Large Dominant Insular Anaplastic Astrocytoma
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Resection of Dominant Large Insular Gliomas poses special challenges due to location of the Broca's in where any case, areas overlying these tumors. Let's discuss the use of mapping strategies to maximize the resection of these tumors. This is a 26-year-old right-handed male who presented with intractable seizures, and underwent an open biopsy which demonstrated an anaplastic astrocytoma in an outside institution. MRI evaluation demonstrated a large insular tumor primarily located in the frontal area, rather than temporal area. The tumor extends far anteriorly rather than mainly posteriorly toward the internal capsule. The functional MRI demonstrated a location of a Broca's Area, just overlying the superior pole of the tumor. The DTI image demonstrates displacement of the functional tracks by the tumor. The trans-Sylvian approach offers a limited opportunity for resection of the superior pole of the tumor, and therefore a corticotomy within the inferior frontal gyrus is necessary to maximize tumor resection. Therefore, an awake craniotomy is necessary to map the Broca's Area and determine where the corticotomy can be performed. This patient previously underwent an open biopsy using discriminator incision and we had to use an alternative method of applying the incision after a front temporal craniotomy you can see the tumor is extending through the insula into the Sylvian fissure. As much of the tumor as possible has been removed through the trans-Sylvian route, after which the patient is allowed to awaken from the conscious sedation so that mapping can be performed. Let's go ahead and map the Broca's Area.
[Patient] One, two, three, four, five.
So you can see the interruption in the speech, therefore a corticotomy just anterior to the functional cortex sparing about a centimeter of the normal cortex was performed. And the superior pole of the tumor was resected. Subcortical mapping was used for removal of the posterior portion of the tumor close to the internal capsule. Here's the depth of the tumor close to the striatum based neural navigation. Here's the more normal-appearing pre-tumoral area. Postoperative MRI demonstrates good resection of the tumor. More than 80% of the tumor has been resected. Portion of the tumor effecting the dominant caudate has been left behind to avoid significant postoperative cognitive decline. Thank you.
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