The role of endoscopic choroid plexus coagulation in the management of hydrocephalus

Preliminary Experience Suggests the Addition of Choroid Plexus Cauterization to Functional Hemispherectomy May Reduce Posthemispherectomy Hydrocephalus

BACKGROUND

Cerebral hemispherectomy can effectively treat unihemispheric epilepsy. However, posthemispherectomy hydrocephalus (PHH), a serious life-long complication, remains prevalent, requiring careful considerations in technique selection and postoperative management. In 2016, we began incorporating open choroid plexus cauterization (CPC) into our institution's hemispherectomy procedure in an attempt to prevent PHH.

OBJECTIVE

To determine whether routine CPC prevented PHH without exacerbating hemispherectomy efficacy or safety.

METHODS

A retrospective review of consecutive patients who underwent hemispherectomy for intractable epilepsy between 2011 and 2021 was performed. Multivariate logistic regression was used to identify factors independently associated with PHH requiring cerebrospinal fluid (CSF) shunting.

RESULTS

Sixty-eight patients were included in this study, of whom 26 (38.2%) underwent CPC. Fewer patients required CSF shunting in the CPC group (7.7% vs 28.7%, P = .033) and no patients who underwent de novo hemispherectomy with CPC developed PHH. Both cohorts experienced seizure freedom (65.4% vs 59.5%, P = .634) and postoperative complications, including infection (3.8% vs 2.4%, P = .728), hemorrhage (0.0% vs 2.4%, P = .428), and revision hemispherectomy (19.2% vs 14.3%, P = .591) at similar rates. Patients without CPC had greater odds of developing PHH requiring CSF shunting (odds ratio = 8.36, P = .026). The number needed to treat with CPC to prevent an additional case of PHH was 4.8, suggesting high effectiveness.

CONCLUSION

Preventing PHH is critical. Our early experience demonstrated that routinely incorporating CPC into hemispherectomy effectively prevents PHH without causing additional complications, especially in first-time hemispherectomies. A multicenter randomized controlled trial with long-term follow-up is required to corroborate the findings of our single-institutional case series and determine whether greater adoption of this technique is justified.

Choroid plexus epithelium and its role in neurological diseases

Choroid plexus epithelial cells can secrete cerebrospinal fluid into the ventricles, serving as the major structural basis of the selective barrier between the neurological system and blood in the brain. In fact, choroid plexus epithelial cells release the majority of cerebrospinal fluid, which is connected with particular ion channels in choroid plexus epithelial cells. Choroid plexus epithelial cells also produce and secrete a number of essential growth factors and peptides that help the injured cerebrovascular system heal. The pathophysiology of major neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, as well as minor brain damage diseases like hydrocephalus and stroke is still unknown. Few studies have previously connected choroid plexus epithelial cells to the etiology of these serious brain disorders. Therefore, in the hopes of discovering novel treatment options for linked conditions, this review extensively analyzes the association between choroid plexus epithelial cells and the etiology of neurological diseases such as Alzheimer's disease and hydrocephalus. Finally, we review CPE based immunotherapy, choroid plexus cauterization, choroid plexus transplantation, and gene therapy.

Postoperative seizures following endoscopic third ventriculostomy and choroid plexus cauterization: a case series

OBJECTIVE

In this study, the authors sought to investigate variables associated with postoperative seizures following endoscopic third ventriculostomy and choroid plexus cauterization (ETV/CPC) for treatment of pediatric hydrocephalus.

METHODS

A retrospective analysis of 37 patients who underwent ETV/CPC for treatment of hydrocephalus at an academic medical center from September 2016 to March 2021 was conducted. Demographics, etiology of hydrocephalus, operative details, electroencephalography (EEG) data, MRI findings, need for subsequent procedures, perioperative laboratory tests, medical history, and presence of clinical postoperative seizures were collected. Postoperative seizures were defined as clinical seizures within 24 hours of surgery. Eighteen patients received levetiracetam intraoperatively as well as over the next 7 days postoperatively for seizure prophylaxis.

RESULTS

Of 37 included patients, 9 (24%) developed clinical seizures within 24 hours after surgery, 5 of whom subsequently had electroclinical seizures captured on video-EEG. The clinical seizures in 4 of those 5 patients (80%) may have been associated with the hemisphere of the brain through which the endoscope was introduced. The median corrected age of the cohort was 3.4 months. The median corrected age of patients who did not develop postoperative seizures was 2.3 months compared with 0.7 months for patients who did develop postoperative seizures (p > 0.99). Postoperative seizures occurred in 43% (3/7) of prenatally repaired myelomeningocele patients versus 29% (2/7) of postnatally repaired myelomeningocele patients. Of the 18 patients who received prophylactic levetiracetam, none (0%) developed postoperative seizures compared with 9 of the 19 patients (47%) who did not receive prophylactic levetiracetam (p = 0.014).

CONCLUSIONS

Postoperative seizures were recorded in 24% of the pediatric patients who underwent ETV/CPC for hydrocephalus, which is higher than previously reported rates in the literature of 5%. Since 80% of the postoperative electrographic seizures may have been associated with the hemisphere through which the endoscope was introduced, the surgical entry site may contribute to postoperative seizure development. In patients who received prophylactic perioperative levetiracetam, the postoperative seizure incidence dropped to 0% compared with 47% in those who did not receive prophylactic perioperative levetiracetam. This finding indicates that the use of prophylactic perioperative levetiracetam may be efficacious in the prevention of clinical seizures in this patient population.

Bilateral hyperplasia of choroid plexus with severe CSF production: a case report and review of the glymphatic system

BACKGROUND

An important feature of hydrocephalus is the alteration of the cerebral spinal fluid (CSF) homeostasis. New insights in the understanding of production, secretion, and absorption of CSF, along with the discovery of the glymphatic system (GS), can be useful for a better understanding and treatment of hydrocephalus in disorders with CSF overproduction.

CASE DESCRIPTION

A 1-year-old patient was diagnosed with communicating hydrocephalus; ventricle peritoneal shunt (VPS) is installed and ascites developed. VPS is exposed, yielding volumes of 1000-1200ml/day CSF per day. MRI is performed showing generalized choroidal plexus hyperplasia. Bilateral endoscopic coagulation of thechoroid plexus was performed in 2 stages (CPC) however the high rate of CSF production persisted, needing a bilateral plexectomy through septostomy, which finally decreased the CSF outflow.

