[Rathke cysts, craniopharyngioma, and colloid cysts : What are the differences between these pathologies?] / Rathke-Zyste, Kraniopharyngeom und Kolloidzyste : Was unterscheidet diese Pathologien?

CLINICAL ISSUE: Headache is the most common symptom of colloid cysts, Rathke cysts, and craniopharyngioma due to their location in the midline, being extra-axial and typically presenting in the parasellar region. THERAPEUTIC PROBLEMS: Although these tumors are generally considered benign, each has its typical characteristics defined by its location and histology. These individual characteristics define whether surgery is necessary at all and if so, the preferred surgical approach and resection's totality. The histopathological findings primarily indicate that embryonic malformations-at the first glance, ectodermal in nature-cause these tumors. ACHIEVEMENT: Due to the fact that these disturbances occur at the boundary between ectodermal stomodeum and endodermal cephalogaster, however, does leave some doubts.

[Relevance and therapy of intracranial arachnoidal cysts]. / Relevanz und Therapie intrakranieller Arachnoidalzysten.

Intracranial arachnoidal cysts (AC) are relevant due to their space-demanding character. The pathophysiological sequelae are dependent on the size and location of the cyst and the patient's age. Direct pressure on surrounding tissue causes headaches (meninges) or rarely seizures (brain tissue). Cerebrospinal fluid (CSF) circulation disturbances resulting from brain mass displacement with occlusion of, for example, the foramen monroi or the aqueduct cause occlusive hydrocephalus, which can lead to an increase in intracranial pressure. Depending on age, the typical primary clinical symptoms or findings differ. In adults and older children, headaches are usually the first clinical symptom. Children, in whom skull growth is not yet complete, present with a head circumference above the 97th percentile. An abnormal one-sided deflection of the calotte in the region of the underlying AC may also be present. Cranial magnetic resonance imaging (cMRI), the first-line diagnostic tool of choice to demonstrate size and location of the cysts and the surrounding intracranial structures, is of utmost importance for therapy planning. In addition, further malformations can be detected. Moreover, cMRI may also be useful for a rough assessment of increased intracranial pressure (ICP). In most symptomatic AC, surgical treatment is unavoidable. The primarily goal is to establish communication between the CSF and the cysts' content in order to effect pressure equalization. If the CSF reabsorption capacity is insufficient, it may also be necessary to implant a CSF shunt. Asymptomatic arachnoidal cysts should be strictly followed clinically and by cMRI over time. The reasonable frequency for follow-up depends on the size and location of the cyst.

[Clinical symptoms of hydrocephalus]. / Klinische Symptome des Hydrozephalus.

CLINICAL ISSUE: A correct interpretation of radiological data in cases of suspected hydrocephalus is not possible when ignoring patient age and clinical symptoms. STANDARD TREATMENT: An in-depth knowledge of clinical findings is accordingly essential. INNOVATIONS: New pathophysiological findings and a detailed assignment of previously unrecognized or ignored clinical symptoms to various entities of the spectrum of hydrocephalus disorders allow a coherent diagnosis drawn from clinical and radiological data. For this purpose it is necessary to know the specific symptoms of hydrocephalus in relation to age. Especially in chronic hydrocephalus, this is of utmost importance to avoid misdiagnosis. DIAGNOSTIC WORK-UP: The radiological method of choice depends on the age and the specific issue to be addressed. ACHIEVEMENTS: The typical clinical symptoms of different hydrocephalus entities presented here must be considered as confirmed knowledge. PRACTICAL RECOMMENDATIONS: Only the synopsis of clinical and radiological findings currently allows correct interpretation of imaging. There is a threat of misdiagnosis if interpretation is restricted purely to radiological findings as the sole predictive value of modern imaging is still too limited despite all innovations.

Is it possible to minimize overdrainage complications with gravitational units in patients with idiopathic normal pressure hydrocephalus? Protocol of the randomized controlled SVASONA Trial (ISRCTN51046698).

