Key points are not available for this paper at this time.
mesh'' A systematic search of the literature was performed in January 2012 using Medline, PubMed, Cochrane library, and reference lists. The search found 27 articles, and 9 were added by hand search. However, only 12 articles were suitable for this review in terms of content.
Bittner et al. (Wed,) studied this question.