Table 1 Basic characteristics of included studies and results of literature quality

Lu, 2017

China

Retrospective study

6 months–5 years

92/76

20–74

44.05

0.8–4.0 cm

Surgery time, Tumor recurrence, Temporary facial nerve paralysis, Salivary fistula, Frey's syndrome

8

Ogreden, 2016

Turkey

Retrospective study

5 years

32/18

44.5

50

Frey's syndrome, Tumor recurrence

7

Al-Aroomi, 2021

China

Prospective study

12 months

20/35

18–77

56.4

2.8 cm

Surgery time, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Sialocele, Hematoma

7

Ruohoalho, 2017

Finland

Prospective study

12 months

53/32

20–86

44.7

0.3–5.5 cm

Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Salivary fistula

8

Zhang,2013

China

Retrospective study

18 months

163/105

51

56

<  = 2 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Salivary flow

6

Koch, 2010

German

Retrospective study

76.7 months

34/134

50.7

54.5

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Salivary fistula

7

Li,2014

China

Retrospective study

62 months

58/71

40.8

44

< 2 cm, 2–4 cm, > 4 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Salivary fistula, Frey's syndrome, Operative time

7

Ciuman, 2012

German

Retrospective study

>  = 1 year

95/52

52

Temporary facial nerve, Permanent facial nerve, Frey's syndrome

6

Stathopoulos, 2018

Ireland

Prospective study

5 years

135/43

55.9

45

3.38 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Sialocele, Hematoma

6

Roh, 2007

Korea

Prospective study

48 months

52/49

11–82

47

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Sialocele, Surgery time

7

Mlees, 2020

Egypt

Retrospective study

7 years

44/40

19–76

36

2.6/2.4

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Sialocele, Hematoma, Surgery time

8

Huang, 2015

China

Retrospective study

79/241

19–83

41

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome

8

Kilavuz, 2018

Turkey

Retrospective study

79 months

131/190

18–87

57

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Salivary fistula, Hematoma, Surgery time

8

Emodi, 2010

Israel

Retrospective study

57 months

30/18

43

39.6

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Surgery time

7

Papadogeorgakis, 2004

Greece

Retrospective study

55 months

42/17

30–77

61

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Sialocele

7

Witt, 2009

USA

Retrospective study

1 month

100/20

57.3

45

2.1 cm

Sialocele

5

Plaza, 2015

Spain

Retrospective study

4 years

25/25

42

60

1.2–3.3 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Surgery time

6

Witt, 2002

USA

Retrospective study

8 years

20/20

42.2/45.7

43

1.94/2.0 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Frey's syndrome

6

Schapher, 2021

German

Retrospective study

13.1 years

6/30

47.6

36

2.4 cm

Frey's syndrome

8

Zheng, 2019

China

Retrospective study

3 years

91/92

49/48

56

2.6/2.7 cm

Tumor recurrence, Temporary facial nerve, Permanent facial nerve, Sialocele, Frey's syndrome, Surgery time

7

Wong, 2018

New Zealand

Prospective study

31.58 weeks

56/40

18–86

46.5

Temporary facial nerve, Permanent facial nerve, Salivary fistula, Sialocele, Frey's Syndrome, Hematoma

8

Gao, 2017

China

Retrospective study

29.8 months

50/49

18–85

57.6

2.96/2.78

Temporary facial nerve, Permanent facial nerve, Frey's syndrome, Salivary fistula, Surgery time

7

Eski, 2018

Turkey

Retrospective study

41.79 months

22/17

51/57

51.3

2.5 cm

Tumor recurrence, Temporary facial nerve

8