Pathogenesis and diagnostic pitfalls of ventricular diverticula: case report and review of the literature

Ventricular pseudodiverticula from intraparenchymal cerebrospinal fluid dissection secondary to high-grade obstructive hydrocephalus in children: magnetic resonance imaging findings

We report on a series of three children who presented with a focal cerebrospinal fluid collection within the periventricular white matter of the temporal and occipital lobes in the setting of high-grade obstructive hydrocephalus. Magnetic resonance imaging showed a focal defect within the ventricular wall associated with leakage of cerebrospinal fluid into the adjacent white matter. The white matter tracts appeared primarily displaced. This entity should be referred to as ventricular pseudodiverticulum, not lined by ependymal cells, in contrast to a true ventricular diverticulum in which the cerebrospinal fluid is contained by a focal outpouching of the intact ventricular wall lined by a dilated and prolapsed layer of ependymal cells. Correct interpretation and classification of the findings may be helpful in predicting prognosis and outcome.

[Lateral ventricle diverticulum as a variant of hydrocephalus evolution]

A clinical case of a 12 year-old girl with hydrocephalus complicated by rare condition, lateral ventricular diverticulum, is reported. Progression of the diverticulum was followed up according to MRI. The diverticulum of the lateral ventricular wall has emerged in the interval of 1 year (14 months have passed between the two MRI examinations) and spread towards the quadrigeminal cistern. In addition, compression of cerebellum, aqueductus cerebri Sylvii, and the fourth ventricle of the brain have emerged. A surgical treatment was suggested after the hydrocephalus had been initially revealed (when the diverticulum had not been formed yet); however, the child's parents refused the therapy. One year later, a series of epileptic seizures emerged, and MR scans showed a cystic neoplasm in the postcranial fossa above the cerebellum. The genesis of the cyst and its nature were unclear and additional invasive examination methods were required. MSCT ventriculography confirmed the diverticulum of the right lateral ventricle towards the quadrigeminal cistern.

Expansion diverticulum of the suprapineal recess causing cerebellar ataxia. A case report

As a result of long-standing cerebrospinal fluid (CSF) pulsation against the thinnest segments of the ventricular walls, focal enlargement of the ventricular system (diverticulum) may occur, mainly at the medial wall of the trigone of the lateral ventricles (atrial diverticula) or at the posterior wall of the third ventricle (expansion of the suprapineal recess). In the latter case, ocular signs are the most common symptoms, due to the severe deformation of the periaqueductal region. We describe a case of non-communicating hydrocephalus in a 36-year-old woman who presented a three-year history of cerebellar ataxia. Preoperative brain magnetic resonance (MR) scan showed marked supratentorial hydrocephalus with an apparently patent aqueduct of Sylvius, and an enlarged suprapineal recess causing cerebellar and tentorial dislocation. The patient was successfully treated by endoscopic third ventriculostomy and monitored by MR scans with phase-contrast sequences for assessment of CSF flow. Cerebellar ataxia is a very rare symptomatic onset for a suprapineal recess expansion diverticulum, which may cause obstructive hydrocephalus that can be effectively treated by endoscopic third ventriculostomy.

Contrast ventriculo-cisternography: an auxiliary test for suspected fourth ventricular outlet obstruction

PURPOSE

Fourth ventricular outlet obstruction (FVOO) causes obstructive hydrocephalus. Often, despite high-quality MRI sequences, differentiation between FVOO and communicating (absorptive) hydrocephalus is not easy. We describe our initial experience with five children with suspected FVOO that underwent CT ventriculography (CTV) or cisternography (CTC), to assist with this difficult diagnosis.

METHODS

Over 2.5 years, five children with suspected FVOO (5 months-7.5 years old) underwent CTV or CTC. Technical and clinical data were retrospectively collected.

RESULTS

Four children had progressive macrocephaly, and one child had progressive ventriculomegaly. On CTV/CTC, four of five children showed communication between the ventricular system and spinal subarachnoid space or prepontine cistern, as evidenced by passage of contrast material. One child had a FVOO and therefore underwent an endoscopic third ventriculostomy, and is since, symptom and shunt free for 2.5 years.

CONCLUSION

CT ventriculography in infants, and CT cisternography in elder children, may assist to differentiate between FVOO and communicating hydrocephalus. The importance of these tests is for children with MRI suggestive of FVOO related hydrocephalus, but with no clear demonstration of the obstruction site. The implication of this differentiation may be for deciding between treatment of hydrocephalus with a ventriculoperitoneal shunt or with an endoscopic third ventriculostomy.

