Obstruction of Magendie's and Luschka's foramina. Cine-MRI, aetiology and pathogenesis

The endoscopic treatment of fourth ventricle outlet obstruction: Report of two children and systematic review

Fourth ventricle outlet obstruction (FVOO) is a rare cause of hydrocephalus. In the last century, the standard treatment was the suboccipital craniotomy with magendieplasty or ventriculoperitoneal shunt (VP shunt). Since the beginning of the 21st century, the endoscopic third ventriculostomy (ETV) has been considered a less invasive alternative. The medical literature lacks sufficient reports of FVOO cases and strong evidence about ETV's efficacy in treating this condition. We report two cases of FVOO treated with ETV and review published similar cases. Clinical and radiological findings of two FVOO cases with outcomes after ETV were presented. Moreover, we conducted a systematic review after protocol registration in PROSPERO (CRD42021281474). MEDLINE, Embase, Scopus, and Web of Science were searched from inception till December 31, 2022. Studies were included if they reported cases of FVOO treated initially with ETV. Cases with Chiari malformation, Dandy-Walker malformation, tuberous sclerosis, trapped fourth ventricle, or space-occupying lesions were excluded. Two reviewers independently examined title/abstract records in the first stage and full-text publications in the second for eligibility. The primary outcome was the recurrence rate, defined by the need for re-ETV or other invasive treatments (e.g., VP shunt or magendieplasty). Other outcomes included clinical state at follow-up and mortality. Two cases, a 3-year-old male and 3.5-year-old female, with FVOO, were treated with ETV in our department by the same neurosurgeon (SH) in 2013 and 2021. Both cases improved significantly after ETV, and there was no recurrence through the follow-up. Besides the present cases, we found 57 other cases of FVOO treated with ETV reported in 17 studies between 2001 and 2021. The median age was 26 years, with an IQR from 2.4 to 59 years, and 56% of cases were females. The recurrence rate was 32% in the sample (19 out of 59), with a 95% CI from 21% to 46%. The median time to recure was 2 months with IQR from 1.25 to 26. A VP shunt was the treatment for recurrence in 68% and a re-ETV in 32%. At the follow-up (41 ± 29 months), only one case died, and one deteriorated clinically. FVOO is a rare cause of hydrocephalus encountered mainly in the first or sixth decades of life. ETV provides the first reasonable treatment. Despite the moderate recurrence rate, the outcomes are favorable.

Tetraventricular hydrocephalus with aqueductal flow void: an overlooked entity having consistent improvement following endoscopic third ventriculostomy

BACKGROUND

Tetraventricular Hydrocephalus (TetHCP) is a heterogeneous group of cerebrospinal fluid (CSF) flow disorders having varying success rates with Endoscopic third ventriculostomy (ETV). This is report on the efficacy and rationale of ETV in a specific subset of primary TetHCP with aqueductal CSF flow voids.

METHODS

Patients of primary acquired TetHCP presenting with increasing head size and/or headache having aqueductal CSF flow void on sagittal Magnetic Resonance Imaging (MRI) were included in this study. All of them underwent ETV. All patients were evaluated for clinical improvement & MRI at 3 months, and need for any additional procedure, in contrast to those without CSF flow void. The pathophysiology of hyperdynamic CSF circulation and its correlation to ETV was further reviewed.

RESULTS

Eleven patients had tetraventricular hydrocephalus and aqueductal flow void, with age ranging from 10 months to 59 years. Two patients who could undergo quantitative flow study confirmed the hyperdynamic flow across the aqueduct. Following ETV, all showed clinical improvement. MRI at 3 months showed CSF flow void across the third ventricular stoma in addition to across the aqueduct. None of these patients required any redo procedures for a mean follow-up of 39.2 months. In contrast, there was 30% failure rate after ETV among 10 patients of tetraventricular hydrocephalus without aqueductal flow void.

