February 10, 2015
Metastatic tumors can often invade very unusual locations, such as the Cerebellar Peduncle. This is a 65 year-old female, with history of breast cancer, who was noted to have gait disturbance. MRI evaluation revealed an enhancing mass within the left Cerebellar Peduncle, potentially adherent to the underneath surface of the medial tentorium. This mass also led to some mild Edema. Due to excellent control of her systemic disease, she underwent a left-sided Retromastoid Craniotomy. You can see the Sigmoid Sinus leading to the Transverse Sinus. Dural or the petrous bone, the 7th and 8th cranial nerves, brain stem auditory evoked responses, were monitored during this procedure. All their arachnoid bands were generously dissected, so that the nerves are not under any traction. The nerves are further mobilized away from the middle Cerebellar Peduncle. Where the tumor is suspected to come to the surface. Here, you can see the bones related to, the protuberance of the tumor. The pial surface of the middle Cerebellar Peduncle is prepared. Here's the tentorium. The 5th nerve would be just slightly deeper or slightly here. An incision is made within the middle Cerebellar Peduncle, and the tumor is gently mobilized away from the surrounding fibers. This is a relatively large tumor and its debulking would be necessary before it can be removed completely. It was gently mobilized anteriorly. Now that a portion of the tumor is apparent, some debulking would be necessary. Here's further mobilization of the tumor, from the middle cerebellar peduncle, due to the small space available. Obviously, debulking is mandatory. Some venous bleeding is apparent. Carotenoid patties are used to tame and aid the venous bleeding. Now, tumors removed piecemeal, feeding vessels that are clearly leading to the tumor are coagulated and cut. Here's a piece of tumor that's ready to be delivered. This removal provides some space. Due to retraction of the Cerebellum, one of the bridging veins is avulsed. The end of the vein, leading to the Cerebellum is coagulated, where the opening of the vein into the tentorium is not coagulable. And coagulation, using bipolar forceps on the surface of the tentorium may lead to exacerbation of the venous bleeding. In this situation, I used Gelfoam, soaked in Thrombin, on back of a piece of cotton and gently seal off the opening in the tentorium with a Gelfoam. This maneuver is quite effective. Postoperative CT scan demonstrated, complete removal of the mess, without any complicating features. And this patient made an excellent recovery. Thank you.
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