摘要:

AbstractAn overall review of the authors' anatomical perspective, approach, and experience with multichannel intracochlear implantation is presented. This report includes pertinent anatomical observations and experimental surgical procedures on fresh temporal bones. Although the scala tym‐pani in the basal turn of the cochlea has an adequate space laterally for the insertion of electrodes, in the upper turns the adequate space is located medially. This is, in practice, the single‐most limiting factor for an electrode, inserted via the round window, to reach the apical turns without damaging the basilar membrane. An experimental surgical procedure is described in which a second electrode is inserted in the middle turn via a mastoidotomy‐tyinpanotomy approach and reaches a point near the apex. Studies of horizontal sections of human temporal bones include a review of potential structures that could be stimulated by the electrical currents generated by electrodes. The wall of the carotid artery, located at 750 μm from the basal turn at the level of the round window niche, is considered a potential structure to be affected by long‐term stimulation. Anatomical principles and surgical considerations for the mastoidotomy‐tym‐panotomy approach are described as an alternative to the facial recess approach. In the authors' experience, this procedure is technically easier, eliminates the possibility of postauricular flap complications, provides a better angle for insertion of electrodes, requires shorter hospitalization, and permits faster recovery than the facial recess approach. The authors' clinical approach, results, and observations are reviewed. Of note is a successful home‐based rehabili

ISSN:0023-852X    

DOI:10.1288/00005537-199002001-00001

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractAn ultrastructural study of peripheral extensions (dendrites) of type I ganglion cells in seven healthy adult cats and one cat that underwent bilateral cochlear injection of neomycin was undertaken. Morphologic evidence revealed that the peripheral process (dendrite) consistently has a smaller diameter than the central process. As the dendrite reaches the cell body, there is a constricted segment with a length that ranges from 10 to 30 μm, and a diameter of 0.5 μm. This region is covered by a continuous myelin sheath that does not thin. The central process (axon) does not have a corresponding constriction, and consists of a myelin covered, smoothly tapered segment that extends to the first axonal node of Ranvier. In the deafened cat, some cell bodies of the surviving ganglion cells appeared to have a residual portion of dendrite. These morphologic characteristics might have physiologic implications both in the mechanisms of normal hearing and in cochlear implantatio

ISSN:0023-852X    

DOI:10.1288/00005537-199002001-00002

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY