September 08, 2015
Let's review resection of a small acoustic neuroma via the retromastoid approach. This is a 34-year-old female who was found to have a growing acoustic neuroma on serial imaging. You can see the morphology of the small acoustic neuroma on the right side. She underwent a right-sided retromastoid craniotomy. Sigmoid sinus. Transverse sinus. The sigmoid sinus was unroofed. The dura was incised along the dural venous sinuses and retention sutures were placed at the edges of this sigmoid sinus to mobilize this structure out of our operative corridor. Piece of glove was cut to the size of the catenoid. You know, the rubber dam was used to go round the cerebellum. A catenoid was also used over the rubber dam to a traumatically slide around the cerebellum. Find the petrotentorial junction and divert our attention to the seventh and eighth cranial nerves. Stimulation was performed to exclude a very abnormal route of the facial nerve along the posterior part of the capsule. Arachnoid bands were widely dissected. Here's the tumor. The affected part of the vestibular nerve is also apparent. Tumor was isolated. Here's the affected part of the vestibular nerve entering the tumor. Next, the capsule is entered and the tumor is debulked. Ultrasonic aspirator was used for tumor debulking. The facial nerve was identified within the CP angle. Tumor was rolled laterally. You can see the tumor is becoming very adherent to the nerve. The affected portion of the vestibular nerve was also resected. Next, we divert at our attention to isolation of the IAC and removal of the intracanalicular portion of the mass. Drilling isolates the IAC, circumferentially unroofs the canal. Here you can see the distal part of the tumor that is being rolled now more medially. Facial nerve is identified early and protected. If the tumor is very adherent to the nerve at the level of the porus, I typically leave a very thin sheet of tumor to preserve relatively normal facial function postoperatively. Here's the tumor that is being debulked at the level of the porus. You can see this tumor is exceedingly adherent to the nerve at the porus . Therefore, I felt a very small piece of tumor can be left behind to preserve function. Bone wax was used to seal the air cells within the IAC and the postoperative MRI revealed near radical gross total resection of the tumor. Very small piece was left behind. I typically follow these very small residual tumors on imaging. And if there's any evidence of growth, radical surgical treatment is indicated. Thank you.
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