Bilateral telovelar approach: A safe route revisited for resections of various large fourth ventricle tumors
A 72-year-old male presented with progressive nausea, occasional vomiting, and intractable morning headaches. The patient had an unremarkable past medical history and was treated by his primary care physician for a stomach bug for several weeks.\nEventually, imaging was requested for non-resolving symptoms and MRI with I/V contrast revealed a multilobulated, irregularly shaped, partially cystic but avidly contrast enhancing, mostly well demarcated tumor, which reached from within the mid fourth ventricle posteriorly toward the inferior velum and laterally into the recess of the fourth ventricle []. There was no significant associated hydrocephalus.\nAs for patient 1, this patient underwent standard general endotracheal anesthesia and was placed into prone position in Mayfield fixation pins with the neck in a highly flexed position. The Brain-LAB system was used and best trajectories were determined. A standard wide bilateral suboccipital approach was chosen. Durotomy was performed as described earlier and the arachnoidea was dissected off. The tonsils were retracted, the cerebellomedullary (CM) fissure split and the tela choroidea was opened on both sides to access the posterior-lateral part of the fourth ventricle. Both PICAs were immediately visualized and could be dissected of the tumor mass and the veins of the cerebellomedullary fissure could also be preserved. Tumor tissue in the fourth ventricle was readily identified and some of the left sided cystic portions of the lesion could be accessed and drained, which greatly facilitated our dissection. A small specimen for intraoperative histopathological analysis revealed a well differentiated ependymoma. Careful microscopic dissection in a circumferential plane was performed. Cutting the juncture of the tela and inferior medullary velum on each side created a wide operative field allowing bilaterally panoramic views especially laterally toward the recess. After gross total resection, brisk CSF flow from the aqueduct and through the foramina Luschkae was observed. Absolute hemostasis was achieved, the ventricle was copiously irrigated and the durotomy was closed as described earlier with pericranial autograft and fibrin sealant augmentation. The patient was successfully extubated in the OR and no neurological deficit was noticed upon examination. Postoperative MRI revealed no residual tumor burden []. The patient had an unremarkable postoperative course and was discharged to home on POD #4.