Successful neuroendoscopic third ventriculostomy for hydrocephalus and syringomyelia associated with fourth ventricle outlet obstruction. Case report

Posterior fossa decompression for children with Chiari I malformation and hydrocephalus

INTRODUCTION

Chiari I malformation (CMI) and hydrocephalus often coexist, with no clear understanding of the cause-and-effect relationship. In the absence of other associated etiologies, the traditional teaching has been to treat the hydrocephalus first, partly to minimize the risk of cerebrospinal fluid (CSF) leak from CMI decompression in the setting of elevated ICP. We describe a series of consecutive pediatric patients with CMI and hydrocephalus, the majority of whom were managed with posterior fossa decompression.

METHODS

A retrospective review was conducted on consecutive children who presented to the senior author with both hydrocephalus and CMI, with emphasis on rationale for and outcomes of surgical intervention, including the need for additional surgery.

RESULTS

There were 14 patients aged 2 weeks to 16 years (median 2 years) who presented with Chiari I and hydrocephalus. Four of these underwent posterior fossa decompression without duraplasty (PFD) as first-line therapy (one of whom eventually required duraplasty), 7 had PFD with duraplasty (PFDD), 1 received a ventriculoperitoneal shunt (VPS), and two had endoscopic third ventriculostomy (ETV). Of the 11 who had PFD/D, 9 (90%) had significant symptom improvement/resolution, 7 (55%) showed decrease in ventricle size, and 1 (10%) required VPS placement for persistent hydrocephalus. Both ETV patients improved clinically, and 1 showed decrease in ventricle size. There were no pseudomeningoceles, infections, or neurological deficits. One CSF leak occurred after an ETV and was successfully treated with wound revision.

CONCLUSION

In patients with both CMI and hydrocephalus, treating the CMI first in an effort to avoid a shunt can be safe and effective. In this series, PFDD in the setting of hydrocephalus did not result in CSF leak or pseudomeningocele. While limited by a small sample size, these data support a causative relationship between CMI and hydrocephalus.

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.

Idiopathic fourth ventricular outlet obstruction misdiagnosed as normal pressure hydrocephalus: A cautionary case

Background:

Fourth ventricular outlet obstruction is an infrequent but well-established cause of tetraventricular hydrocephalus characterized by marked dilatation of the ventricular system with ballooning of the foramina of Monro, Magendie, and Luschka. Multiple processes including inflammation, infection, hemorrhage, neoplasms, or congenital malformations are known to cause this pathological obstruction. However, true idiopathic fourth ventricular outlet obstruction is a rare phenomenon with only a limited number of cases reported in the literature.

Case Description:

A 61-year-old female presented with several months of unsteady gait, intermittent headaches, confusion, and episodes of urinary incontinence. Conventional magnetic resonance imaging demonstrated tetraventricular hydrocephalus without transependymal flow, but with ventral displacement of the brainstem and dorsal displacement of the cerebellum without an obvious obstructive lesion on pre- or post-contrast imaging prompting a diagnosis of normal pressure hydrocephalus. However, constructive interference in steady state (CISS) and half-Fourier acquisition single-shot turbo spin echo (HASTE) sequences followed by fluoroscopic dynamic cisternography suggested encystment of the fourth ventricle with thin margins of arachnoid membrane extending through the foramina of Luschka bilaterally into the pontocerebellar cistern. Operative intervention was pursued with resection of an identified arachnoid web. Postoperative imaging demonstrated marked reduction in the size of ventricular system, especially of the fourth ventricle. The patient’s symptomatology resolved a few days after the procedure.

Conclusion:

Here, we describe an idiopathic case initially misdiagnosed as normal pressure hydrocephalus. The present case emphasizes the necessity of CISS sequences and fluoroscopic dynamic cisternography for suspected cases of fourth ventricular outlet obstruction as these diagnostic tests may guide surgical management and lead to superior patient outcomes.

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.

