[Anatomic investigation of facial canal related to middle ear surgery].

OBJECTIVE: To avoid hurting facial nerve in middle ear surgery. METHOD: 20 adult head cadavers with 40 sides tempotal bone were dissected and investigated. RESULT: 1. Prevalence of dehiscent facial nerve canal was 32.5% (13/40), while 2.5% (1/40), 27.5% (11/40), 7.5%(3/40) incidence facial nerve canal were found in the labyrinthine, horizontal, vertical segment respectively. 2. Distance between the vertical portion of facial nerve and posterior semicircular canal was 0.62-5.08(2.48 +/- 0.63) mm. Interspace between the vertical portion of facial nerve and tympanic chorda was 0-4.62 (2.12 +/- 0.76) mm at the level of tympanic ditch, while interspace between the vertical portion of facial nerve and tympanic ditch was 2.96-8.82 (5.86 +/- 1.62) mm. 3. Distance between horizontal portion of facial nerve and lateral semicircular canal was 0-3.02 (1.92 +/- 0.84) mm. Interspace between horizontal portion of facial nerve and stapedial board was 0.92-4.06(2.14 +/- 0.90) mm. CONCLUSION: Familiarity with facial nerve procession should be favorable to decrease facial paralysis with middle ear surgery.