聴神経腫瘍に対する低侵襲後S状静脈洞アプローチ

Tear drop Euro coin hole techniqueの経験と紹介

抄録

We are utilizing the minimally invasive coin hole retrosigmoid approach (RSA) for treatment of vestibular schwannoma with special multiple cranial nerve monitoring as well as the endoscopic “dead-angle” visualization.
Our approach showed a unique shape of the craniotomy. At the craniotomy, a 2 Euro coin-size burr hole was drilled and expand it toward the lower cranial nerves, so the all monitoring electrodes on both the facial nerve and the cochlear nerve could be observed safely and surely. The craniotomy shape appeared as of a tear drop, so our technique was named as “Tear drop Euro coin hole technique”.
In the preservation rate of the facial nerve function, which was 100% even immediately after the operations, the significant difference was not found between the extended RSA and the coin hole RSA. Whereas the result of hearing preservation was different. Hearing preservation rate was 33% in the coin hole RSA, as about 70% in the rest of entire RSA's.
The coin hole RSA was minimally invasive in the aspect of the early recovery from surgery and the applicability to senior patients safely. However, as for the hearing preservation, there were some pitfalls for success. Therefore, we proposed the very careful selection of the approaches depending on the preoperative MRI findings such as the tumor size and the three dimensional pattern and the position of the cochlear nerve associated with tumor mass.