According to the CSF bulk flow theory, hydrocephalus is caused by an imbalance between CSF formation and absorption, or a block at various locations in the major CSF pathway. New theories, however, ...have been proposed in which minor CSF pathways may play a significant role in the development of congenital hydrocephalus. The authors review major contributions to the literature and analyze the evolution of theories of CSF dynamics in relation to hydrocephalus, dividing their development into 4 stages on the basis of historical trends. In Stage I (prior to 1950), 2 systems of classifying hydrocephalus were proposed, namely Dandy's classifications of communicating and noncommunicating hydrocephalus and Russell's nonobstructive and obstructive hydrocephalus. In Stage II (1950-1974), based on these theories of major CSF pathway dynamics, treatment focused on ventriculostomy as an alternative to reduction of CSF production by choroid plexus coagulation. In Stage III (1975-1999), some of the specific forms of hydrocephalus, especially in premature infants, were found to be unsuitable for ventriculostomy. In Stage IV (2000-2008), selection of treatment modalities evolved further, with a focus on analysis of the chronological changes in CSF dynamics and the differences in absorption pathways in the developing and mature brains. The authors focus on "minor pathway hydrocephalus" in the immature brain, differentiating it from the conventional classification of obstructive and nonobstructive "major pathway hydrocephalus."
The specificity of cerebrospinal fluid (CSF) dynamics in the immature brain still remains unknown. In our data previously published, the transependymal intraparenchymal CSF pathway (the minor ...pathway) plays a significant role in various degrees in the alternative CSF passage. Now, there is a growing consensus in the age differences in the outcome of neuroendoscopic ventriculostomy in treatment of non-communicating types of hydrocephalus. The authors discuss the clinical significance of the specific CSF dynamics and propose the new aspect of classification of hydrocephalus with a theory in the development of CSF from the pathophysiological point of view.
Between January 2001 and March 2004, 122 hydrocephalic children were registered at the Jikei University Hospital Women's & Children's Medical Center (JWCMC), Tokyo. Our retrospective study for the efficacy of neuroendoscopic ventriculostomy confirmed the significantly high failure rate of neuroendoscopic ventriculostomy in treating hydrocephalus in neonates and infants with non-communicating hydrocephalus as the initial impression. The prospective CSF dynamic studies using cine-mode MRI and CT ventriculo-cisternography were then routinely started. Altogether, 9 out of 29 (31%) endoscopically treated cases needed shunt placement 3-30 weeks (mean 7.9 weeks) after the endoscopic procedure(s) (publication in preparation). Five out of 11 (45%) neonates/infants under 3 months, 3/5 (60%) infants at 7-12 months, 10/10 (100%) toddlers at 1-4 years and 3/3 (100%) schoolchildren at 5-17 years were cured, as in the condition of "post-endoscopic ventriculostomy arrested hydrocephalus". The pattern of ventriculo-cisternography in neonatal/infantile cases revealed intraparenchymal predominant pattern (minor pathway) of the CSF dynamics rather than passage in the major pathway.
The various basic investigations in rodents, cats and monkeys have suggested that CSF is absorbed not via Pacchionian bodies as the last end of the major pathway, which do not exist in these animals and are recognized after infantile period in human, but through the choroids plexus and the periventricular fenestrated venous capillaries into the deep venous channel. The high incidence of "failure to arrest hydrocephalus" by neuroendoscopic ventriculostomy in fetal, neonatal and infantile periods was considered to depend on the specific CSF dynamics, in which the major CSF pathway has not developed and the minor pathway has a significant role. PROPOSAL OF THEORY: We herein propose a new aspect of classification for hydrocephalus with special reference to the CSF circulation in the minor CSF pathway, i.e. "minor pathway hydrocephalus", differentiating the conventional classification by Dandy (communicating and non-communicating) or Russell (non-obstructive and obstructive) as "major pathway hydrocephalus". We also herein propose a hypothesis that the CSF dynamics develop in the theory of evolution from the immature brain, as in the animals with the minor CSF pathway predominance, towards matured adult human brain together with completion of the major CSF pathway: the "evolution theory in CSF dynamics".
