Endoscopic third ventriculostomy (ETV) for Chiari 1 malformation: a systematic review and meta-analysis

Meta-analysis and systematic review. To understand the role of endoscopic third ventriculostomy (ETV) for the treatment of concurrent Chiari Malformation Type I (CMI) and hydrocephalus in adults. A literature search on PubMed and Medline with MeSH terms relating to ETV and CMI identified 155 articles between 1988 and 2024. After excluding pediatric cases and other CNS pathologies with associated CMI, 11 articles met inclusion criteria. The Newcastle-Ottawa Scale was identified to assess heterogeneity and risk of bias among the 11 studies analyzed in this systematic-review and meta-analyses compared pre- and post-operative outcomes to examine the use of ETV as a treatment modality for CMI with hydrocephalus. From the 11 included studies, 35 cases of concurrent CMI and hydrocephalus treated with ETV were identified. ETV provided a pooled rate of symptom resolution or improvement of 66%. Additionally, meta-analysis discovered the following pooled rates: a reduction of tonsillar descent in 94% of patients, decreased ventriculomegaly in 94%, and ETV patency in 99%. Syringomyelia, nausea, papilledema and cerebellar dysfunction did not have sufficient numbers for meaningful statistical analyses. However, in each of these categories, more than 85% of the symptoms or radiographic findings improved. This review summarizes the safety and efficacy of ETV for the concurrent management of acquired CMI with hydrocephalus. Specifically, ETV improves radiological outcomes of both ventriculomegaly and tonsillar descent as well as the most prevalent neurological symptom, headaches.

Endoscopic third ventriculostomy for management of hydrocephalus associated with Chiari malformation type II in children

BACKGROUND

Hydrocephalus is commonly associated with Chiari malformation (CM) particularly CM type II. The traditional treatment of hydrocephalus in these patients has been cerebrospinal fluid diversion by shunts. Endoscopic third ventriculostomy (ETV) has emerged as an alternative procedure in these patients.

PURPOSE

Assessment of the clinical and radiological outcomes of ETV in the management of hydrocephalus in children with CM II.

METHODS

This is a prospective study conducted on 18 patients with CM II associated with hydrocephalus admitted to Cairo University hospitals between January 2020 and June 2021. These patients had been managed surgically by ETV. Clinical outcome was assessed based on improvement of manifestations of increased intracranial pressure while radiological outcome was based on the findings of postoperative computed tomography. In cases with early failure, serial lumbar puncture (LP) was performed for 2 days.

RESULTS

ETV was performed as a secondary procedure in 4 cases. The overall success rate of the procedure was 72%, and its success rate as a secondary procedure was 100%. Serial LP was effective in decreasing early failure in 44.4% of cases. Radiological regression of hydrocephalic changes was detected in 50% of the cases.

CONCLUSION

ETV is an efficient and safe procedure in the treatment of hydrocephalus in children with Chiari malformation II, particularly when performed as a secondary procedure. Serial LP following the procedure increases the success rate in patients with early failure.

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.

Endoscopic third ventriculostomy for treatment of tonsillar descent with hydrocephalus: CSF flow dynamics and treatment strategies

OBJECTIVE

To explore the role of cerebrospinal fluid (CSF) flow dynamics and develop treatment strategies involving endoscopic surgery for tonsillar descent with hydrocephalus.

METHODS

This study included 15 patients with tonsillar descent with hydrocephalus. All patients underwent cine-magnetic resonance imaging (MRI) preoperatively to measure CSF flow at the entrance of the cerebral aqueduct and foramen of Magendie. Endoscopic third ventriculostomy (ETV) was performed.

RESULTS

All patients exhibited abnormal CSF flow dynamics at Magendie's foramen prior to surgery. After surgery, cine-MRI showed CSF flow through the ventriculostomy. During the follow-up period of 8-72 months, the level of tonsillar descent reduced in 9 patients, and the spinal cord syrinx was reduced in 1 patient. Clinical symptoms were improved in 14 patients. Secondary endoscopically assisted posterior cranial fossa decompression was performed in one patient whose symptoms were not improved after ETV. In no case was secondary ventriculo-peritoneal shunting performed following primary ETV.

