Let's review some of the techniques for improving the safety of resection of fourth ventricle ependymomas adherent to the floor of the fourth ventricle. This is a 56 year old male who presented with gait difficulty and headaches. MRI evaluation demonstrated a relatively heterogeneously enhancing mass, along the inferior aspect of the fourth ventricle. The mass appears to invade the floor of the fourth ventricle at this area, based on a sagittal, and axial enhanced images. The procedure was completed with a patient in the lateral position, midline incision exposed the suboccipital area. You can see the bone over there. Cranial cervical junction was removed to our opening, started at the level of the cranial cervical junction. The midline cerebellar sinus was ligated using sutures. Here you can see the two are between the tonsils, herniating through the fourth ventricle. Posterior inferior cerebellar arteries were dissected along the lateral poles of the tumor. You can see the floor of the fourth ventricle at the lower pole of the tumor is being identified. The adhesions between the tumor, and surrounding neurovascular structures are sharply disconnected. Some of the perforating vessels from the PICA to the tumor are individually coagulated and sharply cut. This should not be avulsed. After skeletonization of the tumor capsule, the next phase of the operation involves tumor debulking. Here's a similar dissection process on the left side of the tumor. Again, the tumor appears to invade the floor of the fourth ventricle inferiorly. Let's go ahead and debulk the tumor using bipolar coagulation, and ultrasonic aspirator. The debulking procedure continues until the superior pole of the tumor is debulked, and the fourth ventricle is identified along the superior pole of the tumor. Since I earlier identified the floor of the fourth ventricle along the inferior aspect of the tumor. at this time I identified the floor of the fourth ventricle along the superior pole of the tumor. These anatomic orientations, allow me to remove the tumor, but to leave a small or thin sheet of the tumor over the invaded portion of the fourth ventricle. I will not dissect the tumor through the floor of the fourth ventricle, as this maneuver can be quite risky. Here you can see this small sheet of the tumor that was left behind. Postoperative MRI demonstrates radical subtotal removal of the tumor. This patient subsequently underwent proton beam therapy, and recovered from his surgery very effectively. Thank you.
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