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Object: The current, generally accepted optimal management for hydrocephalus related to vestibular schwannomas (VSs) is primary tumor removal, with further treatment reserved only for patients who remain symptomatic. Previous studies have shown, however, that this management can lead to an increase in surgery-related complications. In this study, the authors evaluated their experience with the treatment of such patients, with the aim of identifying the following: 1) the parameters correlating to the need for specific hydrocephalus treatment following VS surgery; and 2) patients at risk for developing hydrocephalus-related complications., Methods: This was a retrospective study of a 400-patient series. The complication rates and outcomes following primary hydrocephalus treatment versus primary VS removal were compared. Patients undergoing primary tumor removal were further subdivided on the basis of the need for subsequent hydrocephalus treatment. The 3 categories of parameters tested for correlation with the need for such subsequent treatment as well as with heightened risk for developing complications were patient-, tumor-, and hydrocephalus-related., Results: Of the entire series, 53 patients presented with hydrocephalus. Forty-eight of 53 patients underwent primary VS surgery, of whom 42 (87.5%) did not require additional hydrocephalus treatment. Of the 6 patients who did require additional hydrocephalus treatment, only 3 ultimately required a VP shunt. Factors correlating to the need of hydrocephalus treatment after VS removal were large tumor size, irregular tumor surface, and severe preoperative hydrocephalus. Patients with a longer symptom duration prior to surgery, those with polycyclic tumors, or with inhomogeneous VS, were at heightened risk for the development of CSF leaks. The general and functional outcome of surgery showed no correlation to the presence of preoperative hydrocephalus., Conclusions: Primary tumor removal is the optimum management of disease in patients with VS with associated hydrocephalus; it leads to resolution of the hydrocephalus in the majority of cases, and the outcome is similar to that of patients without hydrocephalus. Certain factors may aid in identifying patients at risk for developing persistent hydrocephalus as well as those at risk for CSF leaks.

The peel-away sheath in neuroendoscopic surgery offers numerous advantages and has many potential applications. However, currently available nontransparent sheaths have a critical disadvantage in that disorientation can occur, given the limited visible operative field. To overcome this obstacle, the authors have developed and clinically applied a new transparent sheath with "navigational orientation markers." The clear peel-away sheath provides a transparenchymal route, parenchymal protection, and, most importantly, direct visualization of the surroundings along the whole trajectory and at the distal edge. The navigational orientation markers add further benefits in terms of facilitating orientation in the endoscope trajectory, making this tool extremely useful in neuroendoscopic surgery.

The authors report on a neonatal patient with traumatic subacute subdural effusion in the posterior fossa associated with secondary acute hydrocephalus. The infant fell from his mother's hand onto the floor, injuring his left parietal region. Computed tomography (CT) scans of the patient's head revealed a linear fracture of the left parietal bone, a small contusion in the right temporal lobe, and a small subdural hematoma in the right posterior fossa with thin subdural effusion. Serial CT scans revealed a progressive increase in subdural effusion bilaterally in the posterior fossa. On Day 7 the anterior fontanelle was tense and CT scans revealed marked hydrocephalus associated with thick subdural effusion in the posterior fossa. External drainage of both the subdural effusion and dilated lateral ventricles improved the patient's condition, and no reaccumulation of subdural effusion has been observed. The origin and treatment of this rare clinical entity is discussed.

Object: Analysis of meningiomas supports the suggestion that loss of heterozygosity (LOH) of chromosome arm 1p plays an important role in malignancy. The aim of this study was to identify genes related to meningioma progression from the benign state to the atypical and anaplastic states by examining 1p LOH and the promoter methylation of RASSF1A and p73., Methods: The authors studied 40 surgical specimens (22 WHO Grade I, 11 Grade II, and seven Grade III) obtained in 37 patients with meningioma. The LOH at 1p36 was analyzed using microsatellite markers, and promoter methylation of p73 and RASSFIA was analyzed using methylation-specific polymerase chain reaction., Results: No 1p LOH was detected in the Grade I tumors, whereas it was detected in more than 80% of the Grade II and III tumors. Methylation of the p73 promoter was observed in 81.8 and 71.4% of the Grade II and III tumors, respectively, but it was not observed in any of the Grade I tumors; methylation of the RASSF1A promoter was observed in 18.2, 63.6, and 42.9% of the Grade I, II, and III tumors, respectively. Interestingly, 1p LOH and p73 promoter hypermethylation were detected in the malignantly transformed tumors but not in the lower-grade primary ones., Conclusions: Based on the hypothesis that meningiomas cumulatively acquire genetic alterations and thus progress from the benign to the atypical and anaplastic states, genetic alterations in the methylation status of p73 or RASSF1A along with 1p LOH may result in the malignant transformation of a meningioma. This type of genetic fingerprint may play both diagnostic and therapeutic roles.

