Intraventricular meningiomas: a surgical challenge

Primary intraventricular meningiomas (IVM) pose a surgical challenge as they often remain asymptomatic until they become very large; have close proximity to vital intraventricular structures; and, their vascular supply is often encountered only after significant tumor debulking. In this study, the surgical management of IVM is discussed.

Between 1989 and 2003, nine patients (7 with lateral and 2 with fourth ventricular) IVM, were operated upon. Raised intracranial pressure, gait ataxia, memory impairment, seizures (motor and sensory) were the main presentations. Four had hydrocephalus while five had either a sequestered temporal or occipital horn. All were large tumors with an average size more than 5.3 cm. The lateral ventricular IVM were accessed by the posterior middle temporal gyrus (n=5) or the superior parietal lobule (n=2) approach. A midline suboccipital craniectomy was used for the fourth ventricular IVM.

Total excision was achieved in eight and partial excision in one. Patients with lateral ventricular tumors required a postoperative intraventricular drain for a minimum period of 48 hours. The main morbidity included visual field defects and transient hemiparesis, seizure and meningitis. The one patient with partial excision died 6 weeks later due to transtentorial herniation as a result of intratumoral bleed and lateral ventricular sequestration.

An IVM, being initially asymptomatic, usually attains a large size before detection. During surgery, its devascularisation is usually achieved only after significant tumor debulking. Development of hydrocephalus or ventricular sequestration should be constantly monitored and may be avoided in the postoperative period by continuous external ventricular drainage.