Table 1 Basic characters of the study population

Age (year, mean ± SD)

45.05 ± 14.32

Gender (male to female)

14 to 12

Laterality (right to left)

19 to 7

Type of SB

 Segmental

 Encircling

11

15

Gas tamponade

 SF6

 C3F8

 Room air

 Not perform

5

5

6

10

Time interval (month, mean ± SD)

 Preoperative HCEC exam to SB

 SB to postoperative HCEC exam

3.3 ± 1.6

9.6 ± 2.1