Classification of hydrocephalus is the most crucial but the most complicated academic challenge within the hydrocephalus research field. The major difficulty in this challenge arises from the fact ...that the classification is based on almost all subjects in hydrocephalus research, i.e., definition and terminology of hydrocephalus, pathophysiology, hydrocephalus chronology, specific forms of hydrocephalus, associated congenital anomalies/syndrome and underlying conditions, diagnostic procedures for hydrocephalus, and treatment modalities in hydrocephalus. The current status of the classification of hydrocephalus in individual subgroups was reviewed and summarized from publications in the last 60 years (1950-2010), and discussed focusing on the variety of characteristics in hydrocephalus, with more and more new aspects recently disclosed not only in fetal and pediatric but also in adult hydrocephalus. A recently-reported classification of hydrocephalus, “Multi-categorical Hydrocephalus Classification” provides comprehensive coverage of the entire aspects of hydrocephalus with current important classification categories and subtypes.
Analysis of the safety and morbidity of neuroendoscopic biopsies (NEBs), as well as the reliability in obtaining an accurate diagnosis, has until now been based on studies with relatively small ...sample sizes. Through the cooperative efforts of several international medical centers, authors of the present study collected data on a large number of patients to obtain better insight into this issue. When possible, they compared pathology obtained through an NEB with the "gold-standard" pathology obtained in open surgery.
Thirteen randomly chosen medical centers in 9 countries collected data for patients who had undergone NEB, which were then analyzed for universal complications, bleeding, navigation technique, pathology, mismatch between biopsy results and final diagnosis, and a number of other potentially influential factors.
Data for 293 patients were analyzed. Sixty percent of the patients were male, and patient ages ranged from 0.1 to 78.7 years (median age 20.4 years). The most common tumor locations were pineal (33.1%), thalamic (16.7%), tectal (13%), and hypothalamic (4.4%). Fifty percent of the tumors were larger than 20 mm, 36% were between 10 and 20 mm, and 14% were smaller than 10 mm. Intraoperative bleeding was seen in 275 patients (94%). The amount of blood was noted as mild in 75%, moderate in 13%, and severe in 6%. Infection occurred in 8 patients (3%). Death occurred in 1 patient (0.3%), which was caused by severe intraoperative bleeding. Biopsies were informative in 265 patients (90.4%). Seventy-eight patients (26.6%) had open surgery following the NEB. For these patients, the pathology results from the NEB were compared with those from the open surgery that followed. In 14 cases (17.9%) there was disagreement on the pathology. Of these cases, a meaningful mismatch, in which the erroneous NEB pathology could have led to an inappropriate management decision, occurred in 9 cases (11.5%). Most of these meaningful mismatches were lesions diagnosed as low-grade or pilocytic astrocytoma on the NEB and later proved to be high-grade astrocytoma (4 cases) and 1 case each of meningioma, cavernoma, primitive neuroectodermal tumor, neurocysticercosis, and pineocytoma.
In experienced hands, NEBs can be performed with low morbidity and mortality, providing meaningful pathological data for the majority of patients with a wide range of tumor types, locations, and presentations. These biopsies also offer other advantages, such as the ability to perform concomitant endoscopic third ventriculostomy and septum pellucidotomy. However, due caution must be maintained, since pathology obtained from an NEB, as with stereotactic biopsies, may be subject to sampling errors, especially when the results seem to indicate a low-grade glial tumor.
We present an overview of the history, development, technological advancements, current application, and future trends of cranial endoscopy. Neuroendoscopy provides a safe and effective management ...modality for the treatment of a variety of intracranial disorders, either tumoral or non-tumoral, congenital, developmental, and degenerative, and its knowledge, indications, and limits are fundamental for the armamentarium of the modern neurosurgeon.