Object: The authors present a novel cine magnetic resonance (MR) imaging, two-dimensional (2D) fast imaging employing steady-state acquisition (FIESTA) technique with parallel imaging. It achieves temporal resolution at less than half a second as well as high spatial resolution cine imaging free of motion artifacts for evaluating the dynamic motion of fetuses in utero. The information obtained is used to predict postnatal outcome., Methods: Twenty-five fetuses with anomalies were studied. Ultrasonography demonstrated severe abnormalities in five of the fetuses; the other 20 fetuses constituted a control group. The cine fetal MR imaging demonstrated fetal head, neck, trunk, extremity, and finger as well as swallowing motions. Imaging findings were evaluated and compared in fetuses with major central nervous system (CNS) anomalies in five cases and minor CNS, non-CNS, or no anomalies in 20 cases. Normal motility was observed in the latter group. For fetuses in the former group, those with abnormal motility failed to survive after delivery, whereas those with normal motility survived with functioning preserved. The power deposition of radiofrequency, presented as specific absorption rate (SAR), was calculated. The SAR of FIESTA was approximately 13 times lower than that of conventional MR imaging of fetuses obtained using single-shot fast spin echo sequences., Conclusions: The following conclusions are drawn: 1) Fetal motion is no longer a limitation for prenatal imaging after the implementation of parallel imaging with 2D FIESTA, 2) Cine MR imaging illustrates fetal motion in utero with high clinical reliability, 3) For cases involving major CNS anomalies, cine MR imaging provides information on extremity motility in fetuses and serves as a prognostic indicator of postnatal outcome, and 4) The cine MR used to observe fetal activity is technically 2D and conceptually three-dimensional. It provides four-dimensional information for making proper and timely obstetrical and/or postnatal management decisions.

Hadju-Cheney syndrome (HCS) is a rare autosomal-dominant disorder with variable expressivity. It is characterized by facial dysmorphism, premature tooth loss, osteolysis of distal phalanges, and skull abnormalities. In some cases, progressive platybasia can occur and can lead to Chiari malformation with an obstruction of cerebrospinal fluid flow. To the best of the authors' knowledge, only five cases of HCS-associated syringomyelia have been reported in the literature. Because of the rarity of this association, little is known about its natural history. The authors present the case of a 16-year-old boy affected by HCS. On initial magnetic resonance (MR) imaging, a severe basilar invagination with Chiari malformation and cervicothoracic syringomyelia was documented. The syringomyelia had no clinical manifestations. A repeated MR image demonstrated a spontaneous resolution of the syrinx with no changes in the tonsil or the platybasia. The regression of the syringomyelia was confirmed by a control MR imaging examination performed after a 2-year period. No changes in the patient's clinical conditions were found during the follow-up period. This is the first case of spontaneous regression of the syringomyelia despite a severe platybasia in HCS. It did not appear correlated to a modification of the tonsil's structure or position. This observation illustrates one possible evolution of syringomyelia in the natural history of HCS and raises the question of the potential mechanisms involved in the spontaneous drainage of the syringomyelic cavity.

Object: 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., Methods: 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., Conclusions: 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.

