Treatment of Chiari malformation, syringomyelia and hydrocephalus by neuroendoscopic third ventriculostomy

Factors affecting endoscopic third ventriculostomy success in adults

BACKGROUND

Endoscopic third ventriculostomy (ETV) is a standard treatment in hydrocephalus of certain aetiologies. The most widely used predictive model is the ETV success score. This is frequently used to predict outcomes following ETV in adult patients; however, this was a model developed in paediatric patients with often distinct aetiologies of hydrocephalus. The aim of this study was to assess the predictive value of the model and to identify factors that influence ETV outcomes in adults.

METHODS

A retrospective study design was used to analyse consecutive patients who underwent ETV at a tertiary neurosurgical centre between 2012 and 2020. Observed ETV outcomes at 6 months were compared to pre-operative predicted ETV success scores. A multivariable Bayesian logistic regression analysis was used to determine the factors that best predicted ETV success and those factors that were redundant.

RESULTS

A total of 136 patients were analysed during the 9-year study. Thirty-one patients underwent further cerebrospinal fluid diversion within 6 months. The overall ETV success rate was 77%. Observed ETV outcomes corresponded well with predicted outcomes using the ETV success score for the higher scores, but less well for lower scores. Location of obstruction at the aqueduct irrespective of aetiology was the best predictor of success with odds of 1.65 of success. Elective procedures were also associated with higher success compared to urgent ones, whereas age under 70, nature and location of obstructive lesion (other than aqueductal) did not influence ETV success.

CONCLUSION

ETV was successful in three-quarters of adult patient with hydrocephalus within 6 months. Obstruction at the level of the aqueduct of any aetiology was a good predictor of ETV success. Clinicians should bear in mind that adult hydrocephalus responds differently to ETV compared to paediatric hydrocephalus, and more research is required to develop and validate an adult-specific predictive tool.

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.

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.

The role of endoscopic third ventriculostomy in adult patients with hydrocephalus

Object

Endoscopic third ventriculostomy (ETV) is the treatment of choice for hydrocephalus, but the outcome is dependent on the cause of this disorder, and the procedure remains principally the preserve of pediatric neurosurgeons. The role of ETV in adult patients with hydrocephalus was therefore investigated.

Methods

One hundred ninety adult patients underwent ETV for hydrocephalus. Cases were defined as primary ETV (newly diagnosed, without a previously placed shunt) and secondary ETV (performed for shunt malfunctions due to infection or mechanical blockage). Causes of hydrocephalus included tumor, long-standing overt ventriculomegaly (LOVA), Chiari malformation Types I and II (CM-I and -II), aqueduct stenosis, spina bifida, and intraventricular hemorrhage (IVH). Successful ETV was defined as resolution of symptoms with shunt independence. Operative complications and ETV failure rate were investigated according to the causes of hydrocephalus and between the primary and secondary ETV groups.

Results

In the primary group, ETV was successful in 107 (83%) of 129 patients, including those with tumors (52 of 66), LOVA (21 of 24), CM-I (11 of 11 cases), CM-II (8 of 9), aqueduct stenosis (8 of 9), and IVH (2 of 2). In the secondary group, ETV was successful in 41 (67%) of 61 patients and was equally successful in cases of mechanical shunt malfunction (35 of 52 patients) and infected shunt malfunction (6 of 9 patients). The median time to ETV failure was 1.7 months in the primary group and 0.5 months in the secondary group. The majority of ETV failures occurred within the first 3 months, and thereafter, the Kaplan-Meier survival curves plateaued. There were no procedure-related deaths, and complications were seen in only 5.8% of cases.

Conclusions

The success rate of ETVs in adults is comparable, if not better, than in children. In addition to the well-defined role of ETV in the treatment of hydrocephalus caused by tumors and aqueduct stenosis, ETV may also have a role in the management of CM-I, LOVA, persistent shunt infection, and IVH resistant to other CSF diversion procedures.

Decompensated hydrocephalus causing syringomyelia and tetraparesis: a case report

OBJECTIVE

Various causes for the development of syringomelia are discussed. The influence of hydrocephalus upon syringomyelia is rarely reported and its role remains unclear.

MATERIAL AND METHODS

We report a young female patient with shunt dysfunction and consequent syrinx development after child delivery.

RESULTS

The patient showed rapid clinical deterioration after delivery. Treatment was shunt revision and reconstitution of CSF flow in the posterior fossa. After surgery, the patient showed regressive syringomyelia going along with a quick and pronounced clinical improvement.

CONCLUSION

Development of syringomyelia can be caused by CSF flow disorders and hydrocephalus and may be aggravated by increased intra-abdominal pressure.

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.

Myelomeningocele: a review of the epidemiology, genetics, risk factors for conception, prenatal diagnosis, and prognosis for affected individuals

Although the use of folic acid before conception decreases the chance that a fetus will have an open neural tube defect, this condition still affects 0.5-1.0/1000 pregnancies in the United States. Results of a recent survey suggest that there are gaps in obstetrician-gynecologists' knowledge of risk factors for conception, strategies for prenatal diagnosis, and prognosis for affected individuals. To address these gaps this paper reviews the epidemiology, genetics, risk factors for conception, prenatal diagnosis, and prognosis for affected individuals, presents current information, and makes suggestions for expanding obstetrician-gynecologists' knowledge of myelomeningocele.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to state that despite a large amount of professional and public education on the use of folic acid in prevention of open neural tube defects (ONTDs) the incidence still affects 0.5-1.0/1000 pregnancies and recall that a recent survey conducted by the ACOG shows substantial misunderstanding and misinformation on major categories of neural tube birth defects.

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.

Late rapid deterioration after endoscopic third ventriculostomy: additional cases and review of the literature

OBJECT

Late rapid deterioration after endoscopic third ventriculostomy (ETV) is a rare complication. The authors previously reported three deaths from three centers. Three other deaths and a patient who experienced rapid deterioration have also been reported. Following the death at the University of Toronto of an additional patient who underwent surgery elsewhere, they canvassed pediatric neurosurgeons in North America, Europe, Australia, and Asia for additional cases.

METHODS

An email was sent to the members of the Canadian Congress of Neurological Sciences who are pediatric neurosurgeons, to the pediatric neurosurgery email list of the American Association of Neurological Surgeons, to the email list of the International Society for Pediatric Neurosurgery, and to designated neurosurgeons in the United Kingdom, France, Japan, Korea, Taiwan, and Australia, who in turn contacted pediatric neurosurgeons in their countries. A data form was provided, and data from previously reported cases were extracted. Nine additional cases were identified, and the results were collated with those of the seven cases previously reported. Patient age at surgery ranged from 2 days to 13 years (mean 7.6 years). The most common causes of hydrocephalus were aqueductal stenosis in 50% of patients and tectal glioma in 25% of patients. The time to treatment failure ranged from 5 weeks to 7.8 years (mean 2.5 years). Thirteen patients died, one patient was in a vegetative state, one patient was mildly disabled, and one patient whose condition deteriorated outside the operating room was alive and well. In the 13 patients in whom the ventriculostomy site was visualized at autopsy or repeated endoscopy, the ventriculostomy was shown to be occluded.

CONCLUSIONS

Late rapid deterioration is a rare but lethal complication of ETV. The mechanism is unclear, but deterioration can occur long after the ETV becomes occluded. Patients and caregivers should be counseled regarding this potential complication. An indwelling ventricular access device is an option for patients undergoing ETV.

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 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.