CONCLUSION

ETV is a low-risk and effective method that can replace ventriculo-peritoneal shunt placement in the treatment of tonsillar descent with obstructive hydrocephalus. Preoperative cine-MRI of CSF flow dynamics in the aqueduct and Magendie's foramen provides valuable information for determining surgical timing and strategies.

Chiari type 1-a malformation or a syndrome? A critical review

OBJECTIVE

As the understanding of pathophysiology behind Chiari malformation still is limited, the treatment of Chiari malformation type 1 remains rather empirical. This may result in suboptimal treatment strategy and outcome in many cases. In this review, we critically address whether the condition known today as Chiari malformation type I should rather be denoted Chiari syndrome.

METHODS

The current knowledge of Chiari malformation type 1 is summarized from the historical, etymological, genetic, clinical, and in particular pathophysiological perspectives.

RESULTS

There are several lines of evidence that Chiari malformation type 1 represents a condition significantly different from types 2 to 4. Unlike the other types, the type 1 should rather be considered a syndrome, thus supporting the reasons to reappraise the traditional classification of Chiari malformations.

CONCLUSION

We propose that Chiari malformation type 1 should rather be denoted Chiari syndrome, while the notation malformation is maintained for types 2-4.

ETV for successful treatment of holocord syrinx with hydrocephalus: a case report

AIM

to present evidence for the use of endoscopic third ventriculostomy (ETV) in the treatment of holocord syrinx.

METHODS

ETV has been used in the treatment of obstructive hydrocephalus and syringomyelia secondary to Chiari 1 malformation. However, there have been no reports of ETV being utilised in the management of a holocord. We report a case of an 18 year old male with a symptomatic holocord syrinx who was successfully treated via ETV.

RESULTS

neurological improvement was noted both immediately and at follow up following ETV.

CONCLUSION

ETV may represent a viable treatment option for holocord syrinx in some population groups.

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.

Endoscopic third ventriculostomy for the management of Chiari I and related hydrocephalus: outcome and pathogenetic implications

BACKGROUND

Hydrocephalus affects 7% to 10% of patients with Chiari I malformation (CIM). It can be successfully treated by endoscopic third ventriculostomy (ETV), possibly improving related CIM and syringomyelia.

OBJECTIVE

To confirm the effectiveness of ETV in the management of Chiari-related hydrocephalus and symptoms and to estimate the posterior cranial fossa volume (PCFV) to find the possible reasons for the success or failure of ETV.

METHODS

Fifteen patients (11 children and 4 adults) underwent ETV for hydrocephalus associated with CIM (syringomyelia was present in 6 patients). Preoperative PCFV, posterior fossa brain volume (PFBV), and PFBV/PCFV ratio were calculated in the last 12 patients in the series by a magnetic resonance imaging-based computerized method.

RESULTS

All patients had symptomatic hydrocephalus (mean third ventricle diameter, 14.1 mm). Mean tonsillar ectopia was 12.7 mm. Postoperatively, hydrocephalus symptoms improved in all cases (mean third ventricle diameter, 8.3 mm); signs and symptoms of CIM and syringomyelia resolved or improved in all patients, although the malformation remained radiologically stable in half of the patients (postoperative mean tonsillar ectopia, 8.8 mm). There were no remarkable differences between cases and controls with regard to PCFV and PFBV. The PFBV/PCFV ratio was comparable in pediatric cases and controls but not among adult patients, suggesting a PCF overcrowding in the controls.

CONCLUSION

ETV is an effective treatment for hydrocephalus associated with CIM. It is successful in improving CIM and syringomyelia in patients with no overcrowding (mainly in children) or with reversible overcrowding of the PCF (mainly in adults).

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.

