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Background: The flow pattern of the cerebrospinal fluid is probably the most important factor related to obstruction of ventricular catheters during the normal treatment of hydrocephalus. To better comprehend the flow pattern, we have carried out a parametric study via numerical models of ventricular catheters. In previous studies, the flow was studied under steady and, recently, in pulsatile boundary conditions by means of computational fluid dynamics (CFD) in three-dimensional catheter models., Objective: This study aimed to bring in prototype models of catheter CFD flow solutions as well to introduce the theory behind parametric development of ventricular catheters., Methods: A preceding study allowed deriving basic principles which lead to designs with improved flow patterns of ventricular catheters. The parameters chosen were the number of drainage segments, the distances between them, the number and diameter of the holes on each segment, as well as their relative angular position., Results: CFD results of previously unreleased models of ventricular catheter flow solutions are presented in this study. Parametric development guided new designs with better flow distribution while lowering the shear stress of the catheters holes. High-resolution 3D printed catheter solutions of three models and basic benchmark testing are introduced as well., Conclusions: The next generation of catheter with homogeneous flow patterns based on parametric designs may represent a step forward for the treatment of hydrocephalus, by possibly broadening their lifespan.

Background: Ventriculoatrial (VA) shunt is a routine technique for the treatment of hydrocephalus. The correct position at the superior vena cava-right atrium junction is generally assessed by radiography. We present the first experience of an alternative, nonradiographic technique to assess the distal end of the VA shunts through an electrocardiographic (EKG) method. The technique has developed from the large experience of central venous catheters (CVC) worldwide; the EKG-guided method is a common and validated alternative to standard radiologic control of the location of the tip of any CVC., Methods: Five consecutive patients underwent VA shunt with venous catheter positioned with the EKG-guided technique. The position of the catheter tip was verified by standard chest radiography., Results: Four men and 1 woman (mean age, 45.4 years) underwent VA shunt for hydrocephalus with the EKG-guided technique. The side of internal jugular vein puncture was the right side in 4 cases and the left side in 1 case. As confirmed by radiography, all VA shunt tips were located within the correct range. There was no radiologic evidence of procedure-related complication or catheters that had to be replaced., Conclusions: The EKG-guided technique for VA shunts is as accurate as fluoroscopy, but simpler, more readily available, less expensive, safer, and more cost effective. It reduces the need of radiography and radiologic exposition for both patients and operators. The EKG method may be a valid and cost-effective alternative to standard radiologic control in VA shunts, as for any central venous access device, and could become the preferential method for confirming tip position during VA shunt surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background/aims: The management of extracerebral collections of fluid in patients with hydrocephalus can be problematic for either their simultaneous separate management or sequential management, each of which may require multiple surgeries and the management of external drains. The object of this report is to review the experience with a shunt configuration that simultaneously diverts ventricular fluid and extracerebral fluid, whether subdural or subarachnoid in location, through different outflow resistances., Methods: The medical records, including neuroimaging of patients with hydrocephalus and clinically significant extracerebral collections of low density who were managed by implanting a differential pressure type shunt, were retrospectively reviewed., Results: Four patients, 3 children and 1 adult, met inclusion criteria. Three had the entire differential pressure shunt implanted under 1 anesthetic, and 1 had a catheter inserted into the subdural space and connected into an existing ventriculoperitoneal shunt system. The extracerebral fluid collections cleared in all 4 patients, and the CSF shunt continued to function normally., Conclusion: A single surgical procedure to implant a differential pressure shunt can simultaneously drain and obliterate an extracerebral fluid collection while managing the hydrocephalus. Compared to routines that include external drainage, differential pressure shunting requires fewer surgeries, shorter hospitalization, with expected less expense., (© 2017 S. Karger AG, Basel.)

Normal pressure hydrocephalus (NPH) is a syndrome found in the elderly, which is characterized by ventriculomegaly and deep white matter ischemia (DWMI) on magnetic resonance imaging (MRI) and the clinical triad of gait disturbance, dementia, and urinary incontinence. NPH has been estimated to account for up to 10% of cases of dementia and is significant because it is treatable by ventriculoperitoneal shunting. Patients with a known cause of chronic communicating hydrocephalus, that is, meningitis or hemorrhage, tend to respond better than patients with the so-called "idiopathic" form, most likely because of poor selection criteria in the past. Good response to shunting has been associated with hyperdynamic cerebrospinal fluid (CSF) flow through the aqueduct. In the early days of MRI, patients with a large CSF flow void extending from the foramen of Monro through the aqueduct to the fourth ventricle had an excellent chance of responding to ventriculoperitoneal shunting (P < 0.003). Today, we use phase-contrast MRI to measure the volume of CSF flowing through the aqueduct in either direction over a cardiac cycle. When this aqueductal CSF stroke volume is sufficiently elevated, there is an excellent chance of shunt responsiveness (100% positive predictive value in 1 study). Idiopathic NPH appears to be a "two-hit" disease-benign external hydrocephalus (BEH) in infancy followed by DWMI in late adulthood. As BEH occurs when the sutures are still open, these infants present with large heads, a finding also noted in patients with NPH. Although BEH has been attributed to immature arachnoidal granulations with decreased CSF resorptive capacity, this now appears to be permanent and may lead to a parallel pathway for CSF resorption via the extracellular space of the brain. With DWMI, the myelin lipid is lost, exposing the polar water molecules to myelin protein, increasing resistance to CSF outflow and leading to backing up of CSF and hydrocephalus., (Copyright © 2016. Published by Elsevier Inc.)