DISCUSSION

New knowledge about the CSF physiology will help to propose better treatment depending on the cause of the hydrocephalus. The GS is becoming an additional reason to better study and develop new therapies focused of the modulation of alternative CSF reabsorption.

CONCLUSION

Despite the current knowledge about hydrocephalus, we remain without a complete understanding of the pathophysiology of this condition. GS could be more important than conventional concept of reabsorption of CSF in the arachnoid villi, therefore GS could be a new key point, which will guide future investigations.

Endoscopic third ventriculostomy and choroid plexus cauterization (ETV/CPC) for hydrocephalus of infancy: a technical review

In the twenty-first century, choroid plexus cauterization (CPC) in combination with endoscopic third ventriculostomy (ETV) has emerged as an effective treatment for some infants with hydrocephalus, leading to the favourable condition of 'shunt independence'. Herein we provide a narrative technical review considering the indications, procedural aspects, morbidity and its avoidance, postoperative care and follow-up. The CP has been the target of hydrocephalus treatment for more than a century. Early eminent neurosurgeons including Dandy, Putnam and Scarff performed CPC achieving generally poor results, and so the procedure fell out of favour. In recent years, the addition of CPC to ETV was one of the reasons greater ETV success rates were observed in Africa, compared to developed nations, and its popularity worldwide has since increased. Initial results indicate that when ETV/CPC is performed successfully, shunt independence is more likely than when ETV is undertaken alone. CPC is commonly performed using a flexible endoscope via septostomy and aims to maximally cauterize the CP. Success is more likely in infants aged >1 month, those with hydrocephalus secondary to myelomeningocele and aqueductal obstruction and those with >90% cauterized CP. Failure is more likely in those with post-haemorrhagic hydrocephalus of prematurity (PHHP), particularly those <1 month of corrected age and those with prepontine scarring. High-quality evidence comparing the efficacy of ETV/CPC with shunting is emerging, with data from ongoing and future trials offering additional promise to enhance our understanding of the true utility of ETV/CPC.

Surgical treatment of post-infectious hydrocephalus in infants

The management of post-infective hydrocephalus in infants remains a challenging task for the pediatric neurosurgeon. The decision-making curve is often complex in that appropriate temporizing measures need to be implemented to properly clear any infection within the CSF before any decision can be made regarding a permanent solution. The etiology differs at varying stages of neonatal development, and the weight of the child, skin fragility, and relevant surgical treatment options are often important limiting factors. Deciding on the optimal treatment option involves assessing the etiology, age, and clinical and radiological features of the individual case and selecting the most appropriate surgical option.

Patients Attitude to Technology : A Way to Improve Hydrocephalus Management and Follow up Using Smartphone Intelligent Application

Smartphone applications ("apps") have become ubiquitous with the advent of smartphones and tablets in recent years. Increasingly the utility of these apps is being explored in healthcare delivery. Hydrocephalus is a condition that is usually followed by a neurosurgeon for the patient's life. We explore patient acceptability of a mobile app as an adjunct to outpatient follow-up of patients with hydrocephalus. A questionnaire was circulated amongst patients with hydrocephalus (adults and children). Patients were asked questions about their hydrocephalus; expectations for outpatient follow up, whether they have smartphone/tablet/internet access and whether they would be interested in a mobile app for their long term hydrocephalus follow up. 191 patients completed questionnaires, 98 respondents were adults (mean age 46.1) and 93 were children less than 18 years old (mean age 8). Overall 36.1% of patients did not know the cause of their hydrocephalus. 96.7% have a shunt. 76.5% of adults and 80.6% of children had 1-4 shunt surgeries, 14.3% of adults and 11.8% of children had 5-9 shunt surgeries, 3.1% of adults and 5.4% of children had 10-14 shunt surgeries. 71.7% of patients expect to be followed-up routinely in clinic for life. All children had smartphones or tablets, compared to 86.7% of adults. Children were more interested in a hydrocephalus app, 84.9% saying yes, compared to 71.4% of adults. Adults who were not interested in the app did not have a smartphone or tablet. Hydrocephalus management is a lifelong task and innovations in technology for engaging patients in its management are vital. The majority of patients are interested in mobile apps for outpatient management of hydrocephalus. We will follow this up with a feasibility study of a custom designed hydrocephalus app.

Long-term follow-up for patients with infantile hydrocephalus treated by choroid plexus coagulation

OBJECTIVEShunt surgery is the most common treatment for hydrocephalus, but it is associated with several long-term complications. Endoscopic choroid plexus coagulation (CPC) and endoscopic third ventriculostomy (ETV) are alternative surgeries that may avoid the need for shunt surgery. Although the short-term efficacy and safety of CPC have been reported in previous studies, long-term outcome, including not only avoiding shunt placement but also intellectual development, remains to be elucidated. The purpose of the present study was to investigate the long-term outcome of CPC.METHODSThe study population comprised patients who had infantile hydrocephalus treated by endoscopic CPC before the age of 24 months and who were followed until at least 5 years of age. Retrospective review was performed using the medical charts. The authors assessed educational status and the full-scale intelligence quotient (FSIQ) using the Wechsler Intelligence Scale for Children (WISC) IV as the means to evaluate the intellectual development.RESULTSFourteen patients with infantile hydrocephalus underwent CPC with or without ETV as a primary surgery. There were no intraoperative complications. In 7 patients (50%), hydrocephalus was successfully controlled without shunt placement. Six patients (43%) eventually required shunt placement. In one patient hydrocephalus was controlled by additional ETV. In the shunt-independent group, 4 patients went to age-appropriate school or achieved age-appropriate development according to intelligence quotient (IQ), 1 patient went to specialized school, and 2 patients had disabilities. In the shunt-dependent group, 4 patients went to an age-appropriate school or achieved age-appropriate development by IQ, 1 patient went to specialized school, and 1 patient had disabilities. The mean FSIQ score in 3 patients without shunts was 90 (range 89-91) and the mean FSIQ score in 4 patients with shunts was 80 (range 48-107). There was no significant difference in the rate of normal development between the shunt-independent group and the shunt-dependent group (p = 0.72).CONCLUSIONSThe CPC with or without ETV can be a safe and effective treatment in children with infantile hydrocephalus. Long-term control of hydrocephalus and normal intellectual development can be achieved in successful cases. Further prospective studies should be required to elucidate appropriate indications.

