Intraoperative assessment of endoscopic third ventriculostomy success

Long-Term Success of Endoscopic Third Ventriculostomy in the Pediatric Population with Aqueductal Stenosis

OBJECTIVE

To evaluate the long-term success rate of endoscopic third ventriculostomy (ETV) in the treatment of hydrocephalus due to aqueductal stenosis in the pediatric population.

METHODS

Between January 2007 and June 2023, a total of 82 children underwent ETV surgery for hydrocephalus and met the inclusion criteria for our study. The children's medical records were reviewed, and cases requiring additional surgery in the months and years following surgery for ventriculostomy failure were reviewed.

RESULTS

The mean age was 5.35 years. Successful ETV was observed in 74 children with a successful ETV rate of 90%. The median follow-up was 6.75 years (2 months to 15.5 years). Eight children (10%) underwent additional surgery. In 7 cases, additional surgery was performed within 3 months, while in the remaining case; a delayed failure was noted (more than 3 years later). At 6 months and 3 years, the cumulative proportion of children with revision-free survival was 91%, declining slightly to 89% at 5 years.

CONCLUSIONS

ETV is highly effective in treating hydrocephalus in pediatric patients with aqueductal stenosis, with a 91% success rate at 6 months and 3 years. Although the success rate drops slightly to 89% at 5 years, it still demonstrates durability. Late failures are usually characterized by symptoms of increased intracranial pressure. While patients with a confirmed successful ETV at 6 months may be considered for reduced follow-up frequency, it is critical to educate them about the symptoms of intracranial hypertension and the importance of seeking medical attention promptly if such symptoms occur.

The Predictive Role of Early Postoperative Magnetic Resonance Imaging After Endoscopic Third Ventriculostomy

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is a treatment option for obstructive hydrocephalus; reported success rates vary. We investigated immediate postoperative magnetic resonance imaging to evaluate the role of imaging parameters associated with outcomes.

METHODS

Retrospective chart review was performed on patients undergoing initial ETV between 2005 and 2019. Patients with preoperative and postoperative magnetic resonance imaging with follow-up>one year were included. The following were noted: changes in subarachnoid cerebrospinal fluid, third ventricle diameter, bowing of the third ventricle floor, and postoperative flow void. Kaplan-Meier survival methods were used to assess ETV success and univariable and multivariable Cox proportional-hazards models were fitted to assess factors contributing to ETV success.

RESULTS

Fifty-eight subjects were included. Nineteen (32.8%) experienced failure within one year; individually, no single imaging parameter predicted success. However, all cases of failure had no identifiable flow void. Any postoperative radiological change was not consistently associated with decreased odds of failure. Obstructive hydrocephalus treated with ETV demonstrated significantly better ETV success than patients treated with nonobstructive hydrocephalus. Interobserver reliability was moderate for 2 of the radiological variables and substantial for 1 of the radiological variables.

CONCLUSIONS

Individually, none of the qualitative radiologic parameters measured in our study predicted ETV success. Absence of a flow void predicted ETV failure, but additional studies are needed to determine its true negative predictive value. Inability to clarify which specific parameter predicts success reflects the limited role of immediate postoperative imaging in influencing clinical management.

Combined Predictive Model for Endoscopic Third Ventriculostomy Success in Adults and Children

BACKGROUND

The selection of patients in whom endoscopic third ventriculostomy (ETV) can be effective remains poorly defined. The ETV success score (ETVSS) and the presence of bowing of the third ventricle have been identified as independent factors for predicting success, each with limitations. The objective of this study is to elaborate a combined predictive model to predict ETV success in a mixed cohort of patients.

METHODS

Demographic, intraoperative, postoperative, and radiologic variables were analyzed in all ventriculostomies performed consecutively at a single institution from December 2004 to December 2022. Qualitative and quantitative measurements of preoperative, immediate, and late postoperative magnetic resonance imaging were conducted. Univariate analysis and logistic regression models were performed.

RESULTS

118 ETVs were performed in the selected period. Of these procedures, 106 met the inclusion criteria. The overall success rate was 71.7%, with a median follow-up of 3.64 years (interquartile range, 1.06-5.62). The median age was 36.1 years (interquartile range, 11.7-53.5). 35.84% were children (median, 7.81 years). Among the 80 patients with third ventricle bowing, the success rate was 88.8% (P < 0.001). Larger third ventricle dimensions on preoperative mid-sagittal magnetic resonance imaging were associated with increased ETV success. The model with the best receiver operating characteristic curves, with an area under the curve of 0.918 (95% confidence interval, 0.856-0.979) includes sex, ETVSS, presence of complications, and third ventricle bowing.

CONCLUSIONS

The presence of bowing of the third ventricle is strongly associated with a higher ETV success rate. However, a combined predictive model that integrates it with the ETVSS is the most appropriate approach for selecting patients for ETV.

Endoscopic third ventriculostomy in previously shunt-treated patients

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is an option for treatment of hydrocephalus, including for patients who have a history of previous treatment with CSF shunt insertion. The purpose of this study was to report the success of postshunt ETV by using data from a multicenter prospective registry.

METHODS

Prospectively collected data in the Hydrocephalus Clinical Research Network (HCRN) Core Data Project (i.e., HCRN Registry) were reviewed. Children who underwent ETV between 2008 and 2019 and had a history of previous treatment with a CSF shunt were included. A Kaplan-Meier survival curve was created for the primary outcome: time from postshunt ETV to subsequent CSF shunt placement or revision. Univariable Cox proportional hazards models were created to evaluate for an association between clinical and demographic variables and subsequent shunt surgery. Postshunt ETV complications were also identified and categorized.

RESULTS

A total of 203 children were included: 57% male and 43% female; 74% White, 23% Black, and 4% other race. The most common hydrocephalus etiologies were postintraventricular hemorrhage secondary to prematurity (56, 28%) and aqueductal stenosis (42, 21%). The ETV Success Score ranged from 10 to 80. The median patient age was 4.1 years. The overall success of postshunt ETV at 6 months was 41%. Only the surgeon's report of a clear view of the basilar artery was associated with a lower likelihood of postshunt ETV failure (HR 0.43, 95% CI 0.23-0.82, p = 0.009). None of the following variables were associated with postshunt ETV success: age at the time of postshunt ETV, etiology of hydrocephalus, sex, race, ventricle size, number of previous shunt operations, ETV performed at time of shunt infection, and use of external ventricular drainage. Overall, complications were reported in 22% of patients, with CSF leak (8.6%) being the most common complication.

CONCLUSIONS

Postshunt ETV was successful in treating hydrocephalus, without subsequent need for a CSF shunt, in 41% of patients, with a clear view of the basilar artery being the only variable significantly associated with success. Complications occurred in 22% of patients. ETV is an option for treatment of hydrocephalus in children who have previously undergone shunt placement, but with a lower than expected likelihood of success.