Noncommunicating hydrocephalus is often referred to as obstructive hydrocephalus and is by definition an intraventricular obstruction of cerebrospinal fluid flow. Patient symptoms depend on the rapidity of onset. Acute obstructive hydrocephalus causes sudden rise in the intracranial pressure, which may lead to death, whereas in chronic hydrocephalus there may not be any symptoms. Computed tomography and magnetic resonance imaging play important roles in the diagnosis and management of hydrocephalus. Advances in magnetic resonance imaging such as the 3D sequences and phase-contrast imaging have revolutionized the preoperative and postoperative assessment of noncommunicating hydrocephalus. We would be discussing the various causes of noncommunicating hydrocephalus and their imaging., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Hydrocephalus basically means an increase in the volume of cerebrospinal fluid (CSF) and the ventricles. As simple as it may sound, the definition and classification of hydrocephalus have been a matter of debate over many decades. Many international neurosurgical and radiological workgroups have tried to develop a consensus and over the last 5-10 years have been able to put forth a more well-defined and standardized approach. Though, the debate and controversy surrounding this topic is expected to continue, we have tried to review the most recent and consensually accepted definition and classification. Although conventionally classified as either "obstructive and nonobstructive" or "communicating and noncommunicating," none of the classification schemes were without confusion and errors. A more precise nomenclature is to divide hydrocephalus as either "communicating": with or without obstruction of CSF absorption, or as "noncommunicating": with definite obstruction to CSF absorption. We discuss communicating hydrocephalus in the current article, and the subsequent article deals with noncommunicating hydrocephalus., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Ventricular access devices (VAD) and ventriculosubgaleal shunts (VSGS) are currently both used as temporising devices to affect CSF drainage in neonatal posthaemorrhagic hydrocephalus (PHH), without clear evidence of superiority of either procedure. In this systematic review and meta-analysis, we compared the VSGS and VAD regarding complication rates, ventriculoperitoneal shunt conversion and infection rates, and mortality and long-term disability., Methods: The review was registered with the PROSPERO international prospective register of systematic reviews (registration number CRD42015019750) and was conducted in accordance with PRISMA guidelines., Results and Conclusions: The literature search of five databases identified 338 publications, of which 5 met the inclusion criteria. All were retrospective cohort studies (evidence class 3b and 4). A significantly lower proportion of patients with a VSGS required CSF tapping compared to patients with a VAD (log OR -4.43, 95% CI -6.14 to -2.72). No other significant differences between the VAD and VSGS were identified in their rates of infection (log OR 0.03, 95% CI -0.77 to 0.84), obstruction (log OR 1.25, 95% CI -0.21 to 2.71), ventriculoperitoneal shunt dependence (log OR -0.06, 95% CI -0.93 to 0.82), subsequent shunt infection (log OR 0.23, 95% CI -0.61 to 1.06), mortality (log OR 0.37, 95% CI -0.95 to 1.70) or long-term disability (p = 0.9). In all studies, there was a lack of standardised criteria, variations between surgeons in heterogeneous cohorts of limited sample size and a lack of neurodevelopmental follow-up. This affirms the importance of an ongoing multicentre, prospective pilot study comparing these two temporising procedures to enable a more robust comparison.

Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5-56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4-41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

Purpose: Inaccurate placement of external ventricular drains (EVDs) is a common issue in cerebrospinal diversion procedures. The conventional freehand technique results in a high fraction of sub-optimally placed catheters, and the use of image guidance can improve these results. The purpose of this paper is the validation of the use of an average model for guidance of EVD procedures., Methods: Three neurosurgeons have tested the model-based technique on three normal volunteers, and we have compared the model-based technique to the freehand technique and neuronavigation based on volunteer-specific images., Results: Our results show that the surgeons perform significantly better when using the model-based technique than when using the freehand technique., Conclusions: Our results suggest that the use of an average model may improve the accuracy of catheter placements. However, further refinement of the method and testing in a clinical setting is required.

Object: Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone of the lateral ventricle. However, techniques for accurate catheter placement have not been developed. The authors recently reported a prospective study designed to test the accuracy of catheter placement with the assistance of intraoperative ultrasound, but the results were poor (accurate placement in 59%). A major reason for the poor accurate placement rate was catheter movement that occurred between the time of the intraoperative ultrasound image and the first postoperative scan (33% of cases). The control group of non-ultrasound using surgeons also had a low rate of accurate placement (accurate placement in 49%). The authors conducted an exploratory post hoc analysis of patients in their ultrasound study to identify factors associated with either catheter movement or poor catheter placement so that improved surgical techniques for catheter insertion could be developed., Methods: The authors investigated the following risk factors for catheter movement and poor catheter placement: age, ventricular size, cortical mantle thickness, surgeon experience, surgeon experience with ultrasound prior to trial, shunt entry site, shunt hardware at entry site, ventricular catheter length, and use of an ultrasound probe guide for catheter insertion. Univariate analysis followed by multivariate logistic regression models were used to determine which factors were independent risk factors for either catheter movement or inaccurate catheter location., Results: In the univariate analyses, only age < 6 months was associated with catheter movement (p = 0.021); cortical mantle thickness < 1 cm was near-significant (p = 0.066). In a multivariate model, age remained significant after adjusting for cortical mantle thickness (OR 8.35, exact 95% CI 1.20-infinity). Univariate analyses of factors associated with inaccurate catheter placement showed that age < 6 months (p = 0.001) and a posterior shunt entry site (p = 0.021) were both associated with poor catheter placement. In a multivariate model, both age < 6 months and a posterior shunt entry site were independent risk factors for poor catheter placement (OR 4.54, 95% CI 1.80-11.42, and OR 2.59, 95% CI 1.14-5.89, respectively)., Conclusions: Catheter movement and inaccurate catheter placement are both more likely to occur in young patients (< 6 months). Inaccurate catheter placement is also more likely to occur in cases involving a posterior shunt entry site than those involving an anterior shunt entry site. Future clinical studies aimed at improving shunt placement techniques must consider the effects of young age and choice of entry site on catheter location.