Objective
Hydrocephalus is a complex pathophysiology with disturbed cerebrospinal fluid (CSF) circulation. There are numerous numbers of classification trials published focusing on various criteria, ...such as associated anomalies/underlying lesions, CSF circulation/intracranial pressure patterns, clinical features, and other categories. However, no definitive classification exists comprehensively to cover the variety of these aspects. The new classification of hydrocephalus, “Multi-categorical Hydrocephalus Classification” (Mc HC), was invented and developed to cover the entire aspects of hydrocephalus with all considerable classification items and categories.
Materials and method
Ten categories include “Mc HC” category I: onset (age, phase), II: cause, III: underlying lesion, IV: symptomatology, V: pathophysiology 1—CSF circulation, VI: pathophysiology 2—ICP dynamics, VII: chronology, VII: post-shunt, VIII: post-endoscopic third ventriculostomy, and X: others. From a 100-year search of publication related to the classification of hydrocephalus, 14 representative publications were reviewed and divided into the 10 categories.
Results and discussion
The
Baumkuchen classification graph
made from the round o’clock classification demonstrated the historical tendency of deviation to the categories in pathophysiology, either CSF or ICP dynamics.
Conclusion
In the preliminary clinical application, it was concluded that “Mc HC” is extremely effective in expressing the individual state with various categories in the past and present condition or among the compatible cases of hydrocephalus along with the possible chronological change in the future.
The management of congenital CNS anomalies differs among countries. This paper reports on a worldwide survey of individual experience and regimens for treating spina bifida (SB) in different patient ...populations and cultural backgrounds. Ten representative members of the International Society for Pediatric Neurosurgery (ISPN) in individual countries registered their experience, prenatal management, and care system for SB. The information collected contained the following major items: intrauterine diagnosis, prophylaxis, and legal termination in prenatal management.
The prenatal diagnosis of SB is extensively performed throughout the world, but the marker alpha-fetoprotein is not widely accepted in Asia, nor is the prophylactic administration of folic acid, which is not part of the routine care in Asia. Morphological analyses by neuroimaging, especially using an advanced technique of magnetic resonance imaging (MRI), are well developed in Asian countries, e.g., Japan and Korea. The prenatal management of SB fetuses differed depending upon the region, i.e., more support for aggressive and intensive treatment in Asia than in Europe and North America. The regional and racial difference in management of and care for spina bifida fetuses will be discussed further based on the data analysis.
Although in recent years endoscopic procedures have been used for intracranial arachnoid cysts with favorable preliminary results in certain locations, optimal surgical treatment is still ...controversial. The purpose of this study was to evaluate the efficacy and safety of endoscopic transventricular ventriculocystostomy in the treatment of intracranial cysts based on the concept of normalizing cerebrospinal fluid (CSF) dynamics.
Twelve symptomatic pediatric patients with congenital intracranial cysts underwent surgery at Jikei University in Tokyo. A neuroendoscopic transventricular ventriculocystostomy was performed in nine patients and an endoscope-assisted craniotomy in the remaining three. Endoscopy was performed using a freehand maneuver with a newly designed rigid-rod neuroendoscope that is frameless and has a small diameter. Clinical results were good in all patients, although cysts in three were not prominently reduced in size when follow-up imaging studies were performed. Neither death nor symptomatic morbidity occurred, and no patient required shunt placement. In three cases the endoscopic fenestration was associated with an endoscopic third ventriculostomy (ETV). Postoperative CSF dynamics studies consisting of computerized tomography ventriculocysternography, and pre- and postoperative cine-mode magnetic resonance imaging demonstrated free communication between fenestrated cysts and ventricular/ cistern CSF pathways consistent with normalization of CSF dynamics.
Neuroendoscopic transventricular ventriculocystostomy constitutes a valid alternative to microsurgery for intracranial cysts located within or adjacent to the ventricles. It creates an effective CSF flow within the cyst with minimal alteration of subarachnoid spaces. It may be combined with an ETV procedure in case of obstruction of CSF pathways and should be preferred to the insertion of shunts.
Object
The goal of this study is to evaluate whether an “ideal shunt” exists.