Chiari type I and hydrocephalus

PURPOSE

The association between Chiari type I malformation (CIM) and hydrocephalus raises a great interest because of the still unclear pathogenesis and the management implications. The goal of this paper is to review the theories on the cause-effect mechanisms of such a relationship and to analyze the results of the management of this condition.

METHODS

A review of the literature has been performed, focusing on the articles specifically addressing the problem of CIM and hydrocephalus and on the series reporting about its treatment. Also, the personal authors' experience is briefly discussed.

RESULTS

As far as the pathogenesis is concerned, it seems clear that raised intracranial pressure due to hydrocephalus can cause a transient and reversible tonsillar caudal ectopia ("pressure from above" hypothesis), which is something different from CIM. A "complex" hypothesis, on the other hand, can explain the occurrence of hydrocephalus and CIM because of the venous engorgement resulting from the hypoplasia of the posterior cranial fossa (PCF) and the occlusion of the jugular foramina, leading to cerebellar edema (CIM) and CSF hypo-resorption (hydrocephalus). Nevertheless, such a mechanism can be advocated only in a minority of cases (syndromic craniosynostosis). In non-syndromic CIM subjects, the presence of hydrocephalus could be explained by an occlusion of the basal CSF pathways, which would occur completely in a minority of cases (only 7-10% of CIM patients show hydrocephalus) while it would be partial in the remaining cases (no hydrocephalus). This hypothesis still needs to be demonstrated. As far as the management is concerned, the strategy to treat the hydrocephalus first is commonly accepted. Because of the "obstructive" origin of CIM-related hydrocephalus, the use of endoscopic third ventriculostomy (ETV) is straightforward. Actually, the analysis of the literature, concerning 63 cases reported so far, reveals very high success rates of ETV in treating hydrocephalus (90.5%), CIM (78.5%), and syringomyelia symptoms (76%) as well as in giving a radiological improvement of both CIM (74%) and syringomyelia (89%). The failures of ETV were not attributable to CIM or syringomyelia. Only 11% of cases required PCF decompression after ETV.

CONCLUSIONS

The association between CIM and hydrocephalus probably results from different, multifactorial, and not yet completely understood mechanisms, which place the affected patients in a peculiar subgroup among those constituting the heterogeneous CIM population. ETV is confirmed as the best first approach for this subset of patients.

Application of endoscopic third ventriculostomy for treating hydrocephalus-correlated Chiari type I malformation in a single Chinese neurosurgery centre

The correlation between hydrocephalus and Chiari type I malformation (CIM) has been debated since Chiari's first descriptions of CIM but some studies have shown that CIM and hydrocephalus (HCP) could cause symptoms/disease of each other or vice versa. Recent research has found that treatment focused on hydrocephalus with ventricle enlargement also provides alleviation of CIM and even of syringomyelia. However, the lack of consensus among previous studies left unanswered the question of how endoscopic third ventriculostomy (ETV) addresses CIM and why it fails. Ten symptomatic hydrocephalic patients associated with CIM underwent ETV from October 2002 to May 2012. The clinical features and neuroimaging of all patients were reviewed. Statistical analysis was applied to evaluate the changes in the tonsillar ectopia and the ventricle dilation after operation. The mean follow-up period of this series was 92 months (range 24-163 months). Eight patients (80%) remained shunt free or experienced symptom relief following ETV. The remaining two patients were identified as failures due to the deterioration of symptoms or subsequent hindbrain decompression. Endoscopic third ventriculostomy provides an effective treatment for hydrocephalus associated with CIM, which can relieve HCP and improve the symptoms of CIM in most patients. The clinical outcomes are related to the major cause of the tonsillar herniation.

Fourth Ventricle Outlet Obstruction with Expanding Space on the Surface of Cerebellum

BACKGROUND

Hydrocephalus is classified as noncommunicating and communicating based on whether all ventricular and subarachnoid spaces are communicating. Although the diagnosis between the two different states is crucial, it is difficult in certain conditions. In particular, communicating hydrocephalus and noncommunicating hydrocephalus owing to fourth ventricle outlet obstruction are highly misdiagnosed. We describe a case of fourth ventricle outlet obstruction of unknown origin that was initially misdiagnosed as communicating hydrocephalus.

