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Resection of Large Recurrent Third Ventricular Epidermoid Tumors

December 02, 2015

Transcript

Hello, my name is Aaron Cohen. This video reviews techniques for resection of large recurrent third ventricular epidermoid tumors in a 36-year-old male who underwent two previous resections through the transcortical approach through the superior parietal lobule for her epidermoid tumor. And subsequent required ventricular peritoneal shunt. He subsequently presented with gait disturbance and left sided spastic hemiparesis. And repeat MRI imaging revealed a large recurrent epidermoid tumor within the area of the third ventricle extending into the lateral ventricle, as well as the suprapineal region. You can see the shunt that was previously placed. That most likely is non-functional because it's been occluded by the large tumor. The tumor also was compressing the right cerebral peduncle the diffusion images demonstrate the hyper-intensity, which is characteristic of epidermoid tumors. In addition, you can see one of the veins, the internal cerebral vein that was draped over the posterior pole of the tumor. This patient subsequently underwent the resection of the tumor in a lateral position to use gravity retraction. You can see the head was fixed in a Mayfield pinion. Stealth neuro navigation was used using MRI. The head was tilted about 45 degrees away from the floor. And a linear incision was used with the supra sagittal sinus marked. The craniotomy on roof the supra sagittal sinus. Here, you can see the angulation of the neck. The dura was open in a curving fashion. This is the supra sagittal sinus. This is the right hemisphere. The section allowed us to untether the hemisphere so the gravity can have its way with the hemisphere in order to mobilize the brain away from the midline. You can see how gravity has mobilized the brain without use of fixed retraction. I use two sutures in order to mobilize the superior sagittal sinus. Both sutures are placed through the superior falx. And these retention sutures as you can see here, mobilize the sinus out of my working zone. In hemisphere the section readily demonstrated that the tumor had eroded through the posterior aspect of the corpus callosum. Further dissection around the falx allowed me to identify the tumor that was eroding through the callosum. Here you can see the fixed retractors are now used. I gently extend the callosotomy through the very attenuated part of the callosum more posteriorly. Here is our operative corridor through the corpus callosum and the tumor is evident. The tumor is now carefully dissected from the attenuated callosum. And the posterior pericallosal arteries are carefully protected. You can see the tumor capsule is being mobilized. The tumor under the lip of the callosum is the blind spot of the surgeon and has to be carefully inspected to assure that residual tumor is not left behind. I continued to use the pituitary rongeurs to emulsify the tumor, and then used suction to remove the emulsified tumor as you can see in the technique demonstrated here. The shunt catheter is readily evident. I continue to use the pituitary rongeurs to fragment the tumor in layers, which can be removed with suction. I continue debulking the tumor using ring curettes under the blind spots of the surgeon, which is primarily under the ipsilateral hemisphere. Here, you can see this tumor is readily suckable. You can see the wall of the ventricle being exposed as the tumor fragments are being removed. Here's a ventricular vein that is evident along the anterior aspect of the capsule. Sharp dissection was used to separate the vein. However, the vein was very adherent to the capsule of the tumor. A small amount of tumor had to be left behind to protect the vein. Here, you can see additional attempts to remove as much of the tumor as possible. Here further debulking allows me to remove as much of the tumor safely deliverable and then I'll come back to the spot a little bit later as more of the tumor has been debulked. The ventricle wall is more evident. I continue again to mobilize the capsule more laterally on the left side. However, as you see, further progress is prevented because of the resistance provided for the falx. Here is additional tumor in the lateral ventricle. The corridor here leads to the foramen of Monro that you can see here. An anterior part of the lateral ventricle. Continue to follow the ventricular catheter and you can see the tumor was tracking into the lateral wall of the ventricle around the shunt catheter. In order to expand the operative corridor toward the left side, the falx was transected. You can see sharp dissection to dissect the falx from the contralateral hemisphere and disconnect the inferior sagittal sinus. The falcine incision is further extended superiorly. A very important landmark here that has to be protected is the anterior aspect of the straight sinus. You can see the vein here within the