Chiari type I malformation in children

The diagnosis of Chiari type I malformation (CIM) is more and more frequent in clinical practice due to the wide diffusion of magnetic resonance imaging. In many cases, such a diagnosis is made incidentally in asymptomatic patients, as including children investigated for different reasons such as mental development delay or sequelae of brain injury. The large number of affected patients, the presence of asymptomatic subjects, the uncertainties surrounding the pathogenesis of the malformation, and the different options for its surgical treatment make the management of CIM particularly controversial.This paper reports on the state of the art and the recent achievements about CIM aiming at providing further information especially on the pathogenesis, the natural history, and the management of the malformation, which are the most controversial aspects. A historial review introduces and explains the current classification. Furthermore, the main clinical, radiological, and neurophysiological findings of CIM are described to complete the picture of this heterogeneous and complex disease.

Pathophysiology of persistent syringomyelia after decompressive craniocervical surgery. Clinical article

OBJECT

Craniocervical decompression for Chiari malformation Type I (CM-I) and syringomyelia has been reported to fail in 10%-40% of patients. The present prospective clinical study was designed to test the hypothesis that in cases in which syringomyelia persists after surgery, craniocervical decompression relieves neither the physiological block at the foramen magnum nor the mechanism of syringomyelia progression.

METHODS

The authors prospectively evaluated and treated 16 patients with CM-I who had persistent syringomyelia despite previous craniocervical decompression. Testing before surgery included the following: 1) clinical examination; 2) evaluation of the anatomy using T1-weighted MR imaging; 3) assessment of the syrinx and CSF velocity and flow using cine phase-contrast MR imaging; and 4) appraisal of the lumbar and cervical subarachnoid pressures at rest, during a Valsalva maneuver, during jugular compression, and following the removal of CSF (CSF compliance measurement). During surgery, ultrasonography was performed to observe the motion of the cerebellar tonsils and syrinx walls; pressure measurements were obtained from the intracranial and lumbar intrathecal spaces. The surgical procedure involved enlarging the previous craniectomy and performing an expansile duraplasty with autologous pericranium. Three to 6 months after surgery, clinical examination, MR imaging, and CSF pressure recordings were repeated. Clinical examination and MR imaging studies were then repeated annually.

RESULTS

Before reexploration, patients had a decreased size of the CSF pathways and a partial blockage in CSF transmission at the foramen magnum. Cervical subarachnoid pressure and pulse pressure were abnormally elevated. During surgery, ultrasonographic imaging demonstrated active pulsation of the cerebellar tonsils, with the tonsils descending during cardiac systole and concomitant narrowing of the upper pole of the syrinx. Three months after reoperation, patency of the CSF pathways was restored and pressure transmission was improved. The flow of syrinx fluid and the diameter of the syrinx decreased after surgery in 15 of 16 patients.

CONCLUSIONS

Persistent blockage of the CSF pathways at the foramen magnum resulted in increased pulsation of the cerebellar tonsils, which acted on a partially enclosed cervical subarachnoid space to create elevated cervical CSF pressure waves, which in turn affected the external surface of the spinal cord to force CSF into the spinal cord through the Virchow-Robin spaces and to propel the syrinx fluid caudally, leading to syrinx progression. A surgical procedure that reestablished the CSF pathways at the foramen magnum reversed this pathophysiological mechanism and resolved syringomyelia. Elucidating the pathophysiology of persistent syringomyelia has implications for its primary and secondary treatment.

Initial management of hydrocephalus associated with Chiari malformation Type I-syringomyelia complex via endoscopic third ventriculostomy: an outcome analysis

OBJECT

The aim of this study was to evaluate the efficacy of endoscopic third ventriculostomy (ETV) in patients with Chiari malformation Type I (CM-I) and hydrocephalus with or without syringomyelia.

