Awake surgery for intrinsic cerebellar tumor involving the middle cerebellar peduncle

Originally introduced for epilepsy surgery,¹ awake brain surgery is now frequently used for resection of brain tumors.^2-4 In such cases, it allows for a more extensive and safer resection of supratentorial lesions in highly eloquent areas, such as motor, sensory, and language regions.⁵ We present the case of a 22-year-old, right-handed woman who underwent awake surgery for an extraventricular cerebellar neurocytoma involving the middle cerebellar peduncle (Video 1). The patient experienced no neurological deterioration, and postoperative imaging revealed no residual tumor. Magnetic resonance imaging performed 6 months later revealed a tumor in the previous lesion bed at the level of the middle cerebellar peduncle. As complete resection is believed to provide significantly better control and survival compared with incomplete resection followed by radiotherapy, surgical removal of the residual tumor was recommended. Given that the lesion was located in a highly functional area, as indicated by her initial symptoms, the second procedure was done under awake craniotomy to allow for intraoperative clinical monitoring of the middle cerebellar peduncle to maximize tumor resection while minimizing the risk of neurological deficits such as intention tremor, dysmetria, and dysdiadochokinesia.⁶ At 3-year follow-up, magnetic resonance imaging showed no recurrence. Tractography confirm a reduced number of highly functional ponto-cerebellar fibers, which could be clinically monitored during awake surgery.⁷ Although previous surgical intervention in the posterior fossa is not a contraindication for awake surgery, within the posterior fossa, working in very close proximity to vital structures that control breathing or heart rate may be a significant limitation. Other potential contraindications⁸ include intracranial hypertension, cerebellar swelling, very large or highly vascular tumor, and others. Awake surgery can be considered for patients with intrinsic posterior fossa tumors in selected cases, especially when highly functional areas such as the middle cerebellar peduncle are at risk.