Endoscopic Third Ventriculostomy for Idiopathic Aqueductal Stenosis

The Cerebral Aqueduct Compliance: A Simple Morphometric Model

BACKGROUND AND OBJECTIVES

This work aimed to identify different configurations of the adytum of the cerebral aqueduct suggesting its safe neuroendoscopic navigation. This concept is intimately connected to the physiological aqueductal dilatability or compliance, which is relatively ignored in the literature. A better knowledge of the extent of physiological aqueductal dilatability might better define the ideal diameter and safer features of dedicated flexible endoscopes.

METHODS

The study includes 45 patients operated on using a flexible scope with a 3.9-mm diameter, where the structural elements of the adytum of the cerebral aqueduct are clearly visible. Patients were grouped according to the pathology (colloid cyst/normal anatomy, intraventricular hemorrhage, tetraventricular obstructive hydrocephalus, normal pressure hydrocephalus, and distal membranous aqueductal stenosis). A simple geometrical scheme was applied to the endoscopic anatomy of the aqueductal adytum in relation to the posterior commissure to measure its pathologic deformations. Eventual damages to the aqueduct walls caused by the endoscope were also reported.

RESULTS

Proceeding from normal anatomy to hydrocephalic condition, the ratio between the commissure and the aqueductal access area progressively decreases, while the vertex angle increases. Interestingly, the entity of the ependymal damages due to the passage of the endoscope correlates with such measures.

CONCLUSION

The cerebral aqueduct, excluding atrophic processes, is provided with a certain degree of dilatability, which we estimate to be around a diameter of 4 mm. This represents the maximum size for a flexible neuroendoscope for a safe aqueductal neuronavigation. The schematic model of the aqueductal adytum as a triangle defines 3 different aqueductal patterns and can be helpful when an intraoperative decision on whether to navigate the aqueduct must be taken.

A Single-Centre Experience of the Management and Surgical Outcomes of Late-Onset Idiopathic Aqueductal Stenosis

Background Although idiopathic aqueductal stenosis is a congenital disorder, some patients present in adulthood. Many theories have tried to account for the late-onset presentation; however, the aetiology remains uncertain. This study aimed to investigate the clinical presentation, management, and outcomes of patients with late-onset idiopathic aqueductal stenosis (LIAS) managed at our centre. Methodology A retrospective study of patients with a diagnosis of LIAS managed at our centre between 1996 and 2018 was undertaken. Data on clinical presentation, imaging, management, and outcomes were retrieved from patient records and radiology reports. Results A total of 20 patients were diagnosed with LIAS during the study period. Endoscopic third ventriculostomy (ETV) was the initial modality of treatment for nine patients, ventriculoperitoneal shunt (VPS) for four patients, and conservative management in seven patients, in four of them intracranial pressure (ICP) was found to be normal following a period of ICP monitoring. The median follow-up period was three years (1 month to 24 years). One patient was lost to follow-up. One ETV failed in the first six months necessitating VPS insertion. Two cases that were initially managed conservatively required a VPS three and nine years following the initial presentation. Of the patients undergoing VPS insertion, all subsequently required valve adjustment or surgical revision. Conclusions The majority of patients with LIAS undergoing ETV were managed successfully, whereas VPS insertion was associated with a high rate of revision surgery in this cohort. ETV should be considered as the treatment of choice to avoid the long-term complications of shunting for patients with LIAS.

Stereotactic anatomy of the third ventricle

PURPOSE

Endoscopic third ventriculostomy (ETV) is a surgical procedure that can lead to complications and requires detailed preoperative planning. This study aimed to provide a more accurate understanding of the anatomy of the third ventricle and the location of important structures to improve the safety and success of ETV.

METHODS

We measured the stereotactic coordinates of six points of interest relative to a predefined stereotactic reference point in 23 cadaver brain hemi-sections, 200 normal brain magnetic resonance imaging (MRI) scans, and 24 hydrocephalic brain MRI scans. The measurements were statistically analyzed, and comparisons were made.

RESULTS

We found some statistically significant differences between genders in MRIs from healthy subjects. We also found statistically significant differences between MRIs from healthy subjects and both cadaver brains and MRIs with hydrocephalus, though their magnitude is very small and not clinically relevant. Some stereotactic points were more posteriorly and inferiorly located in cadaver brains, particularly the infundibular recess and the basilar artery. It was found that all stereotactic points studied were more posteriorly located in brains with hydrocephalus.

