Table 1.

Level of evidence based on Oxford Criteria 2011.

LoE	Study Type
1	Systematic review of randomized controlled clinical trial (RCT).
2	Randomized controlled clinical trial (RCT).
3	Non-randomized controlled clinical trial or follow-up study.
4	Case series or case-control study.
5	Case study, nonsystematic secondary literature, expert opinion, studies other than in vivo studies of human subjects (e.g., animal experiment, cadaver study) or consensus paper.