Historically, the Japanese cerebrovascular surgeons have significantly contributed to the development of cerebrovascular surgery in the world. Even in the near future, it is firmly convinced that the essential role of cerebrovascular surgery does not change in the framework of the multimodal treatments of cerebrovascular diseases. Cerebrovascular surgery keeps on developing through the skill qualification system by the JSSCS with today’s needs. Innovative collaborations with novel technologies such as reconstructive medicine, computational medicine and so on will also provide new avenues in the near future.

  “Brain tumor” is a generic term and represents various tumors in the brain with different malignancy, prognoses, and pathogeneses. There are many societies involved with brain tumor diagnosis, treatment, and surgery. Molecular diagnosis is essential for diagnosis of brain tumors, indicating that genome therapy will be introduced in the near future.

  Although it is essential to consolidate facilities to achieve international competitiveness, equal accessibility to brain tumor therapy is essential to improve regional disparities. The societies involed with brain tumor therapy should cooperate with each other to overcome these two contradictory problems.

  The purpose of this study was to establish a treatment strategy for postcraniotomy infection of expanded polytetrafluoroethylene (ePTFE) sheets used as artificial dura mater. Between 2002 and 2018, 27 cases of infected ePTFE sheets after craniotomy were treated. Several cases of delayed-onset infection and temporary remission were noted. Abscesses were localized to the artificial dura mater in 17 cases (63%), and combined epidural and subdural abscesses were noted in 10 cases (37%). The infected artificial dura mater was removed completely, and it was not replaced after the initial three cases in which autologous fascia lata was grafted for the dural defect. In one of these cases, infection recurred and the graft was removed. Of the 27 cases, 2 had skin defects, for which a vascularized free latissimus dorsi muscle flap with a skin graft was applied. Secondary cranioplasty using artificial bone was performed in 24 cases without complications. During cranioplasty, the pericranium was left intact on the brain surface with subgaleal scalp dissection in six cases in order to prevent cerebrospinal fluid (CSF) leakage. During long-term follow-up, no postoperative complications associated with the dural defect were observed. Subgaleal dissection cranioplasty is preferred for incomplete capsule formation on the brain surface. However, if the pericranium is unavailable, simultaneous transfer of vascularized free latissimus dorsi muscle for replacing the dural defect may be an option in cases with subdural abscesses to prevent CSF leakage during the secondary cranioplasty.

  Multinodular and vacuolating neuronal tumor of the cerebrum (MVNT) is a relatively new tumor classification. There are only a few reports of long-term prognosis for MVNTs. Here we report a 5-year follow-up of our case of MVNT with no recurrence after surgery. We also summarize and discuss the literature for 31 other cases. Median age was 41 years, and there was no sex disparity. In around half of the cases, nodules were visible not only by examination of the pathological tissue but also on MRI. In most symptomatic epilepsy improves with surgery. Thus far no malignant transformation of MVNT has been reported, indicating a good prognosis.

  A 53-year-old man with trigeminal neuralgia and a recurrent epidermoid tumor at the cerebellopontine angle is reported. After craniotomy and subtotal tumor resection, his trigeminal neuralgia, facial palsy, and cerebellar ataxia showed considerable improvement. However, mild trigeminal neuralgia persisted. Three years later, the tumor recurred in association with exacerbation of trigeminal neuralgia. He refused a second operation and consulted us for stereotactic radiosurgery. Gamma knife surgery was carried out targeting the whole tumor with 12.5 Gy at the margins, including the right trigeminal nerve. Although tumor shrinkage was not marked, his neuralgia showed dramatic improvement within one day and resolved completely after one month without any complications. Treatment with carbamazepine was no longer required.

  The mechanism underlying this pain relief is unclear, since significant mechanical decompression or decreased chemical stimulation of the trigeminal nerve by the tumor was not confirmed. It is possible that spontaneous impulses were generated at a site of demyelination where the trigeminal nerve was distorted or showed focal indentation, and gamma knife surgery was successful in reducing hyperactive cranial nerve dysfunction, through electrophysiological effects. In this case, the clinical effect of gamma knife surgery could be considered as radiosurgical neuromodulation.

  Although total surgical resection is the main treatment for epidermoid tumors, radiosurgery can play an important role in controlling the residual tumor and improving the distressing symptoms associated with hyperactivity of the trigeminal nerve.