聴覚路の易傷性に関する実験的研究
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概要
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The influence of the cerebellopontine angle operation on highly vulnerable tissues, particularly on the auditory tract as well as the nerve is an inlportant question. Retraction of a cerebellar hemisphere is an inevitable manipulation in the operation via the posterior fossa. In the search for a clinically applicable meaning, experiments were performed on dogs. In experiment I, the functional effect of the manipulation on the auditory tract up to the inferior colliculus was studied in relation to the auditory brainstem response (ABR) and corresponding anatomical changes; in experiment II, the long-term effect of a partial section of the cochlear nerve on audibility, which is nearly inevitably inflicted in acoustic tumor surgery aiming at preservation of hearing was studied. Experiment I disclosed that wave V disappeared even by such cerebellar retraction as about 1/5 of the diameter of the cerebellum without a morphological change of the brainstem, suggesting occurrence of a dysfunction of the auditory tract in the brainstem. With further retraction of the cerebellar hemisphere, there were marked change in ABR in all wave forms. This fact suggests the possible usefulness of intraoperative ABR monitoring in clinical practice. In experiment II, three out of 8 dogs lost ABR and failed to recover during the follow-up, suggesting that, once the cochlear nerve has been damaged, even by a partial section of the nerve, its functional prognosis may be poor. This poses a clinical problem as a late postoperative deafness in the surgery of acoustic tumors aiming at preservation of hearing.
- 日本脳神経外科学会の論文
- 1985-10-15