Lesions at the Foramen of Monro Causing Obstructive Hydrocephalus

The foramen of Monro has also been referred to by the name of interventricular foramen. The structures comprising this foramen are the anterior part of the thalamus, the fornix and the choroid plexus. Vital structures surround the foramen, the damage to which can be catastrophic leading to disability either temporary or permanent. In the literature it has been shown that tumors occurring in the area of interventricular foramen are rare and usually cause hydrocephalus. The operative approach depends upon the location of the tumor which can be either in the lateral or the third ventricle. Various pathologies which can lead to foramen of Monro obstruction and obstructive hydrocephalus include colloid cyst, craniopharyngioma, subependymal giant cell astrocytoma [SEGA], Neurocysticercosis, tuberculous meningitis, pituitary macroadenoma, neurocytoma, ventriculitis, multiseptate hydrocephalus, intraventricular hemorrhage, functionally isolated ventricles, choroid plexus tumors, subependymomas and idiopathic foramen of monro stenosis. In this chapter, we will discuss the various lesions at the level of foramen of Monro causing obstructive hydrocephalus and the management and associated complications of these lesions based on their type, clinical picture and their appearance on imaging.

Risk Factors for Postoperative Hydrocephalus Following Subependymal Giant Cell Astrocytoma Resection: A Study of Under 18-Year-Old Patients in China

Background: Hydrocephalus may occur after subependymal giant cell astrocytoma (SEGA) resection. In existing literatures, SEGA almost always occurred in patients with tuberous sclerosis complex (TSC), however, many SEGA also occurred alone in our Chinese pediatric patients. Objective: To discuss the risk factors of postoperative hydrocephalus following SEGA resection and the relationship between SEGA and TSC in Chinese children.Materials and methods: A total of 35 children (≤18-year-old) who underwent SEGA resection were selected. From 3 months postoperatively until December 2020 all patients received telephone or clinical follow-up. Related risk factors were first screened by univariate analysis and then analyzed by multivariate logistic regression.Results: The ratio of males to females was 3:2 and the mean age was 11.6 years. Twenty cases were associated with TSC and 15 were not. The mean maximum diameter of the SEGA for patients with and without associated TSC was 49.7mm and 30.5mm, respectively (Z=-3.293, P=0.001). Twenty-eight patients had preoperative hydrocephalus. Sixteen patients developed postoperative hydrocephalus, and amongst these, 2 did not have hydrocephalus before surgery. Multivariate analysis showed that association with TSC [odds ratio (OR), 18.81, P=0.048] and tumor resection rate (OR, 0.042, P=0.025) were independent risk factors for postoperative hydrocephalus. Conclusion:SEGA could be associated with TSC or appear alone. The maximum diameter of SEGA associated with TSC is larger than that without TSC. Hydrocephalus is a common onset symptom and might recur following SEGA resection. Association with TSC and tumor resection rate are risk factors for postoperative hydrocephalus.