Overdrainage is a common complication observed after shunting patients with idiopathic normal-pressure hydrocephalus (iNPH), with an estimated incidence up to 25%. Gravitational units that counterbalance intracranial pressure changes were developed to overcome this problem. We will set out to investigate whether the combination of a programmable valve and a gravitational unit (proGAV, Aesculap/Miethke, Germany) is capable of reducing the incidence of overdrainage and improving patient-centered outcomes compared to a conventional programmable valve (Medos-Codman, Johnson & Johnson, Germany). SVASONA is a pragmatic randomized controlled trial conducted at seven centers in Germany. Patients with a high probability of iNPH (based on clinical signs and symptoms, lumbar infusion and/or tap test, cranial computed tomography [CCT]) and no contraindications for surgical drainage will randomly be assigned to receive (1) a shunt assistant valve (proGAV) or (2) a conventional, programmable shunt valve (programmable Medos-Codman).We will test the primary hypothesis that the experimental device reduces the rate of overdrainage from 25% to 10%. As secondary analyses, we will measure iNPH-specific outcomes (i.e., the Black grading scale and the NPH Recovery Rate), generic quality of life (Short Form 36), and complications and serious adverse events (SAE). One planned interim analysis for safety and efficacy will be performed halfway through the study. To detect the hypothesized difference in the incidence of overdrainage with a type I error of 5% and a type II error of 20%, correcting for multiple testing and an anticipated dropout rate of 10%, 200 patients will be enrolled.The presented trial is currently recruiting patients, with the first results predicted to be available in late 2008.

Infection rate with application of an antibiotic-impregnated catheter for shunt implantation in children - a retrospective analysis.

BACKGROUND: The infection rate of hydrocephalus shunts in children amounts figures of up to 25% and the according mortality rate is alarming high nowadays yet. An antibiotic impregnated shunt-catheter (AIS) was designed to reduce the incidence of shunt infections. PATIENTS AND METHOD: In a non randomized trial 56 children were examined between January 2002 inclusive December 2007. The minimal follow-up was six months. Only children were included, who were shunted for the first time. In the study group (n=34) AIS (Bactiseal ) Codman, Johnson & Johnson, MA, Boston, USA) were used, while the control group (n=22) was provided with conventional, not-antibiotic impregnated catheters. To compare the risk profile for shunt infections, we defined, - according to the literature -, some risk factors. RESULTS: Despite the incidence of shunt infections has been supposed to be higher according to the higher risk profile of the AIS group compared with controls, the shunt infection rate of the AIS group was lower than the shunt infection rate in the control group. CONCLUSIONS: Apparently, AIS can reduce the incidence of shunt infections in children. Further prospective trials with a larger cohort are necessary for a statistically significant prove.

Accuracy of ultrasound-guided puncture of the ventricular system.

OBJECTS: Puncture of the ventricular system as one of the most frequently performed operative procedures in neurosurgery is usually done in a freehand way without guiding devices. The objective of this study is to examine whether ultrasonic guidance is able to heighten the accuracy of ventricular tapping. METHODS: Real-time imaging via a single burr hole approach is achieved by aid of a bajonet-like shaped transducer with a footprint of 8x8 mm only (EUP-NS32, Hitachi Medical Systems). The needle is advanced towards the frontal horn along a displayed guideline. 51 punctures in 48 patients were performed with ultrasonic guidance and compared to 85 punctures in 67 patients without a guiding device. CONCLUSION: The presented ultrasound method was not able to heighten the access rate of ventricular tapping, but it improved correct positioning of the catheter tip inside the frontal horn of the ventricular system significantly.

Analysis of pulse waves in intracranial pressure.

In the therapy of hydrocephalus the dynamic course of the intracranial pressure (ICP) is rarely considered, although it may contain valuable diagnostic information. Several models for intracranial pressure and fluid dynamics are described. Assuming a simplified model and deriving the intracranial pressure wave relationships, this model could be partially confirmed and a characteristic dataset could be given for every patient.

Gravitational valves: relevant differences with different technical solutions to counteract hydrostatic pressure.

Two different technical principles of gravitational valves (G-valves) have been presented: counterbalancer and switcher G-valves. The objective of our prospective study was to look for clinically relevant differences between both. A total of 54 patients with normal-pressure hydrocephalus (NPH) were treated; 30 patients received an Aesculap-Miethke GA-Valve (GAV; counterbalancer), and in 24 patients an Aesculap-Miethke Dualswitch-Valve (DSV; switcher) was implanted. The opening pressure of the posture-independent valve was 5 cm H2O in both devices. The outcome was clearly better with the usage of the GAV than with the DSV. The frequency and severity of complications was pronounced in the DSV group. We recommend the Aesculap-Miethke-GAV valve with a low opening pressure in a posture-independent valve for patients with NPH.

Outcome predictors for normal-pressure hydrocephalus.

The objective of this prospective study was to find outcome predictors for better selection for treatment of normal-pressure hydrocephalus (NPH) patients. A total of 125 patients were evaluated and provided with a gravitational shunt. Cerebrospinal fluid hydrodynamics provided better predictive values if an algorithm to shunt all patients with a pressure/volume index of < 30 mL or resistance to outflow > 13 mmHg/mL x min was used. In general, outcome became worse with increasing anamnesis duration, worse preoperative clinical state, and increasing comorbidity. If one of these parameters was lower than a critical value, the shunt-responder rate was about 90% and the normally negative influence of older age was not seen. The well-known paradigm of a worse prognosis with NPH is not the result of the hydrocephalus etiology itself, but the consequence of a typical accumulation of negative outcome predictors as a consequence of the misinterpretation of normal aging and delayed adequate treatment.