CASE DESCRIPTION

A 66-year-old woman with gait disturbance and incontinence caused by hydrocephalus underwent ventriculoperitoneal shunt surgery. After 9 months, her fourth ventricle became enlarged and could not be controlled by lowering the shunt pressure. Magnetic resonance imaging (MRI) demonstrated obstruction at the foramen of Magendie, foramina of Luschka, and the cerebral aqueduct. Endoscopic surgery for aqueduct plasty with third ventriculostomy was planned. Because the aqueduct was observed to open spontaneously, only the standard third ventriculostomy was performed. When MRI findings were reviewed retrospectively, an unnatural space was observed between the lower cranial nerves and cerebellar hemisphere that grew along with the fourth ventricular enlargement. This space was determined by MRI cisternography to be the cystic membrane ballooning out from the foramen of Luschka. The primary hydrocephalus likely resulted from fourth ventricle outlet obstruction.

CONCLUSIONS

Enlargement of the whole ventricular system with an expanded space between the lower cranial nerves and cerebellar hemisphere can be caused by fourth ventricle outlet obstruction. In such cases, preoperative evaluation of anatomic architecture and cerebrospinal fluid obstruction using MRI cisternography is essential and leads to a successful endoscopic strategy.

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.

Endoscopic third ventriculostomy in the management of hydrocephalus: Outcome analysis of 168 consecutive procedures

BACKGROUND

Endoscopic third ventriculostomy (ETV) is the treatment of choice for obstructive hydrocephalus, but the outcome is still controversial in terms of age and aetiology.

METHODS

Between 1998 and 2011, 168 consecutive procedures were performed in 164 patients, primarily children (56%<18 years of age and 35%<2 years of age). The causes of obstructive hydrocephalus included tumoural pathology, Chiari malformation, congenital obstruction of the aqueduct, post-infectious and post-haemorrhagic membranes, and ventriculo-peritoneal shunt (VPS) malfunctions. Successful ETV was defined by the resolution of symptoms and the avoidance of a shunt.

RESULTS

ETV was successful in 75.6% of patients, but 19% of the patients required VPS in the first month after ETV, and 5.4% required a VPS more than one month after ETV. Four patients were ultimately submitted for second ETVs. In this series, no major permanent morbidity or mortality was observed.

CONCLUSIONS

ETV is a safe procedure and an effective treatment for obstructive hydrocephalus even following the dysfunction of previous VPSs and in children younger than two years.

Current state and future development of intracranial neuroendoscopic surgery

Since the introduction of the modern, smaller endoscopes in the 1960s, neuroendoscopy has become an expanding field of neurosurgery. Neuroendoscopy reflects the tendency of modern neurosurgery to aim towards minimalism; that is, access and visualization through the narrowest practical corridor and maximum effective action at the target point with minimal disruption of normal tissue. Transventricular neuroendoscopy allows the treatment of several pathologies inside the ventricular system, such as obstructive hydrocephalus and intra-/paraventricular tumors or cysts, often avoiding the implantation of extracranial shunts or more invasive craniotomic approaches. Endoscopic endonasal transphenoidal surgery allows the treatment of pathologies of the sellar and parasellar region, with the advantage of a wider vision of the surgical field, less traumatism of the nasal structures, greater facility in the treatment of possible recurrences and reduced complications. However, an endoscope may be used to assist microsurgery in virtually any kind of neurosurgical procedures (endoscope-assisted microsurgery), particularly in aneurysm and tumor surgery. Basic principles of optical imaging and the physics of optic fibers are discussed, focusing on the neuroendoscope. The three main chapters of neuroendoscopy (transventricular, endonasal transphenoidal and endoscope-assisted microsurgery) are reviewed, concerning operative instruments, surgical procedures, main indications and results.

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.

