Surgical Tips for Medial Sphenoid Wing Meningioma

Medial sphenoid wing meningiomas are more problematic than those meningiomas originating at the pterion. Major arteries and perforators are often involved. An essential principle of surgery is given in this paper. In order to do an operation safely, it is important to define at an early stage of surgery whether the arachnoid membrane separates an artery and a tumor. If one cannot find the separating arachnoid, one should decide to leave the part of tumor attached to the artery. I like to use an intradural resection of the anterior clinoid process after removal of the main tumor mass when the tumor is small. In cases of extensive tumors, extradural bone removal is preferred at the initial stage, so that less brain retraction is needed and the feeding artery is managed. Intradurally, one should detach the tumor initially and then debulk it. Tumor can be separated from the brain surface using the arachnoid plane. One must try to preserve large vessels and perforating branches buried in the tumor to avoid major complications. I recommend dividing the tumor into compartments along a blood vessel, so that one can dissect the vessel from the tumor. Simpson 2 removal is usually tried but I do not hesitate to leave part where no arachnoid membrane is separating major vessels or perforators from the tumor. The video shows where to stop removal. In addition, tumor invading into the cavernous sinus is not removed as long as it does not cause ocular motility disorder.