An experimental aneurysm model: a training model for neurointerventionalists.

SUMMARY: Reproducible animal models not only facilitate the pre-clinical assessment of aneurysm therapy but can also help in training for interventional procedures. The objective of this study was to find an animal model that can be used to test different endovascular occlusion techniques. Aneurysms in the right common carotid artery were created in 35 NZW rabbits by distal ligation and intraluminal elastase infusion. A total of 27 aneurysms were occluded by endovascular embolization with GDC-Coils. The time needed for placement of the microcatheter into the aneurysm by a professional interventionalist, a semi-professional interventionalist and a trainee was measured. The percentage of occlusion (occlusion rate) of the aneurysms was determined angiographically after embolization and again three months later, followed by a histological examination. Aneurysms of 2-6 mm size were reliably created in all 35 animals; mean size was 3.0 mm in height and 5.5 mm in diameter. Occlusion was achieved in 27 animals. Five animals from the group of 35 were initially planned as a control group with no embolization. We added to the control group one animal whose aneurysm could not be occluded endovascularly because of partial thrombosis and small size of the aneurysm. The angiographically determined mean occlusion rate was 89.5% +/- 11.3% standard deviation. Histological evaluation of the six aneurysms of the control group showed that they remained patent. Aneurysms that underwent embolization showed organized thrombus formation with no signs of recanalization. Two animals died from anaesthesia related or embolic complications. The time needed by the professional did not significantly decrease, after a little practice the trainee was nearly as quick as the professional. The beginner showed extensive progress, reducing the time for catheter placement by more than 50%. This paper describes the angiographic and histopathologic findings and also demonstrates possible methods for training in interventional procedures. Animal models will play a vital part in the training of future interventionalists. This model has the capability of testing different embolization devices (GDC, Onyx(R))and methods. Histologic long-term prognosis and the physical effect of the coils can be evaluated with this model.

Gravitational shunt management of long-standing overt ventriculomegaly in adult (LOVA) hydrocephalus.

OBJECTIVES: Recently a new subtype of chronic hydrocephalus was described: long-standing overt ventriculomegaly in adults (LOVA). Experience to date has indicated that shunt therapy was contraindicated, due to over-drainage. Therefore we investigated whether this problem could be overcome using gravitational shunts. MATERIALS AND METHODS: Thirty macrocephalic adults (17-72 years of age), suffering from progressive hydrocephalus were managed with two different gravitational shunts. The post-operative observation period was 5-87 months. RESULTS: Only two patients developed hygromas, and only one of these required surgical shunt revision. Eighty-seven percent of patients had a long-lasting clinical improvement. Ventricular size was only slightly reduced in 29 patients. There was no correlation between reduction in ventricular size and clinical improvement. CONCLUSION: Contrary to clinical guidelines issued to date, we demonstrate that LOVA can be treated reliably with gravitational shunts, making them a genuine alternative to endoscopic third ventriculostomy (ETV).

[A grading system for chronic hydrocephalus]. / Ein Graduierungssystem für den chronischen Hydrozephalus.

A generally accepted grading system for patients suffering from chronic hydrocephalus has not been established yet. Therefore we designed a new grading system, which focuses on five symptom categories: gait disturbances, mental disorder, incontinence, headache, dizziness. For each category clearly circumscribed degrees of handicaps are defined. For each degree a value between 0-6 points is assigned in concordance to the severity of handicap. To get a generally accepted validation of the obstruction, the assigned values were oriented on the values provided in Germany to evaluate the degree of obstruction for insurances.[nl]In contrast to the established gradings of Stein and Langfitt and the Black Rating Scale our grading allows a more exact acquisition of the clinical presentation of a patient. Our experiences with the grading seemingly indicate also, that it is reliable. Because the grading allows an incorporation of measurable data such as psychometric analysis or gait analysis, our grading is useful as well for everydays' practice as for scientific purpose.

[LOVA hydrocephalus - a new entity of chronic hydrocephalus]. / LOVA-Hydrozephalus Eine neue Entität des chronischen Hydrozephalus.