Failure of Endoscopic Third Ventriculostomy

Endoscopic third ventriculostomy (ETV) is an alternative to cerebrospinal fluid (CSF) shunting in the treatment of hydrocephalus. Careful patient selection is critical as patient age, etiology of hydrocephalus, and previous shunting have been shown to influence ETV success rates. Intraoperatively, patient anatomy and medical stability may prevent or limit the completion of the ventriculostomy procedure, and findings such as a patulous third ventricular floor or cisternal scarring may portend a lower chance of successful hydrocephalus treatment. Patients in whom a ventriculostomy is completed may still experience continued symptoms of hydrocephalus or CSF leak, representing an early ETV failure. In other patients, the ETV may prove a durable treatment of hydrocephalus for several months or even years before recurrence of hydrocephalus symptoms. The failure pattern for ETV is different than that of shunting, with a higher early failure rate but improved long-term failure-free survival rates. The risk factors for failure, along with the presentation and management of failure, deserve review.

Endoscopic third ventriculostomy in children with chronic communicating congenital hydrocephalus: a single-center cohort retrospective analysis

OBJECTIVE

The aim of this study was to analyze the role of endoscopic third ventriculostomy (ETV) in the treatment of pediatric chronic communicating congenital hydrocephalus (CCCH).

MATERIAL AND METHODS

This retrospective study comprised a series of 11 children with CCCH treated with ETV. Data were recorded on gender, history, presenting symptoms, age at surgery, complications during surgery, clinical evolution, ETV survival, and follow-up period. Radiological variables including ventricular and cephalic diameters were also recorded to determine a series of ventricular indexes in magnetic resonance imaging (MRI) before and after the ETV procedure. The procedure was considered to be successful when there was clinical stability or improvement accompanied by a reduction in the radiological indexes in the postoperative control images, such that there was no need to place an extrathecal cerebrospinal fluid shunt.

RESULTS

Over a mean follow-up period of 35.8 months (range: 6-108 months) from the ETV procedure, three patients required shunt placement; one of these was due to early failure in an 8-month old girl, the only patient younger than 12 months in our series. The radiological indexes were reduced in all patients except for one of the cases of ETV failure. The mean ETV survival among the successful cases was 32.1 months (range: 6-108 months), whilst that of the failed cases was 16 months (range: 6-108 months).

CONCLUSION

Although studies with larger sample sizes are needed, ETV appears to be a promising option for the treatment of this type of patient with CCCH.

Arachnoid and dural reflections

The dura mater is the major gateway for accessing most extra-axial lesions and all intra-axial lesions of the central nervous system. It provides a protective barrier against external trauma, infections, and the spread of malignant cells. Knowledge of the anatomical details of dural reflections around various corners of the skull bases provides the neurosurgeon with confidence during transdural approaches. Such knowledge is indispensable for protection of neurovascular structures in the vicinity of these dural reflections. The same concept is applicable to arachnoid folds and reflections during intradural excursions to expose intra- and extra-axial lesions of the brain. Without a detailed understanding of arachnoid membranes and cisterns, the neurosurgeon cannot confidently navigate the deep corridors of the skull base while safely protecting neurovascular structures. This chapter covers the surgical anatomy of dural and arachnoid reflections applicable to microneurosurgical approaches to various regions of the skull base.

Endoscopic third ventriculostomy for myelomeningocele-related hydrocephalus after shunt failure: Long-term outcome in a series of 8 patients

OBJECTIVE

Endoscopic third ventriculostomy (ETV) has now become an accepted mode of hydrocephalus treatment. However, the long-term effects of ETV for myelomeningocele-related hydrocephalus (MMC-rH) after shunt malfunction remains unclear. We aimed to assess the long-term outcome and the factors associated with the success of ETV for MMC-rH after shunt malfunction.

METHODS

We performed a retrospective analysis of data collected between 2001 and 2018 from 8 patients with MMC-rH after shunt malfunction, who underwent ETV at the Kurume University Hospital and were followed up for at least 5 years. We extracted data regarding age, sex, clinical symptoms, radiological imaging, intraoperative findings, and outcomes.

RESULTS

The overall success rate was 62.5% and their ETV success score is 67.5. The most frequent clinical symptom was intracranial hypertension symptoms (100 %), followed by Chiari type II symptoms (87.5 %). In preoperative MRI scans, we observed aqueduct stenosis in 6 cases, Chiari type II malformations in 7 cases, four patients had a narrow prepontine cistern, five patients had an absent septum pellucidum, and three presented with stenosis of the foramen of Monro. All cases in the failure group had the above 5 symptoms. Based on intraoperative findings, a thick third ventricle floor was found in 5 patients. Two patients had a thin hypothalamic adhesion in the third ventricle floor. They had no major complications.

CONCLUSION

ETV for MMC-rH after shunt malfunction is an effective treatment option. However, we recommend that a neurosurgeon with extensive experience in neuroendoscopy perform ETV because MMC patients more often had intraventricular malformations than those with other hydrocephalus diseases.

A Review of Common Endoscopic Intracranial Approaches

With the evolution of surgical techniques, endoscopy has emerged as a suitable alternative to many instances of more invasive methods. In this review article, we aim to discuss the endoscopic advancements, procedural details, indications, and outcomes of the most commonly practiced neuroendoscopic procedures. We have also summarized the uses, techniques, and challenges of neuroendoscopy in select neurosurgical pathologies.

Predicting endoscopic third ventriculostomy success in adult hydrocephalus: preliminary assessment of a modified ETV success score for adults (ETVSS-A) in a series of 47 patients

BACKGROUND

Endoscopic third ventriculostomy is an established treatment for noncommunicating hydrocephalus. In carefully selected patients, it can be adopted for the management of communicating variant; however controversy exists in regards to the definition of the appropriate candidates. Predictive score of Endoscopic Third Ventriculostomy Success (ETVSS) has been reported for pediatric and mixed populations only. Our purpose was to define a ETV success score for adult population (ETVSS-A), measuring the strength of correlation between preoperative score retrospectively evaluated and the success rates achieved in a class of adult patients.

METHODS

A retrospective analysis of 47 cases which received ETV procedure at our Institution between 2015 and 2018 was run. Demographic data,clinical history,preoperative and postoperative signs were reviewed and ETVSS-A was calculated. Thereafter ETVSS-A results were compared with the actual success rates.

RESULTS

29 patients(61,7%) presented unchanged or improvedclinical status with a mean ETVSS-A of 54.5%;18 patients(38,3%) worsened with mean ETVSS-A of 37,7%. We found that age,type of hydrocephalus and symptoms of admission are each apart important factors in predicting ETV success:older patients and those with non-obstructive hydrocephalus had the lowest predicted ETV success. In patients in whom ETV was actually successful, the pre-operative ETVSS-A was significantly higher as compared to those patients in whom we observed a poor surgical outcome.

CONCLUSIONS

From the results of this series, though small and retrospectively analyzed, it seems that ETVSS-A can be considered as a useful instrument to help neurosurgeon in predicting the ETV success and though define a more accurate surgical strategy in cases of hydrocephalus. Wider series and prospective studies are attended to validate these preliminary results.

Interhypothalamic adhesions in endoscopic third ventriculostomy

INTRODUCTION

An interhypothalamic adhesion (IHA) is a gray mater-like band of tissue traversing across the third ventricle anterior to the mammillary bodies and is similar but distinct from an interthalamic adhesion. These rare anatomic anomalies can be detected with magnetic resonance imaging or, incidentally, during endoscopic ventricular surgery.

METHODS

All cases of interhypothalamic adhesions visualized during endoscopic third ventriculotomy (ETV), outside of the myelomeningocele setting, were identified from two institutions. Retrospective chart and imaging reviews were conducted and compared to intraoperative videos and photos for all cases. IHA variables collected included the following size, location, multiplicity, and associated anatomic anomalies.

