|Budget Amount *help
¥7,100,000 (Direct Cost : ¥7,100,000)
Fiscal Year 1996 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1995 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1994 : ¥4,400,000 (Direct Cost : ¥4,400,000)
To elucidate the pathomorphism of malformed ears, we used 3,3 dimetyl-1 phenyltriazene and got mouse fetuses with congenital aural atresia and malformations of the middle ear. In operations on congenital aural atresia, the most important thing is to improve hearing without damages of the facial nerve. Then we clarified the pathogenesis and pathomorphism of the malformations of the middle ear related to aural atresia. Since in malformed ears the conditions of the stapes and oval window are keys of hearing improvement and the recognition of the course of the facial nerve is necessary, we studied mainly on the facial nerve, stapes, and oval window in malformed mouse fetuses.
Moreover, we demonstrated that apoptosis is involved in development of the external auditory canal. Although previous studies showed that apoptosis playd a role in recannaization, we demonstrated that apoptosis is involved in the formation of the epithelial plate, not recanalization. Recanalization is thought to be ind
uced by the separation of the apposed epithelia by cornification. For the improvement of our success rate in operations on malformed ears, we use helical computed tomography (CT) and perform three dimensional CT (3D-CT) reconstruction. Since by using 3D-CT,we can evaluate preoperatively the degree of anomalies of the ossicles, the spatial relationship between the ossicles and the tympanic cavity, and the course of the facial nerve, we can easily select more proper candidates for surgical intervention among patients with malformed ears. Moreover, we used a navigation system with helical CT and operated on one ear of a patient with malformed ears. By placing the probe on a any point in the operating field, this system can show the position of the present probe on the axial, coronal, and frontal CT sections and the 3D-CT image in the real time. Since we can easily recognize the relationship between a drilling site of a newly created external auditory canal and the tympanic cavity and facial nerve, we can operate on malformed ears more safely without complications.
The 3D CT and navigation system are mandatory tools in therapy for malformed ears. Less