Let's review another video discussing variations of technique in Endoscopic Transnasal Resection of a relatively large Olfactory Groove Meningioma. This is a 52 year old male who presented with progressive confusion and ultimately a seizure. MRI evaluation revealed a sizable, Olfactory groove meningioma with significant evidence of edema in the right frontal lobe. You can see that the tumor extends pretty anteriorly and therefore complete ethmoidectomies are necessary for the tumor to be adequately exposed. Bilateral nasoseptal flaps were elevated. In addition sphenoidotomies and ethmoidectomies were also completed. Here is the alley of the cilia and the cribriform plate. The posterior ethmoid arteries were identified and coagulated early. A transcribriform osteotomy was completed. As you can see here how the frontal sinus was not entered. In other words, sinusotomy was not necessary. Here are the bony cuts for the cribriform osteotomy. First, as you can see on the right side, Again, the ethmoidal arteries were identified both anterior and posterior ones. Here's now the bony cut along the anterior aspect of our osteotomy. The bone can be quite hypertrophied. Upon removal of the bone plate or their cribriform plate. You can see that the tumor is immediately evident as the tumor had eroded through the dura. First, the tumor is debulked since it's already been devascularized during the exposure. Ultrasonic aspirator may be used for gentle debulking of the tumor. After aggressive debulking is completed. I gently draw upon the capsule of a tumor and they sect the brain away from the capsule. may be used for gently mobilizing the brain away from the tumor capsule. Based on the edema on the MRI exam, I suspected that ample amount of pial invasion would be present. The capsule is also coagulated and reduced. Further debulking can be performed as necessary so that the capsule, the tumor can be readily mobilized. Here's again, the maneuver of drawing upon the tumor capsule and gently moving that brain away from the capsule. I constantly watch for vascular structures or branches of the orbital frontal artery that could be adherent or entering the tumor. The smaller branch was entering the tumor and therefore was sacrificed. Microscissors are used to Provide sharp dissection under direct vision. I try to preserve the arachnoid planes as much as possible. Again, pial invasion is present here. ACA branches should be nearby. And the tumors reduced using bipolar coagulation. Tumor feeding vessels are carefully isolated, coagulated and cut sharply. Here's a demagnified view of our operative corridor, You can see the very generous osteotomy and transcribriform Craniectomy. Fair amount of pial invasion at the level of the tumor capsule is present. Some of the tumor nodules at the capsule are evident. Here are some of the branches of the orbital funnel arteries they are micro surgically separated from the tumor capsule. Ultimately the main part of the tumor mass is circumferentially disconnected and removed. This was a sizeable tumor piece, somewhat difficult to remove through the nose. Hemostasis was secured. Importantly, all the dural edges were carefully inspected using the 45 degree angle endoscope. The eadges of the Dural were also coagulated to minimize the future risk of tumor recurrence. The arachnoid bands and tear to the optic nerve were carefully inspected to make sure there's no tumor leading to the level of the optic nerves. An inlay piece of allograph dural was used to cover the dural defect. This was followed by the nasal septal flap coverage. A lumbar drain was used for about 4 days post operatively. 3 months MRI evaluation revealed gross total resection of the mass without any complicating features and the right front edema significantly subsided. Thank you.
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