Spontaneous third ventriculostomy: definition by endoscopy and cerebrospinal fluid dynamics

Chronic obstructive hydrocephalus is known to cause ventricular diverticula and, rarely, spontaneous ventriculostomy. The authors present the case of a patient in whom a spontaneous third ventriculostomy was identified with long-standing hydrocephalus secondary to aqueductal stenosis. To their knowledge, this is the first report in which a spontaneous stoma in the floor of the third ventricle was evaluated using endoscopy and cerebrospinal fluid dynamics studies. Both studies confirmed that the spontaneous stoma is similar in structure and function to surgical third ventriculostomy.

Spontaneous third ventriculocisternostomy in an infant with obstructive hydrocephalus

Spontaneous ventriculocisternostomy, the spontaneous communication between the ventricular system and the subarachnoid space, is rare. The authors report a case of an infant with obstructive hydrocephalus who developed a spontaneous third ventriculocisternostomy. The infant was initially evaluated for progressive ventriculomegaly and increasing head circumference (HC). During follow-up, the patient's HC began to follow percentile lines and magnetic resonance (MR) imaging demonstrated a reduction of the hydrocephalus. Flow-sensitive phase-contrast cine MR images revealed cerebrospinal fluid (CSF) flow through the floor of the third ventricle between the tuber cinereum and the mammillary bodies connecting the ventricular system with the prepontine cistern. Although rare, clinicians should be cognizant of this phenomenon as it may eliminate the need for CSF diversion.

Endoscopic observation of pathophysiology of ventricular diverticulum

BACKGROUND

Although there have been reports dealing with ventricular diverticulum (VD) analyzed by cisternography and computed tomography (CT), those focusing on magnetic resonance imaging (MRI) or neuroendoscopic findings are rare.

CASE REPORT

We present a case of noncommunicating hydrocephalus caused by aqueductal stenosis with cystic lesion located in supracerebellar region. Third ventriculostomy was performed on this case. The conventional CT and MRI were compatible with usual VD, but neuroendoscopic examination suggested otherwise. The endoscopic view inside of the cystic lesion demonstrated passing veins and no membrane. We diagnosed this cystic lesion as a unique subtype of advanced VD mimicking spontaneous ventriculostomy. Endoscopic observation of the cyst was very useful for accurate diagnosis and safe treatment.

Endoscopic third ventriculostomy in adult patients

Endoscopic third ventriculostomy (ETV) has gained popularity and has become the treatment of choice for certain pediatric and adult hydrocephalic conditions. The authors report their experience with 36 adult patients and evaluate the long-term outcome and safety of ETV. They discuss several improvements to the surgical techniques that they have developed based on their experience, including the use of intraoperative Doppler imaging before fenestration to trace the location of vessels underlying the floor of the third ventricle. They also report the use of a Rickham reservoir and endoventricular stent in selected cases and discuss the indications for their use. In cases of obstructive hydrocephalus due to congenital or acquired aqueductal stenosis in adults, the success rate of ETV in avoidance of shunt placement is 72%. Twenty-two percent of the patients in this series in whom ETV was initially successful later experienced closure of the fenestration and recurrent symptoms at a mean interval of 3.75 years. Thus, in patients who undergo this treatment, long-term periodic follow-up review should be performed.

Endoscopic third ventriculostomy for obstructive hydrocephalus

The indications for neuroendoscopy are not only constantly increasing, but even the currently accepted indications are constantly being adjusted and tailored. This is also true for one of the most frequently used neuroendoscopic procedures, the endoscopic 3rd ventriculostomy (ETV) for obstructive hydrocephalus. ETV has gained popularity and widespread acceptance during the past few years, but little attention has been paid to the techniques of the procedure. After a short introduction describing the history of ETV, an overview is given of all the different techniques that have been and still are employed to open the floor of the 3rd ventricle. The spectrum of indications for ETV has been widely enlarged over the last years. Initially, the use of this procedure was restricted to patients older than 2 years, to patients with an obvious triventricular hydrocephalus, and to those with a bulging, translucent floor of the 3rd ventricle. Nowadays, indications include all kinds of obstructive hydrocephalus but also communicating forms of hydrocephalus. The results of endoscopic procedures in treating these pathologies are given under special consideration of shunt technologies. In summary, from the review of the publications since the first ETV performed by Mixter in 1923, this technique is the treatment of choice for obstructive hydrocephalus caused by different etiologies and is an alternative to cerebrospinal fluid shunt application.

Reversible transinsular herniation of the lateral ventricle

We present a 7-year-old boy, with a history of neonatal intraventricular hemorrhage, leading to hydrocephalus with multiple shunt revisions. The current presentation of shunt failure and resultant hydrocephalus was complicated by herniation of the trigone of the lateral ventricle into the posterior fossa. Despite the dramatic radiological appearance, this herniation of the lateral ventricle was not accompanied by any additional clinical signs or symptoms other than those usually attributed to hydrocephalus. Following successful shunt revision, the patient returned to his baseline clinically with the trigone reverting back to its normal position. We also present a second companion case.