Adult idiopatic occlusion of Monro foramina: Intraoperative endoscopic reinterpretation of radiological data and review of the literature

Abstract

Adult idiopathic occlusion of the foramen of Monro (AIOFM) is a rare condition, with only few cases described in the modern literature. We propose that AIOFM may result from unilateral or bilateral occlusion of Monro foramina, as well as from progression of a monolateral hydrocephalus. Different surgical strategies may be required for effective treatment according to the type of occlusion. To date, only 12 cases of AIOFM have been reported in the literature. We report the cases of two patients, aged 20 and 47 years respectively, who presented with intracranial hypertension secondary to bilateral ventricular dilatation due to obstruction at the level of the foramen of Monro. Both patients were successfully treated with endoscopic fenestration of the primarily obstructed foramen of Monro and, in one patient, fenestration of the septum. We propose that septum pellucidum displacement could play a role in the occlusion of the second foramen of Monro. AIOFM can, therefore, result also from unilateral stenosis of Monro. The difference in AIOFM (i.e. unilateral vs bilateral) will be useful in guiding the most suitable surgical approach in this rare condition.

Idiopathic Unilateral Foramen of Monro Stenosis: Neuroimaging Findings in Three Patients

“…Procedures like endoscopic fenestration, foraminoplasty and septostomy can be done for treating idiopathic unilateral obstructed hydrocephalus. [13,14] CONCLUSION: Unilateral lateral ventricular dilatation and slit or normal looking 3 rd ventricle in the absence of focal mass lesion or abnormal post-contrast enhancement at or around the foramen of Monro should raise a radiological suspicion for this uncommon neurosurgically treatable entity.…”

Neuroendoscopic treatment of idiopathic occlusion of unilateral foramen of Monro presenting as chronic headache

“…[ 1 ] Idiopathic occlusion of the foramen of Monro in adulthood is exceedingly rare, with only 14 cases previously described. [ 2 ] These patients present with clinical features of raised intracranial pressure (ICP) necessitating early treatment. [ 2 ] Neuroendoscopic septostomy and/or foraminoplasty are the treatment of choice for this condition.…”

“…[ 2 ] These patients present with clinical features of raised intracranial pressure (ICP) necessitating early treatment. [ 2 ] Neuroendoscopic septostomy and/or foraminoplasty are the treatment of choice for this condition. [ 1 3 4 ] Presentation as chronic hydrocephalus without clinical and radiological features of raised ICP poses a dilemma regarding surgical treatment.…”

Idiopathic stenosis of foramina of Monro in an asymptomatic adult patient: a rare entity radiologists should be aware of

“… 2 We report the case of an idiopathic biventricular hydrocephalus found incidentally in an asymptomatic 42-year-old female with temporomandibular joint disfunction. The fact that some patients with Monro foraminal stenosis may be asymptomatic increases the possibility of underdiagnosis, so we consider it a condition that radiologists should be aware of, mainly taking into account the fact that the diagnosis of this entity is usually radiologic 3 and the potential complications associated with treatment.…”