[The facial nerve study of multi-slice spiral computed tomography in congenital abnormality of external and middle ear]

Abstract

Objective:Images of temporal bone are obtained on Siemens 64 slices spiral CT scanner with high resolution scanning to describe the course of facial nerve for better preoperative evaluation of CAEMA.Method:To describe the course of facial nerve on rectangular coordinate system from three silce on HRCT, 29 patients(35 ears) are enrolled in our study in ENT department from November 2005 to March 2007 in the second affiliated hospital of sun yan sen university, who are all diagnosed not acquired deformity but CAEME, associated with no congenital deformity syndromes and no middle ear or mastoid operations before. Patients with bilateral ears deformity are 6, and unilateral ears deformity are 23 (13 right and 10 left) in the study group. The control group is the normal ears of unilateral ear deformity.Result:In the study group, the shortest distance from FN tympanic segment to oval window is shorter than that of the normal group (P< 0.05). In CAEME of unilateral ears the FN mastoid segment displaces anteriorly about 2.7 mm, and in CAEME of bilateral ears displaces 3.0mm, compared with the normal ears (P< 0.05). The deformity degree of auricle has correlations with anteriorly displacement of facial nerve mastoid segment (P< 0.05).Conclusion:The FN mastoid segment is anteriorly displacement in both bilateral and unilateral ear deformity. The deformity degree of auricle has correlations with anteriorly displacement of facial nerve mastoid segment. The lateral displacement of facial nerve doesn't occur usually in CAEME. The shortest distance between oval window and tympanic segment of FN become shorter than normal ears.

Keywords: abmormality; facial nerver; tomography,X-ray computer.