Background: We hypothesized that shunt dysfunction in the ventricular catheter and the shunt valve is caused by different cellular responses. We also hypothesized that the cellular responses depend on different pathophysiological mechanisms., Methods: Removed shunt material was collected. Macroscopic tissue in the catheters was paraffin-embedded and HE-stained. Valves were incubated with trypsin-EDTA in order to detach macroscopically invisible biomaterial, which was then cytospinned and HE-stained. Associated aetiological and surgical data were collected by reviewing patient files, and ventricular catheter position was examined using preoperative radiology (CT scans)., Results: We examined eleven ventricular catheters and ten shunt valves. Catheters: 6/11 catheters contained intraluminal tissue consisting of vascularised glial tissue and inflammatory cells (macrophages/giant cells and a few eosinophils). Catheter adherence correlated with the presence of intraluminal tissue, and all tissue containing catheters had some degree of ventricle wall contact. All obstructed catheters contained intraluminal tissue, except one catheter that was dysfunctional because of lost ventricular contact. Valves: Regardless of intraoperative confirmation of valve obstruction, all ten valves contained an almost uniform cellular response of glial cells (most likely ependymal cells), macrophages/giant cells, and lymphomonocytic cells. Some degree of ventricle wall catheter contact was present in all examined valves with available radiology (9/10)., Conclusions: The same cellular responses (i.e., glial cells and inflammatory cells) cause both catheter obstruction and valve obstruction. We propose two synergistic pathophysiological mechanisms. (1) Ventricle wall/parenchymal contact by the catheter causes mechanical irritation of the parenchyma including ependymal exfoliation. (2) The shunt material provokes an inflammatory reaction, either nonspecific or specific. In combination, these mechanisms cause obstructive tissue ingrowth (glial and inflammatory) in the catheter and clogging of the valve by exfoliated glial cells and reactive inflammatory cells.

Background: Cerebrospinal fluid (CSF) infections associated with external ventricular drain (EVD) placement attract major consequences. Silver impregnation of catheters attempts to reduce infection., Objective: To assess the efficacy of silver catheters against CSF infection., Methods: We performed a randomized, controlled trial involving 2 neurosurgical centers (June 2005 to September 2009). A total of 356 patients requiring an EVD were assessed for eligibility; 325 patients were enrolled and randomized (167 plain, 158 silver); 278 patients were analyzed (140 plain, 138 silver). The primary outcome measure was CSF infection as defined by organisms seen on Gram stain or isolated by culture. Secondary outcome measures included ventriculoperitoneal (VP) shunting., Results: There was a significant difference in infection risk between the 2 study arms: 21.4% (30/140) for plain catheters vs 12.3% (17/138) for silver catheters (P = .0427; 95% confidence interval [CI]: 1.015-3.713). Patients who had an EVD infection had more than double the risk of requiring a VP shunt compared with patients without an EVD infection (45.7% [21/46] vs 19.7% [45/229], respectively, P = .0002; 95% CI: 1.766-6.682). There was also a significant difference in VP shunt risk with infection: plain (55.2%; 16/29) vs the silver arm (29.4%; 5/17); P = .0244 (95% CI: 1.144-11.695). A multivariate analysis demonstrated that infection risk was increased by duration of EVD placement (odds ratio: 1.160), spontaneous intracranial hemorrhage (odds ratio 4.958) and decreased by silver catheters (odds ratio: 0.423)., Conclusion: The study provides Class I evidence that silver-impregnated catheters reduce CSF infection.

Objective: The germinal matrix hemorrhage in premature infants is related to the immaturity of the subependymal vascular bed. Posthemorrhagic ventricular dilation (PVD) in extremely low birth weight infants (ELBI) is a medical challenge and is associated with a high risk of long-term disability. Our aim was to find a safe and gentle surgical technique for external ventricular drainage implantation for this patient population., Patients and Methods: We implanted eight external ventricular drainages in ELBI with birth weights ranging from 479 to 884 g (24 to 27 weeks gestational age) and a grade III to IV hemorrhage, who developed a PVD soon after birth. A replacement of the drainage was required three times in one infant with a birth weight of 479 g. Due to the subcutaneous tunneling and drawing of the catheter through the sleeve, the skin contact remains slight, and thus, infections are avoided., Results: There were no complications during the procedures which can also be carried out in the neonatal intensive care unit. Only in one case (479 g birth weight and severe concomitant diseases) was an infection observed, though the origin was most likely abdominal. In the same case, a temporary leakage was treated by suture. This patient died of non-neurological complications related to the patient's prematurity. Three of the five preterms were shunted over time., Conclusions: Although there is only a small number of extremely low birth weight infants with posthemorrhagic hydrocephalus who were treated with this technique, our findings suggest that this method is very safe and useful. It reduces the risk of infection and cerebrospinal fluid leaks and might be a better alternative to serial lumbar or transfontanel punctures in extremely low birth weight infants for bridging the first weeks of life.