CONCLUSION

Tetraventricular hydrocephalus with aqueductal CSF flow void may be a unique entity with hyperdynamic CSF circulation and relative resistance at fourth ventricular outlets. ETV is highly efficacious in these patients, resulting in consistent clinico-radiological improvement.

Tetraventricular noncommunicating hydrocephalus: Case report and literature review

BACKGROUND

Tetraventricular hydrocephalus is a common presentation of communicating hydrocephalus. Conversely, cases with noncommunicating etiology impose a diagnostic challenge and are often neglected and underdiagnosed. Herein, we present a review of literature for clinical, diagnostic, and surgical aspects regarding noncommunicating tetrahydrocephalus caused by primary fourth ventricle outlet obstruction (FVOO), illustrating with a case from our service.

METHODS

We performed a research on PubMed database crossing the terms "FVOO," "tetraventriculomegaly," and "hydrocephalus" in English. Fifteen articles (a total of 34 cases of primary FVOO) matched our criteria and were, therefore, included in this study besides our own case.

RESULTS

Most cases presented in adulthood (47%), equally divided between male and female. Clinical presentation was unspecific, commonly including headache, nausea, and dizziness as symptoms (35.29%, 21.57%, and 9.80%, respectively), with ataxic gait (65%) and papilledema (40%) being the most frequent signs. MRI and CT were the imaging modalities of choice (11 patients each), often associated with CSF flow studies, such as cine MRI and CT ventriculogram. Endoscopic third ventriculostomy (ETV) was both the most popular and effective surgical approach (50.85% of cases, with 18.91% of recurrence) followed by ventricle-peritoneal shunt (16.95% of patients, 23.0% of recurrence).

CONCLUSION

FVOO stands for a poorly understood etiology of noncommunicating tetrahydrocephalus. With the use of ETV, these cases, once hopeless, had its morbimortality and recurrence reduced greatly. Therefore, its suspicion and differentiation from other forms of tetrahydrocephalus can improve its natural course, reinforcing the importance of its acknowledgment.

Endoscopic Third Ventriculostomy in the Fourth Ventricle Outlet Obstruction Associated with Chiari Malformation Type I and Syringomyelia: Case Report

Hydrocephalus by the fourth ventricle outlet obstruction (FVOO) associated with a Chiari malformation type I and syringomyelia is a well-known entity but a rare situation in clinical practice. Although suboccipital craniectomy with the opening of the obstruction membrane appears to be the most physiological approach, by restoring the original pathway of cerebrospinal fluid flow, the endoscopic third ventriculostomy (ETV) represents an important minimally invasive alternative. We report the case of an adult patient with tetra ventricular hydrocephalus by FVOO associated with Chiari malformation and syringomyelia. The ETV alone completely resolved all symptoms, as well as neuroimaging abnormalities on the control magnetic resonance imaging. The ETV is a minimally invasive option for the treatment of hydrocephalus in patients with obstruction at the exit of the fourth ventricle, even in cases associated with Chiari malformation and syringomyelia.

Hydrocephalus Caused by Primary Fourth Ventricle Outlet Obstruction: Our Experience and Literature Review

OBJECTIVE

Primary fourth ventricle outlet obstruction (PFVOO) is a rare cause of hydrocephalus with an unclear etiopathogenesis, and thus, consensus regarding the recommended treatment protocol is lacking. This study aims to summarize current knowledge of this condition in the light of our own treatment experience.

METHODS

Retrospective analysis was carried out of all patients treated for noncommunicating tetraventricular hydrocephalus between 2006 and 2019, from which a subgroup of patients with PFVOO was created. A literature review of PFVOO cases was also carried out.