Methods
This is a retrospective analysis based on original papers in the field of
Hydrocephalus and Shunts
. Patients of ...all age groups, who had hydrocephalus, and underwent some form of CSF diversion were included. The study has been divided into four stages: from 1900 to 1949, 1950 to 1974, 1975 to 1999, and from 2000 to 2010.
Results
In stage 1 (
historical era
): Saphenous vein grafts, rubber conduits, and other materials were used in CSF diversions. In 1949, the first implantable shunt tube was developed by Nulsen. In stage 2 (
experimental stage
): the Holter valve was developed. Newer innovations were developed in relation to the ventriculo-atrial shunt, which was the preferred CSF diversion. In stage 3 (
developmental stage
), a large number of different design shunt systems were developed, with the aim of reducing complications. The ventriculo-peritoneal shunt had become the preferred CSF diversion. Also, the programmable valve was born. In stage 4 (
era of programmable valve
, there is a preference for the use of programmable shunt systems. However, shunt failure rate at 1 year being around 25 to 40 %, and shunt survival at 1 and 2 years are 50–70 and 47–53 % in most series.
Conclusion
Every shunt is an ideal shunt provided the choice of the shunt used should be made by the matching performance of the shunt system to the altered profile of CSF dynamics of a given patient. The most important factor being the opening pressure.
Long-standing overt ventriculomegaly in adults (LOVA) is a unique form of hydrocephalus that develops during childhood and manifests symptoms during adulthood. The aim of the present study was to ...analyze the specific pathophysiological characteristics of LOVA.
The specific diagnostic criteria for LOVA include severe ventriculomegaly in adults that is associated with macrocephalus measuring more than two standard deviations in head circumference and/or neuroradiological evidence of a significantly expanded or destroyed sella turcica. Twenty patients who fulfilled these criteria, 14 males and six females, were retrospectively studied. These patients' ages at diagnosis ranged from 15 to 61 years (mean 39.4 years). All had symptoms and/or signs indicating that hydrocephalus first occurred at birth or during infancy in the absence of any known underlying disease. The authors performed a pathophysiological study that included specific variations of magnetic resonance (MR) imaging, such as fluid-attenuated inversion recovery and cardiac-gated cine-mode imaging; intracranial pressure (ICP) monitoring; three-dimensional computerized tomography (CT) scanning; and other techniques. Hydrocephalus was caused by aqueductal stenosis in all patients. Severe ventriculomegaly involving the lateral and third ventricles was associated with a marked expansion or destruction of the sella turcica in 17 cases. Cardiac-gated cine-MR imaging did not reveal any significant movements of cerebrospinal fluid in the aqueduct. Three-dimensional CT ventriculography confirmed that the expanded third ventricle protruded into the sella and, sometimes, extended a diverticulum. Fourteen patients revealed symptoms and signs that indicated increased ICP with prominent pressure waves. Dementia or mental retardation was seen in 11 patients, gait disturbance in 12, and urinary incontinence in eight; all three of these symptoms were observed in seven patients. Thirteen patients experienced visual disturbance. Nine patients underwent ventriculoperitoneal shunt implantation as the initial treatment, leading to postoperative subdural hematoma in all seven cases in which a differential pressure valve was used. Nine patients, three of whom were initially treated by shunt placement, underwent a neuroendoscopic procedure, mainly for third ventriculostomy. Postoperatively, ICP returned to normal, and marked to-and-fro pulsatile movements at the site of ventriculostomy were recognized on cine-MR imaging in patients treated endoscopically. However, the ventriculomegaly was little improved. Consequently, all patients eventually demonstrated improvement in response to either a shunt equipped with a pressure-programmable valve or an endoscopic procedure; however, depression appeared in six patients, who required psychiatric consultation or medication.
Such remarkably decreased intracranial compliance but relatively high ICP dynamics are the pathophysiological characteristics of LOVA. The therapeutic regimen should be determined based on the individual's specific pathophysiological makeup.
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