CONCLUSION

The study describes periventricular structures in cadaver brains and MRI scans from healthy and hydrocephalic subjects, which can guide neurosurgeons in planning surgical approaches to the third ventricle. Overall, the study contributes to understanding ETV and provides insights for improving its safety and efficacy. The findings also support that practicing on cadaveric brains can still provide valuable information and is valid for study and training of neurosurgeons unfamiliar with the ETV technique.

Endoscopic transaqueductal stent placement for tumor-related aqueductal compression in pediatric patients: surgical consideration, technique, and results

PURPOSE

Endoscopic transaqueductal stenting has become a well-accepted treatment option for a selected small subset of aqueductal stenosis-related obstructive hydrocephalus. However, transaqueductal stenting poses unique challenges and risks which requires critical consideration. This report discusses the clinical experiences with transaqueductal stenting for periaqueductal tumor-related aqueductal stenosis focusing on pediatric patients.

METHODS

A retrospective analysis of all patients undergoing endoscopic TAS from 01/1993 to 01/2022 in the author's departments was performed. Demographic, clinical, radiological, and intraoperative endoscopic data were evaluated. All patients with AS-related occlusive hydrocephalus that was treated with TAS were analyzed and prospectively followed. Special attention has been given to providing insights into indications, surgical technique, and limitations.

RESULTS

Out of 28 endoscopic transaqueductal endoscopis stenting procedures, five procedures were performed on periaqueductal tumor-related obstructive hydrocephalus, two children and three adult patients. CSF pathway was obstructed by tumor located in the aqueduct in 2, by tumor in the thalamus/mesencephalon in 1, by a tumor within the third ventricle in 1, and by a tumor of the lamina tecti in 1. Simultaneously with transaqueductal stenting, 2 endoscopic third ventriculostomies (ETV), 3 tumor biopsies, and 1 tumor resection were performed. Postoperative complications included the following: CSF fistula (1 case), and asymptomatic fornix contusion (1 case). A working aqueductal stent was achieved in all cases based on clinical follow-up evaluation. Postoperatively, all patients showed improvement or resolution of their symptoms. The mean follow-up period was 25.2 months (range, 1-108 months). One patient died due to tumor progression during early follow-up. No stent migration was seen.

CONCLUSION

Endoscopic third ventriculostomy remains the gold standard for treatment of CSF circulation obstructions with lesions in the posterior third ventricle and aqueduct. Transaqueductal stenting for periaqueductal tumor-related aqueductal compression is technically feasible. However, because of the potential high risks and subtle advantages compared with ETV transaqueductal stenting, it might be indicated in a small subset of well-selected patients if alternative treatment options are not at hand.

Right Transcephalic Ventriculo-Subclavian Shunt in the Surgical Treatment of Hydrocephalus-An Original Procedure for Drainage of Cerebrospinal Fluid into the Venous System

The objectives of this article are to present an original surgical procedure for the temporary or definitive resolution of hydrocephalus, in the case of repeated failure of standard treatment techniques, and to present a case that was resolved using this surgical technique.

MATERIALS AND METHODS

We present the case of a 20-year-old male patient with congenital hydrocephalus who underwent a number of 39 shunt revisions, given the repetitive dysfunctions of various techniques (ventriculo-peritoneal shunt, ventriculo-cardiac shunt). The patient was evaluated with the ventricular catheter externalized at the distal end and it was necessary to find an emergency surgical solution, considering the imminent risk of meningitis. The patient was also associated with the diagnosis of acute lithiasic cholecystitis.

RESULTS AND DISCUSSIONS

The final chosen solution, right ventriculo-venous drainage using the cephalic vein, was a temporary surgical solution, but there are signs that this procedure can provide long-term ventricular drainage.

CONCLUSIONS

Transcephalic ventriculo-subclavian drainage represents an alternative technical option, which can be used when established options become ineffective.

Long-Standing Overt Ventriculomegaly in Adults: A Systematic Review and Meta-Analysis of Endoscopic Third Ventriculostomy Versus Ventriculoperitoneal Shunt as First-Line Treatment

BACKGROUND

Long-standing overt ventriculomegaly in adults (LOVA) is a heterogeneous term describing forms of adult hydrocephalus. LOVA incidence is increasing, yet the optimal treatment strategy for symptomatic cases remains unclear. We compared success rates and complication rates between endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) as first-line treatment for LOVA.