RESULTS

Four cases of interhypothalamic adhesions were identified during ETV-all of which, either partially or completely, obscured access to the third ventricular floor. The IHAs in our cohort were duplicated in two patients, large (> 3 mm and severely obstructing access to the third ventricular floor) in three patients, and adherent to the floor of the third ventricle in three patients. All four patients had primary absence of the septum pellucidum. Previous reports found associations of IHAs with other congenital, particularly midline, abnormalities. The IHAs in our cohort affected the surgery in three of four cases including misdirecting the ventriculostomy and requiring retraction or division of the IHA. In no case was postoperative pituitary or hypothalamic dysfunction observed.

CONCLUSIONS

Although interhypothalamic adhesions are rare, these anomalies must be recognized as they may hinder access to the third ventricular floor. IHAs may be large, multiple, or adherent to adjacent ventricular structures, they can misdirect or occlude the ventriculostomy or impart risk of bleeding and hypothalamic injury. Techniques for management of IHA include aborting the attempt, re-siting the ventriculostomy, or retracting or dividing the IHA, which enabled technically successful ETV in three of four patients in this series.

Navigated neuroendoscopy combined with intraoperative magnetic resonance cysternography for treatment of arachnoid cysts

Endoscopic cystocysternostomy or cystoventriculostomy is the treatment of choice in patients with symptomatic intracranial arachnoid cysts. There are no objective diagnostic tests for reliable intraoperative evaluation of the effectiveness of performed stomies. The aim of this prospective open-label study is to demonstrate for the first time the usefulness of intraoperative cysternography performed with the low-field 0.15-T magnetic resonance imager Polestar N20 during endoscopic cysternostomies. The study was performed in patients operated for middle fossa arachnoid cysts (n = 10), suprasellar cysts (n = 4), paraventricular or intraventricular cysts (n = 6), and a pineal cyst (n = 1). The operations were performed with use of a navigated neuroendoscope. Intraoperative magnetic resonance (iMR) cysternography was performed before and after the cystostomy. In each case, iMR cysternography was safe and could show clearly the cyst morphology and the effectiveness of performed endoscopic cystostomies. In six cases, iMR cysternography had a significant influence of the surgical decision (p = 0.027). The rate of inconsistency between the intraoperative observations and iMR imaging–based findings was 29%. A good contrast flow through the fenestrated cyst walls correlated with a good long-term clinical outcome (ρ = 0.54, p < 0.05) and good long-term radiological outcome (ρ = 0.72, p < 0.05). Intraoperative low-field MR cysternography is a safe and reliable method for assessment of the efficacy of performed endoscopic cystostomies and has significant influence on the surgical decision. It may be reliably used for prediction of the long-term clinical and radiological outcome.

Endoscopic third ventriculostomy in children with a fiber optic neuroendoscopy

OBJECTIVE

Endoscopic third ventriculostomy (ETV) provides a shunt-free treatment for obstructive hydrocephalus children. With rapidly evolving technology, the semi-rigid fiber optic neuroendoscopy shows a potential application in ETV by blunt fenestration. A retrospective analysis of our experience is reviewed.

METHODS

The authors review infants and children who underwent ETV using this technique from June 2004 to June 2016 with radiological and clinical follow-up done by a single surgeon. Patients who underwent ETV with channel scope were excluded. Demographic variables and operative reports were collected. Improvement of preoperative symptoms and avoidance of additional cerebrospinal fluid (CSF) diversion procedures were considered a success. The ETV success score (ETVSS) was used to correlate with clinical outcomes.

RESULTS

A total of 79 patients were included with a mean age of 8.3 ± 5.5 years, and 40.5% were female. The mean clinical and radiographic follow-up was 38.6 ± 40.9 months. The overall complication rate was 6.3%, while 73.4% were considered successful. The ETV failure cases received conversion to ventriculoperitoneal shunt or redo of ETV with a median time of 2 months. The mean ETV success score was 74.3 ± 11.8 with positive correlation between success rate (P < 0.05). Kaplan-Meier failure-free survival rates of 30-day, 90-day, 6-month, 1-year, and 2-year were 89.9, 83.5, 78.5, 75.9, and 74.6%. Eight patients required redo ETV, and five of these patients required eventual shunt placements. Approximately 61.9% of failure occurred within 3 months. Patients with post-intraventricular hemorrhage (IVH) /infection, and age younger than 12 months had the poorest outcome (P < 0.05).

CONCLUSIONS

Blunt dissection of the third ventricle floor under endoscopic vision with the stylet tip of a fiber optic neuroendoscopy is safe and requires less equipment in the pediatric population. This technique is successful with an optimistic long-term outcome except for infants and the post-IVH and infectious subgroups.

Update on Endoscopic Third Ventriculostomy in Children

Endoscopic third ventriculostomy (ETV) provides a physiological restoration of cerebrospinal fluid and a shunt-free option for hydrocephalus children. Continuous developments in techniques and instruments have improved ETV as the first-line treatment. This paper focuses on the recent advances in surgical techniques, instruments, predictive models, imaging tools, and new cohort studies. The efficacy, safety, indications, and remaining challenges of ETV are discussed. More patients undergo ETV with a better outcome, identifying a new era of hydrocephalus treatment. Deeper understanding of ETV will improve a better shunt-free survival for pediatric hydrocephalus patients.

The effect and evolution of patient selection on outcomes in endoscopic third ventriculostomy for hydrocephalus: A large-scale review of the literature

Endoscopic third ventriculostomy (ETV) has become a popular technique for the treatment of hydrocephalus, but small sample size has limited the generalizability of prior studies. We performed a large-scale review of all available studies to help eliminate bias and determine how outcomes have changed and been influenced by patient selection over time. A systematic literature search was performed for studies of ETV that contained original, extractable patient data, and a meta-analytic model was generated for correlative and predictive analysis. A total of 130 studies were identified, which included 11,952 cases. Brain tumor or cyst was the most common hydrocephalus etiology, but high-risk etiologies, post-infectious or post-hemorrhagic hydrocephalus, accounted for 18.4%. Post-operative mortality was very low (0.2%) and morbidity was only slightly higher in developing than in industrialized countries. The rate of ETV failure was 34.7% and was higher in the first months and plateaued around 20months. As anticipated, ETV is less successful in high-risk etiologies of hydrocephalus and younger patients. Younger patient age and high-risk etiologies predicted failure. ETVs were performed more often in high-risk etiologies over time, but, surprisingly, there was no overall change in ETV success rate over time. This study should help to influence optimal patient selection and offer guidance in predicting outcomes.