Objective: Surgical resection of deep-seated midline brain tumors does not always resolve obstruction of cerebrospinal fluid pathways, and an additional operation--ventricular shunting--is required. To prevent postoperative obstructive hydrocephalus, we combine tumor removal and internal ventricular shunting in 1 stage., Methods: Between 2000 and 2006, 82 patients with deep-seated midline brain tumors (tumors of the third ventricle, pineal region, thalamus, upper brainstem, and superior half of the fourth ventricle) underwent 84 tumor resections with intraoperative internal ventricular shunting. Two types of intraoperative shunting were performed: direct third ventriculostomy with fenestration of the premammillary membrane of the third ventricle floor and Liliequist's membrane, 53 operations; and aqueductal stenting, 30 operations. In 1 patient, third ventriculostomy and aqueductal stenting were performed simultaneously., Results: As most of the tumors had an infiltrative growth pattern, gross total tumor removal was achieved in only 31% of patients in this series. There were no fatal outcomes related to the surgery. Follow-up data were collected in 73 patients (89%) and ranged from 2 to 68 months (median, 16 months). Additional shunting because of inadequate function of stoma or stent was performed in 13 patients at various times after surgery (median, 30 days). The Kaplan-Meier survival analysis demonstrated that at 12 and 24 months the intraoperative direct third ventriculostomy success rates were 67 and 61%, respectively; aqueductal stenting success rates were 93% at both 12 and 24 months., Conclusion: Intraoperative direct third ventriculostomy and aqueductal stenting under direct visual control were found to be reliable methods of hydrocephalus management in patients with deep-seated midline brain tumors.

Background: Since 1992, infants with progressive posthaemorrhagic ventricular dilatation (PHVD) have been treated in the Neonatal Intensive Care Unit, Wilhelmina Children's Hospital, Utrecht, The Netherlands, with a ventricular reservoir., Objective: To retrospectively study the incidence of infection using this invasive procedure., Methods: Between January 1992 and December 2003, 76 preterm infants were treated with a ventricular reservoir. Infants admitted during two subsequent periods were analysed: group 1 included infants admitted during 1992-7 (n = 26) and group 2 those admitted during 1998-2003 (n = 50). Clinical characteristics and number of reservoir punctures were evaluated. The incidence of complications over time was assessed, with a focus on the occurrence of infection of the reservoir., Results: The number of punctures did not change during both periods. Infection was significantly less common during the second period (4% (2/50) v 19.2% (5/26), p = 0.029)., Conclusion: The use of a ventricular reservoir is a safe treatment to ensure adequate removal of cerebrospinal fluid in preterm infants with PHVD. In experienced hands, the incidence of infection of the ventricular reservoir or major complications remains within acceptable limits.

Complications from cerebrospinal fluid shunts are common and can present with a variety of signs and symptoms. In this second part of a two-part review, shunt overdrainage, loculation of the ventricular system in patients with shunts, and abdominal complications related to ventriculoperitoneal shunts are discussed. Familiarity with these types of shunt failure is essential for neurologists and pediatricians because they are often the first to evaluate and triage these children.

The most common treatment for patients with hydrocephalus is the surgical implantation of a cerebrospinal fluid (CSF) shunt. Unfortunately, this device, which is critical for lowering intracranial pressure, has a substantial failure rate (40% in the first year). A leading cause of failure is the obstruction of the ventricular catheter. The goal of this project is to design a ventricular catheter that will resist occlusion through the use of micromachining and micro electro-mechanical systems (MEMS) technologies. We designed, fabricated, and tested magnetic microactuators. The theoretical results show that the fabricated microactuators can produce the force necessary to remove an adherent cellular layer grown over the actuator surface. By integrating the microactuators into the catheters, we hope to produce an improved catheter with the ability to actively combat the health-threatening occlusion process.

Unlabelled: Since 1990, 110 retrograde ventriculo-sinus (RVS) shunts were implanted; 98 patients (89.1%) benefited - 1 of them (0.9%) after shunt revision. The manifestations of high intra cranial pressure (ICP) disappeared, there were no problems related to improper cerebrospinal fluid (CSF) drainage, and the transcranial Doppler (TCD) resistive index (RI) measurements decreased to within normal ranges. Radiologically, the ventriculomegaly showed no regression in patients with open craniums and variable degrees of mild regression in patients with rigid craniums. Complications that needed shunt removal or revision occurred in 13 patients (11.8%); 1 patient (0.9%) died before shunt revision; they were all due to technical errors committed during the stages of evolution of the surgical technique for shunt implantation. The follow-up ranged between 4 months and 11 years (mean 3.42 years)., Conclusion: the RVS shunt is a simple, minimally invasive, physiological procedure for treatment of hydrocephalus and is suitable for all ages., (Copyright (c) 2005 S. Karger AG, Basel.)