METHODS

A systematic review and meta-analysis was conducted in accordance with PRISMA guidelines. Three databases were searched, and articles published from 2000 to October 2022 were included (last search date October 24, 2022). Success rates and complications of both ETV and VPS were compared using random-effects models.

RESULTS

Of 895 articles identified, 22 studies were included in the analysis (556 patients: 346 in ETV group, 210 in VPS group). Mean age was 44.8 years. The most common presenting symptoms were gait disturbance (n = 178), headache (n = 156), and cognitive decline (n = 134). Combined success rates were 81.8% (n = 283/346) in the ETV group and 86.7% (n = 182/210) in the VPS group (median follow-up 41 months). There was no difference in success rates between ETV and VPS groups (odds ratio 0.94, 95% confidence interval 0.86-1.03, I2 = 0%). Combined complication rates were 4.6% (n = 16/346) in the ETV group and 27.1% (n = 57/210) in the VPS group. ETV had a lower rate of postoperative complications (odds ratio 0.22, 95% confidence interval 0.11-0.33, I2 = 0%).

CONCLUSIONS

Symptomatic LOVA can be successfully managed with surgical intervention. ETV and VPS have similar success rates when used as first-line treatment. VPS has a higher complication rate.

Chronic Pleural Effusion in Ventriculoperitoneal Shunt due to Diaphragmatic CSF Fistula: Report of a Case Treated by Endoscopic Choroid Plexus Coagulation and Literature Review

INTRODUCTION

Chronic pleural cerebrospinal fluid (CSF) effusion is a rare complication after ventriculoperitoneal (VP) shunt insertion and only 18 cases in children and adults have been described so far without catheter dislocation to the intrathoracic cavity.

CASE PRESENTATION

We report on a 4-year-old girl with a complex history of underlying neurogenetic disorder, a hypoxic-ischemic encephalopathy after influenza A infection with septic shock and severe acute respiratory distress syndrome, followed by meningitis at the age of 10 months. In consequence, she developed a severe cerebral atrophy and post-meningitic hydrocephalus requiring placement of a VP shunt. At age 4, she was admitted with community-acquired mycoplasma pneumonia and developed increasing pleural effusions leading to severe respiratory distress and requiring continuous chest tube drainage (up to 1,000-1,400 mL/day) that could not be weaned. β trace protein, in CSF present at concentrations >6 mg/L, was found in the pleural fluid at low concentrations of 2.7 mg/L. An abdomino-thoracic CSF fistula was finally proven by single photon emission computerized tomography combined with low-dose computer tomography. After shunt externalization, the pleural effusion stopped and the chest tube was removed. CSF production rate remains high above 500 mL/24 h. An atrial CSF shunt could not be placed, since a hemodynamically relevant atrial septum defect with frail circulatory balance would not have tolerated the large CSF volumes. Therefore, she underwent a total bilateral endoscopic choroid plexus laser coagulation (CPC) within the lateral ventricles via bi-occipital burr holes. Postoperatively CSF production rate went close to 0 mL and after external ventricular drain removal no signs and symptoms of hydrocephalus developed during a follow-up of now 2.5 years.

CONCLUSION

In summary, pleural effusions in patients with VP shunt can rarely be caused by an abdomino-thoracic fistula, with non-elevated β-trace protein in the pleural fluid. The majority of reported cases in literature were treated by ventriculoatrial shunt. This is the 2nd reported case, which has been successfully treated by radical CPC alone including the temporal horn choroid plexus, making the child shunt independent.

Idiopathic Aqueductal Stenosis: Late Neurocognitive Outcome in ETV Operated Adult Patients

Objective

The aim of the present study is to evaluate a neurocognitive outcome in patients affected by late-onset idiopathic aqueductal stenosis (LIAS) who underwent endoscopic third ventriculostomy (ETV).

Materials and Methods

A prospective study was conducted between January 2015 and December 2017 in a series of 10 consecutive adult patients referred to the Neurosurgery Department of IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy. All the adult patients admitted with absence of CSF flow through the aqueduct in phase-contrast (PC)—MRI sequences or a turbulence void signal in T2—weighted images in midsagittal thin-slice MR sequences underwent a specific neuroradiological, neurological, and neurocognitive assessment pre- and postoperatively.

