Table 2.

Quality evaluation of included studies by methodological index for nonrandomized studies (MINORS)^a

Study (first- author)	A clearly stated aim	Inclusion of consecutive patients	Prospective collection of data	Endpoints appropriate to the aim of the study	Unbiased assessment of the study endpoint	Follow-up period appropriate to the aim of the study	Loss to follow up less than 5%	Prospective calculation of the study size	A gold standard control group	Contemporary groups	Baseline equivalence of groups	Adequate statistical analyses	Total scores
Schuchert	1	2	1	2	1	2	2	0	2	2	1	2	18
Mathey-Andrews	2	2	1	2	1	2	2	0	2	2	2	2	20
Lula Lukadi	2	2	1	2	0	1	2	0	2	2	2	2	18
Kagimoto	2	2	0	2	1	2	2	0	2	2	2	2	19
Kagimoto	2	2	0	2	1	1	2	0	2	2	2	2	18
Ikeda	2	2	1	2	0	2	2	0	2	2	0	1	16
Huang	2	2	0	2	0	2	2	0	2	2	2	2	18
Yu	2	2	1	2	0	2	2	0	2	2	2	1	18
Shiono	2	2	0	2	0	2	2	0	2	2	1	2	17
Yanagawa	2	2	0	2	0	2	2	0	2	2	1	2	17
Ren	2	2	1	2	0	1	1	0	2	2	0	2	15
Eguchi	2	2	2	2	0	0	0	0	2	2	2	2	16
Choi	2	2	0	2	1	2	0	0	2	2	1	2	16
Kadota	2	2	2	2	0	2	2	0	2	2	1	2	19

^aStudy scoring between 0 and 8 is considered as low quality, while scores of 9 to 16 indicate moderate quality, 17–24 indicate high quality.