聴神経腫瘍手術における経迷路法のアドバンテージ

抄録

The rationale for use of the translabyrinthine approach (TLA) is to obtain lateral access to the internal auditory canal and the cerebellopontine angle (CPA), which would allow removal of lesions at CPA, including vestibular schwannomas (acoustic neuromas), without cerebellar retraction. The enlarged field provided by the TLA overcomes the anatomical limits represented by the middle cranial fossa dura, the sigmoid sinus, and the jugular bulb. Extensive bone removal over these structures allows them to be retracted during surgery, and together with the subsequent wider incision of the posterior fossa dura, use of the TLA enables surgeons to remove vestibular schwannomas irrespective of the tumor size. In addition, sufficient bone removal surrounding the internal auditory canal (transapical extension of TLA) makes access to the petrous apex easier for removal of more anteriorly extending tumors. This approach also offers the advantage of allowing the facial nerve to be identified at the fundus of the internal auditory canal, which could lead to preservation of the facial nerve function. Moreover, the TLA prevents cerebrospinal fluid leakage resulting from deep insertion of strips of abdominal fat into the cerebellopontine cistern. Most importantly, TLA is considered to be an extension of complete mastoidectomy or subtotal petrosectomy, with which otologic surgeons are much more familiar, and this advantage could encourage otologists to take up the challenge of using the TLA for vestibular schwannoma removal.