Endoscopic third ventriculostomy in children: prospective, multicenter results from the Hydrocephalus Clinical Research Network

OBJECTIVE Endoscopic third ventriculostomy (ETV) is now established as a viable treatment option for a subgroup of children with hydrocephalus. Here, the authors report prospective, multicenter results from the Hydrocephalus Clinical Research Network (HCRN) to provide the most accurate determination of morbidity, complication incidence, and efficacy of ETV in children and to determine if intraoperative predictors of ETV success add substantially to preoperative predictors. METHODS All children undergoing a first ETV (without choroid plexus cauterization) at 1 of 7 HCRN centers up to June 2013 were included in the study and followed up for a minimum of 18 months. Data, including detailed intraoperative data, were prospectively collected as part of the HCRN's Core Data Project and included details of patient characteristics, ETV failure (need for repeat hydrocephalus surgery), and, in a subset of patients, postoperative complications up to the time of discharge. RESULTS Three hundred thirty-six eligible children underwent initial ETV, 18.8% of whom had undergone shunt placement prior to the ETV. The median age at ETV was 6.9 years (IQR 1.7-12.6), with 15.2% of the study cohort younger than 12 months of age. The most common etiologies were aqueductal stenosis (24.8%) and midbrain or tectal lesions (21.2%). Visible forniceal injury (16.6%) was more common than previously reported, whereas severe bleeding (1.8%), thalamic contusion (1.8%), venous injury (1.5%), hypothalamic contusion (1.5%), and major arterial injury (0.3%) were rare. The most common postoperative complications were CSF leak (4.4%), hyponatremia (3.9%), and pseudomeningocele (3.9%). New neurological deficit occurred in 1.5% cases, with 0.5% being permanent. One hundred forty-one patients had documented failure of their ETV requiring repeat hydrocephalus surgery during follow-up, 117 of them during the first 6 months postprocedure. Kaplan-Meier rates of 30-day, 90-day, 6-month, 1-year, and 2-year failure-free survival were 73.7%, 66.7%, 64.8%, 61.7%, and 57.8%, respectively. According to multivariate modeling, the preoperative ETV Success Score (ETVSS) was associated with ETV success (p < 0.001), as was the intraoperative ability to visualize a "naked" basilar artery (p = 0.023). CONCLUSIONS The authors' documented experience represents the most detailed account of ETV results in North America and provides the most accurate picture to date of ETV success and complications, based on contemporaneously collected prospective data. Serious complications with ETV are low. In addition to the ETVSS, visualization of a naked basilar artery is predictive of ETV success.

Is the endoscopic third ventriculostomy success score an appropriate tool to inform clinical decision-making?

INTRODUCTION

The endoscopic third ventriculostomy success score (ETVSS) is a model, which provides each patient with a prediction of the outcome of endoscopic third ventriculostomy. The objective of this study was to determine if there is clinical value to the use of the ETVSS in the decision for ETV.

METHODS

Prospectively collected data on all ETV procedures with the Republic of Ireland in children ≤16 years of age, totalling 112, from 2008 to 2014 was analysed. The percentage chance of success at six months was retrospectively calculated according to the ETVSS. A multivariable model, comprising the risk factors from the ETVSS - age, aetiology and previous shunt - was created and its performance compared to that of the ETVSS.

RESULTS

The ETVSS achieved an AUC of 0.61 (95% CI: 0.49-0.71) with a sensitivity and specificity of 50% and 76%, respectively, at its optimal cutoff. The ETVSS was not significantly well calibrated in this cohort and there was a limited net benefit on decision curve analysis in comparison with the strategy of performing ETV in all patients. The multivariable model achieved an AUC of 0.67 (95% CI: 0.56-0.78), was well calibrated and was associated with a superior net benefit over that of the ETVSS.

CONCLUSION

The ETVSS represents the future of patient risk stratification with an easy to use, individualised approach for each patient. The ETVSS has performed adequately in this study. However, through the addition of novel risk factors, the continuous updating of the model and recalibration where needed, the ETVSS can become a tool that the paediatric neurosurgeon cannot do without.

Long-term follow-up of endoscopic third ventriculostomy performed in the pediatric population

OBJECTIVE Endoscopic third ventriculostomy (ETV) is an effective treatment for obstructive hydrocephalus and avoids the risk for foreign-body infection associated with ventriculoperitoneal (VP) shunts. The short-term failure rate of ETV strongly depends on the indications for its use but is generally thought to be lower in the long term than that of VP shunts. However, few studies are available with long-term follow-up data of ETV for hydrocephalus in children. The authors reviewed the long-term success of ETV at their institution to investigate the rate of any late failures of this procedure. METHODS Between April 1998 and June 2006, 113 children (including neonates and children up to 16 years old) had primary or secondary ETV for different causes of hydrocephalus. The patients' medical records and the authors' electronic operation database were reviewed for evidence of additional surgery (i.e., repeat ETV or VP shunt insertion). These records were checked at both the pediatric and adult neurosurgical hospitals for those patients who had their care transferred to adult services. RESULTS The median length of follow-up was 8.25 years (range 1 month to 16 years). Long-term follow-up data for 96 patients were available, 47 (49%) of whom had additional ETV or VP shunt insertion for ETV failure. Twenty patients (21%) had a second procedure within 1 month, 17 patients (18%) between 1 and 12 months, 7 patients (7%) between 1 and 5 years, and 3 patients (3%) between 5 and 8 years. CONCLUSIONS In the authors' series, ETV had an initial early failure rate for the treatment of pediatric hydrocephalus as reported previously, and this rate significantly depended on patient age and hydrocephalus etiology. Once stabilized and effective, ETV appeared to be durable but not guaranteed, and some late decline in effectiveness was observed, with some ETV failures occurring many years later. Thus, successful ETV in children cannot be guaranteed for life, and some form of follow-up is recommended long term into adulthood.

Predicting success of endoscopic third ventriculostomy: validation of the ETV Success Score in a mixed population of adult and pediatric patients

OBJECT

Endoscopic third ventriculostomy (ETV) has become the first line of treatment in obstructive hydrocephalus. The Toronto group (Kulkarni et al.) developed the ETV Success Score (ETVSS) to predict the clinical response following ETV based on age, previous shunt, and cause of hydrocephalus in a pediatric population. However, the use of the ETVSS has not been validated for a population comprising adults. The objective of this study was to validate the ETVSS in a "closed-skull" population, including patients 2 years of age and older.

METHODS

In this retrospective observational study, medical charts of all consecutive cases of ETV performed in two university hospitals were reviewed. The primary outcome, the success of ETV, was defined as the absence of reoperation or death attributable to hydrocephalus at 6 months. The ETVSS was calculated for all patients. Discriminative properties along with calibration of the ETVSS were established for the study population. The secondary outcome is the reoperation-free survival.

RESULTS

This study included 168 primary ETVs. The mean age was 40 years (range 3-85 years). ETV was successful at 6 months in 126 patients (75%) compared with a mean ETVSS of 82.4%. The area under the receiver operating characteristic curve was 0.61, revealing insufficient discrimination from the ETVSS in this population. In contrast, calibration of the ETVSS was excellent (calibration slope = 1.01), although the expected low numbers were obtained for scores < 70. Decision curve analyses demonstrate that ETVSS is marginally beneficial in clinical decision-making, a reduction of 4 and 2 avoidable ETVs per 100 cases if the threshold used on the ETVSS is set at 70 and 60, respectively. However, the use of the ETVSS showed inferior net benefit when compared with the strategy of not recommending ETV at all as a surgical option for thresholds set at 80 and 90. In this cohort, neither age nor previous shunt were significantly associated with unsuccessful ETV. However, better outcomes were achieved in patients with aqueductal stenosis, tectal compressions, and other tumor-associated hydrocephalus than in cases secondary to myelomeningocele, infection, or hemorrhage (p = 0.03).