Starling forces drive intracranial water exchange during normal and pathological states

AIM

To quantify the exchange of water between cerebral compartments, specifically blood, tissue, perivascular pathways, and cerebrospinal fluid-filled spaces, on the basis of experimental data and to propose a dynamic global model of water flux through the entire brain to elucidate functionally relevant fluid exchange phenomena.

METHODS

The mechanistic computer model to predict brain water shifts is discretized by cerebral compartments into nodes. Water and species flux is calculated between these nodes across a network of arcs driven by Hagen-Poiseuille flow (blood), Darcy flow (interstitial fluid transport), and Starling's Law (transmembrane fluid exchange). Compartment compliance is accounted for using a pressure-volume relationship to enforce the Monro-Kellie doctrine. This nonlinear system of differential equations is solved implicitly using MATLAB software.

RESULTS

The model predictions of intraventricular osmotic injection caused a pressure rise from 10 to 22 mmHg, followed by a taper to 14 mmHg over 100 minutes. The computational results are compared to experimental data with R2=0.929. Moreover, simulated osmotic therapy of systemic (blood) injection reduced intracranial pressure from 25 to 10 mmHg. The modeled volume and intracranial pressure changes following cerebral edema agree with experimental trends observed in animal models with R2=0.997.

CONCLUSION

The model successfully predicted time course and the efficacy of osmotic therapy for clearing cerebral edema. Furthermore, the mathematical model implicated the perivascular pathways as a possible conduit for water and solute exchange. This was a first step to quantify fluid exchange throughout the brain.

The importance of extent of choroid plexus cauterization in addition to endoscopic third ventriculostomy for infantile hydrocephalus: a retrospective North American observational study using propensity score-adjusted analysis

OBJECTIVE Combined endoscopic third ventriculostomy (ETC) and choroid plexus cauterization (CPC)-ETV/CPC- is being investigated to increase the rate of shunt independence in infants with hydrocephalus. The degree of CPC necessary to achieve improved rates of shunt independence is currently unknown. METHODS Using data from a single-center, retrospective, observational cohort study involving patients who underwent ETV/CPC for treatment of infantile hydrocephalus, comparative statistical analyses were performed to detect a difference in need for subsequent CSF diversion procedure in patients undergoing partial CPC (describes unilateral CPC or bilateral CPC that only extended from the foramen of Monro [FM] to the atrium on one side) or subtotal CPC (describes CPC extending from the FM to the posterior temporal horn bilaterally) using a rigid neuroendoscope. Propensity scores for extent of CPC were calculated using age and etiology. Propensity scores were used to perform 1) case-matching comparisons and 2) Cox multivariable regression, adjusting for propensity score in the unmatched cohort. Cox multivariable regression adjusting for age and etiology, but not propensity score was also performed as a third statistical technique. RESULTS Eighty-four patients who underwent ETV/CPC had sufficient data to be included in the analysis. Subtotal CPC was performed in 58 patients (69%) and partial CPC in 26 (31%). The ETV/CPC success rates at 6 and 12 months, respectively, were 49% and 41% for patients undergoing subtotal CPC and 35% and 31% for those undergoing partial CPC. Cox multivariate regression in a 48-patient cohort case-matched by propensity score demonstrated no added effect of increased extent of CPC on ETV/CPC survival (HR 0.868, 95% CI 0.422-1.789, p = 0.702). Cox multivariate regression including all patients, with adjustment for propensity score, demonstrated no effect of extent of CPC on ETV/CPC survival (HR 0.845, 95% CI 0.462-1.548, p = 0.586). Cox multivariate regression including all patients, with adjustment for age and etiology, but not propensity score, demonstrated no effect of extent of CPC on ETV/CPC survival (HR 0.908, 95% CI 0.495-1.664, p = 0.755). CONCLUSIONS Using multiple comparative statistical analyses, no difference in need for subsequent CSF diversion procedure was detected between patients in this cohort who underwent partial versus subtotal CPC. Further investigation regarding whether there is truly no difference between partial versus subtotal extent of CPC in larger patient populations and whether further gain in CPC success can be achieved with complete CPC is warranted.

Cerebrospinal fluid hypersecretion in pediatric hydrocephalus

Hydrocephalus, despite its heterogeneous causes, is ultimately a disease of disordered CSF homeostasis that results in pathological expansion of the cerebral ventricles. Our current understanding of the pathophysiology of hydrocephalus is inadequate but evolving. Over this past century, the majority of hydrocephalus cases has been explained by functional or anatomical obstructions to bulk CSF flow. More recently, hydrodynamic models of hydrocephalus have emphasized the role of abnormal intracranial pulsations in disease pathogenesis. Here, the authors review the molecular mechanisms of CSF secretion by the choroid plexus epithelium, the most efficient and actively secreting epithelium in the human body, and provide experimental and clinical evidence for the role of increased CSF production in hydrocephalus. Although the choroid plexus epithelium might have only an indirect influence on the pathogenesis of many types of pediatric hydrocephalus, the ability to modify CSF secretion with drugs newer than acetazolamide or furosemide would be an invaluable component of future therapies to alleviate permanent shunt dependence. Investigation into the human genetics of developmental hydrocephalus and choroid plexus hyperplasia, and the molecular physiology of the ion channels and transporters responsible for CSF secretion, might yield novel targets that could be exploited for pharmacotherapeutic intervention.

Hydrocephalus in children

Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk flow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that affect ventricular outflow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in brain imaging, technology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder.

