Table 2 The Newcastle-Ottawa Scale (NOS) for evaluating the retrospective trials

Boyer et al. 2015 [11]

***

**

***

8

Burns et al. 2019 [12]

***

*

***

7

Gürpınar et al. 2019 [2]

***

**

**

7

Honda et al. 2018 [13]

***

**

***

8

Hug et al. 2015 [14]

***

*

**

6

Kim et al. 2014 [15]

***

**

**

7

Kim et al. 2018 [16]

***

**

**

7

Millett et al. 2017 [6]

***

**

**

7

Pogorzelski et al. 2019 [17]

***

**

**

7

Zwolak et al. 2022 [19]

***

**

**

7