Results

All patients affected by gait and sphincter disturbances improved after ETV. Attentive and executive functions as well as visuo-spatial memory and verbal executive functions improved in several patients. Similarly, the affective and behavioral scales improved in almost 50% of the patients. No major complications have been recorded, and no patients required a second surgery for shunt placement.

Conclusion

Endoscopic third ventriculostomy represents a safe and effective surgical procedure for the treatment of LIAS. In addition to neurological improvement, we demonstrated also postoperative neurocognitive improvement mainly in attentive and executive functions, visuo-spatial memory, verbal executive functions, and behavioral and affective domains.

Characterization of a mouse model of chronic hydrocephalus induced by partial occlusion of the aqueduct of Sylvius in the adult brain

BACKGROUND

Hydrocephalus is a neurologic disturbance produced by the abnormal production, circulation, and absorption of cerebrospinal fluid (CSF). Late-onset idiopathic aqueductal stenosis induces normal pressure hydrocephalus (NPH) in adults. To date, no animal model replicating chronic NPH is available to study the pathophysiological changes observed in these subjects.

NEW METHOD

We performed and characterized a model that induces chronic hydrocephalus in the adult mouse brain by producing a pre-aqueductal semiobstruction using an acetate lamina inserted into the atrium of the aqueduct of Sylvius. After surgical procedure, we analyzed the hydrocephalus development on days 60 and 120 and sham-operated animals were used as controls. We included an additional group of hydrocephalus resolution in which we removed the obstruction and analyzed the morphological changes in the brain.

RESULTS

The hydrocephalus was fully established on day 60 after the obstruction and remained stable for 120 days. In all animals, the intracranial pressure remained ~4.08 mmHg and we did not find statistically significant differences between the hydrocephalus groups and controls. We did not find motor impairments and anxiety-like behaviors among groups and the analysis of microglia and astrogliosis revealed mild glial reactivity.

COMPARISON WITH EXISTING METHODS

This model generates a long-term ventricular enlargement with normal intracranial pressure and moderate glial reactivity. Importantly, this model allows the reversibility of ventricular enlargement after the removal of the obstructive film from the brain.

CONCLUSIONS

This mouse model may be useful to study the long-term cerebral alterations that occur during NPH or after its surgical resolution.

Assessment of neurological symptoms in adult hydrocephalus occlusus. A pilot study

BACKGROUND

Comprehensively describe and compare (pre⁄postoperatively) the clinical symptomatology in adult non-communicated hydrocephalus. Associated hydrocephalus signs were analyzed with the idiopathic Normal Pressure Hydrocephalus Scale (iNPH Scale). A standardized clinical scale for non-communicated hydrocephalus is currently not in use.

METHODS

Ten patients with hydrocephalus occlusus (HO) were analyzed. Hydrocephalus signs were examined with the iNPH Scale in gait, neuropsychology, continence, and balance before and three months after treatment with shunt operation or third endoscopic ventriculostomy.

RESULTS

Patients significantly improved in iNPH total score (25.8%) and gait score (35.4%) three months after neurosurgical intervention. Domain scores in neuropsychology, continence, and balance reached statistical trends (p ≤ 0.066). Most clinical symptoms and signs at baseline improved after surgery (dizziness, lapse of concentration, gait instability, and headache).

CONCLUSION

Patients with non-communicated HO also showed classical hydrocephalus symptoms as communicated in iNPH patients. The iNPH Scale allows a structured neurological assessment over the disease's progress and surgical intervention. Further studies with a larger patient samples are necessary to support our results.

Implication of image guidance in endoscopic third ventriculostomy: Technical note

Background

Endoscopic third ventriculostomy (ETV) is an advanced surgical procedure and plays a major role in the management of hydrocephalus. The complications associated with this procedure are grave and unforgiving. Image guidance system (IGS) can help reduce these complications. This technical note describes the technique for utilizing image guidance in carrying out ETV with safety and efficacy.

Methods

The authors have performed ETV on more than 75 cases. We describe a step-by-step technique for the implication of image guidance while performing ETV including the trajectory planning, coregistration, approach, and third ventricular floor perforation. For illustration, we present the case of a 54-year-old female with moderate-intensity headache and central vertigo for 2 months presented with no significant findings on examination. Magnetic resonance imaging (MRI) showed dilated lateral and third ventricles with normal sized fourth ventricle. A diagnosis of aqueductal stenosis was made and ETV was performed under image guidance.

