Transcript

This is the case of a recurrent clinoidal meningioma. An interesting one, in its own challenges. This is a 50 year old male with left-sided visual decline, who had a history of olfactory groove meningioma resection years prior. This case also illustrates the importance of gross total resection of meningiomas the first time. As the first time it's the best chance for cure. Here are the preoperative MRIs. You can see bilateral clinoidal recurrent meningiomas. However the left one was symptomatic at this time and was tackled. A left sided front temporal craniotomy was completed. This patient had previously undergone a bifrontal craniotomy for resection of his olfactory groove meningioma. For us to be able to do a left sided frontal temporal craniotomy the part of incision from the previous bicral incision, that vertical arm was used, and it was teed off anteriorly in order to expose just the symptomatic side. Lumbar drain was used. An extradural craniectomy was completed in order to decompress the optic nerve early, and to allow aggressive decompression of the nerve intradurally by opening the falciform ligament. Here's the drilling of clinoid process. Decompressing the nerve. Extradurally. Hollowing out the clinoid. Again, the nerve at the tip of my arrow. The clinoid process. Thorough decompression of the nerve was completed. Lumbar drain allowed a very nice decompression of the dura sac for this purpose. And continue to decompress the optic nerve. Angled curette was used. Potentially some tumor is apparent, transdurally. Here's the final product, before opening the dura. After epidural hemostasis was secured. I went ahead and excised the dura. And now we're going to start our work. The more challenging part of the operation. What was going through my mind right now, was the fact that the tumor is going to be extremely adherent to the surrounding neurovascular structures due to previous history of meningioma resection. And importantly, the optic nerve is going to be, at times, none distinguishable from the capsule, the tumor, and therefore I have to exercise significant caution doing identification of the nerve medial to the tumor. I went ahead and decompressed the tumor as you saw a moment ago, and then peaked over the pool of the tumor to find the optic nerve, which appears to be just about here, but again, very much not easily distinguishable. In going back now posteriorly decompressing the tumor further so I can mobilize it away from the brain and more importantly, be able to mobilize it away from the medial neurovascular structures. Here's the virgin area. You can see the tumor is readily dissectable. Here's the carotid artery. So again, along the posteromedial aspect of the tumor, I'm able to find the carotid artery. Again, the optic nerve, most likely here, and very much adherent to the tumor. Carotid artery. Optic nerve. You can see wasn't easily identifiable, because it's encased in scar. However, the carotid artery was readily identifiable and therefore I was able to estimate the surrounding neurovascular structures. Again, decompressing the tumor so I can mobilize it away from the optic nerve here. Now I'm going to open the arachnoid bands and the scar around the optic nerve, because eventually I need to enter the optic foramen and open the falciform ligament and decompress the nerve thoroughly. Can be a carotid artery. Optic nerve. Ample amount of scar incasing the nerve. Using sharp dissection as much as possible. Here's the tumor. Here's the falciform ligament at the tip of the arrow. Again, continuing to work from the area where the tumor is dissectable to the area of the scar around the optic nerve. Here's portion of the optic nerve there. Again, decompressing the tumor as I go along. Tumor appears more fibrous in its texture. As I get closer to the clinoid process. Here's opening the falciform ligament, identifying the optic nerve and thoroughly decompressing the nerve circumferentially. Again, the optic nerve entering the foramen, and you can see it here. Trying to decompress the nerve. You can see the scar makes it very difficult to identify the nerve. You can see some area of the compression and discoloration of the nerve at the falciform ligament. That's more apparent after the ligament is opened. You can see some tumor within the canal that will be removed just underneath the nerve. You can see it's extremely important for the nerve to be decompressed via the clinoidectomy so that the tumor underneath the nerve can be removed. Ring curettes may also be used to take out more of the tumor within the operative blind spot. Now coming over the nerve, cutting the dura affected by the tumor Here you can see the nerve more superiorly within the canal, continue to dissect the falciform ligament. Some more tumor over the nerve and medial to it, as expected. The potential space within the canal, just medial to the nerve, is often the area where the tumor appears to infiltrate and reside most frequently. This tumor has also being removed, while minimizing the traction on the optic nerve. Any retraction of the nerves should be avoided as under these circumstances, the nerve is very much attenuated and affected by the compression of the tumor. And it's very sensitive to any traction and vasospasm. Here's the circumferential inspection. One has to be very careful to protect the ophthalmic artery beneath the nerve. It should not be mistaken with tumor. Here you can see potentially the origin of the artery from the carotid artery. The origin of ophthalmic artery into the foramen. Again working medial and lateral to the nerve to remove as much of the tumor as possible. Here, you can see more tumor underneath the nerve. The clinoidectomy was crucial in terms of expanding the visualization around the nerve. And specifically, underneath it. You can see more tumor just underneath the nerve more medially. I'm using the right angle hook to deliver more of the tumor within the canal. And also, inspecting the canal to make sure that there are no other areas of compression underneath the nerve. Using the mirror to look underneath the nerve and you can see no residual tumor is apparent. You can see underneath the nerve, relatively healthy. Again, this is the only chance to decompress the nerve thoroughly. And we want to do all we can during this operation to make sure as much of the tumor as possible within the foramen is removed. Here's looking across to the other optic nerve. Making sure there's no obvious areas of compression that can be removed. And no obvious area was recognized medial to the nerve. Here is removing the effected dura around the nerve to avoid tumor recurrence in this area. And contralateral nerve, ipsilateral nerve as you can see here. And thorough the decompression of the nerve as much as possible. Here's the final product. And here's the postoperative MRI demonstrating gross total resection of the tumor. This patient's vision improved after surgery period, since the contralateral nerve was not symptomatic, aggressive manipulation of the nerve was avoided. This is specially important since the results of the surgery from the ipsilateral nerve was not evident during this surgery. And I wanted to avoid any risk of complete blindness by tackling the contralateral nerve at the same time. This patient vision has remained stable for the past two years. Again, this video emphasizes the importance of aggressive resection of olfactory groove meningiomas. So recurring tumors, such as this, can be avoided. Also during the surgery, extradural cliniodectomy is important. Also intradurally for recurrent tumors, one has to always watch for the optic nerve that can be encased in scar and mistakenly injured as scar or adherent tumor. Obviously it's best to start from the area where there is no evidence of scar and the anatomy is more evident and then move away toward the scared area, so one can estimate the location of the neurovascular structures encased in scar and less identifiable. A very thorough decompression of the nerve by opening the falciform ligament is critical and a nerve should be circumferentially inspected for any tumor. Affected dura should be removed to minimize the risk of re-returns. Thank you.

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