Objectives: The aim of this study was to determine whether ventricular size correlates with a positive clinical outcome following shunt placement. Hydrostatic valves (Dual-Switch-Valves) were implanted in 80 patients with NPH at Unfallkrankenhaus Berlin between September 1997 and January 2002. One year postoperatively, these patients underwent computerized tomography scanning, and their ventricular size was ascertained using the Evans-Index. Among 80% of the patients who showed no postoperative change in ventricular volume, 59% nonetheless had good to excellent clinical improvements, 17% satisfactory clinical improvement, and 24% no improvement. Furthermore, a moderate reduction in ventricular size was observed in 14% of patients in this cohort. Among these, 36% experienced a good to excellent clinical improvement, 28% a satisfactory improvement, and 36% unsatisfactory improvement. A marked reduction in ventricular size was observed in 6% of the patients. Of this group, 60% demonstrated good to excellent outcomes, whereas 40% had unsatisfactory outcomes. Favourable outcomes following the implantation of a hydrostatic shunt in patients with NPH did not correlate with decreased ventricular volume 1 year after surgery. In fact, better clinical outcomes were observed in patients with little or no alteration in ventricular size, compared with those in patients with marked decrease in ventricular size. A postoperative change in ventricular volume should be assessed differently in patients with NPH compared with those suffering from hypertensive hydrocephalus.

Objective: This retrospective study examined whether changes in ventricular volume correspond with changes in adjustable valve pressure settings in a cohort of patients who received shunts to treat idiopathic normal pressure hydrocephalus. We also examined whether these pressure-volume curves and other patient variables would co-occur with a positive clinical response to shunting., Methods: We selected 51 patients diagnosed with idiopathic normal pressure hydrocephalus who had undergone implantation of a Codman Hakim programmable valve (Medos S.A., Le Locle, Switzerland). Clinical data were gathered from the patients' records and clinical notes by an investigator blinded to patients' ventricular volumes. Ventricular volume was measured using 3D Slicer, an image analysis and interactive visualization software package developed and maintained at the Surgical Planning Laboratory at Brigham and Women's Hospital., Results: Eighty-six percent of patients with gait disturbance at presentation showed improvement of this symptom, 70% experienced improvement in incontinence, and 69% experienced improvement in dementia. For the group showing 100% clinical improvement, the correlation coefficient of average changes in valve pressure over time (delta P/delta T) and average changes in ventricular volume over time (delta V/delta T) were high at 0.843 (P < 0.05). For the group experiencing no or only partial improvement, the correlation coefficient was 0.257 (P = 0.32), indicating no correlation between average delta V/delta T and average delta P/delta T for each patient., Conclusion: This was a carefully analyzed modeling study of idiopathic normal pressure hydrocephalus treatment made possible only by adjustable valve technology. With careful volumetric analysis, we found that changes in ventricular volume correlated with adjustments in valve pressure settings for those patients who improved clinically after shunting. This suggests that positive clinical responders retained parenchymal elasticity, emphasizing the importance of dynamic changes in this cohort.

Object: It is well known that in patients with communicating hydrocephalus or normal-pressure hydrocephalus (NPH), ventricular size decreases following implantation of shunts with differential pressure valves. The aim of this study was to determine whether ventricular size correlates with a positive clinical outcome following shunt placement., Methods: Hydrostatic valves (dual-switch valves) were implanted in 80 patients with NPH at Unfallkrankenhaus, Berlin, between September 1997 and January 2002. One year postoperatively, these patients underwent computerized tomography scanning, and their ventricular size was ascertained using the Evans Index. Among 80% of the patients who showed no postoperative change in ventricular volume, 59% nonetheless had good to excellent clinical improvements, 17% satisfactory improvement, and 24% no improvement. Furthermore, a moderate reduction in ventricular size was observed in 14% of patients in this cohort. Among these, 36% experienced good to excellent clinical improvements, 28% satisfactory improvement, and 36% unsatisfactory improvement. A marked reduction in ventricular size was observed in 6% of the patients. Of this latter group, 60% demonstrated good to excellent outcomes, whereas 40% had unsatisfactory outcomes., Conclusions: Favorable outcomes following the implantation of a hydrostatic shunt in patients with NPH did not correlate with decreased ventricular volume 1 year after surgery. In fact, better clinical outcomes were observed in patients with little or no alteration in ventricular size, compared with those in patients with a marked decrease in ventricular size. A postoperative change in ventricular volume should be assessed differently in patients with NPH compared with those suffering from hypertensive hydrocephalus.

Object: After demonstrating the anti-siphoning properties of a distensible tube in vitro, El-Shafei constructed a shunting system that directs CSF flow into the internal jugular vein against the flow of blood. Though clinically effective, the in vivo pressure dynamics of this type of shunt system have not been investigated., Methods: After failure at multiple other extracranial absorptive sites, an 18-year-old woman was shunted from the lateral ventricle to the internal jugular vein against the direction of blood flow. The shunt system contained an in-line noninvasive telemonitor allowing examination of postural intracranial pressure dynamics in the awake state. This shunt system demonstrated postural pressure dynamics that were consistent with a stringent nonsiphoning shunting system., Conclusions: These observations validate the use of the El-Shafei shunt placement as a biologically nonsiphoning CSF absorptive system. In addition, the stringency of the anti-siphoning properties of the internal jugular vein open the possibility of preferentially using this shunting system in patients who clearly exhibit symptoms of shunt overdrainage.