A newly designed small-diameter rigid-rod neuroendoscope was created to evaluate the applicability of free-hand maneuvering during high-resolution imaging. The neuroendoscope was designed as a light, handheld tool weighing 550 g. A 20-cm-long objective lens, 2 mm in diameter, is placed in the lower two thirds of the single-space lumen of an oval-shaped outer sheath, 16.5 mm long and 3.5 x 2.5 mm at maximum diameter. Included are microinstruments of 1.3-mm diameter for various neuroendoscopic procedures, including microscissors, biopsy forceps, grasping forceps, monopolar coagulator/cutting rod, and bipolar coagulator that can be introduced through the upper one third of the lumen. Because the endoscope is held steady in the surgeon's left hand, with the handle gripped at the base, quick back-and-forth movements can be made along the long axis, via a peel-away sheath inserted to the ventricle, shifting of the endoscope tip to the side of the objective target will be minimal. Given the instrument's unified configuration, the surgeon will never lose orientation during maneuvering. Using the farthest right of three inlet/outlet orifices, the short and handy semiflexible microinstruments can be guided and controlled by the surgeon's right hand. After experience in 66 cases in which various neuroendoscopic procedures yielded excellent operative outcomes (morbidity rate in complications related to the endoscopic procedure 0%; mortality rate 0%), the endoscope prototype was finalized in the ideal form for frameless maneuvering that uses a rigid-rod endoscope. The "gun-butt" holder for use with the operator's left hand provides stability and allows the endoscope to be handled with improved control. These new aspects of the neuroendoscope and surgical technique offer substantial improvement over the flexible-steerable fiberoptic endoscopes.

Object: In this study the authors evaluate the safety, efficacy, and indications for endoscopic third ventriculostomy (ETV) in patients with a history of subarachnoid hemorrhage or intraventricular hemorrhage (IVH) and/or cerebrospinal fluid (CSF) infection., Methods: The charts of 101 patients from seven international medical centers were retrospectively reviewed; 46 patients had a history of hemorrhage, 42 had a history of CSF infection, and 13 had a history of both disorders. All patients experienced third ventricular hydrocephalus before endoscopy. The success rate for treatment in these three groups was 60.9, 64.3, and 23.1%, respectively. The follow-up period in successfully treated patients ranged from 0.6 to 10 years. Relatively minor complications were observed in 15 patients (14.9%), and there were no deaths. A higher rate of treatment failure was associated with three factors: classification in the combined infection/hemorrhage group, premature birth in the posthemorrhage group, and younger age in the postinfection group. A higher success rate was associated with a history of ventriculoperitoneal (VP) shunt placement before ETV in the posthemorrhage group, even among those who had been born prematurely, who were otherwise more prone to treatment failure. The 13 premature infants who had suffered an IVH and who had undergone VP shunt placement before ETV had a 100% success rate. The procedure was also successful in nine of 10 patients with primary aqueductal stenosis., Conclusions: Patients with obstructive hydrocephalus and a history of either hemorrhage or infection may be good candidates for ETV, with safety and success rates comparable with those in more general series of patients. Patients who have sustained both hemorrhage and infection are poor candidates for ETV, except in selected cases and as a treatment of last resort. In patients who have previously undergone shunt placement posthemorrhage, ETV is highly successful. It is also highly successful in patients with primary aqueductal stenosis, even in those with a history of hemorrhage or CSF infection.