Results

Since 2012, we performed 78 cases of ETV with the help of image guidance. None of the patients had any episode of intraoperative hemorrhage. Two patients (2.56%) had fornix contusions.

Conclusion

Image guidance can help reduce complications and is becoming an essential tool in performing ETV. IGS ETV technique may benefit young neurosurgeons the most and can help them overcome the learning curve with safety.

A New Optimal Marker to Evaluate the Effectiveness of Endoscopic Third Ventriculostomy During Operation: "Folding Sign"

OBJECTIVE

Endoscopic third ventriculostomy (ETV) remains the mainstay of treatment for noncommunicating hydrocephalus these days. However, there has been no adequate clue for the intraoperative assessment of ETV efficacy until now. This time, we propose a newly defined finding, "folding sign," which is visible and enables us to confirm penetration of both the third ventricle floor and the Liliequist membrane (LM) during operation. In this report, we describe consecutive ETV cases and discuss the mechanism of folding sign and its clinical meanings.

METHODS

A folding sign is a formation of a sequence of folds at the tectal region, which is easily detectable. A total of 30 patients with newly diagnosed hydrocephalus between October 2014 and February 2018 at Tokyo Women's Medical University were enrolled in our case series (age range, 3 months to 74 years). The difference between proportions was analyzed by the χ² method.

RESULTS

In all, 12 patients (40%) showed a folding sign: congenital hydrocephalus including aqueductal stenosis (AS) and isolated fourth ventricle in 4 patients, and brain tumor-associated noncommunicating hydrocephalus in 8 patients. Statistical analysis showed that the emergence of a folding sign was related to successful ETV, indicating it as an optimal intraoperative sign to assess the effectiveness of this procedure (P = 0.0298).

CONCLUSION

The folding sign is a newly defined sign to predict the success of ETV during operation. This optimal finding appears only when the LM is sufficiently opened; therefore, it could be a good candidate for an intraoperative assessment tool.

Management of Obstructive Hydrocephalus in Pregnant Patient

De novo obstructive hydrocephalus is a rare event during pregnancy. There are only case reports presented in literature. We aimed to discuss the pathophysiological basis and management options with an exemplary case presentation and review of the current literature. A 28-year-old G2P1 patient presented to our clinic with headache, vomiting, and deteriorated vision at the 8^th week of gestation. She had no history of central nervous system infection or trauma. A brain magnetic resonance imaging was obtained. There was hydrocephalus due to cerebral aqueduct stenosis (Evan's index of 58%). She was managed conservatively with bed rest and diuretics; however, she got no relief. A ventriculoperitoneal shunt was inserted at the 13^th week of gestation. At the 38^th week, she had cesarean section (C/S) due to previous history of C/S in the first pregnancy and present cord entanglement of the fetus. C/S was conducted under epidural anesthesia after conforming she had no increased intra cranial pressure findings. Delivery was uneventful with a healthy newborn. Obstructive hydrocephalus is a very rare complication during pregnancy. Hydrocephalus becomes obvious and necessitates treatment, before the third trimester of pregnancy. Timely diagnosis, especially differentiation from preeclampsia, is a life-saving step. If no complication happens during intervention for hydrocephalus, spontaneous vaginal delivery is a safe way of delivery for both mother's and newborn's well-being. C/S should be saved for obstetrical indications and can be conducted under epidural anesthesia if intracranial pressure is kept under control. Interdisciplinary approach of neurosurgeons and anesthesiologists is pivotal for delicate care of the patient and the baby.

Clinical analysis of aqueductal stenosis in patients with hydrocephalus in a Kenyan setting

Introduction

Aqueductal stenosis is the commonest cause of congenital hydrocephalus. The scope of this paper is to highlight the disease burden of hydrocephalus attributed to aqueductal stenosis which still remains unknown in our setting.

Methods

In a descriptive cross-sectional study, 258 records of patients diagnosed with hydrocephalus were analyzed after ethical approval from Kenyatta National Hospital- University of Nairobi (KNH-UON) ethics and research committee from January 2010 to May 2016. Patients with a diagnosis of hydrocephalus due to aqueductal stenosis were included in this study. Patients age, sex, mode of delivery, associated comorbidities, presenting complaints, neurosurgical intervention performed, Kafarnosky score were recorded. Data were divided into 2 sets based on the patient's age i.e. whether < 1 year or > 12 years. Data were recorded on google data collection form and analyzed using Google spreadsheets.

