Since the introduction of neuroendoscopy to Japan in the 1990s, endoscopic diversions of the intracranial cerebrospinal pathway, such as endoscopic third ventriculostomy (ETV), have been performed. However, ventriculo-peritoneal shunt (VPS) is still the standard procedure because indications for ETV are limited. The effectiveness of ETV is believed to be considerably influenced by age, and indications for ETV in infants have been controversial. In 2016, a prospective multicenter study compared ETV and VPS in children with aqueductal stenosis aged<2 years. Six-month ETV success rates were found to be 59% in infants aged<6 months and 80% in children aged≥6 months. ETV appeared to have a higher failure than VPS in infants aged<6 months. However, ETV showed results equivalent to VPS in children aged≥6 months. Recent reports have indicated that the use of ETV with choroid plexus cauterization (CPC) increases its effectiveness ; however, indications for CPC remain unclear.

  The best available procedure for the treatment of pediatric hydrocephalus should be selected from a wide range of procedures such as VPS, ETV, combined use of endoscopic diversions of the intracranial cerebrospinal pathway and VPS, and combined use of ETV and CPC taking into consideration the child’s condition and age.

  There has been an increase in the number of incidentally diagnosed arachnoid cysts (ACs) with the increased use of magnetic resonance imaging and computed tomography (CT). Clinicians face challenges in selecting treatment strategies because the symptoms of ACs tend to be ambiguous and the risks of surgery are not negligible. In the present study, we reviewed selected reports addressing the natural history of intracranial ACs in pediatric patients, with special emphasis on cyst enlargement and rupture, surgical indications, and treatment strategies. In addition, we retrospectively reviewed a single-institutional experience with 27 pediatric patients who underwent surgical treatment of middle cranial fossa ACs during a 9-year period and evaluated risk factors for shunt placement following successful cyst-cistern fenestration.

  A review of the natural history indicated that a younger age is associated with cyst enlargement, and larger ACs and recent head trauma are risk factors for cyst rupture/hemorrhage. However, restriction from athletic activity cannot be recommended because such rupture/hemorrhage incidents are rare. Surgical indication remains a controversial subject except in cases of symptomatic ACs. For pediatric patients, it is very important to consider this problem from the perspective of protecting brain development. The surgical procedures of membranectomy, microsurgical or endoscopic fenestration, or shunting can be selected depending on cyst location and age. Endoscopic surgery for infants younger than 6 months of age is not recommended because of the high failure rate. In cases of symptomatic ruptured cysts, burr hole drainage and/or fenestration and/or shunting are generally performed ; however, surgical treatment may not be the absolute indication. In our brief survey of data, younger age, abnormal head enlargement, and progressive cyst expansion were found to be the risk factors for shunt placement after cyst fenestration in pediatric patients with middle cranial fossa ACs.

  Finally, further studies are needed to clarify whether surgical interventions can preserve brain development in pediatric patients with asymptomatic ACs.

  Spina bifida occulta (SBO) is a malformation of the spinal cord and its surrounding structures. It is caused by the failure of neurulation and is defined as a condition characterized by the absence of cerebrospinal fluid leakage without skin defects ; therefore, it is also known as closed spinal dysraphism. Here we have reviewed the embryology-based pathogenesis, outlined clinical pictures of whole SBO including our clinical data, and mentioned individual disease states.

  SBO comprises various pathological conditions related to the type of failure during notochord formation and primary and secondary neurulations. Neurological disorders are caused by spinal cord tethering, mass effect, and dysplasia of the nerve tissue. Comorbid cutaneous abnormalities and lower intestinal and urogenital anomalies are initial signs for the diagnosis of SBO. Surgery for tethered spinal cord and mass effect, except for dysplasia of the nerve tissue, possibly help in the improvement or stabilization of symptoms. Surgery is generally recommended in symptomatic SBO cases and in asymptomatic SBO cases in children ; however, prophylactic surgery is controversial. Comprehensive care and postoperative follow-up are necessary over a prolonged period.

  In this study, we describe the basic concept of surgical treatment of craniosynostosis primarily focusing on the conventional method. The appropriate surgical treatment differs depending on patient age at the time of surgery. The surgical procedure is of two types : suturectomy and expanding cranioplasty. The latter includes a conventional method, gradual distraction, and multi-directional cranial distraction osteogenesis. Depending on the part of the skull to be enlarged, the procedure is classified into fronto-orbital advancement (FOA), total cranial remodeling, or posterior cranial vault expansion. The key to achieving surgical success is understanding the affected suture and complex pathophysiology and performing surgical simulation before the actual surgery. Here we provide notes for each surgical phase and suggestions to avoid complications.

  Typical neurological symptoms of lumbar disc hernia (LDH) are determined by the level of the lesion. However, a discrepancy between symptoms and morbidity exists in patients with nerve root anomaly (NRA), which is not a rare condition. Here we present the case of a patient with LDH and NRA as well as the observations during diagnosis and surgery. The patient was a 67-year-old male with left leg pain. LDH in the left L4/5 was diagnosed, and he was conservatively treated in another hospital. Recurrence of lumbar pain and leg pain occurred after 7 months. His symptoms involved pain from the gluteal area to the posterior thigh and posterior and lateral lower leg and sole ; these are atypical of L4/5 disc hernia. Therefore, coexistence of L3/4 disc hernia was considered. He was transferred to our hospital for surgery. Magnetic resonance imaging (MRI) revealed a caudally migrated disc fragment compressing nerve roots at the L4/5 level. One of the roots was followed caudally on continuous axial MRI images, and it was found to be an S1 root. A type 2a NRA per the Kadish classification, with a cranial origin of the nerve root, was diagnosed. The disc hernia was planned to be surgically removed between the L5 and S1 root via left L4/5 hemilaminectomy. The possibility of excess bleeding from L5 root axilla and dural tears were points of concern. The surgical procedure was performed meticulously, and disc hernia was removed as planned. The patient’s symptoms improved immediately. To the best of our knowledge, this is the first case report of surgical therapy for LDH of type 2a per Kadish classification. Surgery in patients with LDH and NRA requires special care, and preoperative diagnosis is also important.

  Spinal cord stimulation (SCS) is essentially used to relieve chronic neuropathic pain that is resistant to medication, but it might also improve motor function. Triaxial accelerometry can objectively and quantitatively assess walking. This report describes a 46-year-old woman with failed back surgery syndrome that resulted in lower extremity pain and spasticity, which SCS subjectively and visually improved. Values for cadence, speed, step length, floor reaction, coefficients of variance, time per step, number of steps and walking cycles under SCS OFF determined by triaxial accelerometry considerably differed from those of controls, whereas most of those determined under SCS ON were similar to those of controls. Therefore, triaxial accelerometry can objectively assess the effects of SCS.

  Most postoperative granulomas are caused by surgical materials, which is why they are referred to as foreign body granulomas. These granulomas are often discovered over time after surgery, and differentiating those granulomas from a condition such as a malignancy or a fungal or tuberculous infection is difficult. In the current case, fluid-attenuated inversion recovery and diffusion-weighted MRI revealed hyperintensity in the right temporal lobe 7 years after a craniotomy. The patient also developed symptoms of aphasia, so surgery was performed. Based on intra-operative findings and pathology findings, looseness of the RapidFlap^® SpinDown System due to trauma had caused mechanical irritation that in turn resulted in an inflammatory granuloma. If a patient who had craniotomy hit the head, he or she must be closely followed for a prolonged period.