April 28, 2016
Posterior Insular Lesions can be quite difficult to reach. This video reviews techniques for removal of such lesions. This is a 55 year old female with subtle speech difficulty. MRI evaluation revealed a partially hemorrhagic mass in the dominant posterior insula. This mass ultimately was diagnosed as hemorrhagic metastatic lung cancer lesion. Left frontotemporal craniotomy was completed. The Sylvian fissure was widely dissected, here is the temporal lobe, frontal lobe. The superior or superficial Sylvian vein had to be sacrificed and transected for me to be able to move more posteriorly and dissect the posterior aspect of the Sylvian fissure. Most often we'd get away with sacrificing the superior Sylvian vein, as long as other dominant things are present in this area. Here's the dissection of the posterior aspect of the insula away from the frontal and temporal opercular. Let's go ahead and use Stealth Neuronavigation. You can see that at this point, we are essentially located around the posterior aspect of the insula, however, most of the tumor is still unreachable. As the most anterior extent of the exposure is still somewhat separate from the anterior part of the lesion. Therefore, more posterior exposure is mandatory for complete removal of the mass. So the nuance in this case involves mobilization of the temporal opercular. In this case the MC branches in this area allow easy mobilization and dissection of the temporal opercular. Mobilization of the frontal opercular can be more challenging. You can see the distal M2 branches are being freed. Further dissection continues following the route of the distal M2 branches. These M2 branches are mobilized when safe. They're perforating vessels, especially those heading toward the motor cortex, have to be preserved. Here he's creating some space within the posterior inferior aspect of the insula. Neuronavigation now confirms a closer operative trajectory toward the lesion. Here is a more demagnified view of our operative cavity. So we'll go ahead and now work just next to the distal M2 branches to create a corticotomy within the insula. A self retaining retractor was used to hold the temporal lobe gently in place. This maneuver expanded our operative corridor. I was able to further mobilize the distal M2 branches. The corticotomy that I discussed a moment ago is now created. One has to be very careful of the MCA branches. Here's the anterior and superior pole of the tumor. Is relatively well-defined. I'll continue to extend now my, corticotomy. So more of a capsule of the tumor is evident. Pieces of cotton may be used to keep the fissure open. An angled dissector was used to create additional planes around the capsule of the tumor. Here you can see the most anterior aspect of the tumor. Here's some of the middle of the tumor that is being debulked using pituitary Rongeur's. The hematoma cavity is also found and a blood clot is removed. Now I work around the capsule of the tumor. Any perforating vessels in this area are protected. Now that the tumor is debulked, I can mobilize the capsule of the tumor and roll it more anteriorly. Here are some of the hematomas encountered and evacuated. And the capsule is very well-defined. Relatively small operative corridor to work through. Pieces of Cottonoid may be used to maintain the dissection planes. Hemostasis is secured. There was a vein attached to the capsule, the tumor in this case, again, we're along the anterior capsule of the tumor. Another Cottonoid is placed to maintain our anterior dissection plane. These Cottonoids are important, as ultimately I have to use an ultrasonic aspirator to debulk the tumor and remove it. Since the corticotomy is too small to pass this large tumor through. The cotton patties protect the surrounding walls of the brain. So tumor removal can be conducted. Without worrying about the ultrasonic aspirator injuring the normal brain through the capsule of the tumor. Hemostasis was secured in this case. More demagnified view of our operative cavity. Papaverine soaked Gelfoam was used to bathe the vessels in the area of our resection cavity to relieve their vasospasm. Three months postoperative MRI, demonstrated gross total removal of the mass. The patient did not suffer from any neurological deficits, and in fact, her speech is significantly improved at the time of this MRI. Thank you.
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