leaves of the falx. It is critical that this venous structure is carefully protected and a piece of the falx is left over it. Here you can see that this mobilization allowed me to nicely look on the contralateral side and be able to deliver more tumor. The blind spot again is underneath the lip of the corpus callosum, also contralaterally. This is the area where the previous two surgeries were conducted and therefore there is much scarring that has to be worked through with a bipolar cautery. Here is a couple of vessels that are entangled within the tumor. Obviously these vessels within the ventricle are important and carefully protected. Here is again, the wall of the third ventricle. And I try to peel off as much of the tumor as possible. Again, there are nodules of the tumor that are extending into the ventricular wall. Since this is the third resection of the patient and most likely his last resection, we wanna be able to be as aggressive as possible. Due to his young age, I continue to use sharpened blunt dissection and dissect the ventricular wall away from the nodules of the epidermoid cyst that indent and encroach upon the wall of the ventricle. Here, you can see how this nodule has really embedded itself into the wall of the ventricle. And I continue to deliver the nodule out of the area. Further mobilization of the tumor is possible. You can see the tumor capsule is at locations, very easily dissectable and the wall of the ventricle is very much well delineated. We're approaching the posterior aspect of the lateral ventricle. We see some CSF through the aqueduct draining into our resection cavity. Pituitary rongeurs are really effective in removing this tumor that is quite laminated. Here is again the operative corridor to orient you to where we are working without fixed retraction and using thin cottonoids to cover the brain. Any contusion on the surface of the brain is avoided. Now again, removing and delivering the tumor from the contralateral aspect. Just in a subcolossal region. And here is removing the tumor and fragments. Again, this was the vein. Probably one of the internal cerebral veins that had a small amount of tumor over it that I had to leave behind in order to protect the vein. Additional tumor is being delivered into the resection cavity from the posterior aspect of the third ventricle until the aqueduct is demonstrated. Working in different spots, here you can see again the shunt catheter. Here you can see again, some of the veins anteriorly. Some of the scarring from previous surgery that's been coagulated. Ultimately again, trying to see how safely I can remove as much of the tumor as possible. You can see the wall of the ventricle is relatively clean. Here again is another orientation image. Now you can see the posterior aspect of the resection cavity with clot within the aqueduct into the superior aspect of the fourth ventricle that is being removed. Obviously we want to keep the CSF pathways connected. Here is another view through the aqueduct. You can see again, the blind spot just underneath the callosum on both sides where the surgeon has to pay special attention to deliver the tumor and keep the capsule intact. Now as much of the tumor has been safely removed, we'll go ahead and use the endoscope to look around. Here is another round of inspection before we'll bring the endoscope and you can see that careful inspection continues to be rewarding by finding additional tumor. The nerve is being massaged to see if I can remove any of the last layers of the epidermoid. Here is again the final resection cavity. But again, when you look through the scarred cavity with septations, you can be surprised how the tumor can really be hiding within these membranes that look like ventricular wall. Instead of being aggressive with coagulation on the wall of the ventricles to avoid any injury as a piece of cotton is used with gentle tamponade to achieve hemostasis. Here's the 45 degree endoscope that's been entered into the field, and you can see that this is the area into the fourth ventricle and there's tumor just in the area of the suprapineal recess. So we use the angle instrument to dissect the tumor from the vein of Galen. You can see the arachnoid layers over the vein of Galen. And these angle instruments can be quite effective to remove as much of the tumor as safely possible. So I gently peel off the tumor and then inspect additional small piece that was subsequently removed. However, complete resection is impossible as it will cause injury to the wall of the ventricles. Small pieces had to be left behind to protect the arteries and the peel and the ependymal surface of the ventricle. Here's the postoperative MRIs, which demonstrates good resection of the tumor close to the cerebral peduncles and the floor of the third ventricle. You can see our operative corridor. No evidence of injury to the surrounding structures. Thank you for your attention.

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