Willis 輪前半部の脳動脈瘤に対する orbitocranial approach の有用性

Abstract

The pterional approach has become popular in operations for anterior circulation aneurysms. With the conventional pterional approach, however, some aneurysms are difficult to access safely because of the ristricted operative field, in spite of greater brain retraction. In this paper, our experience of 20 cases with the orbitocranial approach are presented. In 12 cases, we have used this approach in the early stage after subarachnoid hemorrhage. The orbitocranial approach comprises of removing the orbital rim, the orbital roof and the sphenoid ridge. This approach is characterized by multidirectional operative views of the skull base lesions with less brain retraction.In 5 patients, the high position aneurysms of the anterior communicating artery were approached with less rectal gyrus resection and brain retraction than with the pterional approach. In 6 patients, IC giant (1 case), IC ophthalmic (3 cases), MCA giant (1 case) and MCA (1 case) aneurysms were approached through the wide operative field after the removal of the anterior clinoid process. The low and lateral operative view was very useful for the ICPC aneurysms, the dome of which directed posteromedially in the remaining 9 cases. After the single bone flap was replaced, there was no functional, anatomical or cosmetic deficits of the supraorbital nerve and the frontotemporal branch of the peripheral facial nerve.The orbitocranial approach is recommended as intermediate procedure between the pterional and orbitozygomatic approaches