Object: This prospective study is based on a consecutive series of 20 patients with pineal region tumors who underwent minimally invasive preferential management. The purpose of this report is to discuss the role of neuroendoscopic procedures in the management of pineal region tumors., Methods: If the tumor markers alpha-fetoprotein and human chorionic gonadotropin were not detected in serum and there was significant ventricular dilation visualized on neuroimages, neuroendoscopic surgery was first applied for tumor debulking with tissue diagnosis and gross morphological analysis of the tumor and the intraventricular structures, followed by third ventriculostomy. Subsequent procedures were determined on the basis of verified individual tumors. For treatment of germinomas and pineoblastomas, if no tumor dissemination was confirmed by pre-, intra-, or postoperative findings, stereotactic radiotherapy or radiosurgery was performed after one course of chemotherapy with the ICE regimen (isofomid, cisplatin, and etoposide) and followed by two additional courses of chemotherapy. For treatment of malignant germ cell tumors, after extensive surgery, adjuvant chemotherapy with the ICE regimen was performed in three courses in all cases. Then radiotherapy was started using various methods, depending on the evidence of tumor dissemination. For treatment of teratomatous and neuroectodermal tumors other than pineoblastomas, extensive surgical removal was performed. As for adjuvant therapy, if the tumor was a low-grade glioma or if the patient was younger than 5 years of age, postoperative treatment did not include radiotherapy. If the tumor was a malignant teratoma or high-grade glioma, conventional focal radiotherapy was performed, followed by chemotherapy with ICE for 1 year. All but two treated patients had ventriculomegaly. Neuroendoscopic procedures were performed in six of 15 treated patients. Neuroendoscopic biopsy with tumor debulking offered enough material for tissue diagnosis, including immunohistochemical analysis and, in one case, revealed evidence of tumor dissemination undetectable on neuroimaging. With one exception, no shunt was required in any patient undergoing endoscopic third ventriculostomy. Stereotactic radiotherapy was performed in indicated cases. Favorable therapeutic outcomes were obtained in all cases of germinoma and pineoblastoma, with follow-up periods ranging from 24 months to 6.5 years., Conclusions: Our minimally invasive preferential regimen clarified the precise indication for neuroendoscopic procedures, and the majority of our patients with dilated ventricles and no evidence of tumor markers were treated satisfactorily with effective neuroendoscopic procedures as the initial procedure, avoiding unnecessary craniotomy and radiotherapy and promising excellent therapeutic outcomes. The treatment for malignant pineal region tumors remains a subject for further study.

Object: 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., Methods: 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., Conclusions: 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.

Object: It is possible to diagnose hydrocephalus prenatally based on the morphological appearance of the fetus on neurodiagnostic images; however, the prognosis of this disease shows wide variation. The authors previously proposed a classification system for the prediction of postnatal outcome based on progression of hydrocephalus and affected brain development, known as the "Perspective Classification of Congenital Hydrocephalus (PCCH)." In this study the authors have used their classification system to analyze long-term follow-up results obtained in each clinicoembryological stage of fetal hydrocephalus., Methods: Sixty-one fetuses with hydrocephalus were examined to predict postnatal outcome by using this newly developed classification. The authors' recently developed method of using heavily T2-weighted imaging with a superconducting magnet clearly delineated the cerebrospinal fluid (CSF) space and the malformed brain and spinal cord. Imaging was achieved in less than 1 second per slice and required no sedation of the fetus. The technique appears to be simple and good at delineating intrauterine anatomy. Hydrocephalus was diagnosed in two fetuses at PCCH embryological Stage I (8-21 gestational weeks), in 28 fetuses at Stage II (22-31 weeks), and in 31 fetuses at Stage III (32-40 weeks). Among these 61 fetuses, clinicopathological typing showed that 19 had primary hydrocephalus (nine in Stage II and 10 in Stage III), 34 had dysgenetic hydrocephalus (two in Stage I, 16 in Stage II, and 16 in Stage III), and eight had secondary hydrocephalus (three in Stage II and five in Stage III). When the hydrocephalic state developed during PCCH Stage I or II, the prognosis was very poor, and only one of 18 fetuses with dysgenetic hydrocephalus and none of three fetuses with secondary hydrocephalus had an acceptable postnatal outcome. Even within the same category or subtype of fetal hydrocephalus, such as primary hydrocephalus in its simple form, or hydrocephalus with spina bifida aperta (myeloschisis), the postnatal outcomes differed depending on the time of onset of hydrocephalus. When the diagnosis of hydrocephalus was made during PCCH Stage II, the fetuses had a poorer postnatal outcome compared with those at Stage III (p < 0.05)., Conclusions: It is emphasized that postnatal prognosis is not simply a function of the form of the diagnosis but is also dependent on the progression of hydrocephalus and the degree to which that process affects neuronal development. Early decompressive procedures, conventionally performed after but, hopefully, performed before birth, are indicated to obtain the optimal postnatal prognosis of fetuses with hydrocephalus diagnosed at PCCH Stage II.

Tail-like caudal appendages may be associated with spinal dysraphism, particularly with spinal lipomas or lipomyelomeningoceles. An unusual case is presented of a patient with a myelomeningocele and a thick filum terminale with tethered spinal cord, which presented with the external appearance of a human tail. A review of the literature reveals that human tails may be associated with dysraphic conditions. Extensive neuroradiological examinations should be performed for all such cases of apparent tails.