Results

Out of 258 cases of hydrocephalus, 52 had aqueductal stenosis. Male to female sex ratio for this condition was 3:2. There were 25 cases < 1year and 27 cases > 12 years old who were diagnosed with hydrocephalus due to aqueductal stenosis. Associated conditions were bilateral congenital talipes equinovarus, spina bifida, Arnold Chairi malformations, meningitis and HIV. The presenting complaints differed according to the age groups. Neurosurgical interventions included Endoscopic Third Ventriculostomy (ETV) in 21 cases, insertion of Ventriculoperitoneal (VP) shunt and ETV were done in 3 cases while the rest had only insertion of VP shunt. The Kafanosky score improve from < 50 pre-op to 19 cases achieving a score of 100, six months post-op.

Conclusion

Aqueductal stenosis contributes a significant burden of morbidity in patients with hydrocephalus. Clinical presentation differs according to patients age. Accurate diagnosis and treatment remain a cardinal to improving patient outcome.

Herpes simplex virus Type 1 encephalitis in an adolescent presenting with acute hydrocephalus

Herpes simplex virus Type 1 (HSV-1) is a human neurotropic virus causing encephalitis, corneal blindness or several peripheral nervous system disorders. Herpes Simplex encephalitis (HSE) is the most devastating clinical syndrome with severe morbidity and mortality. Hydrocephalus associated with viral meningoencephalitis is an extremely rare entity with only few documented cases, predominantly due to HSV-2 infection. HSV-1 infection of central nervous system present in the majority of the cases as encephalitis. We report a rare case of an 11-year-old child suffering from HSV-1 infection of central nervous system causing hydrocephalus without evidence of encephalitis.

Lower rates of symptom recurrence and surgical revision after primary compared with secondary endoscopic third ventriculostomy for obstructive hydrocephalus secondary to aqueductal stenosis in adults

OBJECT

Endoscopic third ventriculostomy (ETV) is the treatment of choice for obstructive hydrocephalus; however, the success of ETV in patients who have previously undergone shunt placement remains unclear. The present study analyzed 103 adult patients with aqueductal stenosis who underwent ETV for obstructive hydrocephalus and evaluated the effect of previous shunt placement on post-ETV outcomes.

METHODS

This study was a retrospective review of 151 consecutive patients who were treated between 2007 and 2013 with ETV for hydrocephalus. One hundred three (68.2%) patients with aqueductal stenosis causing obstructive hydrocephalus were included in the analysis. Postoperative ETV patency and aqueductal and cisternal flow were assessed by high-resolution, gradient-echo MRI. Post-ETV Mini-Mental State Examination, Timed Up and Go, and Tinetti scores were compared with preoperative values. Univariate and multivariate analyses were performed comparing the post-ETV outcomes in patients who underwent a primary (no previous shunt) ETV (n = 64) versus secondary (previous shunt) ETV (n = 39).

RESULTS

The majority of patients showed significant improvement in symptoms after ETV; however, no significant differences were seen in any of the quantitative tests performed during follow-up. Symptom recurrence occurred in 29 (28.2%) patients after ETV, after a median of 3.0 (interquartile range 0.8–8.0) months post-ETV failure. Twenty-seven (26.2%) patients required surgical revision after their initial ETV. Patients who received a secondary ETV had higher rates of symptom recurrence (p = 0.003) and surgical revision (p = 0.003), particularly in regard to additional shunt placement/revision post-ETV (p = 0.005). These differences remained significant after multivariate analysis for both symptom recurrence (p = 0.030) and surgical revision (p = 0.043).

CONCLUSIONS

Patients with obstructive hydrocephalus due to aqueductal stenosis exhibit symptomatic improvement after ETV, with a relatively low failure rate. Patients with a primary history of shunt placement who undergo ETV as a secondary intervention are at increased risk of symptom recurrence and need for surgical revision post-ETV.