RESULTS

A total of 62 patients with PFVOO were discovered, of whom 8 were treated at our institution, representing 3.8% of our patients with noncommunicating hydrocephalus. Patients most commonly presented with headaches, gait disturbance, or symptoms of intracranial hypertension. The mean follow-up duration was 75.4 months among our patients and 29.9 months in the literature. Most patients (54.8%) were treated by endoscopic third ventriculostomy (ETV), with the remainder undergoing suboccipital craniotomy alone (17.7%) or in combination with shunt surgery (9.7%), or endoscopic magendieplasty (12.9%). Treatment failure was noted in 28.6% of ETVs and 9% of craniotomies. No failures were recorded after endoscopic magendieplasty. The risk of treatment failure was found to be significantly higher with ETV compared with other treatment modalities (P < 0.0005).

CONCLUSIONS

Despite the fact that PFVOO can be defined as an obstructive hydrocephalus, there seems to be a higher risk of ETV failure in such cases. The alternative treatment modalities presented are still recommended. Confirmation of these findings requires a larger multicenter study.

Fourth Ventricular Outflow Obstruction in an Infant with Ileal Atresia and Laryngomalacia: Endoscopic Management

Fourth ventricle outflow obstruction (FVOO) is a rare cause of obstructive hydrocephalus. In this study, we described a case of idiopathic FVOO with ileal atresia and laryngomalacia which was managed with endoscopic third ventriculostomy (ETV) and re-endoscopy. We also described the techniques of fenestration of Liliequist membrane and partial removal of arachnoid membrane over dorsum sella (DS) to prevent closure of fenestration and recurrence of hydrocephalus. The patient was a 4-month-old infant presented with progressively increasing head size, feeding difficulty, respiratory distress, and tense fontanel. The infant had a history of laparotomy for ileal atresia. CT scan showed panventriculomegaly due to FVOO. ETV with fenestration of Liliequist membrane was done on emergency basis. After operation, the patient improved clinically and radiologically. Four weeks later, the patient returned with recurrent hydrocephalus. Endoscopic reoperation showed closure of fenestration in arachnoid membrane (Lilieqiest membrane). Endoscopic refenestration with partial excision of arachnoid on DS was done. The patient again recovered radiologically and clinically till last follow-up. In idiopathic FVOO, ETV with wide fenestration of Liliequist membrane, preferably with partial removal of arachnoid on DS, may be very useful in treating hydrocephalus (HCP) and preventing recurrent HCP even in infants.

Morphology of the Vascular Bodies of the Encephalon’s Ventricles of Cow (Bos Taurus Taurus)

The aim of the research was to establish the morphology of the vascular bodies of the encephalon ventricles of cow (Bos taurus taurus). Methods used: thin anatomical preparation, histological method of examination, transmission electron microscopy. Given the relationship, structure and general origin of the vascular bodies, they were divided into bodies III, IV and the lateral ventricles of the encephalon. This unit has topographical nature. Functionally, vascular bodies are an indivisible organ whose main function is the secretion of the cerebrospinal fluid, which maintains the constancy of the central nervous system internal environment. Three types of capillaries, differing in their morphology, were found in the composition of the vascular bodies’ villi in Bos taurus taurus.

Primary Obstruction of the Foramen of Luschka: Anatomy, Histology, and Clinical Significance

BACKGROUND

The foramen of Luschka is a natural aperture between the fourth ventricle and the subarachnoid space at the cerebellopontine angle. Membranous closure of this foramen is referred to as primary obstruction. Available information about this variant and its role in the development of the cysts of the posterior fossa is contradictory.

METHODS

The macroscopic and histologic features of the obstructed foramina were examined in 61 formalin-fixed human brains (122 foramina). Three rhomboid lips of various sizes with lateral recess were used for comparison. Five postoperative cases of diverticulum of the foramen of Luschka were included in this study, with 1 case presented in detail to illustrate anatomic and histologic findings.

RESULTS

Primary obstruction was present in 11 of 122 cases. In 1 case, an enlarged rigid pouch with a thick wall was found. The wall of the membrane in primary obstruction and the rhomboid lip were composed of an inner ependymal, a middle glial, and an outer leptomeningeal layer.