CONCLUSIONS

The ETVSS did not show adequate discrimination but demonstrated excellent calibration in this population of patients 2 years and older. According to decision-curve analyses, the ETVSS is marginally useful in clinical scenarios in which 60% or 70% success rates are the thresholds for preferring ETV to CSF shunt. Previous history of CSF shunt and age were not associated with worse outcomes, whereas posthemorrhagic and postinfectious causes of the hydrocephalus were significantly associated with reduced success rates following ETV.

Change in optic nerve sheath diameter as a radiological marker of outcome from endoscopic third ventriculostomy in children

PURPOSE

The purpose of this study was to investigate the value of the change in optic nerve sheath diameter (ONSD) as a radiological marker of endoscopic third ventriculostomy (ETV) outcome in children.

METHODS

Magnetic resonance imaging (MRI) scans of patients on whom ETVs were performed between the periods of January 2009 and June 2013 were reviewed. ONSD measurements on pre- and post-operative images were performed by two blinded observers, and the relationship between the change in these measurements and outcome from ETV were investigated. These findings were then also compared to conventional imaging features associated with ETV outcome.

RESULTS

MRI scans of 24 patients were adequate to measure the ONSD pre- and post-operatively. In patients with successful ETV (n = 19), the mean change in ONSD was 0.73 mm and in patients with a failed ETV (n = 5), the mean change in ONSD was 0.18 mm (p = 0.0007). A change in ONSD of 7.5 % of the initial measurement demonstrated a sensitivity of 92.9 % and a sensitivity of 85.7 % for ETV outcome (area under the receiver operating characteristic curve (AUROC) = 0.96).

CONCLUSION

Change in ONSD is a useful radiological marker of ETV outcome and may be used in combination with conventional radiological parameters to aid decision-making in this difficult group of patients.

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.

Usefulness of intraoperative magnetic resonance ventriculography during endoscopic third ventriculostomy

BACKGROUND

Endoscopic third ventriculostomy (ETV) is the preferred method for the treatment of noncommunicating hydrocephalus. The different success rates of ETV indicate the difficulties in predicting the success of this procedure.

OBJECTIVE

To show the usefulness of intraoperative ventriculography performed by the low-field 0.15-T magnetic resonance imager Polestar N20 during ETV.

METHODS

The study was conducted in 11 patients with noncommunicating hydrocephalus caused by tumors or cysts of the third ventricle (n = 5), nontumoral stenosis of the sylvian aqueduct (n = 3), and fourth ventricle outlet obstruction (n = 3). Intraoperative magnetic resonance (iMR) ventriculography was performed before and after the ETV.

RESULTS

In each case, iMR-ventriculography was a safe procedure and determined the exact site of obstruction of cerebrospinal fluid flow. In all cases, iMR-ventriculography performed after ETV showed with the greatest accuracy the patency of the performed fenestrations, demonstrating in 9 patients good flow of the contrast from the third ventricle to the basal cisterns, restricted flow in 1 patient, and no flow in 1 patient. The results of ventriculography were consistent with the postoperative neurological status of operated-on patients. In 3 patients, the opinion of the surgeons about the patency of endoscopic fenestration, based on intraoperative observation of the third ventricle floor, was inconsistent with the results from iMR-ventriculography.

CONCLUSION

Low-field iMR-ventriculography is a safe procedure that can be successfully applied during ETV to determine the site of obstruction in hydrocephalus and the patency of performed ventricle fenestration.

Efficacy and safety of endoscopic transventricular lamina terminalis fenestration for hydrocephalus

BACKGROUND

Endoscopic third ventriculostomy (ETV) has become the procedure of choice in the treatment of obstructive hydrocephalus. In certain cases, standard ETV might not be technically possible or may engender significant risk.

OBJECTIVE

To present an alternative through the lamina terminalis (LT) by a transventricular, transforaminal approach with flexible neuroendoscopy and to discuss the indications, technique, neuroendoscopic findings, and outcomes.

METHODS

Between 1994 and 2010, all patients who underwent endoscopic LT fenestration as an alternative to ETV were analyzed and prospectively followed up. The decision to perform an LT fenestration was made intraoperatively.

RESULTS

Twenty-five patients, ranging in age from 7 months to 76 years (mean, 28.1 years), underwent endoscopic LT fenestration. Patients had obstructive hydrocephalus secondary to neurocysticercosis (11 patients), neoplasms (6 patients), congenital aqueductal stenosis (3 patients), and other (5 patients). Thirteen patients (52%) had had at least 1 ventriculoperitoneal shunt that malfunctioned; 6 patients (24%) had undergone a previous endoscopic procedure. Intraoperative findings that led to an LT fenestration were the following: ETV not feasible to perform, basal subarachnoid space not sufficient, or adhesions in the third ventricle. No perioperative complications occurred. The mean follow-up period was 63.76 months. Overall, 19 patients (76%) had resolutions of symptoms, had no evidence of ventriculomegaly, and did not require another procedure. Six (24%) required a ventriculoperitoneal shunt.

CONCLUSION

Endoscopic transventricular transforaminal LT fenestration with flexible neuroendoscopy is feasible with a low incidence of complications. It is a good alternative to standard ETV. Adequate intraoperative assessment of ETV success is necessary to identify patients who will benefit.

Hyponatremia following endoscopic third ventriculostomy: a report of 5 cases and analysis of risk factors

OBJECT

Electrolyte and endocrinological complications of endoscopic third ventriculostomy (ETV) are infrequent but serious events, likely due to transient hypothalamic-pituitary dysfunction. While the incidence of diabetes insipidus is relatively well known, hyponatremia is not often reported. The authors report on a series of 5 patients with post-ETV hyponatremia.

METHODS

The records of patients undergoing ETV between 2008 and 2010 were reviewed. All ETVs were performed with a rigid neuroendoscope via a frontal bur hole, standard third ventricle floor blunt perforation, Fogarty catheter dilation, and intermittent normal saline irrigation. Postoperative MR images were evaluated for endoscope tract injury as well as the trajectory from the bur hole center to the fenestration site.

RESULTS

Thirty-two patients (20 male and 12 female) underwent ETV. Their median age was 6 years (range 3 weeks-28 years). Hydrocephalus was most commonly due to nontumoral aqueductal stenosis (43%), nontectal tumor (25%), or tectal glioma (13%). Five patients (16%) had multicystic/loculated hydrocephalus. Five patients (16%) developed hyponatremia between 1 and 8 days following ETV, including 2 patients with seizures (1 of whom was still hospitalized at the time of the seizure and 1 of whom was readmitted as a result of the seizure) and 3 patients who were readmitted because of decline in their condition following routine discharge. No hypothalamic injuries were noted on imaging. Univariate risk factors consisted of age of 2 years or less (p = 0.02), presence of cystic lesions (p = 0.02), and ETV trajectory angle 10° or more from perpendicular (p = 0.001).

CONCLUSIONS

Endoscopic third ventriculostomy is a well-tolerated procedure but can result in serious complications. Hyponatremia is rare and may be more likely in younger patients or those with cystic loculations. Patients with altered craniometry may be at particular risk with a rigid endoscopic approach requiring greater manipulation of subforniceal or hypothalamic structures.

