定位脳手術における術中ナビゲーションの活用

Utilization of Intraoperative Navigation in Stereotactic Neurosurgery

Point

・基底核構造物の輪郭を自動的に描出できるsegmentation機能を有するソフトウェアは，定位脳手術のtentative targetの設定や術前のプランニングに有用である．

・術後CTから電極情報を抽出してMRI画像にfusionさせる機能は，刺激電極の位置確認に有用である．

・刺激調整用のプログラマに刺激電極や基底核構造物のsegmentation画像を3D画像として取り込むことにより，刺激の広がりとtargetとの解剖学的な位置関係を見ながらの刺激調整が可能である．

　Recently, a navigation software has been introduced in the field of stereotactic neurosurgery. BrainLab Elements (BrainLab Corp.) has several functions in image analysis, such as image fusion, auto-segmentation, software for stereotactic surgery, and lead localization. In preparation for deep brain stimulation (DBS) electrode implantation, many sequences of magnetic resonance (MR) and computed tomography (CT) images are imported into the elements and fused automatically. Subsequently, important deep structures, such as the subthalamic nucleus (STN）, thalamus, and globus pallidus, were automatically segmented. This segmentation provides information on the outline of those that are invisible based on normal MR equipment and helps set the tentative target. Postoperatively, the DBS electrode data were extracted from postoperative CT images and fused with preoperative MR images. Using Stimview XT software (Boston Scientific Corp.) installed in the stimulation programmer, we confirmed the anatomical relationship between the location of the electrodes and structures of the stimulation target and adjusted the stimulation conditions. In robot-assisted DBS electrode implantation, elements could be useful in setting the tentative target and frame-based stereotactic surgery. Navigation systems are useful in the field of stereotactic neurosurgery and can be further developed eventually.