February 13, 2016
I have frequently sought after innovative and minimally disruptive operative routes to resect giant falcotentorial or bilateral posterior parafalcine meningiomas. This case is an excellent example of how we can use minimally invasive unilateral methods through the transfalcine approach to resect, large bilateral parafalcine and falcotentorial meningiomas. This is a 28 year old male who presented with progressive memory difficulty and headaches, and on MRI and CT angiogram evaluation, was noted to have a large bilateral parafalcine posterior meningoma compressing the ventricle. You can see on the CT angiogram, the origin of this large meningioma along their falcotentorial junction, most likely engulfing, the vein of Galen. Obviously the internal cerebral veins are compressed inferiorly, the tumor is relatively homogeneous. There is no obvious hydrocephalus. I approached this tumor only through a small unilateral right sided approach, decompressing the tumor, cutting the falx, and ultimately removing the contralateral portion of the tumor. I use the lateral approach placing the right side down in order to use gravity retraction. A lumbar drain was installed at the beginning of the procedure to achieve generous CSF drainage and brain decompression. Placement of the lumbar during, is especially important in my opinion, to decompress the brain, to be able to de vascularize the tumor early, before it's decompression so that the amount of blood loss is more efficiently controlled. Let's go ahead and review the events of this procedure as they unfolded. I'm going to use a lumbar drain at the beginning, as we just mentioned, this is an overlay model of the brain and the tumor. The right side is down. The non-dominant hemisphere is positioned in this configuration. So gravity retraction can mobilize the right poster parietal region, allowing early access to the tumor. Obviously neuro navigation was used to avoid the bridging veins in this location. Here's neuro navigation watching for the veins and staying behind the vein of Trolard. Here is the point of entry. Only a small linear incision was used in this case. You can see the dura was exposed primarily on the right side, but small amount of dura on the left was also exposed. So retraction sutures on the superior falx can mobilize the sinus airway from the operative corridor. About 60 CCs of CSF was gradually drained and the tumor generously de vascularized from the falx. Ultrasonic aspirator, decompressed, and de-bulk the tumor. Here is the capsule of the tumor posteriorly, further, de-bulking allowed efficient mobilization of the capsule without undue traction on the surrounding neurovascular structures. You can see the veins poster to the capsule and the corpus callosum that is being protected with a piece of cotton. Decompression of the tumor allowed mobilization of the lateral capsule on the right side. After the right portion of the tumor has been removed, the falx is caught and a transfalcine approach is used to remove the contralateral component of the tumor. As this cut is made, one has to be very careful not to injure this straight sinus. Here is the operative corridor in a more de magnified view. Now the contral portion of the tumor is being de-bulked and similar maneuvers on the ipsilateral side are used to further mobilize the capsule. Coagulation shrinks the capsule away from the brain. Here is the more inferior aspect of the left side of the capsule. The corpus callosum is approached, and the tumor capsule gently dissected. Here's a large piece of the tumor from the left side. Now I have to manage the portion of the tumor attached to the falcotentorial junction and angiography demonstrates the location of the straight sinus. You can see the tumors intimately associated with the vein of Galen and the falcotentorial junction. Here's the vein of Galen that is being dissected, from the tumor. Here's the falcotentorial junction. Small portion of tumor has to be left behind to protect the vein of Galen. Here you can see the vein of Galen joining the straight sinus. As much of the tumor was shaved off before risking any injury to the vein of Galen. Here's the final result with the residual part of the tumor. Heavily coagulated to minimize the risk of future recurrence. Post operative MRI demonstrates radical near total resection of the tumor, except this small amount of tumor that was left over the vein of Galen. This patient awoken from anesthesia from very mild foot drop that resolved within a week after surgery. And the patient has a returned to his preoperative neurological status with radical improvement in his memory and has returned to work. Thank you.
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