Endoscopic third ventriculostomy and choroid plexus cauterization with a rigid neuroendoscope in infants with hydrocephalus

OBJECT Combining endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) has been shown to improve the success rate compared with ETV alone in infants (less than 24 months) with hydrocephalus who were treated in developing countries. The authors sought to evaluate the safety and efficacy of this procedure, using a rigid neuroendoscope, in a single North American center, and to assess whether the ETV success score (ETVSS), the CURE Children's Hospital of Uganda ETVSS (CCHU ETVSS), and other pre- and intraoperative variables could predict success. METHODS The authors performed a retrospective review of consecutive ETV/CPC procedures performed using a rigid neuroendoscope to treat infantile hydrocephalus. The infants underwent the procedure at Miami Children's Hospital between January 2007 and 2014, with at least one postoperative follow-up. Duration of follow-up or time to failure of ETV/CPC, the primary outcome measure, was documented. A repeat CSF diversion procedure or death was considered as a failure of ETV/CPC. The time to event was measured using a Kaplan-Meier analysis. The authors analyzed ETVSS, CCHU ETVSS, and pre- and intraoperative variables to determine their suitability to predict success. RESULTS Eighty-five patients (45 boys) with a mean age of 4.3 months (range 1 day to 20 months) underwent ETV/CPC. Etiology included intraventricular hemorrhage of prematurity in 44 patients (51.7%), myelomeningocele (MMC) in 7 (8.2%), congenital aqueductal stenosis in 12 (14.1%), congenital communicating hydrocephalus in 6 (7.1%), Dandy-Walker complex in 6 (7.1%), postinfectious hydrocephalus in 5 (5.8%), and other cause in 5 (5.8%). Six procedure-related complications occurred in 5 (5.8%) patients, including 2 hygromas, 1 CSF leak, and 3 infections. There were 3 mortalities in this cohort. ETV/CPC was successful in 42.1%, 37.7%, and 36.8% of patients at 6, 12, and 24 months follow-up, respectively. The median (95% CI) time to ETV/CPC failure was 4.0 months (0.9-7.1 months). In univariate analyses, both the ETVSS (hazard ratio [HR] 1.03; 95% CI 1.01-1.05; p = 0.004) and CCHU ETVSS (HR 1.48; 95% CI 1.04-2.09; p = .028) were predictive of outcome following ETV/CPC. In multivariate analysis, the presence of prepontine scarring was associated with ETV/CPC failure (HR 0.34; 95% CI 0.19-0.63; p < 0.001). Other variables, such as radiological criteria (prepontine interval, prepontine space, aqueductal stenosis, Third Ventricular Morphology Index) and intraoperative findings (ventriculostomy pulsations, extent of CPC), did not predict outcome. CONCLUSIONS ETV/CPC is a feasible alternative to ETV and ventriculoperitoneal shunt in infants with hydrocephalus. Both the ETVSS and CCHU ETVSS predicted success following ETV/CPC in this single-center North American cohort of patients.

Volumetric analysis of cerebrospinal fluid and brain parenchyma in a patient with hydranencephaly and macrocephaly--case report

The aim of this study was to perform for the first time the intracranial volumetric analysis of cerebrospinal fluid (CSF) and brain parenchyma in the supratentorial and infratentorial space in a 30-year-old female patient with hydranencephaly and macrocephaly. A head scan performed using a 3T magnetic resonance was followed by manual segmentation of the brain parenchyma and CSF on T2 coronal brain sections. The volume of CSF and brain parenchyma was measured separately for the supratentorial and infratentorial space. The total volume of the intracranial space was 3645.5 cm³. In the supratentorial space, the volume of CSF was 3375.2 cm³ and the volume of brain parenchyma was 80.3 cm³. In the infratentorial space, the volume of CSF was 101.3 cm³ and the volume of the brain parenchyma was 88.7 cm³. In the supratentorial space, there was severe malacia of almost all brain parenchyma with no visible remnants of the choroid plexuses. Infratentorial structures of the brainstem and cerebellum were hypoplastic but completely developed. Since our patient had no choroid plexuses in the supratentorial space and no obstruction between dural sinuses and CSF, development of hydrocephalus and macrocephaly cannot be explained by the classic hypothesis of CSF physiology with secretion, unidirectional circulation, and absorption as its basic postulates. However, the origin and turnover of the enormous amount of intracranial CSF volume, at least 10-fold larger than normal, and the mechanisms of macroencephaly development could be elucidated by the new hypothesis of CSF physiology recently published by our research team.

Early outcome of combined endoscopic third ventriculostomy and choroid plexus cauterization in childhood hydrocephalus

OBJECT

Although shunts have been the mainstay in treating hydrocephalus over the past 5 decades, the use of endoscopic techniques in addressing this disorder in children offers both the neurosurgeon and the patient a unique opportunity to avoid shunting and its attendant complications. The combination of endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) remains uncommon in most centers despite its potential promise. The authors sought to investigate the efficacy of combining ETV and CPC (ETV+CPC) in treating childhood hydrocephalus in Nigeria. Infection and spina bifida contribute a high percentage of the cases of hydrocephalus in Nigeria.

METHODS

Over a 2-year period, all children 0-18 years of age who had endoscopic treatment for hydrocephalus were prospectively evaluated to determine the need for subsequent treatment. Children who had the combination of ETV+CPC were identified as a subcategory and form the basis of this retrospective study.

RESULTS

Twenty-two of 38 endoscopically treated children had undergone the combination of ETV+CPC for hydrocephalus of varied etiology. There was a male preponderance (2.5:1), and 90% of the patients were infants. The overall success rate was 75%, with the best outcome in children with spina bifida. One child required a repeat ETV.

CONCLUSIONS

The combination of ETV+CPC is useful in treating children with hydrocephalus of varied etiology. The complication profile is acceptable, and the overall success rate is comparable to that associated with shunt insertion.

