Endoscopic management of intranasal meningoceles and meningoencephaloceles

Meningocele (MC) and meningoencephalocele (MEC) are protrusion of meninges through a defect in the skull base forming a cyst filled with cerebrospinal fluid in the nasal cavity or paranasal sinuses. They may have only liquid content (cerebrospinal fluid) or brain tissue. The brain tissue inside is usually not functional. The skull base defect can be either congenital or acquired (intracranial hypertension, trauma, surgery, expansive tumors, etc.). If there is no bone defect, with heterotopic brain tissue, it is called glioma. The incidence of congenital MC is 1 per 3,000-10,000 newborns. The underlying mechanism may be defects of the neural tube caused by genetic alterations (approximately 10% of the cases). Treatment of these lesions is based on repairing the bone defect in order to avoid the risk of meningitis. There are different approaches to treat MC or MEC. The endoscopic endonasal approach with multilayer technique is preferred because of its low morbidity and high success rate.