METHODS

The authors identified, in a prospective endoscopy database, 16 adults and children (age range 2-68 years) with CM-I and hydrocephalus that had been managed with ETV. They reviewed the clinical features and radiographic findings for all patients. Fifteen patients underwent ETV as a primary treatment, whereas 1 patient underwent the procedure at the time of shunt failure. All patients had symptomatic hydrocephalus with either aqueductal or fourth ventricular outflow obstruction. The mean duration of follow-up was 42 months.

RESULTS

Fifteen patients (94%) remain shunt free following ETV for CM-I. Five (83%) of the 6 patients with a syrinx had improvement or resolution of the syrinx following ETV. Six patients (37.5%) underwent foramen magnum decompression for persistent CM-I -- or syrinx-related symptoms. There was no cerebrospinal fluid leakage or intracranial pressure-related problem following foramen magnum decompression.

CONCLUSIONS

Endoscopic third ventriculostomy provides a durable method of treatment for hydrocephalus associated with CM-I. It is effective as a primary treatment, and the authors advocate its use as a replacement for routine ventriculoperitoneal shunt insertion in these patients. Management of the hydrocephalus alone is often sufficient and may obviate decompression, although a significant proportion of patients will still need both procedures.

Simultaneous endoscopic third ventriculostomy and ventriculoperitoneal shunt for infantile hydrocephalus

OBJECTIVE

We analyzed a series of consecutive hydrocephalic infants treated with implantation of a ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV) simultaneously.

MATERIALS AND METHODS

Between 1995 and 2006, we treated the 111 hydrocephalic infants. Among those patients, 31 infants underwent VPS and ETV simultaneously, and 45 patients underwent only VPS. The ETV plus VPS group had 17 males and 14 females with a mean age of 6.32 months. The VPS only group consisted of 25 males and 20 females with a mean age of 4.43 months. There was no difference in etiology of hydrocephalus or clinical characteristics between the two groups. We compared shunt effectiveness by calculating the pre- and postoperative ventricular index and shunt failure rates during the follow-up period between the two groups. The follow-up period ranged from 6 to 140 months (mean, 53.23 months) in the ETV plus VPS group and from 6 to 148 months (mean, 75.98 months) in the VPS only group. The success rate was 83.9% (26 of 31) in the ETV plus VPS group and 68.9% (31 of 45) in the VPS only group. There were three infections and two shunt obstructions in the ETV plus VPS group versus eight obstructions, five infections, and one overdrainage in the VPS group. The preoperative and postoperative ventricular ratio of both groups showed statistically significant change (P < 0.000).

CONCLUSION

This simultaneous procedure could be the first choice of action for the hydrocephalic patients less than 1 year old.

[Idiopathic acute obstructive hydrocephalus. Case report]

Acute hydrocephalus is rarely encountered in adults without venticuloperitoneal or venticuloatrial shunts. The purpose of this report is to describe a case of acute hydrocephalus due to no identifiable cause. A 40-year-old man developed a typical clinical picture of intracranial hypertension within a 24-hours period. On the morning of hospitalization, the patient consulted his physician for severe headache followed quickly by nausea and vomiting. After cerebral CT-scan, the patient was referred to our department. His condition rapidly worsened, with confusion, then drowsiness. Magnetic resonance imaging (MRI) demonstrated quadri-ventricular hydrocephalus with a Chiari I malformation. In view of his rapidly deteriorating clinical condition, emergency endoscopic third ventriculostormy was performed. The patient recovered rapidly and was discharged 8 days after the procedure. Diagnostic work-up included lumbar puncture showing normal cerebrospinal fluid (thereby eliminating multiple sclerosis, low-grade intracranial hemorrhage, and meningitis (bacterial, viral, fungal)), spinal MRI depicting no medullary lesions, and brain angiography revealing no vascular abnormalities. Follow-up brain MRI carried out at six months after hospitalization demonstrated normal ventricles and complete disappearance of the Chiari I malformation. No conclusion can be drawn as to whether the Chiari I malformation was the consequence or cause of hydrocephalus. The explanation of this acute hydrocephalus is the acute decompensation without identifiable cause of idiopathic stenosis of the foramen of Magendie and Luschka. Treatment with endoscopic third ventriculostomy is effective.