A computational model of cerebrospinal fluid production and reabsorption driven by Starling forces

Experimental evidence has cast doubt on the classical model of river-like cerebrospinal fluid (CSF) flow from the choroid plexus to the arachnoid granulations. We propose a novel model of water transport through the parenchyma from the microcirculation as driven by Starling forces. This model investigates the effect of osmotic pressure on water transport between the cerebral vasculature, the extracellular space (ECS), the perivascular space (PVS), and the CSF. A rigorous literature search was conducted focusing on experiments which alter the osmolarity of blood or ventricles and measure the rate of CSF production. Investigations into the effect of osmotic pressure on the volume of ventricles and the flux of ions in the blood, choroid plexus epithelium, and CSF are reviewed. Increasing the osmolarity of the serum via a bolus injection completely inhibits nascent fluid flow production in the ventricles. A continuous injection of a hyperosmolar solution into the ventricles can increase the volume of the ventricle by up to 125%. CSF production is altered by 0.231 µL per mOsm in the ventricle and by 0.835 µL per mOsm in the serum. Water flux from the ECS to the CSF is identified as a key feature of intracranial dynamics. A complete mathematical model with all equations and scenarios is fully described, as well as a guide to constructing a computational model of intracranial water balance dynamics. The model proposed in this article predicts the effects the osmolarity of ECS, blood, and CSF on water flux in the brain, establishing a link between osmotic imbalances and pathological conditions such as hydrocephalus and edema.

Ventricular endoscopy in the pediatric population: review of indications

INTRODUCTION

Neuroendoscopy has greatly impacted pediatric neurosurgery over the past few decades. Improved optics and microsurgical tools have allowed neuroendoscopes to be used for a multitude of neurosurgical procedures.

DISCUSSION

In this review article, we present the breadth of intraventricular neuroendoscopic procedures for the treatment of conditions ranging from hydrocephalus and brain tumors to congenital cysts and other pathologies. We critically discuss treatment indications and reported success rates for neuroendoscopic procedures. We also present novel approaches, technical nuances, and variations from recently published literature and as practiced in the authors' institution.

Endoscopic third ventriculostomy and choroid plexus cauterization in infants with hydrocephalus: a retrospective Hydrocephalus Clinical Research Network study

OBJECT

The use of endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) has been advocated as an alternative to CSF shunting in infants with hydrocephalus. There are limited reports of this procedure in the North American population, however. The authors provide a retrospective review of the experience with combined ETV + CPC within the North American Hydrocephalus Clinical Research Network (HCRN).

METHODS

All children (< 2 years old) who underwent an ETV + CPC at one of 7 HCRN centers before November 2012 were included. Data were collected retrospectively through review of hospital records and the HCRN registry. Comparisons were made to a contemporaneous cohort of 758 children who received their first shunt at < 2 years of age within the HCRN.

RESULTS

Thirty-six patients with ETV + CPC were included (13 with previous shunt). The etiologies of hydrocephalus were as follows: intraventricular hemorrhage of prematurity (9 patients), aqueductal stenosis (8), myelomeningocele (4), and other (15). There were no major intraoperative or early postoperative complications. There were 2 postoperative CSF infections. There were 2 deaths unrelated to hydrocephalus and 1 death from seizure. In 18 patients ETV + CPC failed at a median time of 30 days after surgery (range 4-484 days). The actuarial 3-, 6-, and 12-month success for ETV + CPC was 58%, 52%, and 52%. Time to treatment failure was slightly worse for the 36 patients with ETV + CPC compared with the 758 infants treated with shunts (p = 0.012). Near-complete CPC (≥ 90%) was achieved in 11 cases (31%) overall, but in 50% (10 of 20 cases) in 2012 versus 6% (1 of 16 cases) before 2012 (p = 0.009). Failure was higher in children with < 90% CPC (HR 4.39, 95% CI 0.999-19.2, p = 0.0501).

CONCLUSIONS

The early North American multicenter experience with ETV + CPC in infants demonstrates that the procedure has reasonable safety in selected cases. The degree of CPC achieved might be associated with a surgeon's learning curve and appears to affect success, suggesting that surgeon training might improve results.

Obliteration of the choroid plexus after endoscopic coagulation

OBJECT

Endoscopic choroid plexus coagulation (CPC) with or without endoscopic third ventriculostomy (ETV) has been shown to be effective for selected patients with hydrocephalus. However, whether the effect of the coagulation is temporary and the choroid plexus regenerates or can be obliterated has remained largely unknown. The authors evaluate the effectiveness of CPC and report 3 cases of obliteration demonstrated by direct endoscopic observation.

METHODS

The authors retrospectively analyzed the surgical results of patients with hydrocephalus primarily treated by CPC with or without ETV. Charts were reviewed for demographic data, clinical presentations, surgical therapies, and clinical outcomes.

RESULTS

Eighteen patients with hydrocephalus were surgically treated using endoscopic CPC between July 2002 and July 2012. In 12 patients, ETV was concurrently performed. The etiology of hydrocephalus was posthemorrhagic in 5 patients, myelomeningocele in 3, postmeningitis in 2, congenital aqueductal stenosis in 1, hydranencephaly in 1, porencephaly in 1, and idiopathic in 5. The mean age at surgery was 8 months (range 0.3-24 months). The mean follow-up was 64 months. In 9 cases (50%), control of hydrocephalus was successful and the patients did not require further surgeries. In 9 patients (50%), treatment failed. Of these, 3 patients underwent repeat ETV 2, 3, and 38 months after the initial surgery. Endoscopic observation of the previous coagulation site revealed no regeneration of the choroid plexus in 2 patients, who underwent repeat ETV 2 and 3 months after CPC. In 1 patient who underwent repeat ETV 38 months after CPC, no regeneration of the choroid plexus, except for that in the proximity of the foramen of Monro, was observed.

CONCLUSIONS

Endoscopic CPC with or without ETV can be a safe and effective treatment alternative to shunt placement in infantile hydrocephalus. Obliteration of the choroid plexus can persist in the relatively long term following CPC, which may contribute to the long-term control of hydrocephalus in successful cases.

Choroid plexus coagulation in infants with extreme hydrocephalus or hydranencephaly

OBJECT.: Severe hydrocephalus and hydranencephaly are common congenital conditions in Kenya. In patients with these conditions, ventriculoperitoneal (VP) shunts are associated with appreciable complications and endoscopic third ventriculostomies (ETVs) have limited success. Endoscopic choroid plexus coagulation (CPC) to diminish CSF production is a potential treatment option. The purpose of this study was to evaluate the effect of CPC without ETV in infants with severe hydrocephalus or hydranencephaly.

