Fig. 2

Prisma study flow diagram of search results for TTI. Note: Some studies were excluded for more than one reason. For studies excluded based on abstract, 1 study was excluded for 1 reason; 4 studies excluded for 2 reasons; and 4 studies excluded for 3 reasons. For studies excluded based on full-text, 30 studies were excluded for 1 reason; 11 studies excluded for 2 reasons; 28 studies excluded for 3 reasons; and 6 studies excluded for 4 reasons