Neuronavigation-guided endoscopic and hodotopic approach to an arachnoid cyst
A 68-year-old elderly female who has been suffering from mild left hemiparesis for the past 4 years presented to our hospital with history of sudden onset of left sided tonic-clonic seizures that became generalized. She was intubated because of airway compromise. Physical examination prior to intubation disclosed that the patient had left hemiplegia and hyperreflexia on the left limbs with extensor plantar reflex. The cranial nerves and systemic examination were normal. The computed tomography (CT) scan of the brain showed a large right fronto-parieto-temporal cystic lesion measuring 7 × 5 × 5 cm with a midline shift of 1 cm, suggestive of an arachnoid cyst [Figure -]. A neuronavigation-guided endoscopic fenestration of the cyst was done to communicate the arachnoid cyst with the ipsilateral sylvian cistern [Figure -]. Fenestration of the cyst to directly communicate with the ipsilateral lateral ventricle was thought as an inappropriate choice because of the close proximity of the cyst wall with important ipsilateral white matter projection pathways and inferior occipito-frontal fasciculus or inferior longitudinal white matter tracts revealed by the 3 Tesla MR system with DTI and MR tractography (Gyroscan Intera, Philips Medical System, Eindhoven, Netherlands) [Figure and ]. By using an endoscope mounted navigational system (Medtronic StealthStation TREON™ cranial software; Medtronic Inc., Minneapolis, USA), an appropriate burr hole with intended trajectory to the ipsilateral sylvian cistern was made guiding the neurosurgeon safely while inside the cystic cavity to the area of interest. Subsequently, fenestration was performed with the aid of a biopsy and bipolar forceps. The surgery was uneventful and lasted approximately an hour.\nPostoperatively, a repeated CT scan of the brain revealed a smaller arachnoid cyst with correction of the midline shift [Figure -]. The patient was weaned off from the ventilator and her hemiplegia improved gradually.