Table 1 Patient characteristics and anatomical measurements

Years

65.18 ± 18.77

Sex (Male)

51(42.5)

[Tympanic sinus]

  Average Class

1.88 ± 0.79

Class1:46(38.3)

Class2:43(35.8)

Class3:31(25.8)

  Posterior depth(a)

0.73 ± 0.78

  Lateral depth(b)

0.27 ± 0.61

[Vertical portion of facial nerve]

  Posterior length from EAC(c)

3.24 ± 0.81

  Lateral length from TM(d)

0.37 ± 1.32

[High jugular bulb]

  Average Class

1.18 ± 1.03

Class0:42(35)

Class1:26(21.7)

Class2:40(33.3)

Class3:12(10)

  Horizontal length from ITM(e)

4.39 ± 2.44

  Vertical length from ITM(f)

2.9 ± 1.36

[EAC]

  Antero-posterior length of TM(g)

8.08 ± 0.77

  Superio-inferior length of TM(h)

7.68 ± 1.07

  Angle of ACOH(i)

165.77 ± 15.6

  Angle of PCOH(j)

164.9 ± 13.59

  Angle of ICOH(k)

151.97 ± 13.79