Location of tympanic segment and mastoid segment of facial nerve and prevention of prosopoplegia in operations / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the location of facial nerve and prevent facial nerve injury in middle ear surgery according to dissection of temporal bone and experience of middle ear surgery.@*METHOD@#Thirty sides of temporal bones were exposed tympanic and mastoid segment of facial nerve with facial nerve decompression. The course of facial nerve was located by the markers of middle ear.@*RESULT@#Tympanic segment of facial nerve passed between horizontal semicircular canal and stapes,then superior and anterior to the cochleariform process. Mastoid segment of facial nerve located in posterior wall of tympanic cavity. The mastoid segment of facial nerve travelled below the level of horizontal semicircular canal and annulus membrane tympani, and the extension line of its posterior margin and posterior-one-third of horizontal semicircular canal intersected to form an included angle (117.04 +/- 2.42) degrees. External genu of facial nerve located anterior and inferior to the horizontal semicircular canal. The shortest distance was (1.97 +/- 0.53) mm between middle point of horizontal semicircular canal and facial nerve, (1.03 +/- 0.29) mm between incus short process and facial nerve, (0.93 +/- 0.25) mm between cochleariform process and facial nerve, (1.18 +/- 0.42) mm between head of stapes and facial nerve, (3.08 +/- 0.28) mm between tympani sulcus and facial nerve at the vestibule window level, and (2.13 +/- 0.34) mm between tympani sulcus and facial nerve at round window level, respectively.@*CONCLUSION@#Horizontal semicircular canal carina, incus short process, stapes, annulus membrane tympani and cochleariform process are ideal landmarks of tympanic and mastoid segment of facial nerve, which are helpful in middle ear surgery.

Destruction of ossicular chain and its impact on hearing of patients with chronic suppurative otitis media / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the characteristic of destructive ossicular chain and to evaluate integrity of ossicular chain and its impact on bone-conduction hearing of patients with chronic suppurative otitis media.@*METHOD@#The destruction of ossicular chain with microscopy during operation and the preoperative pure tone audiometry were observed in 148 patients (176 ears) with chronic suppurative otitis media.@*RESULT@#Destruction of ossicular chain was often observed in patients with chronic otitis media of cholesteatoma type, granuloma type and pars flaccid perforation of tympanic membrane. It initiated destructed malleo-incudal and incudostapedial joint for pars flaccid and pars tensa perforation of tympanic membrane respectively. Normal ossicular chain structure was observed in 52 ears. Destruction of ossicular chain was observed in 124 ears. Difference were significant for speech frequency air-conduction threshold and air-bone gap between group of normal ossicular chain and group of abnormal ossicular chain (P< 0.01). There was no difference for bone-conduction threshold between the above two groups.@*CONCLUSION@#Destruction of ossicular chain was often observed in patients with chronic otitis media of cholesteatoma type and granuloma type. The ossicular chain was normal in the patients who were both less than 40 dB in speech frequency air-conduction threshold and 30 dB of air-bone gap. The ossicular chain was destructed in the patients who were both over 55 dB in air-conduction threshold and 40 dB of air-bone gap. High frequency hearing loss was observed in patients with chronic suppurative otitis media.