

Fisher et al. 2009 [25]

13

P

S

No

Krishna et al. 2009 [21]

12

P

S

Yes

Touchefeu et al. 2009 [22]

13

P

S

No

Cherian et al. 2010 [7]

10

P

S

No

Uehara et al. 2011 [26]

9

R

S

No