METHODS

Medical records of infants with severe congenital hydrocephalus or hydranencephaly who underwent CPC in Kijabe Hospital from November 2010 to April 2013 were reviewed retrospectively. Thirty-three patients with complete medical records and preoperative radiographic images were identified. After CPC, the infants were followed in the Kijabe Hospital outpatient department, in mobile clinics, or by telephone. Success of the CPC was defined as resolution of preoperative symptoms, stabilization of head size, and avoidance of VP shunt placement.

RESULTS

Patients were followed from 30 to 608 days (median of 120 days). Three patients were lost to follow-up. Of the 30 evaluable patients, CPC was considered to be successful in 13 (43.3%), including 8 of 20 patients with severe hydrocephalus and 5 of 10 with hydranencephaly. Failure of CPC was evident from increased head circumference in 14 (82%) of 17 patients and from CSF leakage in 3. Of the 17 failures, 13 occurred within 3 months of surgery. Six patients died: 3 whose CPC procedures were failures, 2 whose CPC was successful, and 1 postoperatively. Of the 17 in whom CPC failed, 10 subsequently underwent VP shunt insertion.

CONCLUSIONS

CPC stabilizes macrocephaly in approximately 40% of infants with severe congenital hydrocephalus and hydranencephaly and can be considered as an alternative to VP shunt placement.

John Edwin Scarff (1898-1978) and endoscopic choroid plexus coagulation: A historical vignette

John Edwin Scarff (1898-1978) was one of the pioneers of neuroendoscopy and the head of the Department of Neurological Surgery at Columbia University in New York from 1947 to 1949. In this article, we highlight the pioneering and longstanding efforts of John E. Scarff in support of endoscopic choroid plexus coagulation. These efforts represent an important part of the rich history of neuroendoscopy and a legacy to which the current procedure owes a great credit.

Congenital idiopathic hydrocephalus of infancy: the results of treatment by endoscopic third ventriculostomy with or without choroid plexus cauterization and suggestions for how it works

BACKGROUND

The traditional bulk flow model of communicating hydrocephalus does not support treatment by endoscopic third ventriculostomy (ETV), but successful treatment is reported in adults. This study is the first to report long-term success of ETV +/- choroid plexus cauterization (CPC) for infants with congenital idiopathic hydrocephalus (CIH). The results are interpreted in the context of current models for hydrocephalus.

METHODS

The CURE Children's Hospital of Uganda prospective database was reviewed for the years 2001-2006 to identify children <24 months of age meeting the criteria for CIH who underwent ETV with or without bilateral CPC. Kaplan-Meier method was used to assess treatment success survival. Gehan-Breslow-Wilcoxin and logrank tests were used to determine significance of survival differences. Fisher's exact test was used to determine the significance of differences between groups.

RESULTS

Sixty-four infants (mean/median age, 6.1/5.0 months) met the inclusion criteria. Sixteen consecutive patients were treated by ETV alone, and the subsequent 48 by ETV/CPC (mean/median follow-up 34.4/36.0 months). ETV was successful in 20 % and ETV/CPC in 72.4 % at 4 years (p < 0.0002, logrank test; p = 0.0006, Gehan-Breslow-Wilcoxin; hazard ratio 6.9, 95 % CI 2.5-19.3).

CONCLUSIONS

ETV/CPC was significantly more successful than ETV alone in treating CIH. The primary effect of ETV, as a pulsation absorber, and of CPC, as a pulsation reducer, may be to abate the net force of intraventricular pulsations that produce ventricular expansion. ETV alone may be less successful for infants because of greater brain compliance. ETV/CPC should be considered an effective primary treatment option.

Choroid plexus coagulation for hydrocephalus not due to CSF overproduction: a review

OBJECTIVE

This study aims to review the role of choroid plexus coagulation (CPC) for hydrocephalus not due to CSF overproduction.

METHODS

The literatures covering CPC/cauterization/extirpation and ablation searched through PubMed were reviewed.

RESULTS

The history of CPC goes back to early 1900s by open surgery. It has evolved to mainly an endoscopic surgery since 1930s. With the development of other treatment methods and the understanding of CSF dynamics, the application of CPC dramatically decreased by 1970s. In late 2000, there was a resurgence of CPC in combination with endoscopic third ventriculostomy (ETV) performed in Africa.

CONCLUSIONS

CPC remains one of the options for the treatment of hydrocephalus in selected cases. CPC might provide a temporary reduction in CSF production to allow the further development of CSF absorption in infant. Adding CPC to ETV for infants with communicating hydrocephalus may increase the shunt independent rate thus avoiding the consequence of late complication related to the shunt device. This is important for patients who are difficult to be followed up, due to geographical and/or socioeconomic constrains. Adding CPC to ETV for obstructive hydrocephalus in infant may also increase the successful rate. Furthermore, CPC may be an option for cases with high chance of shunt complication such as hydranencephaly. In addition, CPC may act as an adjunct therapeutic measure for complex cases such as multiloculated hydrocephalus. In comparison with the traditional treatment of CSF shunting, the role of CPC needs to be further evaluated in particular concerning the neurocognitive development.

Infantile posthemorrhagic hydrocephalus

INTRODUCTION

Intraventricular/germinal matrix hemorrhage affects 7-30% of premature neonates, 25-80% of whom (depending on the grade of the hemorrhage) will develop hydrocephalus requiring shunting. Predisposing factors are low birth weight and gestational age.

MATERIAL

There is increasing evidence for the role of TGF-β1 in the pathogenesis of hydrocephalus, but attempts to develop treatment modalities to clear the cerebrospinal fluid (CSF) from blood degradation products have not succeeded so far. Ultrasound is a valuable screening tool for high-risk infants and magnetic resonance imaging is increasingly utilized to differentiate progressive hydrocephalus from ex vacuo ventriculomegaly, evaluate periventricular parenchymal damage, decide on the surgical treatment of hydrocephalus, and follow up these patients in the long term. Treatment of increasing ventriculomegaly and intracranial hypertension in the presence of hemorrhagic CSF can involve a variety of strategies, all with relative drawbacks, aiming to drain the CSF while gaining time for it to clear and the neonate to reach term and become a suitable candidate for shunting. Eventually, patients with progressive ventriculomegaly causing intracranial hypertension, who have reached term and their CSF has cleared from blood products, will need shunting.

