Endoscopic excision of an aqueduct of Sylvius cavernoma causing obstructive hydrocephalus: technical note.

BACKGROUND AND IMPORTANCE: Acquired lesions within the aqueduct of Sylvius are rare and their surgical management is challenging. Open transcranial approaches require dissection and manipulation of surrounding eloquent structures. Use of an endoscope can avoid potential morbidity from traversing and handling eloquent structures during open approaches whilst providing better visualisation of an intraventricular lesion. CLINICAL PRESENTATION: A 62-year-old female presented with insidious onset short-term memory loss, unsteady gait, urinary incontinence and left-sided dysaesthesia. Magnetic resonance imaging (MRI) revealed hydrocephalus from an obstructive haemorrhagic lesion consistent with a cavernoma at the central midbrain within the aqueduct of Sylvius. An endoscopic approach was selected to provide optimal visualisation of the lesion. As only a single instrument could be accommodated, rotational movements were employed to tease out the lesion. Gross total resection was achieved. Her symptoms improved immediately postoperatively and she made a complete recovery by 2 months. Post-operative MRI showed resolution of hydrocephalus and no evidence of residual/recurrence of the lesion. Unfortunately, she developed hydrocephalus 3 months post-op and required placement of a ventriculoperitoneal shunt. CONCLUSIONS: Endoscopic resection is safe and feasible for selected periaqueductal lesions as it provides direct access while minimising disruption of the surrounding anatomical structures. The limitation of only having a single instrument can be overcome by employing rotational movements.