Fig. 1

Prisma study flow diagram of search results for SEM. Note: Some studies were excluded for more than one reason. For studies excluded based on abstract, 9 studies were excluded for 1 reason; 6 studies excluded for 2 reasons; 2 studies excluded for 3 reasons; and 1 study excluded for 4 reasons. For studies excluded based on full-text, 71 studies were excluded for 1 reason; 73 studies excluded for 2 reasons; 48 studies excluded for 3 reasons; 22 studies excluded for 4 reasons; and 13 studies excluded for 5 reasons