Success criteria in pediatric neuroendoscopic procedures. Proposal for classification of results after 67 operations

PURPOSE

Controversial issues exist concerning criteria for patient selection and long-term success in pediatric neuroendoscopic procedures. We designed a classification of success grades applicable to high-pressure and chronic hydrocephalus and also to those cases in which different endoscopic maneuvers are performed during the same procedure. We then evaluated the success rate and complications in our series.

METHODS

A total of 59 patients underwent 67 neuroendoscopic procedures between January 2003 and January 2011. A retrospective study was made of the preoperative history, operative reports, and postoperative imaging findings and medical records. A 5-grade scale was developed to assess the type of success depending on clinical and radiological data. Complications related to the surgical procedure were also recorded.

RESULTS

Two patients were excluded from the success analysis due to insufficient follow-up time. The final results for the first procedures in 57 patients were complete and permanent success (grade I) in 49.1%, complete but transitory success (grade II) in 10.5%, partial success (grade III) in 12.3%, doubtful success (grade IV) in 5.3%, and failure (grade V) in 22.8%. In eight cases a second procedure followed the failure of the first: grade I success was achieved in seven cases (87.5%) and grade V in one case (12.5%). The highest success rates were achieved in cases of hydrocephalus caused by tumors or arachnoid cysts and the lowest in slit ventricle syndrome.

CONCLUSIONS

A common classification of degrees of success, such as that proposed here, would aid the development of comparative and cooperative studies.

Indication for endoscopic third ventriculostomy

BACKGROUND

Endoscopic third ventriculostomy (ETV) is increasingly prevalent among pediatric neurosurgeons as the initial treatment for hydrocephalus. The combination of ETV and choroid plexus cauterization (ETV/CPC) has improved the success rate among infants with hydrocephalus for whom ETV alone is much less successful. In parts of the developing world where there are economic and human resource constraints, this mode of treatment may be more appropriate than the routine use of shunts, which are prone to failures that require urgent surgical treatment. Here we review indications for the use of ETV or ETV/CPC as the primary treatment for hydrocephalus.

CONCLUSION

Primary treatment of hydrocephalus by ETV can avoid shunt-dependence and its complications for many patients. Optimal results depend upon proper patient selection and the use of combined ETV/CPC when treating infants.

Preoperative third ventricular bowing as a predictor of endoscopic third ventriculostomy success

OBJECT

Patients with hydrocephalus often present with both intraventricular obstructive and communicating components, and determination of the predominant component is difficult. Other investigators have observed that third ventricular floor deformation, or "bowing" of the third ventricular floor, is a good indicator of intraventricular obstructive hydrocephalus, resulting in higher success rates with endoscopic third ventriculostomy (ETV). However, additional third ventricular bowing assessment and statistical evidence demonstrating a difference in ETV outcome with third ventricular bowing is needed. The authors hypothesized that patients with preoperative bowing of the third ventricle would exhibit greater long-term success rates after ETV and that lack of bowing would result in increased failure rates after ETV.

METHODS

The authors determined success and failure for 59 ETVs performed in 56 patients, and recorded patient age, time to failure, and preoperative third ventricular anatomy, as well as history of infection, intraventricular hemorrhage, and previous shunt. Third ventricular anatomy was assessed on MR imaging for bowing, which was classified as any of the following: depression of the third ventricular floor, enlargement of the supraoptic recess, anterior curvature of the lamina terminalis, dilation of the proximal aqueduct to a greater extent than the distal aqueduct, and blunting or posterior bowing of the suprapineal recess. Univariate and multivariate analyses of ETV failure and the time to failure were performed using logistic regression and the Cox proportional hazards model, respectively.

RESULTS

After adjusting for patient age and history of infection, there was a significant association between lack of anterior third ventricular preoperative bowing (either lamina terminalis, supraoptic recess, or third ventricular floor) and ETV failure (adjusted HR 2.79, 95% CI 1.08-7.20). Of the patients with bowing, 70.5% experienced success with ETV, as did 33.3% of the patients without bowing. Among the individual structures, absence of bowing in the anterior aspect of the third ventricular floor was significantly associated with censored time to ETV failure (multivariate HR 2.59, 95% CI 1.01-6.66; final model including age and history of infection).

CONCLUSIONS

The presence of preoperative third ventricular bowing is predictive of ETV success, with nearly a 3-fold likelihood of success compared with patients treated with ETV in the absence of such bowing. Although bowing is predictive, 33% of patients without bowing were also treated successfully with ETV.

The constant flow ventricular infusion test: a simple and useful study in the diagnosis of third ventriculostomy failure

Object

The evaluation of third ventriculostomy function in hydrocephalic patients is challenging. The utility of the constant flow infusion test in predicting response to shunt insertion in normal-pressure hydrocephalus, as well as in identifying shunt malfunction, has been previously demonstrated. The object of this study was to evaluate its usefulness in determining whether a revision CSF diversion procedure was indicated in patients presenting with recurring symptoms and persisting ventriculomegaly after endoscopic third ventriculostomy (ETV).

Methods

The authors conducted a prospective study of all patients who, after undergoing ETV at their institution, presented postoperatively with recurring symptoms and persisting ventriculomegaly.

Results

Forty-six patients (mean age 40.7 years, including 11 patients younger than 18 years) underwent 56 constant flow ventricular infusion tests (VITs) at a mean of 24.7 months post-ETV. Thirty-three patients with resistance to CSF outflow (Rout) less than 13 mm Hg/ml/min underwent follow-up (median 17 months) and experienced resolution of symptoms. In 10 episodes Rout was greater than 13 mm Hg/ml/min; the patients in these cases underwent revisional CSF diversion. Two patients demonstrated high and frequent B (slow) waves despite a low Rout; these patients also underwent successful revisions. Patients who improved after surgery had increased B wave activity in the plateau phase of the VIT (p = 0.01). Thirty-four patients underwent MR imaging at the same time; 4 had high Rout despite evidence of flow across the stoma. These 4 patients underwent surgery and experienced resolution of symptoms. Of 9 patients without flow, Rout was less than 13 mm Hg/ml/min in 4; these patients were successfully treated conservatively.

Conclusions

The VIT is a useful and safe adjunct to clinical and MR imaging evaluation when ETV failure is suspected.

Anatomical and histological study of Liliequist's membrane: with emphasis on its nature and lateral attachments

PURPOSE

In previous studies, some disagreements regarding the nature (inner or outer arachnoid membrane) and lateral boundaries (temporal uncus or tentorial edge) of Liliequist's membrane remain. The aim was to clarify whether Liliequist's membrane is an inner or outer arachnoid membrane, and the distribution of Liliequist's membrane with emphasis on its lateral attachments.

METHODS

Liliequist's membrane was investigated by microsurgical dissection in 24 formalin-fixed adult cadaver heads and by histological sections of sellar-suprasellar specimens from another four formalin-fixed adult cadaver heads.

RESULTS

The results obtained in the present study indicated that 1) Liliequist's membrane arises from the basal arachnoid membrane and has two components: a basal part comprising a folding inner layer of the arachnoid mater and an attaching part consisting of accumulated arachnoid trabeculae; 2) similar histological features are also present in other inner arachnoid membranes with attachments on basal arachnoid membrane, demonstrating Liliequist's membrane is an inner arachnoid membrane; 3) laterally, Liliequist's membrane attaches to the anterior tentorial edge constantly and to the mesial temporal uncus in more than half; 4) the oculomotor nerve courses above Liliequist's membrane and is fixed on Liliequist's membrane by the oculomotor membrane, which can also attach on temporal uncus and should be differentiated from the true temporal attachments of Liliequist's membrane.

