Table 3. Quality assessment conducted according to the Newcastle-Ottawa criteria for all the included studies in this meta-analysis.

First author	Year	Quality indicators
		Selection	Comparability	Outcome
Rossi et al.	2015	***	**	**
de Albuquerque et al.	2015	****	***	**
Kekik et al.	2011	**	*	**
Capilla et al.	2007	***	**	***
Hermann et al.	2007	***	*	***
Barisani et al.	2006	***	**	***
Garrote et al.	2005	**	**	***
Lio et al.	2005	***	*	***
Cataldo et al.	2003	***	*	***
Hahn zoric et al.	2003	**	*	***
Garrote et al.	2002	****	**	***