Dolenc approach—前床突起削除・海綿静脈洞への硬膜外アプローチ

Dolenc's Approach:Anterior Clinoidectomy and Extradural Approach to Cavernous Sinus

Point

・Dolenc approachでは，側頭葉内側の固有硬膜を海綿静脈洞外側壁から剝離することがポイントとなる．

・硬膜外からの視神経管開放や前床突起削除によって，視神経や内頚動脈の可動性が得られる．

・側頭葉を硬膜ごと後方へ移動し，中頭蓋窩前方のスペースから頭蓋底中心部へのアプローチが可能となる．

　The combined epidural and subdural approach pioneered by Dolenc allows opening of the lateral wall of the cavernous sinus（CS）to treat various pathologies such as tumors and aneurysms in the cavernous, para-cavernous, and central skull base regions. The Dolenc's approach is occasionally performed with the orbitozygomatic approach（OZA）, which enables us to look up highly located lesions. We prefer the two-piece method when performing OZA: it involves removing the orbitozygomatic bar separately after frontotemporal craniotomy. Dolenc's approach requires dividing the meningo-orbital band and opening the superior orbital fissure to expose the junction between the dura propria of the temporal lobe and inner membrane of the CS, which separates the neurovascular structures and the venous plexus inside. Peeling of the dura propria from the inner membrane is continued until the anterior clinoid process is exposed epidurally. Extradural clinoidectomy and optic canal opening are then performed. After the epidural procedures, intradural procedures are also performed. The falciform ligament and the distal dural ring are incised to mobilize the optic nerve and the internal carotid artery. The tentorium is incised along the anterior petroclinoid ligament. Dolenc's approach allows extradural retraction of the temporal lobe, which provides a surgical corridor to the retro-carotid space and the inter-peduncular cistern through the opened anterior part of the CS.