CONCLUSIONS

The rhomboid lip is a remnant of the roof of the fourth ventricle. Imperforation of the foramen of Luschka results in a pouch in the cerebellopontine angle that contains choroid plexus (Bochdalek's flower basket) and communicates with the fourth ventricle. This pouch has the potential to grow to a diverticulum and cause clinical symptoms. Based on our clinical observations, detailed radiologic and surgical-anatomic criteria were proposed to support the differential diagnosis of a diverticulum of the foramen of Luschka. Treatment strategies were also suggested.

Hydrocephalus secondary to obstruction of the lateral apertures in two dogs

BACKGROUND

Traditionally, hydrocephalus is divided into communicating or non-communicating (obstructive) based on the identification of a blockage of cerebrospinal fluid (CSF) flow through the ventricular system. Hydrocephalus ex vacuo refers to ventricular enlargement as a consequence of neuroparenchymal loss. Hydrocephalus related to obstruction of the lateral apertures of the fourth ventricles has rarely been described.

CASE REPORT

The clinicopathologic findings in two dogs with hydrocephalus secondary to obstruction of the lateral apertures of the fourth ventricle are reported. Signs were associated with a caudal cervical spinal cord lesion in one dog and a caudal brain stem lesion in the other dog. Magnetic resonance imaging (MRI) disclosed dilation of the ventricular system, including the lateral recesses of the fourth ventricle. In one dog, postmortem ventriculography confirmed obstruction of the lateral apertures. Microscopic changes were identified in the choroid plexus in both dogs, yet a definitive cause of the obstructions was not identified. The MRI findings in both dogs are similar to membranous occlusion of the lateral and median apertures in human patients.

CONCLUSION

MRI detection of dilation of the entire ventricular system in the absence of an identifiable cause should prompt consideration of an obstruction of the lateral apertures. In future cases, therapeutic interventions aimed at re-establishing CSF flow or ventriculoperitoneal catheterisation should be considered.

Idiopathic fourth ventricle outlet obstruction successfully treated by endoscopic third ventriculostomy: a case report

Introduction

Fourth ventricle outlet obstruction (FVOO) is a rare cause of obstructive hydrocephalus. We describe a case of idiopathic FVOO that was successfully treated with endoscopic third ventriculostomy (ETV).

Case report

A 3-year old boy without any remarkable medical history presented with a headache and vomiting. Computed tomography (CT) images, which had incidentally been taken 2 years previously due to a minor head injury, showed no abnormality. Magnetic resonance imaging on admission showed tetra-ventricular hydrocephalus associated with the dilatation of the fourth ventricle outlets, without any obstructive lesions. However, CT ventriculography, involving contrast medium injection through a ventricular catheter, suggested mechanical obstruction of the cerebrospinal fluid (CSF) at the fourth ventricle outlets. Thus, the patient was diagnosed with FVOO and ETV was performed; the hydrocephalus was subsequently resolved. Although hydrocephalus recurred 1 year postoperatively, re-ETV for the highly stenosed fenestration successfully resolved this condition.

Conclusions

ETV should be considered for FVOO treatment, particularly in idiopathic cases without CSF malabsorption.

Fourth Ventriculostomy in Occlusion of the Foramen of Magendie Associated with Chiari Malformation and Syringomyelia