Hydrocephalus in aqueductal stenosis--a retrospective outcome analysis and proposal of subtype classification

Treatment of aqueductal stenosis (AQS) has undergone several paradigm shifts during the past decades. Currently, endoscopic ventriculostomy (ETV) is recommended as treatment of choice. Several authors have addressed the issue of variable ETV success rates depending on age and pathogenetic factors. However, success rates have usually been defined as "ETV non-failure." The aim of the study was a retrospective analysis of radiological and neurological treatment response after ETV or VP-shunting (VPS) in age-dependent subtypes of AQS.

PATIENTS AND METHODS

Eighty patients (median age 12.0 years, range 0-79 years) have been treated for MRI-proven aqueductal stenosis. Neurological treatment success was defined by neurological improvement and, in childhood, head circumference. Radiological response was measured as Evan's index in follow-up MRI. Initial signs and symptoms, type of surgery, and complications were analyzed.

RESULTS

Four types of AQS have been defined with distinct age ranges and symptomatology: congenital type I (n = 24), chronic progressive (tectal tumor-like) type II (n = 23), acute type III (n = 10), and adult chronic (normal-pressure hydrocephalus-like) type IV (n = 23). Retrospective analysis of neurological and radiological outcome suggested that congenital type I (<1 years of age) may be more successfully treated with VPS than with ETV (81 vs. 50 %). Treatment of chronic juvenile type II (age 2-15) by ETV 19 % compared to 57 % after VP-shunt, but similar neurological improvement (>80 %). There has been no influence of persistent ventriculomegaly in type II after ETV in contrast to VPS therapy for neurological outcome. Adult acute type III (age > 15 years) responded excellent to ETV. Chronic type IV (iNPH-like) patients (age > 21) responded neurologically in 70 % after ETV and VPS, but radiological response was low (5 %).

CONCLUSION

AQS can be divided into four distinct age groups and types in regards of clinical course and symptomatology. Depending on the AQS type, ETV cannot be unequivocally recommended. Congenital type I AQS may have a better neurological outcome with VP-shunt whereas acute type III offers excellent ETV results. Chronic progressive type II still requires prospective investigation of long-term ETV outcome, especially when ventriculomegaly persists. Late chronic type IV seems to result in similar outcome after VP-shunt and ETV.

Investigating cerebral oedema using poroelasticity

Cerebral oedema can be classified as the tangible swelling produced by expansion of the interstitial fluid volume. Hydrocephalus can be succinctly described as the abnormal accumulation of cerebrospinal fluid (CSF) within the brain which ultimately leads to oedema within specific sites of parenchymal tissue. Using hydrocephalus as a test bed, one is able to account for the necessary mechanisms involved in the interaction between oedema formation and cerebral fluid production, transport and drainage. The current state of knowledge about integrative cerebral dynamics and transport phenomena indicates that poroelastic theory may provide a suitable framework to better understand various diseases. In this work, Multiple-Network Poroelastic Theory (MPET) is used to develop a novel spatio-temporal model of fluid regulation and tissue displacement within the various scales of the cerebral environment. The model is applied through two formats, a one-dimensional finite difference - Computational Fluid Dynamics (CFD) coupling framework, as well as a two-dimensional Finite Element Method (FEM) formulation. These are used to investigate the role of endoscopic fourth ventriculostomy in alleviating oedema formation due to fourth ventricle outlet obstruction (1D coupled model) in addition to observing the capability of the FEM template in capturing important characteristics allied to oedema formation, like for instance in the periventricular region (2D model).

Endoscopic Third Ventriculostomy in 250 Adults With Hydrocephalus

BACKGROUND:

Endoscopic third ventriculostomy (ETV) has been used predominantly in the pediatric population in the past. Application in the adult population has been less extensive, even in large neurosurgical centers. To our knowledge, this report is one of the largest adult ETV series reported and has the consistency of being performed at 1 center.

OBJECTIVE:

To determine the efficacy, safety, and outcome of ETV in a large adult hydrocephalus patient series at a single neurosurgical center. In addition, to analyze patient selection criteria and clinical subgroups (including those with ventriculoperitoneal shunt [VPS] malfunction or obstruction and neurointensive care unit patients with extended ventricular drainage before ETV) to optimize surgical results in the future.

METHODS:

We conducted a retrospective review of adult ETV procedures performed at our center between 2000 and 2014.

