“…Twenty-four articles were excluded (Online Appendix B). Two articles were case reports (Berkowitz, 1996; Hellquist, 1971), 4 articles had no adequate control group (Hellquist and Skoog, 1976; Hellquist and Ponten, 1979; Hellquist et al, 1983; Han et al, 2016), 1 study had both GPP and SBG done in the same group (Lee et al, 2004), 4 studies compared data from different centers (Henkel and Gundlach, 2002; Flinn et al, 2006; Grisius et al, 2006; Zemann et al, 2007), 7 articles didn’t report the outcomes of interest (Hellquist et al, 1979; Millard et al, 1999; Pfeifer et al, 2002; Chan et al, 2003; Berkowitz et al, 2004; Renkielska et al, 2005; Wojtaszek-Slominska et al, 2010), and 2 articles did not have GPP performed in their intervention group (Larson et al, 1983; Tan et al, 2015). One study had no available full-text article (Yee et al, 2014), 2 studies had pooled results for unilateral and bilateral cases (Santiago et al, 1998; Sato et al, 2008), and 1 study was a duplicate (Henkel and Gundlach, 1998).…”