We present four cases of hydrocephalus caused by occlusion of foramen of Magendie associated with Chiari Type I malformation and syringomyelia. The aim of this study is to evaluate the results of surgical treatment via fourth ventriculostomy with catheter from the fourth ventricle to the upper cervical subarachnoid space. Obstructive tetraventricular hydrocephalus due to occlusion of the foramina of Luschka and Magendie can be treated with cerebrospinal fluid shunting, opening the membranes with suboccipital craniotomy, placement of a catheter, endoscopic third ventriculostomy, and endoscopic fourth ventriculostomy. Our aim was to solve all the pathologies such as Chiari malformation, hydrocephalus, and syringomyelia in one approach. Thus, the treatment consisted of posterior fossa decompression and exploration. All the patients were treated with suboccipital craniectomy and C1 laminectomy with excision of the membrane obstructing the foramen of Magendie. Fourth ventriculostomy with cathetering from fourth ventricle to upper cervical subarachnoid space was performed. The postoperative period was uneventful in all the patients. Neurological status of all the patients improved. Tetraventricular hydrocephalus and syrinx were reduced in the control cranial magnetic resonance imaging. Complications such as infection and catheter migration were not observed during the follow-up period. Treatment with fourth ventriculostomy using a catheter from fourth ventricle to upper cervical subarachnoid space could be a treatment of choice in cases with hydrocephalus caused by occlusion of the foramina of Magendie, with associated Chiari Type I malformation and syringomyelia.

Rapid deterioration of primary fourth ventricular outlet obstruction resulting in syndrome of inappropriate antidiuretic hormone secretion

Fourth ventricular outlet obstruction (FVOO) is a rare cause of obstructive hydrocephalus. Although FVOO accompanied by malformative syndrome and secondary causes of obstruction are common, there are few reports of primary FVOO (PFVOO). The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare presenting feature of hydrocephalus. A 1-year, 8-month-old boy with a normal head circumference developed SIADH accompanied by rapid deterioration of symptoms of intracranial hypertension. PFVOO was diagnosed because magnetic resonance imaging revealed an enlarged ventricular system with a barely visible membranous obstacle at the foramen of Magendie. All symptoms were resolved by endoscopic third ventriculostomy. PFVOO should be considered as a rare form of congenital obstructive hydrocephalus, especially in patients with tetraventricular hydrocephalus. To the best of our knowledge, this is the first case of an infant with SIADH, resulting from acute deterioration of non-tumoral raised pressure hydrocephalus.

Endoscopic Transventricular Transaqueductal Magendie and Luschka Foraminoplasty for Hydrocephalus

BACKGROUND:

Routinely, hydrocephalus related to fourth ventricular outlet obstruction (FVOO) has been managed with ventriculoperitoneal (VP) shunting or endoscopic third ventriculostomy (ETV). Few reports on Magendie foraminoplasty exist, and Luschka foraminoplasty has not been described.

OBJECTIVE:

To present an alternative technique in the management of FVOO via an endoscopic transventricular transaqueductal Magendie and Luschka foraminoplasty and to discuss the indications, technique, findings, and outcomes.

METHODS:

Between 1994 and 2011, all patients who underwent endoscopic Magendie and Luschka foraminoplasty were analyzed.

RESULTS:

A total of 33 Magendie (28) and/or Luschka (5) foraminoplasties were performed in 30 patients. Twenty-three were adult and 7 were pediatric patients. The etiology of the FVOO was divided into primary etiologies (congenital membrane in 5 and atresia in 2) and secondary causes (neurocysticercosis in 14 patients, bacterial meningitis in 9). Fifteen (50%) had previously failed procedures. Intraoperative findings that led to Magendie/Luschka foraminoplasty were ETV not feasible to perform, nonpatent basal subarachnoid space, or primary FVOO. Minor postoperative complications were seen in 3 patients. Only 26 patients had long-term follow-up; 17 (65.3%) of these had clinical improvement and did not require further procedures. Nine (34.7%) did not improve. Eight required another procedure (7 shunts, and 1 endoscopic procedure). One patient died.

CONCLUSION:

Flexible neuroendoscopic transventricular transforaminal Magendie and Luschka foraminoplasty is feasible and safe. These procedures may prove to be viable alternatives to standard ETV and VP shunt in appropriate patients. Adequate intraoperative assessment of ETV success is necessary to identify patients who will benefit.

