The evolution of the pathophysiological concept and the surgical treatment of pediatric hydrocephalus are reviewed in this article.
  From the era of the ancient Greeks to the 19th century, hydrocephalus has been recognized as the accumulation of cerebrospinal fluid (CSF) in the brain. In the 20th century, the major CSF pathway was elucidated as follows : the majority of CSF was produced from choroid plexuses, passing through the ventricles to the subarachnoid space, then absorbed from the arachnoid granules. The main pathophysiology of hydrocephalus was proposed as disorders of the major CSF pathway. The minor CSF pathway was proposed as CSF exchanges among transependymal, intraparenchymal, perivascular, and interstitial spaces. The concept of minor pathway hydrocephalus in infants was proposed as well as evolution theory in CSF dynamics. In addition, it appears that interstitial fluid and CSF are formed by water filtration from the walls of arterial capillaries, and absorbed from venous capillaries and postcapillary venules.
  Hydrocephalus had been treated by open- or closed-ventricular drainage until the 19th century. The third ventriculostomy and the choroid plexectomy were employed in the beginning of the 20th century, but declined in use because of poor results. In recent years, third ventriculostomy has become the first choice of treatment for non-communicating hydrocephalus, because of the technical advancements made utilizing neuroendoscopy. As for shunts, various attempts were made the before the 1960’s, but these were often complicated by infections or by thrombotic obstructions. Ventriculoperitoneal shunts have become the most popular since the 1960’s, and various shunt products have been made to reduce shunt malfunction.

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  Current treatment protocols for medulloblastomas stratify patients into high and average risk groups according to their age, metastatic status, and the presence of residual tumor after resection. Recent intensive genomic and molecular biological analyses of medulloblastomas have revealed that they can be classified into at least four core subgroups, WNT, SHH, Group 3, and Group 4, based on differences in their cytogenetics, mutational spectra, and gene expression signatures, as well as in their clinical phenotypes and outcomes. This four-subgroup system for medulloblastomas will become a useful prognostic marker, and, in combination with metastatic and other characteristics, will lead to improved diagnosis and risk stratification systems. Novel treatments are already being designed and developed according to the molecular and clinical properties of each subgroup. The molecular and genetic diagnosis of medulloblastomas will be integrated into their clinical diagnosis, and will contribute to the development of therapeutic strategies for these tumors.

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  Recently, a consensus on the management of central nervous system germ cell tumors was published by an international panel of experts in this field using the Delphi survey. Overall, 34 of 38 original statements met consensus criteria, and a couple of the statements could not reach a consensus level. Here one of the authors tells and comments on the consensus statements, their consensus levels, and on the non-consensus statements as well for a better understanding of the statements.

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  Occult spinal dysraphism (OSD), recognized as a twin word for cystic spinal dysraphism, is uncommon to general neurosurgeons.
  It is a big problem that OSD is apt to be overlooked, because the most cases might have only tiny signs of cutaneous stigmata in the lumbosacral region with insidious worse of the neurological symptoms.
  Moreover, the entity of OSD is complicated that it is strictly classified into many divisions ; spinal lipoma, congenital dermal sinus, thickened filum terminale, terminal myelocystocele, diastematomyelia, and so on. Therefore, the proper time and method for the treatment differs in each malformation.
  To study the mechanisms and differences among those embryonic malformations is a valuable clue in interpreting the structural malformation on the graphical images, understanding the neurological symptoms with combined anomalies in other organs, and also learning the important keys of surgical treatment.
  In this paper, I have demonstrated the representative cases of OSD operated in our hospital in the classified order, and argued on what kind of cutaneous stigmata should be suspected of OSD and how we should deal with the lesion along with some discussion and review of literature.

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  The effect of rehabilitation in pediatric acquired brain injury (ABI) is often discussed. The aim of this study was to identify clinical recovery after ABI in children where such recovery was better than in adults due to the child-brain’s plasticity and development. The main disorders of pediatric ABI are traumatic brain injury (TBI), acute encephalopathy, hypoxic encephalopathy and cerebro-vascular accident (CVA). In this study, I discuss TBI cases and CVA cases because they are typical neurosurgical disorders.
  We enrolled patients who sustained injury and were younger than 16 years. I discuss TBI in 210 cases and CVA in 71 cases (bleeding 42 cases, infarction 29 cases). We collected data on 3 parameters : etiology, functional disturbance and prognosis.
  The etiology of TBI was traffic accident 151 cases, abuse 29 cases, etc. The functional disturbance after TBI was physical disability in 109 cases, mental disability in 100 cases, higher brain dysfunction in 167 cases and epilepsy in 54 cases. It is important to note that the prognosis was the worst in abuse, followed by traffic accident to a lesser degree. The etiology of intracranial bleeding was mainly rupture of an arteriovenous malformation, and that of infarction was primarily complications of TBI, intracranial vessel abnormalites and complications of some sort of operation. The functional disturbances after CVA were physical disability in 64 cases, mental disability in 22 cases, higher brain dysfunction in 57 cases and epilepsy in 11 cases. The prognosis was slightly worse in infarction than in bleeding.
  I discussed the effect of pediatric rehabilitation after ABI.

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  With recent advances in molecular genetics, MRI diagnosis of congenital CNS malformations has become more important. In this review, to promote more accurate MRI diagnoses, we present some anomaly groups such as spinal cystic anomalies with or without Chiari II malformation, infratentorial midline cystic malformations (i.e. Dandy-Walker cyst/variant vs. Blake’s pouch cyst), and supratentorial dorsal cyst malformations (i.e. Callosal agenesis/hypogenesis with communicating interhemispheric cyst vs. holoprosencephaly with dorsal sac), that have similar morphological features, and explain the morphogenetic differences in these anomalies based on embryologic considerations.

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  A 62-year-old woman, suffering from a sudden onset headache, was referred to our hospital. Computed tomography (CT) revealed a subarachnoid hemorrhage, but neither CT angiography nor digital subtraction angiography (DSA) demonstrated aneurysms on day 1. A distal anterior cerebral artery aneurysm was detected by repeated DSA on day 33, and direct surgery was performed on day 38. Because the aneurysm contained a firm thrombus in the lumen, blood flow within the aneurysm could not be observed by intraoperative indocyanine-green video angiography. Neck clipping was achieved after removal of the thrombus by incising aneurysmal dome. Intraaneurysmal thrombus demonstrated angiogenesis, indicating recanalization. Histopathological findings, including the formation of intraaneurysmal thrombus with recanalization, explain a temporal change of angiographical appearance of the present aneurysm, which may represent the initial stage of development of large/giant thrombosed aneurysms due to repeated thrombosis and recanalization.

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