The clinical features and pathophysiology of specific forms of hydromyelia are analyzed in this report together with the chronological changes of associated hydrocephalus. Nine patients were studied; all had hydromyelia with varying degrees of associated hydrocephalus. Clinically applicable classification systems were used to evaluate the progression of hydrocephalus (Stages I to IV) and to define the compartment isolated after shunting in the previously communicating cerebral ventricles (Types I to IV). Four patients had Stage IV disease (holoneural canal dilatation); one had Stage II and four had Stage I disease (both Stages I and II with supratentorial hydrocephalus). All patients were initially treated by ventriculoperitoneal shunting at an average age of 9.9 years. Five patients had progressive spinal symptoms before or after treatment of their hydrocephalus. Two patients had Type III isolation (an isolated rhombencephalic ventricle) with a functioning ventricular shunt; ventriculography confirmed a communication between the fourth ventricle and the hydromyelia, and both patients improved after placement of a shunt in the fourth ventricle. The remaining patients had Type IV isolation (isolated central canal dilatation) with a functioning ventricular shunt. This study indicates that in some cases the pathophysiology of hydromyelia is closely related to associated hydrocephalus. A new concept of the development of an isolated compartment after shunting is proposed to explain the progression of hydromyelia in these cases.

Extensive histological and immunohistochemical studies were performed to elucidate the histopathogenesis of exencephaly induced in chick embryo as an experimental model. The findings were compared with those identified in a chick myeloschisis experimental model and in human autopsy cases. The experimental model of exencephaly in chick embryos was developed by induction with various teratogens including ethylnitrosourea, salicylate, and phenytoin. None of the cases of exencephaly was exposed to a teratogen prior to or within Hamburger and Hamilton stage 12 (45 to 49 hours postincubation), when the anterior neuropore closes. The process of overgrowth in development of exencephaly was identical to that of myeloschisis, and the results suggested neuronal overmaturation in the histological and immunohistochemical studies. Although the late-stage degenerative change with neovascularization over the exposed neural tissue (placode) was more severe in human exencephaly, the present experimental study may suggest a possible common embryopathogenesis of dysraphism. Exencephaly should be regarded as the most severe form of cranium bifidum, as myeloschisis is in spina bifida.

A hypothesis for embryopathogenesis of myeloschisis is described on the basis of experimental studies analyzing the stage specificity and immunohistochemical/histological characteristics of the exposed neural tissue (placode). Myeloschisis developed in six fetuses among 205 chick embryos treated in various stages with teratogens including ethylnitrosourea, and anticonvulsant and antipyretic agents. All but one case (with associated cephalothoracopagus) demonstrated myeloschisis in the thoracic region with a lamina defect of two and three levels. No fetus was exposed to a teratogen prior to or within Hamburger and Hamilton stage 12 (45 to 49 hours postincubation), when the neuropore closes. Immunohistochemical studies of chick myeloschisis clearly indicated that neuron-specific enolase-positive elements were extremely active only in the overgrown placode, corresponding to the histological findings with Kluver-Barrera's special stain. These findings were compared with observations in a case of myeloschisis in a human neonate. The results of this study imply the possibility of another mechanism for the embryopathogenesis of myeloschisis: namely, the overgrowth and reopening hypothesis.

The case history of a patient with a xanthogranuloma of the third ventricle is presented. This type of lesion formed by desquamation of epithelium is usually noted as an incidental autopsy finding in the choroid plexus of the lateral ventricles. Total removal via a transcortical transventricular route led to complete recovery. These tumors should be suspected in the geriatric population. The computerized tomography findings and a review of the literature are included.

A patient is presented who developed a fatal hemorrhage immediately after balloon occlusion of an extracranial vertebral arteriovenous fistula. The fistula was associated with marked retrograde flow not only from the contralateral vertebral artery but also from the carotid artery system through the posterior communicating artery and the basilar artery. The bleeding appeared to be caused by acute hemodynamic effects following abrupt occlusion of the long-standing fistula. A gradual staged occlusion or trapping procedure should be considered for the treatment of such vertebral arteriovenous fistulae.