Fourth ventriculostomy: an alternative treatment for hydrocephalus due to atresia of the Magendie and Luschka foramina

Atresia of the foramina of Magendie and Luschka is a rare cause of obstructive hydrocephalus. Although this condition has been classically treated by CSF shunting, recent treatments have also included endoscopic third ventriculostomy. In the present study, the authors present the case of a patient with hydrocephalus in whom an alternative method was used following a CSF shunt malfunction. A young female patient in whom a shunt was placed during the patient's 1st year of life was faring well until she was 8 years old. She was admitted to the emergency department 5 times with signs of CSF shunt malfunction. Each time, the CT scan showed a slight dilation of the lateral and third ventricles and a large increase in the size of the fourth ventricle. In comparison, ventricles were smaller in a previous imaging study obtained when the patient was asymptomatic. Magnetic resonance imaging showed the same slight dilation of all the ventricles and a significant increase in the fourth ventricle. There was no aqueductal stenosis. An important enlargement of both lateral recesses of the fourth ventricle suggested the possibility of an atresia of the foramina. The foramen of Monro and the width of the third ventricle would not allow the passage of an endoscope. The decision was made to open those foramina endoscopically through the fourth ventricle. After induction of general anesthesia, with the patient in the prone position, a bur hole was made in the left paramedian and suboccipital region. The endoscope was introduced underneath the cerebellar hemisphere. The authors were then able to distinguish the floor of the fourth ventricle and other anatomical landmarks. Navigation through the lateral recesses allowed them to see the fine membranes closing the foramina. These membranes were opened with a monopolar cautery as a blunt instrument. The orifice was then enlarged with a 3 Fr Fogarty catheter. The authors also opened a bulging thin membrane located at the foramen of Magendie. During the postoperative period, the authors observed a marked improvement in the state of the patient's alertness as well as a disappearance of her headaches and cessation of vomiting. In addition, the patient's gait ataxia improved slowly. Six-month postoperative MR imaging demonstrated an unequivocal reduction in the size of the fourth ventricle. The patient was still doing well 36 months after the surgery. Endoscopic fourth ventriculostomy, the opening of the 3 foramina of the fourth ventricle, may be an alternative treatment in cases in which these structures are congenitally closed.

PRIMARY OBSTRUCTION OF THE FOURTH VENTRICLE OUTLETS

OBJECTIVE

Primary obstruction of the foramina of Magendie and Luschka is an uncommon and still unclear cause of noncommunicating hydrocephalus. The aim of this work is the description, for the first time, of the inner aspect of these velar obstructions of the fourth ventricle outlets and the demonstration of the efficacy of neuroendoscopic treatment.

METHODS

Of 240 hydrocephalic patients treated in our institution with endoscopic third ventriculostomy, a subgroup of 10 cases with closure of the fourth ventricular outlets without associated Chiari malformation and syringomyelia was selected. In all of these cases, a transaqueductal endoscopic navigation of the fourth ventricle was performed, and the obstructed outlets were inspected. All of the clinical data and, in particular, the videotape records of endoscopic operations, as well as the cine-magnetic resonance imaging scans, were reviewed to evaluate their patency status.

RESULTS

Various degrees of stenosis were found endoscopically: restriction of the Magendie contour with thick and opaque membrane, transparent spider web-like membrane, and dense membrane with fissures acting as valves. Endoscopic third ventriculostomy was effective in almost all patients, although we noticed an unforeseen high incidence of closure of the stoma. The restored normal cerebrospinal fluid flux after ventriculocisternostomy and magendieplasty was demonstrated by comparative study of cerebrospinal fluid flow measurements by cine-magnetic resonance imaging.

CONCLUSION

This report demonstrates the effectiveness of neuroendoscopic third ventriculostomy as well as magendiestomy in cases of tetraventricular hydrocephalus attributable to primary obstruction of the outlets of the fourth ventricle and, for the first time, presents direct images of various types of outlet obstructive pathology.