The recently defined term "longstanding overt ventriculomegaly in adults" (LOVA) describes a unique entity of chronic occlusive hydrocephalus. The experiences so far using conventional DP valves were not encouraging because of a high percentage of overdrainage. The objective was to evaluate whether gravitational shunts could be used for this condition with an acceptable overdrainage risk. Twenty-three macrocephalic adults aged 17-72 years suffered from chronic progressive hydrocephalic conditions. They received two different types of gravitational shunt. Follow-up ranged from 6 months to 75 months. Only two patients presented small subdural effusions postoperatively, and only one required additional treatment for that. Eighty-two percent were shunt responders. Ventricular size was only marginally reduced in 22 of the 23 patients. There was no correlation between clinical benefit and the reduction in ventricular size. Gravitational shunts clearly have the potency for safe treatment of LOVA, significantly reducing the risk of overdrainage over conventional valves, and may be considered an equivalent alternative to third ventriculostomy.

Five years experience with gravitational shunts in chronic hydrocephalus of adults.

OBJECTIVE: Gravitational shunts for management of chronic hydrocephalus are supposed to avoid or at least to reduce the risk of overdrainage. In order to find out if this hypothesis is correct, we did a prospective study and analysed the results of a series of 185 hydrocephalic adults, treated by using gravitational shunts. For the few cases in whom overdrainage occurred, we wanted to establish the reason for it. Especially it should be proven or excluded that overdrainage was caused by shortcomings of the principle of gravitational shunts. Another goal was to compare post-shunting changes of the ventricular size with clinical outcome. A comparably large study has not yet been published. METHODS: 185 adult patients who suffered from chronic hydrocephalus were shunted between 1996-2000, either using the combination of an adjustable Codmann Hakim Valve & Miethke Shunt Assistant (35 patients) or a Miethke Dual Switch Valve (150 patients). The clinical course of each patient has been followed until the end of 2000. Average follow-up time was 26 months (range 6-60 months). RESULTS: 88% of our patients were shunt responders, 70% had a good or excellent outcome. Overdrainage occurred in only 4%. It turned out that this complication was not a failure of the concept of gravitational shunts, but the result of a wrongly estimated intraperitoneal pressure. After shunting the ventricular size was reduced only marginally. In 92% of the patients the Evans-Index decreased less than 20% after the shunt insertion, but 69% of these patients had a good or excellent outcome. The most obvious difference comparing pre- and postoperative imaging was a better visibility of the high apical sulci after shunting. CONCLUSION: In our series gravitational shunts proved to be effective in preventing overdrainage. The 4% negative exceptions are mainly avoidable. There was no correlation between outcome and ventricular size reduction, and as a rule ventricular size was only marginally reduced.

Vertex epidural hematoma with communicating bifrontal subgaleal hematomas treated by percutaneous needle aspiration.

The case of an 11-year-old boy is presented who suffered a bicycle accident with a parasagittal skull fracture, a small vertex epidural hematoma, frontal contusions and a frontal subgaleal hematoma. Enlargement of the vertex epidural hematoma was diagnosed after development of a slight paraparesis on day 11 with the aid of MRI. Three percutaneous needle aspirations of the subgaleal hematoma with a total of 59 ml being evacuated led to quick recovery and disappearance of the subgaleal as well as the vertex epidural hematoma. It is speculated that both hematomas communicated via the skull fracture thus making the evacuation of the epidural hematoma by subgaleal punctures possible.

[The importance of hydrostatic valves in the treatment of adult chronic hydrocephalus]. / Importancia de las válvulas hidrostáticas en el tratamiento de la hidrocefalia crónica del adulto.

BACKGROUND AND OBJECTIVE: Earlier designs of hydrocephalus valves, focusing on a reduction of the problem of overdrainage, were proved to be insufficiently. Since the middle of the 90's hydrostatic valve, constructions are available, which should solve this problem. The objective of the study was to evaluate, whether these gravitational shunts would indeed reduce the percentage of overdrainage in shunted patients. METHODS: In 51 patients clinical evaluation and MRI was performed pre- and in regular intervals postoperatively. 21 received a Dual-Switch valve, 14 a programmable Codman Hakim plus Shuntassistent and 6 a combination of a conventional valve with Shuntassistent. RESULTS: Over 90% of the patients had clear and persisting (over 24 months) clinical benefit from shunting. Only one suffered for some days after shunt implantation from headache in the upright position. No other clinical or imaging hints were given on an overdrainage. The ventricular size was unchanged in patients with a normal pressure hydrocephalus after shunting. In patients with occlusive hydrocephalus only a few showed a significant reduction of the ventricular wide. CONCLUSION: Gravitational shunts seem to decrease the overdrainage linked to the treatment of chronic hydrocephalus in shunted patients, therefore its use should be standardised when treatment chronic hydrocephalus.

