Anterior Pontomedullary AVM: In Situ Occlusion Technique

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This is a rare case of an anterior pontomedullary AVM that was removed or disconnected via the In Situ Nidal Occlusion. The hematoma that was associated with this AVM within the pons was also evacuated. This is a 32 year-old male who unfortunately presented with two brainstem or pontine hemorrhages immediately after each other upon admission. He suffered from right side hemiplegia and multiple cranial nerve palsies. This was the CT scan upon his presentation. Unfortunately within two hours he had significant expansion or repleting from the arteriovenous malformation with additional neurological deficits. Here's a view of their CT angiogram demonstrating potentially evidence of hyper vascularity in the lateral and anterior aspect of the pons and medulla. MRI evaluation again reveals the impressive size of the hematoma within the pons. You can see the location of the hematoma related to potential hypervascularity just inferior to the location of the clot. An angiogram was performed, this is the lateral vertebral injection demonstrates a small arteriovenous malformation at the level of the medulla with a lateral vein. You can see on the AP view that defeating arteries are from the left ICA and are again leading to the nidus from the superior aspect of the nidus. Here again is another view of the lateral vertebral artery injection with their feeding vessels from ICA. Patient underwent a left sided retro mastoid craniotomy transfer sinus, sigmoid sinus. It's the fifth cranial nerve, seven and eighth cranial nerves. Cerebellum was micro surgically mobilized more medially away from these nerves so I can reach the anterior aspect of the pons and medulla. Due to the presence of significant preoperative deficits, I was planning to remove the hematoma within the pons as well to facilitate the patient's recovery. Here is potentially arterialised vein moving laterally over the area of the punt imaginary junction. Here's the ninth cranial nerve. You can see hyper vascularity in this area. I'll go ahead and work between the ninth and 10th cranial nerves. You can see the malformation clearly evident. Defeating vessels Coming from the superior pole of the nidus from ICA. It's hard to see the more anterior part of the malformation. Part of it is because of their swollen brain stem related to the presence of the hematoma. I opened the arachnoid membranes more effectively exposing the basilar and vertebral arteries. Some of the feeding vessels were disconnected using the Epipeel insightu technique. I was not planning to remove the nidus but circumferentially disconnected. I still need more space to be able to see some of the more medial feeding vessels at this juncture. I decided to enter the pons where the hematoma had approached the anterior peel surface of the pons most predominantly. Here's the area where I entered into the pons, just above the ninth nerve. You can see the hematoma under significant pressure being evacuated by the suction device. Additional large pieces of cloth were removed. This led to a significant decompression of the pons. Heres looking into their hematoma cavity removing additional clot fragments. Very small incision was created within the pons to reach the hematoma. Hemostasis was performed using a piece of thrumisol cotton. I avoided aggressive coagulation of the brain stem. Obviously this piece of cotton was removed at the end of the procedure. Here's further dissection of that knife nerves so I can reach around the anterior aspect of the brain stem. Looking across the entire aspect of the pon to major neuro junction. I was able to find additional feeding ranches. This is a normal draining vein. Here's another view of the feeding vessels to the malformation. These feeding vessels were also coagulated. Again decompression of the brain stem after clog evacuation allowed me to be able to identify these additional feeding arteries. You can see there are corkscrew. They are leading to the malformation. Obviously all the emphisage vessels have to be carefully protected in this area. Fallen coagulation of these feeding vessels, they were sharply cut. Here's the residual nidus of the malformation. Couple of perforating vessels leading to the malformation from its inferior order were also disconnected. Here's the draining vein. No additional feeding vessels more medially are apparent. The draining vein appears to be darker. The nidus was circumferentially disconnected epipeerly. Only the draining vein is not apparent that appears darker. Ultimately the vein was also coagulated. Again only the vein is apparent. before the vein is coagulated I carefully inspected the area for any presence of a feeding artery to the malformation. See the vein is not even darker now. Here is the location of entry into the pons in relation to the AVM nidus. The draining vein is now being also coagulated. View of the operative field at the end of the operation. knife cranial nerve. Further hemostasis within the hematoma cavity was secured. Piece of cotton was removed. No further bleeding was noted. Postoperative angiogram revealed complete disconnection of the nidus. Postoperative CT scan also demonstrated adequate removal of the clot despite the use of a very small incision within the pons. Within three months this patient made a dramatic improvement in his neurological deficits. Thank you.

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