Objective: To report five children with slit-ventricle syndrome who were found to have increased intracranial pressure despite functioning cerebrospinal fluid shunts., Methods: Computed tomographic scans demonstrated erosion of the inner table of the cranium and sclerosis of the cranial sutures, particularly the coronal suture. Magnetic resonance imaging scans demonstrated no cerebrospinal fluid over the convexities. The patients were treated with cranial expansion operations that included removal of the sclerotic sutures, which were examined histologically., Results: Postoperatively, symptoms resolved for all children. Sutures were abnormal and contained foci of cartilage and bone within abnormally arranged fibrous tissue., Conclusion: We postulate that chronic overdrainage of cerebrospinal fluid via shunts dampens the normal cerebral pressure waves; growth of the calvarium is thus understimulated, and this leads to ossification of the sutures, which become unable to expand to allow normal brain growth. Shunt-induced craniostenosis should be considered for children with symptoms of slit-ventricle syndrome for whom shunts are functional but intracranial pressure is increased. Cranial expansion operations may be more appropriate treatments than subtemporal decompressions for such children, given the diffuseness of the suture pathological features.

Objective: The multicenter, randomized pediatric cerebrospinal fluid shunt valve design trial found no difference in the rate of shunt failure between a standard valve, a siphon-reducing valve (Delta; Medtronic PS Medical, Goleta, CA), and a flow-limiting valve (Orbis Sigma; Cordis, Miami, FL); however, the valves were expected to have different effects on ultimate ventricular size. Also, the catheter position or local environment of the ventricular catheter tip might have affected shunt failure. Therefore, we performed a post hoc analysis to understand what factors, other than valve design, affected shunt failure and to identify strategies that might be developed to reduce shunt failure., Methods: Ventricular size was measured at as many as six different intervals, using a modified Evans' ratio (with incorporation of the frontal and occipital dimensions), in 344 patients. Ventricular catheter location was defined as being in the frontal horn, occipital horn, body of the lateral ventricle, third ventricle, embedded in brain, or unknown. The ventricular catheter tip was described as surrounded by cerebrospinal fluid, touching brain, or surrounded by brain parenchyma within the ventricle (slit ventricle). Repeated measures analysis of variance for unbalanced data was used to analyze ventricular size. A Cox model (with incorporation of time-dependent covariates) was used to evaluate the contribution of age, etiology, shunt design, ventricular size, ventricular catheter location, and environment among the cases., Results: Ventricular volume decreased in an exponential fashion, forming a plateau at 14 months, and was similar for the three valves (P = 0.4). Frontal and occipital ventricular catheter tip locations were associated with a reduced risk of shunt failure (hazard ratios, 0.60 [P = 0.02] and 0.45 [P = 0.001], respectively). Ventricular catheter tips surrounded by cerebrospinal fluid or touching the brain were associated with a reduced risk of failure (hazard ratios, 0.21 and 0.33, respectively; P = 0.0001). Patients with myelomeningocele or large ventricles had increased risk of malfunction (hazard ratios, 1.78 [P = 0.006] and 2.33 [P = 0.03], respectively)., Conclusion: Decline of ventricular size over time is not affected by these different shunt valve designs. This suggests that the mechanical models of hydrocephalus on which the designs were based are inadequate. Ventricular catheter tip location and ventricular catheter environment are important. Techniques to accurately place ventricular catheters and new valve designs that effectively control ventricular size might reduce shunt malfunction.

A functioning shunt must have a patent proximal catheter within the cerebrospinal fluid space. Occlusion with choroid plexus or ependymal tissue might be expected if these tissues are in contact with the proximal inlets. This study was undertaken to define the intraventricular distances available for a standard-placement shunt cather and to compare the available distances with actual ventricular catheter inlets. In 52 normal subjects (age range from 1 month to 20 years; median 7.7 years) magnetic resonance imaging was used to measure the dimensions of the anterior horn in planes typically used for cather placement. For anterior placements, the intraventricular length (ventricle entry to the foramen of Monro) was measured for a standardized catheter route ('As') and for a route yielding a maximum lenght ('Amax'). For posterior placements, the length (ventricle tip to foramen of Monro) was obtained for a standardized catheter placement to the ipsilateral ('Pi') and the contralateral ventricle ('Pc') as well as measuring a maximum length in a curved trajectory ('Pmax'). The average length (and range) in centimeters for the various trajectories was: As = 1.5 (1.1-1.9), Amax = 1.7 (1.2-2.2), Pi = 1.6 (1.2-2.1), Pc = 2.0 (1.4-2.9), and Pmax = 2.8/3.1 (2.1-3.6). Minor variations from a standard shunt insertion site did not affect the length of catheter within the ventricle. Current ventricular catheters have proximal inlets extending 1.6-2.4 cm from the catheter tip. Variations in standard ventricular catheter placement should have no measurable effect on how much ventricle is available for the proximal catheter. It may not be possible to place a standard ventricular catheter and keep the inlets within the ventricle and placed consistently away from choroid plexus and ependyma, regardless of approach. This may contribute to the similar proximal occlusion rates reported for the differing placements. Subsequent studies of shunt placement should correlate proximal occlusion rates with ventricular size. To prevent ventricular size from directly affecting proximal conclusion, consideration should be given to altering the design of ventricular catheters by placing inlets over a shorter distance (1.0 cm) from the tip.

