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Giant Anterolateral Foramen Magnum Meningioma

October 27, 2019

Transcript

This is a very nice video describing resection of a giant anterolateral frame and Magnum meningioma. This is a 52 year old female with an 18 year history of hemiglossal atrophy. Shores or recently diagnosed with gait imbalance. MRI evaluation reveals this very large meningioma, this meningioma is quite impressive in causing this significant thinning in compression on the brain stem. In this case, the meningioma extends into the hypoglossal canal obviously causing the weakness in the tongue. This tumor is quite challenging to remove, obviously because of the chronic significant compression of a brain stem. However, a lateral Suboxone craniotomy is more than adequate to remove this tumor. Let's go ahead and see what we find intraoperatively. Before we do surgery, we went ahead with an angiogram, to demonstrate the vascularity of the tumor and the location of the vertebral artery and its vessels relative to the tumor. Obvious you can see the pica branches that are bracing around the capsule of the tumor, in this case. Here is suboccipital craniotomy. Patient is in the lateral position. The more posterior part of the condyle was removed in this case. Far lateral approach was deemed unnecessary. Here, you can see the drilling of the post condyle. This is a, we're in a right-sided approach. Here you can see the tumor and this is the midline vermis is here. Here's the tumor. You can see the left side is down. Here's the right tonsil. Here's the posterior capsule, the tumor, the arachnoid bands are versed, very efficient way to open the arachnoid in this area. Here are the branches of the accessory nerve then the right tonsil. Here's the upper cervical spinal cord again the left tonsil foramen of magendie, capsule of the tumor. In this case, there's so much sensory evoked potential as well as motor evoked potentials were monitored. Tumor was coagulated and it's capsule. The capsule was open and then debulked. Aggressive debulking is mandatory in this case so that the capsule can be easily moved away from the spinal cord without any undue traction, or other forces on the cord. Tumor's relatively firm. Again, ultrasonic aspirator is quite effective in minimizing traction forces on the neurovascular structures. Here, you can see the inferior very pole of the tumor. One has to be careful not to let the tumor bounce back and inadvertently hit the spinal cord. If adequate tumor removal or enucleation of the tumor is accomplished, the capsule can be reasonably well mobilized away from the spinal cord. Cut noid paddy can be used to protect the peel of the spinal cord while the ultrasonic aspirator removes additional tumor near the cord. Tumor is very firm. Therefore one has to do very aggressive decompression so that the capsule is mobilizable. Again we cannot let the capsule come back and hit the cord. I hold the capsule with a suction while the ultrasonic aspirator removes tumor. Can see the cord is extremely attenuated in this area. I go ahead and shrink the capsule by quiet leading it, this somewhat mobilizes the capsule away from the spinal cord. Again, the firmness of the capsule requires that the inside of the capsule is very aggressively decompressed before the capsule can be mobilized. I went ahead and decompress the tumor further Here's the more lateral part of the tumor here's the retrial artery and other neurovascular structures in the region. Here, you can see the artery is wrapping around, along the anterior pole of the capsule. We wanna go ahead and save this branch of the retrial artery. Should not be sacrificed until it's distal length and end is defined. We wanna make sure if it's a tumor vessels versus an emphasized vessel. Here, you can see this vessel appears to actually irrigate the cord or supply the cord. Therefore, it's very important to preserve it. I also use intermittent irrigation of papaverine or some papaverine soaked pieces of gel foam to pave the neurovascular structures to prevent the vessel spasm. Again, the suction protects the important structures. Here, you can see this vessel is actually going toward the brain stem. It's critical to preserve it. Can see the fine dissection here Using the same technique as discussed before, regarding holding the tumor capsule with a suction, creating the distance away from the cord, and then evacuating the tumor using the ultrasonic aspirator. Here against the retrial artery leading PICA along the more anterior aspect of the tumor, and tumor vessel or sacrificed. And this is the challenging part of the tumor that is facing the lower aspect of the brain stem. It's very firm, aggressive debulking is necessary to make this part of the capsule more and more plausible. Again, holding the capsule away from the artery and then using the ultrasonic device to evacuate more tumor. Shrinking the tumor capsule away from the neurovascular structures. Here, the distal part of the retrieval artery and other perforating vessel to the cord, probably branch of the lower cranial nerves, were just visible a moment ago. Here you can siphon the nodule of the tumor that was embedded within the lateral aspect of the brain stem. Continue to de-bulk mobilize the capsule away from the tumor. Small bleeding is evident from one of the veins on the lateral aspect of the brain stem. I use a paddy to protect the pear and just quite lead exactly at the place that I need to while avoiding indiscriminate coagulation. The pear vessels. We're getting close to removing most of the tumor that's facing the brain stem. Can hear, can see PICA other perforating arteries they're being protected. Here's the most superior part of the tumor. Obviously the part of the tumor that's invading the hypoglossal canal will not be removed. Here you can see the accessory nerve. So prior pull the tumor. Here are the lower cranial nerves, at the tip of my arrow. Here's the residual aspect of the tumor entering the canal. I'll go ahead and use the fixed retractor, just holding the cerebellum in place in debulking, the tumor. This is part of the tumor that's ending into the canal. Here, were again dissecting the vessels sharply from the superior pole of the tumor. Lower cranial nerves, accessory nerve, Continue to debulk the tumor using the bipolar forceps to mobilize some of the finer vessels away. Here you can see some of the vessels that are adhering to that part of the capsule. Can you see this branches embedded within the tumor? What appears to be dissectable? Tumor vessel that was sacrificed in the last parts of the tumor that are entering the hypoglossal canal. Far lateral approach, as you can see is not necessary. Here are the lower cranial nerves entering the juggler foramen. Here's the tumor. Here's the papaverine sol-gel foam that is paving all the fine perforating vessels to avoid it's spasm or their spasms. Very satisfied with the extent of resection to compression of the brain stem protection of all the perforating vessels to the brain stem. Here's the final result. Here's the three months postoperative scan, which reveals course toward removal of the tumor that was within the cisterns around the upper cervical spinal cord and the brain stem. Small residual tumor within the canal was left intact and underwent radio surgical treatment. This patient made an excellent recovery and her gait completely improved and returned to normal. However, tongue weakness remained stable. This case demonstrates the techniques for decompression and mobilization of the firm tumor capsule away from the brainstem and the upper cervical cord. And again, the importance of preservation of the perforating vessels is also important, how to mobilize the very firm capsule away from brain stem and the cervical cord, while preserving the pia of these important structures. Thank you.

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