Limited dorsal myeloschisis (LDM), first proposed by Pang et al., is thought to originate from a small segmental failure of the dorsal closure of the neural folds during primary neurulation. The disjunction between the cutaneous and neural ectoderm is impaired at the focal limited nonclosure site. This results in a retained fibroneural stalk linking the skin lesion and the dorsal spinal cord, which results in tethering of the cord. Based on skin manifestations, LDMs were originally categorized as saccular and nonsaccular (flat). Saccular LDM consists of a skin-based cerebrospinal fluid sac topped by a squamous epithelial dome, whereas the flat LDM has a squamous epithelial flat surface or a sunken crater or pit typically called a “cigarette-burn” skin lesion. Recently, we reported a human tail-like cutaneous appendage as an additional morphological type of skin lesion. The recommended treatment consisted of prophylactic untethering of the stalk from the cord. Because of the shared origin of LDM and congenital dermal sinus (CDS), CDS elements may be found within the fibroneural LDM stalk with a 10-20% possibility. When part of the CDS invested in the intradural stalk is left during untethering surgery, inclusion tumors such as dermoid cysts may develop in the patient. Although the central histopathological finding of LDM stalk is the presence of glial fibrillary acidic protein (GFAP) -immunopositive neuroglial tissues in the fibrocollagenous tract, immunopositivity for GFAP was observed in 50-60% of pathologically examined cases. The presence of neural crest cells, such as peripheral nerve fibers and melanocytes, also assists in the histopathological diagnosis of LDM. In this case report, the diagnostic and surgical strategies of LDM are discussed accordingly.

  The goal for the treatment of pediatric hydrocephalus is to achieve normal growth and development, and the surgical indications and procedures should be selected for the long future of children. Although the guidelines on the treatment of pediatric hydrocephalus was published in 2014, the only recommended treatments with evidence were the use of preoperative antibiotics and antibiotic-impregnated catheters (AIC). The guideline was updated on the following two points in 2020. The evidence level of AIC was upgraded from 3 to 1, and neuroendoscopic lavage has been added as a level 3 option for the treatment of posthemorrhagic hydrocephalus. There were no revisions about endoscopic third ventriculostomy (ETV), which is considered to be an equivalent therapeutic option to ventriculo-peritoneal shunt, even though the indication of ETV has been extended. Pediatric hydrocephalus is a field with little evidence, however it is important to select the optimal treatment for each patients and perform safe surgery without complications or reoperations considering the pathology of their underlying disease and age.

  Childhood and AYA generation brain tumors, especially malignant brain tumors, were considered incurable. Increase of treatment intensity aimed for cure has been most important subjects recently. However, recent advancements in surgery, radiation therapy, chemotherapy and molecular target therapy have improved the prognosis of malignant brain tumors. This results in increasesed number of brain tumor survivors and their quality of life (QOL) has begun to attract attention. Accumulated data on long-term follow-up of brain tumor survivors revealed many problems including late effects that are directly related to QOL. The late effects of brain tumor survivors are : cognitive impairment, neurodevelopmental disorders, endocrine deterioration, spinal deformity, short stature, cranial deformity, early fusion of sutures, tooth disease, infertility, anemia, neuropathy, epilepsy, vasculopathy including Moyamoya syndrome, cavernous malformation, secondary tumors, leukoencephalopathy, cystic malacia, and so on. To minimize these late effects and treatment sequelae, neurosurgeons need to learn minimally invasive surgical techniques, optimal monitoring, latest diagnostic techniques, genomic medicine, multidisciplinary treatment (e.g. advancement of radiotherapy including proton therapy, chemotherapy, molecular target therapy and so on). Since the late effects on brain tumor survivors are wide-ranging, it is essential to establish a long-term follow-up system with interdisciplinary approach to health care. By understanding the current status of brain tumor survivors, neurosurgeons can plan treatment of pediatric and AYA generation brain tumors from a long-term perspective, and have an important perspective for development of future treatment strategies.

  Traumatic brain injury is one of the most frequent causes of morbidity and mortality in children. Even after appropriate treatment, the impact of traumatic brain injury on a child's life can be long-lasting and devastating. Higher brain dysfunction is likely to interfere with academic performance, impair health-related quality of life, and lead to mental health problems. However, the pathophysiological features specific to pediatric traumatic brain injury remain largely unexplored, and there are few clinical studies with a high level of evidence or basic studies that take into account the growth and development of the central nervous system. International efforts are required to clarify pediatric-specific findings without linearly transferring adult data. To elucidate the current status and issues of pediatric head injury, we will introduce the latest findings on acute care and the most important points of the “Guidelines for the Management of Pediatric Severe Traumatic Brain Injury, Third Edition.” In addition, we will discuss the latest issues related to the diagnosis of abusive head trauma, which has become a serious social problem on a global scale, and treatment options for abusive head trauma.

  A cavernous angioma arising from a cranial nerve is relatively rare, and ones originating from the optic nerve, in particular, have been reported to cause visual field disturbances. A case of a cavernous angioma that occurred at the optic chiasm is presented along with a review of the literature.

  The patient was a 52-year-old man who developed symptoms headache and bitemporal hemianopia. On the preoperative MRI, the chiasmal lesion was 15mm×12mm in size, showed iso-intensity on T1 and low intensity on T2, and was Gd-enhanced on its inner side. The lesion had low intensity on T2^＊ and was suspected to be a cavernous angioma. During the surgery, the lesion attached to the optic chiasm was checked ; it was dark red in color with an incision, and hematoma outflow was observed. Remains of an old hematoma were also observed, which was found to be a soft tumor, grayish white in color ; it was removed in a clump so as to not damage the surrounding tissue. After surgery, MRI showed the total removal of the lesion in the chiasm. The patient was discharged on the 26th postoperative day (Karnofsky Performance Status 90%). On visual field examination, the bitemporal hemianopsia was improved.

  Considering the present case and published cases, gross total resection is the optimal treatment for patients with cavernous angiomas of the optic nerve in terms of accurate diagnosis and good clinical outcomes.

  New surgical tools, such as the exoscope, are being developed, and even skilled neurosurgeons need to learn the differences between an exoscope and a microscope. A middle cerebral artery aneurysm was clipped using an exoscope. Before clinical use, we simulated clipping by exoscope using model aneurysms. The characteristics of the position, quantity of light, and movement of the camera were recorded. Such simulation may be useful for new operative techniques.

  The inferior fronto-occipital fasciculus (IFOF) is a white matter association fiber bundle connecting the occipital cortex and the frontal brain. The IFOF is assumed to function in semantic and syntactic language processing. Thus, damaging the IFOF during glioma surgery could result in temporary semantic paraphasia. Identification of the IFOF via direct subcortical stimulation during awake surgery could help avoid this complication.

  Here, we report two cases of glioma involving the insula, where IFOF was successfully identified by direct cortical and subcortical stimulation during awake surgery. Semantic paraphasia occurred during subcortical stimulation at a location that was presumed to be close to the IFOF.