Open third ventriculostomy (OTV) was performed on 4 infants with noncommunicating hydrocephalus and intractable shunt infections. All patients were resistant or relapsed after treatment with intravenous and intraventricular antibiotics along with change of the shunt apparatus. We performed phase-contrast cine magnetic resonance imaging (MRI) for preoperative and postoperative evaluation of cerebrospinal fluid (CSF) flow at the aqueduct of Sylvius. All patients required a second OTV approximately 3 weeks after the first OTV due to closure of the patency. Our experience led us to view OTV as an unsuccessful procedure in infantile noncommunicating hydrocephalus due to an insufficiently developed subarachnoid space. The patients' data, operative findings and probable causes of failure are presented here.

Most shunt malfunctions present with signs and symptoms of high intracranial pressure, and computed tomography scans demonstrate ventricular enlargement. However, several authors have described a rare 'low-pressure' hydrocephalic state in which ventricular enlargement can occur in the face of low, or even negative, intracranial pressures. We report 2 children with obstructive hydrocephalus in whom this 'low-pressure state' followed a lumbar puncture; in both children, the shunts were functioning properly despite increased ventricular size on computed tomography scans, and all symptoms resolved (and the ventricles returned to baseline) following a period of enforced recumbency without shunt revision. We hypothesize that subarachnoid cerebrospinal fluid leakage through the puncture site in the lumbar theca decreases the intracranial pressures globally to a point below the opening pressures of the shunt valves. The ventricular cerebrospinal fluid, unable to be drained through either the subarachnoid space or the shunt, accumulates within the ventricular system under low pressure. One consistent feature in our 2 patients has been the postural nature of the headaches. We recommend enforced recumbency and, if necessary, a blood patch to seal the lumbar leakage. Shunt revision or prolonged external ventricular drainage appears to be unnecessary in these patients. Finally, neurosurgeons should be aware of this potential complication.

Proper ventricular catheter placements are associated with improved shunt performance. When placing ventricular catheters via the posterior approach, the surgeon must determine an optimum trajectory and then pass a catheter along that trajectory. The incidence of optimal posterior catheter placements is increased by using a posterior catheter guide (PCG); however, errors may still occur because of poor selection of a posterior burr-hole site. In this report an easy-to-use posterior burr-hole localizer (Localizer) is described that defines the optimum burr-hole location based on geometric relationships involving the ear and supraorbital rims. The basic design principle of the Localizer was formulated and tested by using neuronavigational imaging tools to examine normal adult ventricular anatomy in relation to surface landmarks and by reviewing imaging studies obtained in 50 adult patients with hydrocephalus. Subsequently, the Localizer was used in 28 consecutive patients scheduled to undergo shunt surgery performed by using the PCG. In all cases the catheter entered the ventricle on the first pass and postoperative imaging studies demonstrated successful placement in the ipsilateral anterior horn. There were no catheter-related complications. These early results indicate that the Localizer and PCG devices may be safe and effective when used in combination for placement of posterior ventricular catheters.

A retrospective study was conducted on 105 pediatric patients who underwent shunt revision between 1986 and 1993 at the Alberta Childrens Hospital (Calgary) to determine the frequency of intraventricular hemorrhage (IVH) with ventricular catheter revision. Ventricular catheter revision was performed 143 times in 74 patients. Intraventricular hemorrhage was noted intra-operatively or on post-operative computed tomographic (CT) scans on 45 occasions for an overall incidence of 31%. IVH was associated with a significantly shorter time (p < 0.0002) to subsequent shunt revision (227.33 +/- 392.24 days) compared to catheter survival when no hemorrhage was noted (735.02 +/- 1,001.11 days). This study raises several important questions about the prevention and management of IVH during shunt revision. It also provides the first published report on the incidence of IVH during shunt revision, thereby setting a standard to which future studies can be compared.

The reactions of periventricular tissue of the lateral ventricle to non-infected and infected (Staphylococcus Epidermidis) silicone shunt tubing were examined by light and transmission electron microscopy. It was shown that reactive changes occurred in periventricular tissue in response to the implant of sterile shunt tubing. On the other hand in infected implanted silicone shunt tubing, proliferation of inflammatory cells within the ventricle and periventricular tissue, loss of integrity of the ependyma, glial cell proliferation, and excessive extracellular oedema were demonstrated. Proliferation of ependymal cells combined with inflammatory responses may be a factor in the pathogenesis of infected shunt obstruction.

In a retrospective study of 300 children who underwent placement or revision of cerebrospinal fluid (CSF)-peritoneal shunts during a 10-year period, 15 (5%) developed shunt-related abdominal complications with ventricular sepsis and two developed acute perforated appendicitis. Abdominal complications and associated shunt infections suggested two potential modes of development: (1) descent of contaminated CSF from an infected shunt into the abdomen (CSF ascites--four patients, CSF pseudocysts--four patients, and shunt-induced abscess/peritonitis--five patients); and (2) ascent of bacteria into the shunt from an abdominal source (visceral perforation by the shunt catheter--two patients and acute perforated appendicitis--two patients). Three types of shunt systems were placed during the study period; five of the seven (71%) most serious septic complications were associated with the use of Raimondi spring-reinforced catheters. Bacteria isolated in this series were associated with differing modes of sepsis: those involving descent of bacteria into the abdomen from an infected shunt were predominantly gram-positive, cutaneous microorganisms, whereas those associated with ascent of bacteria from the abdomen into the shunt were mixed, gram-negative intestinal microorganisms. Appendicitis did not result in shunt infections. Aggressive treatment resulted in no operative or complication-related deaths. Removal of the shunt catheter from the abdomen and intravenous antibiotics were essential for eradication of sepsis; laparatomy was required only for cases with suspected peritonitis. In eight of the 17 (47%) patients, reestablishment of CSF-peritoneal shunts was performed after resolution of shunt-related complications. In recent years improved shunting materials and supportive care have reduced the incidence of the most serious of these complications.

