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Frontal Insular Glioma

October 28, 2019


Here's another video describing resection of a frontal insular tumor using transsylvian and transcortical approaches. This is a young male who presented with intractable generalized seizures. MRI evaluation demonstrated relatively large insular tumor, primarily within the frontal lobe, however, some extension into the temporal lobe. This tumor is relatively large and a transsylvian approach by itself will not be adequate to remove this tumor. And a transcortical approach along the posterior inferior frontal operculum would be necessary to provide adequate pathway or operative corridor for resection. Let's go ahead and review the intraoperative findings. Here's the position. Obviously the patient underwent the procedure awake. Here's the left front temporal craniotomy, a left sided fissure opening using the standard techniques described elsewhere in the Atlas using the jeweler forceps to open the superficial arachnoid bands. The veins were protected as much as possible. Although some of the bridging veins to the frontal lobe have to be sacrificed. The operculum can be quite adherent in these cases. This is the part of the frontal operculum affected by the tumor. It is bulging. It is swollen and can be very adherent to the temporal operculum. Here is using the sort of micro tear technique in order to mobilize the operculum atraumatically. Again, because of the tumor the frontal operculum is swollen making the resection more difficult. Again, you can see how I pull beyond the arachnoid bands and split the operculum from each other. Superficial arachnoid bands, more anteriorly are cut sharply. Again, a very wide split of the fissures is necessary in this case all the way toward the interclinoid process. You can see the sphenoid wing and the dural overlying it. Here's the white fissure, here's tumor, here's the M2 branches and more specifically the temporal trunk. We'll make sure the superior and inferior pre insular sulci are widely exposed for anatomical orientation. Here you can see the bifurcation and one further extension of the dissection more posteriorly is necessary. Often the cortices affected by the tumor are very friable and easily bleed. Again, you can see such a wide opening, the bifurcation frontal and temporal branches superior and inferior peri insular sulci are identified readily. We'll, go ahead and enter the frontal operculum and remove the discolored and relatively friable tumor. You can see the quarter is relatively small. So I'll go ahead and push this quarter as far as I can, to remove the tumor while protecting the M2 branches, working around them, creating these working channels to remove this friable and relatively suckable tumor. Again, the bipolared cautery emulsifies the tumor, the texture of the tumor is quite different than the normal brain, especially the response of the tumor to the bipolar coagulation is different. The tumor easily emulsifies, as you can see here, it's relatively discolored grayish. The response of the tumor to bipolar coagulation is especially important, and clearly defines it from the normal peritumoral region. We'll go ahead and furrow in one there dissect the fissure a little bit more immediately. We'll enter the frontal operculum more posteriorly, obviously neuronavigation is used during the entire process. As you can see, I'm creating these working channels on each and different sides of the M2 branches. So I can remove the tumor and increase my access. Tumor quite friable, often the surgeon overestimates his or her extent of tumor removal under the microscope through these tiny working channels. I would say that's one of the major pitfalls of this surgery, where surgeon the actually feels he or she is removing much more tumor than possible through these working channels. Go ahead and extend these working channels along the temporal M2 branch expanding the operative corridor more posteriorly. Try to preserve the branches that are going to the white matter towards the motor cortex. You can see these working channels between the M2 branches. Hemostasis can be quite a challenge around the arteries. Here you can see the very discolored tumor. I can see a little bit of a normal brain, a moment ago, but this is again discolored tumor and it should be removed. Here is slightly more normal looking brain, but still affected by the tumor. You can see the response of the tumor to the bipolar coagulation, which makes tumor quite friable and easily emulsifiable. It seems like this is the most I can remove via the transsylvian approach. We'll go ahead and map the face area and motor cortex, and create a corticotomy just anterior to that. This would allow us to remove additional tumor underneath the frontal operculum. Here's the mapping process for identifying the motor cortex As well as the speech area, obviously this is the dominant hemisphere, therefore the speech has to be mapped as well. Following mapping of the motor speech or basal ganglia we'll go ahead and create a corticotomy, just anterior to the basal ganglia. And this would allow us to further access the portion of the tumor underneath the frontal operculum. Small corticotomy is often very effective. You can see how much tumor is left underneath the frontal operculum. There is plenty of tumor left and will continue to protect the M2 branches I'll work around them to expand the operative corridor. The inferior to superior operative trajectory is especially important to remove as much as the tumor underneath the frontal operculum while minimizing the need for a further corticotomy, Gentle mobilization of the M2 branches via the suction device is critical in order to expand the operative corridors or the working channels. Again, an ample amount of tumor left. We can mobilize the motor cortex more posteriorly. Based on neuronavigation navigation, we'll go ahead and expand or extend the corticotomy so we can also elevate the anterior frontal operculum or the anterior inferior frontal gyrus to work under it, undermine it and remove the tumor. You can see this small corticotomy really expands the operative corridor by creating an expanded channel. Here you can see ample amount of tumor left that can be removed by undermining the inferior frontal gyrus, both anteriorly and posteriorly. Intermittent intraoperative neurological examinations, specially for speech and language are conducted to make sure that the patient remains intact. We'll continue to aggressively remove the tumor, very discolored tumor. Again, this corticotomy is further extended based on neuronavigation data and the discoloration and intraoperative findings of the brain tissue affected by the tumor. Then here you can see the user navigation to make sure we are on the top most superior pole of the tumor. You can see the peritumoral area, which is also affected by the tumor will continue to aggressively remove until the lateral lenticulostriate arteries are encountered. Obviously these arteries have to be carefully protected. You can see relatively normal brain, but not make an appearance of the putamen is also an important landmark that should be respected. Irrigation is used intermittently as well as papaverine soaked gel foam to relieve any vasospasm afflicted on the M2 branches. Now we'll continue to tackle the temporal extension of the tumor via the corticotomy. Having the patient awake provides the patient with significant amount of confidence to push the limits of the dissection while being assured that the patient is neurologically intact. You can see relatively intact peritumoral area. Any of the perforator arteries from the M1 should be carefully protected. Again using papaverine soaked gel foam to relieve the spasm within the lenticulostriate arteries. Here is now pushing the limits of the working channel more posteriorly along the posterior aspect of the insula. This tends to be the most difficult part and close to the internal capsule and motor fibers. And therefore subcortical mapping may also be used as necessary. We'll continue to push to the limits of resection on the temple side. Irrigation is used to clear the blood and identify the part of the brain affected by the tumor more clearly. In the blind spot it's more posterior and superior. I'm inspecting that, pushing the limits of resection. Continuing to have my colleagues examine the patient intraoperatively frequently. Relatively satisfied with the extent of resection, you can see relatively normal brain and not make appearance of the putamen is apparent And a more magnified view of this area of the lateral basal ganglia. Papaverine soaked gel foam may be used and for hemostasis thrombin soaked cotton may be used. Here's the final result. And here's the postoperative MRI examination, which revealed at least more than 80 to 90% resection of the mass. And this patient made an excellent recovery without any deficits. Thank you.

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