CONCLUSION

Liliequist's membrane is an inner rather than outer arachnoid membrane. Understanding of its individual variation and topographic relationships with surrounding neurovascular and arachnoid structures is important for neurosurgical practice.

Neuroendoscopic diagnosis of central nervous system histoplasmosis with basilar arachnoiditis

OBJECTIVE

Histoplasmosis of the central nervous system (CNS) is seen in 10% to 20% of patients with disseminated histoplasmosis and/or in association with immunocompromised patients. Meningitis, arachnoiditis, and hydrocephalus are the most common clinical manifestations of CNS histoplasmosis. Patients with CNS histoplasmosis present similarly to other infectious etiologies, and confirmatory diagnosis is important in the management of these patients. However, diagnosis of CNS histoplasmosis can be difficult, and sometimes performing a parenchymal biopsy is necessary to confirm the diagnosis.

METHODS AND RESULTS

We describe the case of a 41-year-old man with HIV/AIDS who presented with the signs, symptoms, and radiologic evidence of basal meningitis and hydrocephalus. Cerebrospinal fluid (CSF) analysis from multiple lumbar punctures was negative. The patient underwent a neuroendoscopic procedure with diagnostic and therapeutic goals. Internal CSF diversion (endoscopic third ventriculostomy) and biopsy of the floor of the third ventricle and subarachnoid space were performed; surgical biopsies identified noncaseating granulomas, and ventricular CSF was positive for Histoplasmosis antibodies. The patient was treated with liposomal amphotericin B and itraconazole. The patient had resolution of his symptoms immediately after surgery, and 1-month follow-up computed tomography of the head demonstrated resolution of the hydrocephalus. At the last follow-up 12 months postoperatively, the patient has not required insertion of a ventriculoperitoneal shunt.

CONCLUSION

Clinicians should maintain a high index of suspicion for fungal basal meningitis in patients with AIDS and hydrocephalus. With nondiagnostic lumbar CSF sampling, neuroendoscopy can be considered as an alternative for diagnosis and treatment of basal meningitis and hydrocephalus.

Endoscopic third ventriculostomy in the treatment of childhood hydrocephalus: validation of a success score that predicts long-term outcome

OBJECT

The goal of this study was to externally validate the proposed Endoscopic Third Ventriculostomy Success Score (ETVSS), which predicts successful treatment for hydrocephalus on the basis of a child's individual characteristics.

METHODS

The authors retrospectively identified 181 cases of consecutive endoscopic third ventriculostomy (ETV) performed in children at a single neurosurgery center in the United Kingdom. They compared actual success at both 6 and 36 months, with mean predicted probabilities for low, moderate, and high chance of success strata based on the ETVSS. Long-term success was calculated using Kaplan-Meier methods and comparisons were made by means of unpaired t-tests.

RESULTS

Overall, 166 primary ETVs were performed; ETV success was 72.9% at 6 and 64.5% at 36 months. At long-term follow-up, the mean predicted probability of success was significantly higher in those with a successful ETV (99 patients) than in those with a failed ETV (67 patients) (p = 0.001). The ETVSS accurately predicted outcome at 36 months; the low, medium, and high chance of success strata had mean predicted probabilities of success of 82%, 63%, and 36%, and actual success of 76%, 66%, and 42%, respectively. The overall complication rate was 6%.

CONCLUSIONS

The ETVSS closely predicted the overall long-term success rates in high-, moderate-, and low-risk groups. The results of this study suggest that the ETVSS will aid clinical decision making in predicting outcome of ETV.

Evaluating the Children's Hospital of Alabama endoscopic third ventriculostomy experience using the Endoscopic Third Ventriculostomy Success Score: an external validation study

OBJECT

Endoscopic third ventriculostomy (ETV) success is dependent on patient characteristics including age, origin of hydrocephalus, and history of shunt therapy. Using these factors, an Endoscopic Third Ventriculostomy Success Score (ETVSS) model was constructed to predict success of therapy. This study reports a single-institution experience with ETV and explores the ETVSS model validity.

METHODS

A retrospective chart review identified 151 consecutive patients who underwent ETV at a pediatric hospital between August 1995 and December 2009. Of these 151, 136 patients had at least 6 months of clinical follow-up. Data concerning patient characteristics, operative characteristics, radiological findings, complications, and success of ETV were collected. The actual success rates were compared with those predicted by the ETVSS model.

RESULTS

The actual success rate of ETV at 6 months was 68.4% (93 of 136 patients), which compared well to the predicted ETVSS of 76.5% ± 12.5% (± SD). The C-statistic was 0.74 (95% CI 0.65-0.83), suggesting that the ability of the ETVSS to discriminate failures from successes was good. Secondary ETV was found to have a hazard ratio for failure of 4.2 (95% CI 2.4-7.2) compared with primary ETV (p < 0.001). The complication rate was 9.3% with no deaths. At the first radiological follow-up, the increased size of ventricles had a hazard ratio for failure of 3.0 (95% CI 1.5-6.0) compared with patients in whom ventricle size either remained stable or decreased (p = 0.002).

CONCLUSIONS

The ETVSS closely predicts the actual success of ETV, fitting the statistical model well. Shortcomings of the model were identified in overestimating success in patients with ETVSS ≤ 70, which may be attributable to the poor success of secondary ETVs in the authors' patient population.

Long-term operative failure of endoscopic third ventriculostomy in pediatric patients: the role of cine phase-contrast MR imaging

Object

Although a rarely reported occurrence, late failure of endoscopic third ventriculostomy (ETV) may occur in children as a result of a variety of factors. Delay in recognition of symptoms can lead to harmful deterioration in the patient's condition. The authors undertook this study to assess the capacity of cine phase-contrast MR imaging to identify late failure in asymptomatic pediatric patients treated with ETV for hydrocephalus.

Methods

This study was a retrospective evaluation of cases involving patients who underwent ETV between January 1, 1999, and December 31, 2008, at the pediatric neurological surgery service of the University of Padua. Before 2004, patients were routinely followed up with cine MR imaging at 3, 6, and 12 months after ETV. In 2004, a protocol of annual cine MR follow-up was instituted as a result of a case of fatal late failure. The authors evaluated all cases of late failure identified through cine MR imaging and performed a statistical analysis to investigate the relationship between ETV failure and several variables, including the cause of hydrocephalus for which ETV was originally indicated.

Results

In a series of 84 patients (age range 6 days–16 years), 17 patients had early ETV failure. Of the remaining 67 patients, 5 (7%) were found to have no CSF flow through the fenestration and recurrent ventriculomegaly when assessed with cine MR imaging at 1, 2, 3, 4, and 7 years after ETV. The patient in whom ETV failure was identified 1 year postoperatively had Dandy-Walker malformation. The patients in whom ETV failure was identified 2, 3, and 4 years postoperatively all had undergone ETV for treatment of postinfective hydrocephalus. The patient in whom ETV failure was identified 7 years postoperatively had a cystic arachnopathy in the fourth ventricle after cerebellar astrocytoma removal.