Cine phase-contrast MR images failed to predict clinical outcome following ETV

BACKGROUND

To predict success of endoscopic third ventriculostomy (ETV) in patients with obstructive hydrocephalus, we evaluated pre- and post- operative phase-contrast cine magnetic resonance images (PC MRI) on cerebrospinal fluid (CSF), cine flow in basal cisterns around the brain stem, and cervical medullar junction (CMJ) retrospectively.

METHODS

The study involved 102 patients with mean age of 36.74+/-23.25, and F/M = 1.55. All patients had PC MRI taken both pre- and post-operatively. A dynamic MRI video of PC MRI was reviewed at sagittal, axial, and coronal sections to determine cistern flows around the brain stem and CMJ. For quantitative analysis, quadrants were divided around midbrain axially to evaluate interpeduncular, quadrageminal, and ambient cisterns of both sides using scores of 0 to 60. Pre- and post- pontine and CMJ flows were shown in sagittal view and scored 0 to 20, and lateral cerebellopontine cisterns of both sides were measured on coronal image and scored 0 to 20.

RESULTS

No significant difference in CSF flow was seen from three individual views and total cine score, or between ETV success and failure groups by multivariate analysis of variance. Kaplan-Meier Analysis and Spearman's Correlation Test produced no relationship between MRI cine flow scores and interval period after surgery to ETV failure.

CONCLUSION

PC MRI cine flow failed to demonstrate significant differences between successful and failed ETV groups. This indicates in addition to achieving an adequate fenestration, CSF pathways beyond the basal cisterns around the brain stem and CMJ may play an essential role in achieving ETV success.

Is all "communicating" hydrocephalus really communicating? Prospective study on the value of 3D-constructive interference in steady state sequence at 3T

BACKGROUND AND PURPOSE

3D-constructive interference in steady state (3D-CISS) sequence has been used to assess the CSF pathways. The aim of this study was to investigate the additive value of 3D-CISS compared with conventional sequences in the diagnosis of obstructive membranes in hydrocephalus.

MATERIALS AND METHODS

A total of 134 patients with hydrocephalus underwent MR imaging examination with a 3T unit consisting of turbo spin-echo, 3D-CISS, and cine phase-contrast (cine PC) sequences. 3D-CISS was used to assess obstructive membranes in CSF pathways compared with other sequences. Cine PC, follow-up imaging, and surgical findings were used to confirm obstructive membranes.

RESULTS

Comparing the number of noncommunicating cases by using the conventional and 3D-CISS images, we found 26 new cases (19.4%) of 134 cases that were previously misdiagnosed as communicating hydrocephalus by conventional images. 3D-CISS sequence identified obstructive membranes invisible in other sequences, which facilitated selection of neuroendoscopy in the treatment of 31 patients (23.1%) in total who would have been otherwise treated with shunt insertion. These patients included 26 newly diagnosed noncommunicating cases after demonstration of intraventricular and/or fourth ventricular outlet membranes and 5 cases of communicating hydrocephalus with obstructing cisternal membranes. There were obstructions of the foramina of Luschka in 22 of 26 newly found noncommunicating cases.

CONCLUSIONS

Conventional sequences are insensitive to obstructive membranes in CSF pathways, especially in the fourth ventricular exit foramina and the basal cisterns. 3D-CISS sequence, revealing these obstructive membranes, can alter patient treatment and prognosis.

Expression of the murine Pomt1 gene in both the developing brain and adult muscle tissues and its relationship with clinical aspects of Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is the most severe of a group of congenital disorders that have in common defects in the O-glycosylation of alpha-dystroglycan. WWS is characterized by congenital muscular dystrophy coupled with severe ocular and brain malformations. Moreover, in at least one-fifth of the reported cases, mutations in the POMT1 gene are responsible for this disease. During embryonic development (E8.5 to E11.5), the mouse Pomt1 gene is expressed in the tissues most severely affected in WWS, the muscle, eye, and brain. In this study, we show that mPomt1 expression is maintained in the muscle and eye in later developmental stages and, notably, that its expression is particularly strong in regions of brain and cerebellum that, when affected, could generate the defects observed in patients with WWS. We show that the Pomt1 protein is localized to the sarcoplasmic reticulum of muscle tissue cells in adult mice, where alpha-dystroglycan is O-glycosylated. Furthermore, the Pomt1 protein is localized to the acrosome of maturing spermatids, where alpha-dystroglycan is not glycosylated, so that Pomt1 might have a different target for O-mannosylation in the testes. This expression pattern in the testes could also be related to the gonadal anomalies observed in some patients with WWS.