CONCLUSION

Cognitive long-term outcome is influenced more by the effect of the initial hemorrhage and other perinatal events and less by hydrocephalus, provided that this has been addressed timely in the early postnatal period. Shunting can have many long-term side effects due to mechanical complications and overdrainage. In particular, patients with posthemorrhagic hydrocephalus are more susceptible to multiloculated hydrocephalus and encysted fourth ventricle, both of which are challenging to treat.

Development of hydrocephalus and classical hypothesis of cerebrospinal fluid hydrodynamics: facts and illusions

According to the classical hypothesis of the cerebrospinal fluid (CSF) hydrodynamics, CSF is produced inside the brain ventricles, than it circulates like a slow river toward the cortical subarachnoid space, and finally it is absorbed into the venous sinuses. Some pathological conditions, primarily hydrocephalus, have also been interpreted based on this hypothesis. The development of hydrocephalus is explained as an imbalance between CSF formation and absorption, where more CSF is formed than is absorbed, which results in an abnormal increase in the CSF volume inside the cranial CSF spaces. It is believed that the reason for the imbalance is the obstruction of the CSF pathways between the site of CSF formation and the site of its absorption, which diminishes or prevents CSF outflow from the cranium. In spite of the general acceptance of the classical hypothesis, there are a considerable number of experimental results that do not support such a hypothesis and the generally accepted pathophysiology of hydrocephalus. A recently proposed new working hypothesis suggests that osmotic and hydrostatic forces at the central nervous system microvessels are crucial for the regulation of interstial fluid and CSF volume which constitute a functional unit. Based on that hypothesis, the generally accepted mechanisms of hydrocephalus development are not plausible. Therefore, the recent understanding of the correlation between CSF physiology and the development of hydrocephalus has been thoroughly presented, analyzed and evaluated, and new insights into hydrocephalus etiopathology have been proposed, which are in accordance with the experimental data and the new working hypothesis.

Endoscopic minimally invasive neurosurgery: emerging techniques and expanding role through an extensive review of the literature and our own experience - part I: intraendoscopic neurosurgery

BACKGROUND/AIMS

Minimally invasive neurosurgery is a growing field, more so in recent decades. The modernization of tools, especially the endoscope, has allowed for critical improvements and crucial advancements in minimally invasive neurosurgery. The current classification scheme for endoscopic procedures needs to be updated to reflect these advancements.

METHODS

Although the field of neuroendoscopy is continually evolving, the terminologies utilized to describe endoscopic procedures reflect and favor its use as mostly an assisting device complementing the microscope. Even though the classification was adequate for its time, it has become inexact and therefore confusing. We therefore propose a new classification scheme that encompasses the growing independence of endoscopic minimally invasive neurosurgery (EMIN) as well as the changing landscape within EMIN procedures.

RESULTS

We have classified our EMIN procedures, since 2002, as either 'intraendoscopic' (IEN) or 'extraendoscopic' (XEN) in relation to the endoscope's axis. Exemplary cases of IEN and a review of the literature are presented as well.

CONCLUSION

Our proposed classification scheme for solely endoscopic procedures is presented. The role of the endoscope as an independent tool is clarified.

Possible detrimental effects of neurosurgical irrigation fluids on neural tissue: an evidence based analysis of various irrigants used in contemporary neurosurgical practice

Physiological saline and other solutions used as irrigation fluids during neurosurgical procedures have long been debated to cause adverse effects on neural tissue. Laboratory based research over the past fifty years has described the possible harm caused to central nervous system cells by normal saline, and has advocated the use of safer alternatives such as lactated Ringer's solution and artificial cerebrospinal fluid. However, there is a dearth of corresponding clinical studies to support this standpoint. Worldwide, normal saline remains the most widely used neurosurgical irrigation fluid. We have attempted to document the preference of practicing neurosurgeons worldwide regarding the irrigation fluids via an electronic mail survey, and have analyzed the available evidence on the relative safety of various irrigation fluids. We recommend the use of lactated Ringer's solution and artificial cerebrospinal fluid as neurosurgical irrigants, especially during neuroendoscopy and longer procedures requiring application of copious amount of irrigation fluid.

Endoscopic choroid plexus cauterization versus ventriculoperitoneal shunt for hydranencephaly and near hydranencephaly: a prospective study

OBJECTIVE

To prospectively evaluate the results of endoscopic choroid plexus cauterization (ECPC) and ventriculoperitoneal shunts (VPSs) in infants with hydranencephaly or near hydranencephaly.

METHODS

We prospectively collected clinical data from all untreated hydranencephalic and near hydranencephalic children from October 2006 to March 2008. All patients treated were randomly divided into 2 groups, ECPC or VPS, and submitted to either endoscopic choroid plexus cauterization or ventriculoperitoneal shunt placement.

RESULTS

Seventeen patients were entered into the study. ECPC was completed in 9 patients; the procedure successfully controlled excessive head circumference and signs of increased intracranial pressure in 8 of these patients (88.8%). One endoscopic procedure in a hydranencephalic child failed after 7 months, resulting in VPS placement. Thus, of the 10 patients randomized to ECPC, 8 were treated successfully by ECPC (80%), and 2 went on to have a VPS. There were no complications related to this method of treatment. Seven children were randomized to the VPS group; and of these, 2 patients (28.5%) required shunt revisions during follow-up. There were no complications related to shunt placement. There was no difference in the success rate between patients randomized to ECPC and VPS, but the ECPC was more economical.

CONCLUSION

ECPC is an acceptable alternative to VPS for treatment of hydranencephaly and near hydranencephaly. It is a single, definitive, safe, effective, and economical treatment that may avoid the complications of shunting.

