February 03, 2016
Let's review resection of a posterior parafalcine meningioma. This is a 52 year old female with headaches, who was noted to be suffering from a parafalcine parietal meningioma. You can see the posterior location of this meningioma relative to the local anatomy. The inferior border of the tumor appears to come in contact with the vein of Galen and its junction with the straight sinus. MRV evaluation reveals potential depression of the vein of Galen by the inferior border of the tumor. My operative strategy involved performance of a right-sided parietal parasagittal craniotomy, devascularization of the tumor from the falx, de-bulking of tumor, followed by its dissection away from the brain. Then I removed the part of the falx that was affected by the base of the tumor. One has to remember that the dura of the falcotentorial junction has to be left behind and protected, even if it's infiltrated with a tumor. The right side was placed down during patient positioning, oriented dependent position, as you can see here. A lumbar drain was used. A generous horseshoe skull flap was utilized. You can see the position of the head of the patient with a slight turn. Following completion of the craniotomy, you can see the location of the superior sagittal sinus right side down, right parietal lobe. Sutures were placed just underneath the sinus, in the falx, to mobilize the sinus out of our working zone. The bone over the superior sagittal sinus was also removed. You can see ample amount of brain relaxation because of the presence of the lumbar drain and CSF drainage. Approximately 50cc of CSF was removed, in 10cc aliquots. Here's the disconnection of the base of the tumor from the falx. I continued as thorough of a devascularization as I can carry on, in order to minimize the risk of bleeding during tumor de-bulking. I continue to follow the contours of the falx until the corpus callosum is evident at the base of the tumor. Here I'm using the anterior board of the tumor as a landmark, to be able to estimate the level of the corpus callosum. Here is some of the tumor de-bulking in progress. Despite early devascularization, the tumor remained heavily vascular. Piecemeal removal of the tumors is accomplished. Next, the capsule of the tumor is mobilized away from the medial parietal lobe. No fixed retractor was necessary. Tumor is being removed piecemeal. Another piece of the tumor resected. Now that most of the tumor is removed, I attempted to remove as much of the affected falx as possible. Here's the contralateral medial parietal lobe. Working more inferiorly, the inferior sagittal sinus is disconnected. One has to be careful to evaluate the importance of the inferior sagittal sinus in tumors that more specifically affect the superior sagittal sinus on pre-operative MRV evaluation. Again, this tumor did not affect the super sagittal sinus. So transection of the inferior sagittal sinus was not a concern. Now I continued to extend my incisions on both sides. Again, protecting the falcotentorial junction. The junction was located there however, there were some venous lakes more anteriorly. These venous lakes have to also be protected and I tried to use bipolar coagulation to preserve the safety and the integrity of the dura in this area. However, the bleeding was quite vigorous and I had to use pieces of thrombin soaked gelfoam to seal off the bleeding in these areas. But again, neuronavigation was recruited so that I can carefully localize the location of the falcotentorial junction and avoid any injury to the important veins in this area. Here is a piece of cotton that was used to control the bleeding. Intravenous bleeding appeared quite vigorous in this area. Ultimately, I was able to achieve hemostasis using bipolar electrocautery. I felt that is the most posterior extent of my dural incision. Here's a piece of dura that was left over the falcotentorial junction. Last connection of the affected dura is being handled. Here's that piece of the dura that was affected by the tumor. Here's the final result. A small piece of the tumor was left on the falcotentorial junction. Here's a more de-magnified view of our operative corridor. And the postoperative MRI revealed gross total resection of mass without any complicating features. Thank you.
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