Endoscopic opening of the foramen of Magendie using transaqueductal navigation for membrane obstruction of the fourth ventricle outlets

✓A membrane obstruction of the foramina of Magendie and Luschka is an uncommon origin of hydrocephalus characterized by unusual clinical symptoms of rhomboid fossa hypertension. Various surgical approaches have been proposed to alleviate this obstruction, including opening the obstructed foramen of Magendie using suboccipital craniectomy, shunting procedures, and more recently, endoscopic third ventriculostomy (ETV). In some cases, however, reshaping of the posterior fossa due to the collapse of the prepontine cistern could make ETV difficult for the surgeon and dangerous to the patient. In these cases, endoscopic opening of the foramen of Magendie by transaqueductal navigation of the fourth ventricle is a suitable and feasible therapeutic option.

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.

Long-term resolution of acute, obstructive, triventricular hydrocephalus by endoscopic removal of a third ventricular hematoma without third ventriculostomy. Case report and review of the literature

The authors describe a new extension of the use of neuroendoscopy beyond that which is ordinarily performed. The authors report on the resolution of acute, obstructive, triventricular hydrocephalus in a 42-year-old woman with hypertensive caudate hemorrhage that migrated into the ventricular system. The patient underwent emergency endoscopic removal of a third ventricular hematoma, which was obstructing the orifice of the aqueduct, and restoration of cerebrospinal fluid (CSF) flow but no third ventriculostomy. The authors believe that this is the first such case to be reported. In selected cases of third ventricular hemorrhage, endoscopic removal of the intraventricular hematoma may represent a useful and effective treatment option even in emergency conditions as well as a better alternative to prolonged CSF external ventricular drainage. A reduction in the duration of hospitalization is a beneficial consequence. The authors assert that third ventriculostomy is not always needed.

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.

Chronic hydrocephalus in adults

Chronic hydrocephalus is a complex condition, the incidence of which increases with increasing age. It is characterised by the presence of ventricular enlargement in the absence of significant elevations of intracranial pressure. The clinical syndrome may develop either as a result of decompensation of a "compensated" congenital hydrocephalus, or it may arise de novo in adult life secondary to a known acquired disturbance of normal CSF dynamics. The latter may be due to late onset acqueductal stenosis or disruption of normal CSF absorptive pathways following subarachnoid hemorrhage or meningitis ("secondary" normal pressure hydrocephalus (NPH)). In some cases the cause of the hydrocephalus remains obscure ("idiopathic" NPH). In all forms of chronic hydrocephalus the clinical course of the disease is heavily influenced by changes in the brain associated with aging, in particular cerebrovascular disease. Recent research has challenged previously held tenets regarding the CSF circulatory system and this in turn has led to a radical rethinking of the pathophysiological basis of chronic hydrocephalus.

Surgical experience of syringomyelia with reference to the findings of magnetic resonance imaging

We present our surgical experience of 20 patients with syringomyelia, who were divided into two groups based on the findings of magnetic resonance (MR) imaging: a "non-visible cisterna magna" group, in which MR imaging did not reveal cerebrospinal fluid (CSF) in the cisterna magna, and a "visible cisterna magna" group. Patients with non-visible cisterna magna were associated with Chiari malformation (14 patients) or tight cisterna magna (4 patients) and underwent craniocervical decompression. Intradural exploration was performed when CSF movement in the cisterna magna or CSF outflow from the fourth ventricle appeared to be insufficient. It is important to confirm CSF outflow from the foramen of Magendie. Patients with visible cisterna magna were associated with tuberculous meningitis (2 patients) and underwent shunting procedures. Postoperatively, improvement in symptoms and a reduction in syrinx size were demonstrated in all patients except one. Two patients experienced recurrence of symptoms and syrinx dilatation.