Table 4. Literature Search: Summary of Levels of Evidence of the Included Studies.

Level of evidence [28]	Trial type	Originally selected studies	Studies included	Total number of patients in studies exposed to fibrin sealant
I	Meta-analysis	0	0	0
Ib—Ib-	Randomized controlled trial	2	2	123
II	Prospective cohort studies / randomized controlled trial with quality issues	2	2	126
III	Case-control studies	2	2	167
IV	Prospective and retrospective case series	27	26	2519
Total	-	33*	32*	2935

Note: multiple publications addressing data from the same study are counted once:

*The total of included studies for efficacy and safety is 32, two studies are reporting on the same patients [10, 11].