RESULTS:

The overall rate of success (no further cerebrospinal fluid diversion procedure performed plus clinical improvement) of 243 completed ETVs was 72.8%. Following is the number of procedures with the success rate in parentheses: aqueduct stenosis, 56 (91%); communicating hydrocephalus including normal pressure hydrocephalus, nonnormal pressure hydrocephalus, and remote head trauma, 57 (43.8%); communicating hydrocephalus in postoperative posterior fossa tumor without residual tumor, 14 (85.7%); communicating hydrocephalus in subarachnoid hemorrhage without intraventricular hemorrhage, 23 (69.6%); obstruction from tumor/cyst, 42 (85.7%); VPS obstruction (diagnosis unknown), 23 (65.2%); intraventricular hemorrhage, 20 (90%); and miscellaneous (obstructive), 8 (50%). There were 9 complications in 250 intended procedures (3.6%); 5 (2%) were serious.

CONCLUSION:

Use of ETV in adult hydrocephalus has broad application with a low complication rate and reasonably good efficacy in selected patients.

The Use of an Aspirating/Resecting Device to Reduce Stoma Closure Following Endoscopic Third Ventriculostomy for Aqueductal Stenosis

BACKGROUND

Endoscopic third ventriculostomy (ETV) is commonly used to treat obstructive hydrocephalus. Closure of the stoma can be associated with symptom recurrence and need for further surgical intervention.

OBJECTIVE

To describe the use of a side-cutting aspiration device for treatment of aqueductal stenosis in patients undergoing ETV.

METHODS

A retrospective review of 30 consecutive adults with aqueductal stenosis treated with ETV using an adjunct side-cutting aspiration device between 2011 and 2013 was performed. Patients included in the study ranged from 35 to 64 years of age. ETV success was determined by the absence of stoma closure (aqueductal and cisternal flow assessed by high-resolution, gradient-echo magnetic resonance imaging), post-ETV symptom recurrence, and need for subsequent surgical intervention.

RESULTS

Patients treated by using a side-cutting aspirator had no observed stoma closure (0%) and a 10% (n = 3) rate of post-ETV symptom recurrence. Three patients (10%) demonstrated a need for surgical revision following initial ETV with the side-cutting aspirator.

CONCLUSION

Adult patients with obstructive hydrocephalus secondary to aqueductal stenosis exhibited a low rate of stoma closure with the use of a side-cutting aspiration device, and a rate of complications comparable to the known literature. Likewise, patients treated with a side-cutting aspirator may have lower symptom recurrence post-ETV and require fewer revisions in comparison with the known literature. As such, a side-cutting aspirator may be considered as a useful adjunct to traditional ETV for the treatment of obstructive hydrocephalus secondary to aqueductal stenosis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Exploring the efficacy of endoscopic ventriculostomy for hydrocephalus treatment via a multicompartmental poroelastic model of CSF transport: a computational perspective

This study proposes the implementation of a Multiple-Network Poroelastic Theory (MPET) model coupled with finite-volume computational fluid dynamics for the purpose of studying, in detail, the effects of obstructing CSF transport within an anatomically accurate cerebral environment. The MPET representation allows the investigation of fluid transport between CSF, brain parenchyma and cerebral blood, in an integral and comprehensive manner. A key novelty in the model is the amalgamation of anatomically accurate choroid plexuses with their feeding arteries and a simple relationship relaxing the constraint of a unique permeability for the CSF compartment. This was done in order to account for the Aquaporin-4-mediated swelling characteristics. The aim of this varying permeability compartment was to bring to light a feedback mechanism that could counteract the effects of ventricular dilation and subsequent elevations of CSF pressure through the efflux of excess CSF into the blood system. This model is used to demonstrate the impact of aqueductal stenosis and fourth ventricle outlet obstruction (FVOO). The implications of treating such a clinical condition with the aid of endoscopic third (ETV) and endoscopic fourth (EFV) ventriculostomy are considered. We observed peak CSF velocities in the aqueduct of the order of 15.6 cm/s in the healthy case, 45.4 cm/s and 72.8 cm/s for the mild and severe cases respectively. The application of ETV reduced the aqueductal velocity to levels around 16-17 cm/s. Ventricular displacement, CSF pressure, wall shear stress (WSS) and pressure difference between lateral and fourth ventricles (ΔP) increased with applied stenosis, and subsequently dropped to nominal levels with the application of ETV. The greatest reversal of the effects of atresia come by opting for ETV rather than the more complicated procedure of EFV.