Importancia de las válvulas hidrostáticas en el tratamiento de la hidrocefalia crónica del adulto / The importance of hydrostatic valves in adult chronic hydrocephalus

FUNDAMENTO Y OBJETIVO: Anteriores diseños de válvulas para el tratamiento de la hidrocefalia crónica del adulto, dirigidos a disminuir el problema del hiperdrenaje, han resultado insatisfactorios. Desde mediados de los años noventa están disponibles en el mercado las válvulas hidrostáticas, enfocadas a resolver este problema. El objetivo del estudio fue evaluar si estas válvulas gravitatorias reducirían el porcentaje de hiperdrenaje en pacientes con shunt. MÉTODOS: A 51 pacientes se les realizó un examen clínico y una resonancia magnética o tomografía axial computarizada preoperatoria y en intervalos regulares tras la operación. Veintiuno recibieron una válvula Dual-Switch®, 14 una combinación formada por una válvula programable Codman Hakim® y un asistente de la derivación (Shuntassistent®) y 6 un asistente de la derivación (Shuntassistent®) adicional a una válvula convencional implantada previamente. RESULTADOS: Más del 90 por ciento de los pacientes experimentaron una clara y persistente mejoría clínica (más de 24 meses) con la implantación de estas válvulas. Sólo uno de los pacientes padeció unos días tras la operación de cefalea secundaria al hiperdrenaje en posición ortostática. No se dieron signos ni clínicos ni en el diagnóstico por la imagen de hiperdrenaje en el resto de los pacientes. La amplitud ventricular no varió en pacientes con hidrocefalia normotensiva tras la colocación de la derivación. Sólo unos pocos pacientes con hidrocefalia obstructiva mostraron una disminución significativa en la amplitud de los ventrículos. CONCLUSIÓN: Las válvulas reguladas por la gravedad parecen disminuir el hiperdrenaje secundario al tratamiento de la hidrocefalia crónica mediante una derivación, por ello su uso debería estandarizarse en el tratamiento de la misma. (AU)

The dynamic infusion test in rats.

Although the hydrocephalic H-Tx rat is a widely used model, data on the cerebrospinal fluid (CSF) dynamics in hydrocephalic rats are rare or - as the pressure volume index (PVI) - not available. We used hydrocephalic and nonhydrocephalic H-Tx rats, a stock with a high percentage of inherited hydrocephalus, for the evaluation of such data. In addition, a new, simple mathematical algorithm ("dynamic infusion test"), which has not formerly been used in animal experiments, was used as a pathophysiological model of CSF dynamics. Compared with classical methods for evaluation of these data, the dynamic infusion test gives a deeper insight into the relation between ICP and CSF dynamics. It was found that the resistance to outflow (ROF) in hydrocephalic rats was at least twice that in nonhydrocephalic rats. The PVI measured was similar in hydrocephalic and nonhydrocephalic animals, but clearly higher than the values reported in the literature. This may be attributable to the fact that the classically used bolus test, in contrast to the "dynamic infusion test", is representative only for the CSF compartment which is directly exposed to the bolus application.

[Significance of hydrostatic valves in therapy of chronic hydrocephalus]. / Der Stellenwert hydrostatischer Ventile in der Therapie des chronischen Hydrozephalus.

Earlier design changes in hydrocephalus valves focusing on reducing overdrainage failed. Since the middle of the 1990s, hydrostatic valve constructions have been available which are claimed to solve this problem. The objective of this study was to evaluate the efficiency of these constructions. Clinical status and ventricular size were evaluated in 45 patients with chronic hydrocephalus before and 1, 6, and 26 weeks after operation. In 35 of these, a Miethke dual-switch valve was implanted (treatment group 1), and the others received a combination of a programmable Codman-Hakim valve and a Miethke shunt assistant as the hydrostatic element of the configuration (treatment group 2). A third group (n = 6) had already been shunted but suffered from overdrainage symptoms which could not be overcome by conservative measures. In these cases, the only operative treatment was the implantation of a Miethke shunt assistant adjunctively to the existing valve. In groups 1 and 2, there was a significant permanent improvement in the clinical state in nearly 80% of cases and a moderate permanent improvement in about 10%. Mild clinical and radiological signs of overdrainage occurred in three patients during the first postoperative week but resolved without further operative measures within the next 5 weeks. Typically, the ventricular width was not or only marginally reduced in these 45 patients. In the patients treated for symptoms of overdrainage (group 3), complaints resolved within the first week after implantation of the shunt assistant. The study indicates that gravitational shunts may be very effective in preventing overdrainage in chronic hydrocephalus, and therefore these constructions could represent the gold standard in the treatment of chronic hydrocephalus.