ナビゲーションシステムを利用した経蝶形骨洞手術

Transsphenoidal Surgery Assisted by Navigation System

I．はじめに

　近年，低侵襲脳神経外科治療（minimally inva-sive neurosurgery）が脚光を浴びるようになり，トルコ鞍部病変に対する経蝶形骨洞手術においても内視鏡下に手術の全行程を行う方法が報告されている^5,8,12）．顕微鏡下経蝶形骨洞手術においても必要最小限の切開，剥離で操作が行われるようになった^2,6,10）．通常，狭い術野ではより正確なオリエンテーションを必要とするが，このような手術操作を支援する技術として手術ナビゲーションが急速に発達し，最近では実用的な機器が開発されてきている^7,11,13）．われわれはナビゲーションシステムを利用した経蝶形骨洞手術を行ってきたので，今回その有用性と問題点について検討を加え，報告する．

Microneurosurgical technique combined with precise localization of lesions, can minimize the invasive- ness of neurosurgical procedures. This report describes the usefulness of the neuronavigation system in transsphenoidal surgery. Nineteen transsphenoidal operations for sellar lesions including pituitary adeno -ma, clival chorcloma, Rathke's cleft cyst and suprasellar germinoma were assisted by the optical tracking system (OTS). Operations were performed either through the sublabial or the endonasal approach using an operative microscope and, to a certain extent, the endoscope. All five microadenomas were totally re- moved. The tumors could be precisely localized by the navigation system. Four out of seven macroadeno-mas were totally removed. The operations were assisted effectively by the excellent guidance to the lateralmargin of the tumors and the internal carotid arteries provided by the navigation system. The endonasalapproach, in which the surgeon looks through a nostril at the sellar floor obliquely, was especially facili-tated by the three-dimensional view provided by the system. The navigation system, however, was not use-ful in estimating the amount of the suprasellar residual tumor because of the dislocation that occurred dur-ing the tumor removal.