Eighteen hydrocephalic children who presented with subtle deterioration when their shunts malfunctioned were studied during shunt revision by means of the pressure-volume index (PVI) technique. Bolus manipulation of cerebrospinal fluid (CSF) was used to determine the PVI and the resistance to the absorption of CSF (Ro). Ventricular size was moderately to severely enlarged in all the children. Steady-state intracranial pressure (ICP) at the time of shunt revision was 17.5 +/- 7.3 mm Hg (range 8 to 35 mm Hg). Pressure waves could not be induced by bolus injections in the 8- to 35-mm Hg range of ICP tested. The mean +/- standard deviation (SD) of the predicted normal PVI for this group was 18.5 +/- 2.7 ml. The mean +/- standard error of the mean of the measured PVI was 35.5 +/- 2.1 ml, which represented a 187% +/- 33% (+/- SD) increase in volume-buffering capacity (p less than 0.001). The ICP did not fall after bolus injections in three children, so that the Ro could not be measured. In the remaining 15 patients, Ro increased linearly as a function of ICP (r = 0.74, p less than 0.001). At ICP's below 20 mm Hg, Ro ranged from 2.0 to 5.0 mm Hg/ml/min, but increased to as high as 21 mm Hg/ml/min when ICP was above 20 mm Hg. This study documents that subtle deterioration in shunted hydrocephalic children is accompanied by abnormally compliant pressure-volume curves. These children develop ventricular enlargement and neurological deterioration without acute episodic pressure waves. The biomechanical profile of this group differs from other children with CSF shunts.

The use of ventriculo-atrial shunts for the various forms of hydrocephalus can lead to an excessive drainage of cerebro-spinal fluid, resulting in a collapse or increasing obliteration of the ventricular system. This finding was confirmed in 76 children with congenital or acquired hydrocephalus who were examined by computerised axio-tomography (CAT scan). If raised intracranial pressure develops there will be symptoms of raised pressure which are discussed. The acute as well as the prophylactic management is described and the dehydrating effect of dexamethazone in children with hydrocephalus and a collapsed ventricular system is discussed.

Over a period of 34 months from 1987 to 1990 we inserted ventricular catheter reservoirs (VCR) into 20 premature low-birth-weight infants who had developed progressive, symptomatic posthemorrhagic hydrocephalus following grade III or IV intraventricular hemorrhages. The mean estimated gestational age was 27.7 +/- 5.3 weeks and mean birth weight was 1,041 +/- 699 g. The ventricular catheter reservoirs were placed on day of life 30.7 +/- 29.7 and tapped for a total of 3-34 days at varying frequencies and for varying volumes. Of the 20 patients, 4 died on days of life 25, 76, 88, and 187. There were two reservoir infections, both occurring in infants who eventually died. The 16 survivors have been followed from 2 to 24 months (adjusted age). Four (25%) remain shunt-free and 3 have undergone VCR removal. There have been two shunt infections in the 12 shunted patients; ten shunt revisions have been performed overall. At the time of last follow-up, 14 patients were old enough to undergo neurodevelopmental evaluation. Five patients (36%) were 'normal' on gross neurological screening examination, 5 (36%) had 'mild developmental delay' and 4 (28%) had 'significant developmental delay'. We feel these data support the continued use of ventricular catheter reservoirs in the management of posthemorrhagic hydrocephalus and offer hope that some of these patients might remain shunt-free and most will have a normal or mildly delayed neurodevelopmental outcome.

Migration of the whole shunting system of a ventriculo-peritoneal shunt into the lateral ventricle of a three-month-old male infant is presented. This is a very rare complication of ventriculo-peritoneal shunt.

The incidence of slit ventricles of shunt treated hydrocephalic children was evaluated in a follow up study of 141 patients. Slit like ventricles on computer tomography was seen in 75 patients (53%). 52 patients (37%) suffered from clinical symptoms corresponding with overdrainage of cerebrospinal fluid. Those 52 patients with the "Slit Ventricle Syndrome" (SLVS) were treated by changing the valve to one with a higher opening pressure and/or adding an antisiphon device (ASD) to the shunt. 22 patients, initially treated by changing the opening pressure of the valve, needed the ASD later. Altogether 74 episodes of the SLVS were treated. The ASD proved reliable for the management of the SLVS. Normalization of ventricular size occurred in 54% of patients. whereas only in 15% treated without the ASD. Reduction of paroxysmal activity on EEG was seen in 70% of patients treated with the ASD, whereas only in 23% of patients treated without the ASD. Clinical relief of symptoms occurred in every patient, and ventricular catheter obstructions could be avoided, even if the ventricular size remained slit-like on CT.

This report describes a computed tomography-based computer-assisted stereotactic technique for performing 3rd ventriculostomy. The procedure has been performed on seven patients with acquired obstructive hydrocephalus of various etiologies. None of these patients have yet required shunting.