Endoscopic management of complex hydrocephalus

BACKGROUND

The management of complex hydrocephalus is challenging. There is no consensus of the best treatment for isolated fourth ventricles, arachnoid cysts, and multiloculated hydrocephalus, although the avoidance of multiple shunts is desirable. We reviewed our experience with the use of endoscopic techniques to simplify complex multicompartmental hydrocephalus to determine its efficacy and safety.

METHODS

We performed a retrospective study of 114 consecutive adults and children undergoing endoscopic management of hydrocephalus by a single surgeon. The type of hydrocephalus and endoscopic procedure performed were recorded. The management algorithm for simplification of complex hydrocephalus is reviewed. All patients were followed up in the office or by telephone.

RESULTS

A total of 143 endoscopic procedures were performed on 114 patients with a mean age of 4.4 years (4 weeks to 32 years). The endoscopic procedures performed included cyst fenestration, septum pellucidotomy, endoscopic third ventriculostomy, aqueductal plasty with and without stent, and removal of cystercicotic cysts. Twenty-two (19.3%) patients had planned staged endoscopic procedures. Mean follow up was 65 months (range 33-122 months). Eighty-two (72%) patients were reduced to 1 shunt, shunt independence was achieved in 32 (28%) patients, and only 8 (11%) patients required shunt revision in the follow-up period.

CONCLUSIONS

Endoscopic simplification of complex hydrocephalus enables dependence on only a single shunt in the majority of patients, and a significant proportion achieve shunt independence. Endoscopic management should be considered before the placement of a second shunt, and some cases require staged endoscopic procedures to adequately communicate multicompartmental hydrocephalus.

Hydrocephalus and Chiari type I malformation

INTRODUCTION

[corrected] Hydrocephalus has been related to Chiari type I malformation (CIM) for a long time. The pathogenesis of this association is complex and still debated.

DISCUSSION

A supratentorial hypertensive hydrocephalus may cause CIM, exerting pressure from above. Another pathogenetic hypothesis is based on the clinical and radiological data from patients affected by complex craniosynostosis, in which this association is more commonly observed as the consequence of a "cephalo-cranial disproportion" ultimately leading to a secondary hydrocephalus. In some cases, the concomitant presence of a stenosis of the jugular foramina would determine a condition of upward venous hypertension, resulting in the development of CIM and an associated hydrocephalus due to cerebellar parenchyma turgor.

CONCLUSIONS

The radiological association of ventricular enlargement and hindbrain herniation would be the result of heterogeneous pathogenetic mechanisms which would then require specific therapeutic approaches. In this context, the endoscopic third ventricle-cisternostomy is gaining an increasing interest because of its more physiologic correction of the altered CSF dynamics and its minor interference on the developmental processes responsible for the association of hydrocephalus and CIM.

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.

Endoscopic third ventriculostomy

Among patients with idopathic aqueductal stenosis or impedance of cerebrospinal fluid (CSF) flow in the posterior fossa due to tumour, endoscopic fenestration of the floor of the third ventricle creates an alternative route for CSF flow to the subarachnoid space via the prepeduncular cistern. By reestablishing CSF flow, this procedure dissipates any pressure gradient on midline structures. This may obviate the need for traditional CSF shunt diversion techniques in such settings. Currently, endoscopic third ventriculostomy is indicated in approximately 25% of patients with hydrocephalus and can be performed instead of shunt placement. Appropriate patients are those with aqueductal stenosis (10%), obstructive tumours (10%), and obstructive cysts (5%). Additional recent data suggest the favorability of third ventriculostomy over shunt implantation in additional patient cohorts. Operative technique is discussed.

Endoscopic third ventriculostomy in the management of Chiari I malformation and syringomyelia associated with hydrocephalus

BACKGROUND

Chiari malformation with syringomyelia is conventionally managed with foramen magnum decompression and duroplasty. In presence of hydrocephalus, a ventriculoperitoneal shunt insertion has been the initial preferred mode of treatment.

METHODS

Two patients of Chiari I malformation with syringomyelia who had associated hydrocephalus were initially treated with endoscopic third ventriculostomy (ETV).