Conclusions

Patients who undergo ETV for infective hydrocephalus and Dandy-Walker malformation should receive long-term follow-up, because late closure of the stoma may occur progressively and slowly. Intraoperative observation of thickened arachnoid membranes at the level of the interpeduncular cisterns at the first ETV and a progressive decreasing of CSF flow through the stoma on routine cine MR imaging should be considered unfavorable elements entailing a significant risk of deterioration.

Predicting who will benefit from endoscopic third ventriculostomy compared with shunt insertion in childhood hydrocephalus using the ETV Success Score

OBJECT

The authors recently developed and internally validated the ETV Success Score (ETVSS)--a simplified means of predicting the 6-month success rate of endoscopic third ventriculostomy (ETV) for a child with hydrocephalus, based on age, etiology of hydrocephalus, and presence of a previous shunt. A high ETVSS predicts a high chance of early ETV success. In this paper, they assess the clinical utility of the ETVSS by determining whether long-term survival outcomes for ETV versus shunt insertion are different within strata of ETVSS (low, moderate, and high scores).

METHODS

A multicenter, international cohort of children (≤ 19 years old) with newly diagnosed hydrocephalus treated with either ETV (489 patients) or shunt insertion (720 patients) was analyzed. The ETVSS was calculated for all patients. Survival analyses with time-dependent modeling of the hazard ratios were performed.

RESULTS

For the High-ETVSS Group (255 ETV-treated patients, 117 shunt-treated patients), ETV appeared to have a lower risk of failure right from the early postoperative phase and became more favorable with time. For the Moderate-ETVSS Group (172 ETV-treated patients, 245 shunt-treated patients), ETV appeared to have a higher initial failure rate, but after about 3 months the instantaneous risk of ETV failure became slightly lower than shunt failure (that is, the hazard ratio became < 1). For the Low-ETVSS Group (62 ETV-treated patients, 358 shunt-treated patients), the early risk of ETV failure was much higher than the risk of shunt failure, but the instantaneous risk of ETV failure became lower than the risk of shunt failure at about 6 months following surgery (the hazard ratio became < 1).

CONCLUSIONS

Across all ETVSS strata, the risk of ETV failure becomes progressively lower compared with the risk of shunt failure with increasing time from the surgery. In the best ETV candidates (ETVSS ≥ 80), however, the risk of ETV failure is lower than the risk of shunt failure very soon after surgery, while for less-than-ideal ETV candidates (ETVSS ≤ 70), the risk of ETV failure is initially higher than the risk of shunt failure and only becomes lower after 3-6 months from surgery. These results need to be confirmed by larger, prospective, and preferably randomized studies.

Minimally invasive neurosurgery for cerebrospinal fluid disorders

This article focuses on minimally invasive approaches used to address disorders of cerebrospinal fluid (CSF) circulation. The author covers the primary CSF disorders that are amenable to minimally invasive treatment, including aqueductal stenosis, fourth ventricular outlet obstruction (including Chiari malformation), isolated lateral ventricle, isolated fourth ventricle, multiloculated hydrocephalus, arachnoid cysts, and tumors that block CSF flow. General approaches to evaluating disorders of CSF circulation, including detailed imaging studies, are discussed. Approaches to minimally invasive management of such disorders are described in general, and for each specific entity. For each procedure, indications, surgical technique, and known outcomes are detailed. Specific complications as well as strategies for their avoidance and management are addressed. Lastly, future directions and the need for structured outcome studies are discussed.

Intraoperative assessment of cerebral aqueduct patency and cisternal scarring: impact on success of endoscopic third ventriculostomy in 403 African children

OBJECT

In the setting of a developing country where preoperative imaging may be limited, the authors wished to determine whether cisternal scarring or aqueduct patency at the time of surgery was sufficiently predictive of the failure of endoscopic third ventriculostomy (ETV) to justify shunt placement at the time of the initial operation.

METHODS

The status of the prepontine cistern and aqueduct at the time of ventriculoscopy was prospectively recorded in 403 children in whom an ETV had been completed. Kaplan-Meier methods were used to construct survival curves. A Cox proportional hazards model was used to provide estimates of HRs for the time to ETV failure. Several independent variables were tested in a single multivariable model, including those previously shown to be associated with ETV survival, that is, age, hydrocephalus etiology, and extent of choroid plexus cauterization (CPC). In addition, intraoperative variables of particular interest were included in the analysis: status of the aqueduct at surgery (closed vs open) and status of the prepontine cistern at surgery (scarred vs clean/unscarred). Multicollinearity was not a concern since the variance inflation factors for all variables were < 2. The examination of stratified survival curves confirmed the appropriateness of the proportional hazards assumption for each variable.

RESULTS

Overall actuarial 3-year success was 57%. Consistent with previous results, age, hydrocephalus etiology, and extent of CPC were significantly associated with ETV success. A closed aqueduct and an unscarred cistern were each independently associated with significantly better ETV success (HRs of 0.66 and 0.44, respectively). The presence of cisternal scarring more than doubled the risk of ETV failure, and an open aqueduct increased the risk of failure by 50%.

CONCLUSIONS

Intraoperative observations of the aqueduct and prepontine cistern are independent predictors of the risk of ETV failure and can be used to further refine outcome predictions based on age, hydrocephalus etiology, and extent of CPC. Further studies will test validity in several African centers and determine what threshold of failure risk should prompt shunt placement at the initial operation.

Subarachnoid dissemination of intraventricular tumors following simultaneous endoscopic biopsy and third ventriculostomy

OBJECT

Endoscopic biopsy with concomitant third ventriculostomy (ETV) is a well-established diagnostic and therapeutic maneuver in patients presenting with noncommunicating hydrocephalus resulting from a tumor of the pineal region or posterior third ventricle. Fenestration of the floor of the third ventricle theoretically provides a conduit for the subarachnoid dissemination of an intraventricular tumor. The aim of this study was to ascertain the rate of leptomeningeal dissemination following this surgical procedure.

METHODS

The authors conducted a review of all patients for whom an ETV and simultaneous endoscopic biopsy procedure or tumor resection had been performed at their institutions between 1995 and 2008. Patients were divided into high or low risk groups by leptomeningeal metastatic potential based on pathology. All available postoperative clinical and radiographic data, including MR imaging of the brain and spinal cord, as well as CSF sampling were evaluated when available. A review of the literature was then conducted to establish rates of distant leptomeningeal dissemination for comparative purposes.

RESULTS

Thirty-two patients satisfied the criteria for study inclusion. Pathology revealed that 22 had a high risk for leptomeningeal dissemination. New leptomeningeal disease (1 yolk sac tumor and 1 pineoblastoma) occurred in 2 patients. The median clinical and brain MR imaging follow-ups overall were 34 (range 2-103 months) and 38 months (range 1-94 months), respectively. Follow-up MR imaging of the spine was performed in 12 patients (median 7 months postoperation), and CSF was analyzed in 15 patients (median 1 month postoperation). A Kaplan-Meier survival analysis predicted a 2-year metastasis-free survival of 94.7% for high-risk patients. Baseline rates of dissemination when ETV was not performed were in general between 8 and 24% for various high-risk pathologies according to a literature review.

CONCLUSIONS

The rate of leptomeningeal metastasis of tumors in this biopsy and ETV study was not increased when compared with rates from large series in the literature.