Intracranial hemorrhage in the preterm infant: understanding it, preventing it

New discoveries in neonatal imaging, cerebral monitoring, and hemodynamics, and greater understanding of inflammatory and genetic mechanisms involved in intracranial hemorrhage (ICH) in the preterm infant are creating opportunities for innovative early detection and prevention approaches. This article covers the spectrum of ICH in the preterm infant, including germinal matrix intraventricular hemorrhage, its complications, and associated phenomena, such as the emerging role of cerebellar hemorrhage. The overall aim of this article is to review the current knowledge of the mechanisms, diagnosis, outcome, and management of preterm ICH; to revisit the origins from which they develop; and to discuss future expectations.

Various irrigation fluids affect postoperative brain edema and cellular damage during experimental neurosurgery in rats

BACKGROUND

This study was conducted to investigate how various irrigation fluids used during neurosurgical procedures affect the degree of postoperative brain edema and cellular damage during experimental neurosurgery in rats.

METHODS

The cerebral cortex was exposed and incised crosswise with a surgical knife under irrigation with an artificial CSF, lactated Ringer's solution, or normal saline. Four hours after injury, irrigation was stopped and brain tissue samples were obtained from injured and uninjured sites. Specific gravity, cerebrovascular permeability, and TTC staining of the samples were evaluated. Incision and irrigation of the brain were not performed on the control group.

RESULTS

At the injured site, specific gravities of the samples in the normal saline group and the lactated Ringer's solution group were significantly lower than the specific gravity in the artificial CSF group. The EB concentration was significantly higher in the lactated Ringer's solution group and relatively high in the normal saline group as compared with the artificial CSF group. TTC staining did not differ significantly between the artificial CSF group and the control group. It was significantly lower in the lactated Ringer's solution group and the normal saline group than in the control group and the artificial CSF group.

CONCLUSIONS

As compared with normal saline and lactated Ringer's solution, artificial CSF reduced postoperative brain edema, cerebrovascular permeability, and cellular damage in sites injured by experimental neurosurgery in rats.

Destruction of choroid plexus cells in vitro: a new concept for the treatment of hydrocephalus?

OBJECTIVE

The current treatment of hydrocephalus using ventriculoperitoneal shunts and third ventriculostomies remains problematic. We revisited the concept of destruction of the choroid plexus for the treatment of hydrocephalus by using an immunotoxin-based technique to specifically destroy this tissue. This approach was based on the observation that, as an epithelial tissue, choroid plexus expresses a number of specific cell-surface proteins that represent excellent potential targets for the creation of a choroid plexus-specific immunotoxin.

METHODS

In this study, we characterized sheep and human choroid plexus cells (including atypical and carcinoma cell lines) using fluorescence microscopy in combination with histochemical staining of rat brain and confirmed the presence of a number of epithelium-specific proteins in choroid plexus cells. Immunotoxins were then manufactured by linking these antibodies to ricin A chain and ricin A-B chain. These immunotoxins were delivered to choroid plexus-derived cells in culture, and the results were compared with results of exposure to a nonspecific immunotoxin.

RESULTS

Complete cell death of choroid plexus cells was seen after only a 1-hour exposure to the specific immunotoxin, as opposed to the minimal cell death seen with a nonspecific immunotoxin after several hours of exposure.

CONCLUSION

These results suggest that immunotoxin-mediated ablation of choroid plexus may be a viable method of treating hydrocephalus and choroid plexus-derived tumors.

Possible harmful effects on central nervous system cells in the use of physiological saline as an irrigant during neurosurgical procedures

BACKGROUND

Physiologic saline is routinely used as an irrigant in neurosurgery especially in Japan. Cerebrospinal fluid (CSF) differs from physiologic saline in its concentration of inorganic salts, osmolality, and pH and is completely different insofar as it contains glucose, protein, cholesterol, and other lipids. The present study was designed to compare the possible functional and morphologic deleterious influence of these differences on cultured rat neural cells using saline (S), Ringer's solution with glucose (Lactec G, LG; Otsuka Pharmaceutical Co.; Tokyo, Japan) and without glucose (Lactec, L; Otsuka Pharmaceutical Co.), and an artificial CSF (ACSF).

METHODS

Primary cultured rat neurons and astrocytes were divided into five groups according to the medium used, the four experimental groups (ACSF, L, LG, and S) and one control group (C). At various time points up to 24 hours, the rhodamine 123 uptake by neuronal or astrocytic cellular mitochondria was evaluated as cell function assessment. Morphologic assessment for both neuron and astrocyte culture was carried out with scanning electron microscopy (SEM) at the 24-hour time point.

RESULTS

SEM showed little difference between the C and ACSF groups, whereas morphologic deterioration was particularly severe in the S group for both neurons and astrocytes. In the case of neuronal mitochondrial activity, the L and S groups demonstrated respectively severe and some deterioration, particularly in the mitochondria of the neuronal processes. The deleterious effects in mitochondrial activity of the S group were even more apparent in the astrocytic cells.

CONCLUSION

These results suggest that physiologic saline, when used as an irrigant in neurologic surgery, might in some circumstances cause damage to exposed and compromised neural cells.

Subdural hygroma as a complication of endoscopic neurosurgery--two case reports

Two cases of subdural hygroma occurred in a series of 77 neuroendoscopic procedures. An 8-year-old boy underwent neuroendoscopic cysto-cisternostomy of a left temporal arachnoid cyst. Routine postoperative magnetic resonance imaging 7 days later showed a large left-sided subdural hygroma without clinical symptoms. During the following 3 months, the subdural hygroma did not resolve spontaneously, so it was drained through a burr hole. A 3-month-old boy with aqueductal stenosis developed bilateral subdural hygromas after third ventriculostomy. Several punctures through the open anterior fontanelle relieved the hygromas but increasing head circumference required ventriculoperitoneal shunting 12 months later. Complications of neuroendoscopic procedures are increasingly reported, including various kinds of bleeding, infections, or damage of neuronal tissue. Only three previous cases of subdural hygroma or hematoma after neuroendoscopic interventions have been reported. The possible etiologies and clinical consequences of this rare complication have to be considered before selecting neuroendoscopy treatment.

Posthaemorrhagic ventricular dilatation

Posthaemorrhagic ventricular dilatation is the most serious direct complication of intraventricular haemorrhage after preterm birth. It results initially from multiple small blood clots throughout the cerebrospinal fluid channels impeding circulation and reabsorption. Management is difficult and new treatment approaches are needed.