RESULTS

At follow up, both the patients symptomatically improved. Repeat MRI studies revealed collapse of the syrinx cavity and reduction of the Chiari malformation.

CONCLUSIONS

Chiari malformation and syrinx associated with hydrocephalus may be effectively managed with endoscopic third ventriculostomy.

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.

Endoscopic Third Ventriculostomy for Treatment of Noncommunicating Syringomyelia Associated with a Chiari I Malformation and Hydrocephalus: Case Report and Pathophysiological Considerations

OBJECTIVE AND IMPORTANCE

A Chiari I malformation associated with syringomyelia and hydrocephalus is a rare condition. We report the successful use of endoscopic third ventriculostomy for the treatment of this pathological entity. The successful use of this technique in such a case has not been previously described, and the results allow us to speculate on the pathophysiological mechanism involved.

CLINICAL PRESENTATION

A 34-year-old woman presented with headaches, a motor deficit of the right upper limb, and gait dyspraxia. Magnetic resonance imaging scans demonstrated dilation of all ventricles, compression of the retrocerebellar cerebrospinal fluid space, downward displacement of the tonsils, and syringomyelia. Syringomyelia involved the cervicodorsal cord below C3, with a syrinx-free segment between C1 and C3 and no enlargement of the rostral part of the central canal.

INTERVENTION

Endoscopic third ventriculostomy resulted in prompt improvement of the clinical symptoms. Postoperative magnetic resonance imaging scans demonstrated shrinkage of the syrinx and return of the cerebellar tonsils to their physiological positions.

CONCLUSION

This experience demonstrates that endoscopic third ventriculostomy, which is a simple, safe technique, may be the treatment of choice for associated Chiari I malformations, hydrocephalus, and syringomyelia (even the noncommunicating type).

Chiari I malformation: a rare cause of noncommunicating hydrocephalus treated by third ventriculostomy

OBJECT

Hydrocephalus associated with Chiari I malformation is a rare entity related to an obstruction in the flow of cerebrospinal fluid (CSF) in the foramen of Magendie. Like all forms of noncommunicating hydrocephalus. it can be treated by endoscopic third ventriculostomy (ETV). The object of this study is to report a series of five cases of hydrocephalus associated with Chiari I malformation and to evaluate the use of ETV in the treatment of this anomaly.

METHODS

Five patients (four women and one man with a mean age of 29.6 years) underwent ETV for hydrocephalus associated with Chiari I malformation between April 1991 and February 1997. All patients had presented with paroxysmal headaches, which in two cases were associated with visual disorders. All patients had also presented with hydrocephalus (mean transverse diameter of the third ventricle 12.79 mm; mean sagittal diameter of the fourth ventricle 18.27 mm) with a mean herniation of the cerebellar tonsils at 13.75 mm below the basion-opisthion line. Surgery was performed in all patients by using a rigid endoscope. No complications occurred either during or after the procedure, except in one patient who experienced a wound infection that was treated by antibiotic medications. The mean duration of follow up in this study was 50.39 months. Four patients became completely asymptomatic and remained stable throughout the follow-up period. One patient required an additional third ventriculostomy after I year, due to secondary closure, and has remained stable since that time. Postoperative magnetic resonance images demonstrated a significant reduction in the extent of hydrocephalus in all patients (mean transverse diameter of the third ventricle 6.9 mm [p = 0.0035]; mean sagittal diameter of the fourth ventricle 10.32 mm [p = 0.007]), with a mean ascent of the cerebellar tonsils from 13.75 mm below the basion-opisthion line to 7.76 mm below it (p = 0.01). In addition, CSF flow was identified on either side of the orifice of the third ventriculostomy in all patients postoperatively.

CONCLUSIONS

Results in this series confirm the efficacy of ETV in the treatment of hydrocephalus associated with Chiari I malformation. It is a reliable, minimally invasive technique that also provides a better understanding of the pathophysiology of this malformation.