Value of phase contrast magnetic resonance imaging for investigation of cerebral hydrodynamics

OBJECTIVE

Phase Contrast Magnetic Resonance Imaging (PCMRI) is a noninvasive technique that can be used to quantify variations of flow during the cardiac cycle. PCMRI allows investigations of blood flow dynamics in the main arteries and veins of the brain but also the dynamics of cerebrospinal fluid. These cerebral flow investigations provide a description of the regulation mechanisms of intracranial pressure during the cardiac cycle. The objective of this paper is to describe the contribution of this technique in diseases related to disorders of cerebral hydrodynamics in the light of 5 clinical cases.

METHOD

Flow measurements were performed using PCMRI sequences on a 1.5 Tesla MR imager in 4 patients with symptomatic ventricular dilation and 1 patient with a syringomyelic cavity.

RESULTS

Flow quantification in these 5 patients, representative of the diseases mainly concerned by cerebral hydrodynamics, is useful to guide the indication for ventricular shunting in patients with hydrocephalus, to demonstrate obstruction of the cerebral aqueduct, to demonstrate recirculation of ventricular CSF after ventriculostomy and to characterize the dynamic features of CSF inside a spinal cavity.

CONCLUSION

PCMRI, now available to neurosurgeons, is complementary to morphological MR and provides quantitative information on cerebral hydrodynamics. This information is mainly used to confirm alteration of CSF flow in the cerebral and spinal compartments. PCMRI is also a functional tool to better understand the pathophysiology of hydrocephalus and syringomyelia.

Hydrocephalus due to idiopathic stenosis of the foramina of Magendie and Luschka. Report of three cases

Idiopathic stenosis of the foramina of Magendie and Luschka is a rare cause of obstructive hydrocephalus involving the four ventricles. Like other causes of noncommunicating hydrocephalus, it can be treated with endoscopic third ventriculostomy (ETV). Three patients who were 21, 53, and 68 years of age presented with either headaches (isolated or associated with raised intracranial pressure) or vertigo, or a combination of gait disorders, sphincter disorders, and disorders of higher functions. In each case, magnetic resonance (MR) imaging demonstrated hydrocephalus involving the four ventricles (mean transverse diameter of third ventricle 14.15 mm; mean sagittal diameter of fourth ventricle 23.13 mm; and mean ventricular volume 123.92 ml) with no signs of a Chiari Type I malformation (normal posterior fossa dimensions, no herniation of cerebellar tonsils). The diagnosis of obstruction was confirmed using ventriculography (in two patients) and/or MR flow images (in two patients). All patients presented with marked dilation of the foramen of Luschka that herniated into the cisterna pontis. All patients were treated using ETV. No complications were observed. All three patients became asymptomatic during the weeks following the surgical procedure and remained stable at a mean follow-up interval of 36 months. Postoperative MR images demonstrated regression of the hydrocephalus (mean transverse diameter of third ventricle 7.01 mm; mean sagittal diameter of fourth ventricle 16.6 mm; and mean ventricular volume 79.95 ml), resolution of dilation of the foramen of Luschka, and good patency of the ventriculostomy (flow sequences). These results confirm the existence of hydrocephalus caused by idiopathic fourth ventricle outflow obstruction without an associated Chiari Type I malformation, and the efficacy of ETV for this rare indication.