*3.2. Methodological Quality of Included Studies*

The risk of bias among the included studies was assessed using MINORS, as most of the studies were nonrandomized clinical studies. The maximum possible score was 16 for those without a control group and 24 for those with a control group. The mean quality score was 10.06 (range: 8–14) for noncomparative studies and 20 (range: 18–22) for comparative studies (Table 2). All but one study [53] clearly stated their aim. Nine studies adequately described the follow-up period, including the percentage lost to follow-up. No study included a prospective sample size calculation. All comparative studies had adequate control groups, and the study groups were contemporary with baseline equivalence of groups and adequate statistical analyses. In one study [49], the control group consisted of historical patients.


**Table 2.** Methodological Index for Non-Randomized Studies.

Items are scored as 0 (not reported), 1 (reported but inadequate), or 2 (reported and adequate). The maximum score is 16 for noncomparative studies and 24 for comparative studies. A—A clearly stated aim; B—Inclusion of consecutive patients; C—Prospective collection of data; D—Endpoints appropriate for the aim of the study; E—Unbiased assessment of study endpoint; F—Follow-up period appropriate for the aim of the study; G—Loss to follow-up less than 5%; H—Prospective calculation of the study size; I—Adequate control group; J—Contemporary groups; K—Baseline equivalence of groups; L—Adequate statistical analyses.
