Endovascular surgery (EVT) has been more and more widely applied with introduction of the innovative devices such as a flow-diverter. In Japan, EVT as well as direct surgery (DS) has been mainly performed by neurosurgeons since the dawn of EVT. Young neurosurgeons are now eager to acquire both skills of EVT and DS. All neurosurgeons in charge of the cerebrovascular disease perform both EVT and DS in our hospital. We describe the current status of so-called “collaboration of EVT and DS” in our “hybrid” team by presenting the representative cases.

  In the last two decades, endoscopic surgery, such as endonasal surgery and keyhole surgery, for the treatment of benign brain tumors has evolved to be a viable strategy to achieve maximal safe resection of the tumors, thereby resulting in diversified surgical options. To provide minimally invasive treatment for the long-term QOL of benign brain tumor patients, neurosurgeons must be familiar with the characteristics of transcranial microsurgery and endoscopic surgery and have the ability to select appropriate surgical methods for each individual patient. In this article, the authors present an overview of the current status of the optimal surgical management using transcranial microsurgery and endoscopic surgery for representative benign brain tumors and discuss further problems to be solved in the future.

  In the field of functional neurosurgery, an ecosystem has been formed in which the development of therapeutic techniques has led to the elucidation of the pathophysiology of disease, and the understanding of pathophysiology has led to the development of new therapeutic techniques. Recently, a closed-loop deep brain stimulation (DBS) for Parkinson's disease was introduced to Japan for the first time, contributing to further improvement of the effectiveness of DBS treatment for Parkinson's disease. This system can collect and record local field potentials in the nuclei of the deep brain. These data can be used to elucidate the pathophysiology of Parkinson's disease, which has been difficult to do using previously utilized methods. Additionally, it is expected to lead to the development of new treatment methods for Parkinson's disease.

  Recently, it has become difficult to solve problems fundamentally and effectively based on single excellent scientific advancement or by limited numbers of researchers or laboratories due to the increasing advancement of science and technology, along with increasing complexities of the problems to be solved. In addition to the introduction of methodologies such as design thinking, skills, professionals, or infrastructure utilized to solve these problems are discussed. Example cases from world leading institutes and from Tohoku University Hospital are presented.

  Malignant brain tumors are cancerous, and the prognosis remains poor. However, in recent years, patient outcomes have gradually improved because of advances in surgical techniques, new instruments, innovative radiotherapy approaches, and the emergence of new drugs. Moreover, various basic research and clinical development programs are being conducted for malignant brain tumors. In basic research, the development of molecular targeted drugs, gene therapy, oncolytic viruses, single-cell sequencing, and liquid biopsy are actively being pursued. As for clinical development, high-resolution endoscopes and exoscopes, augmented reality (AR) navigation, robotics, and artificial intelligence have been established. Thus, it is clear that a multifaceted therapeutic approach is important from both a basic and clinical perspective. Furthermore, it is necessary to conduct translational and reverse translational research, and it is crucial to develop human resources with a research mindset that can generate logical thinking and diverse ideas.

  Primary extradural meningioma is a rare disease, accounting for 1 to 2% of all meningiomas. We present a rare case in which primary extradural meningioma led to a giant deformity. An 80-year-old man was admitted to the hospital due to his complaint of left hemiplegia for half a year. During the examination, a painless elastic and soft mass was noted on the parietal region. CT scan showed osteolytic destruction of the parietal bone, and MRI with contrast showed a 15cm×11cm×11cm irregularly enhanced epidural mass and a subdural mass penetrating the dura mater and compressing the right frontoparietal lobe.

  Cerebral angiography showed dark staining of bilateral external carotid arteries. The patient was diagnosed with a meningioma and considered to be at high risk of bleeding. We planned a two-stage operation : epidural tumor resection, followed by subdural tumor resection and cranioplasty. Prior to the operation, tumor embolization was performed, and the superficial temporal artery and occipital artery were ligated immediately before the operation. However, after both operation, an epidural hematoma developed, and the patient had to undergo hematoma evacuation. We considered that this was due to hemorrhage from the scalp, which is rich in blood flow, and that the issue is how to prevent it. We report the operational strategy and treatment course of this rare case with a review of literature.

  Intracranial cerebral artery dissection is a rare cause of pediatric occlusive cerebrovascular disease with no widely accepted medical or surgical treatment. In this report, we describe a case of a spontaneous intracranial carotid artery dissection in a 14-year-old boy presenting with right hemiparesis. Despite maximal medical treatment, the patient's neurological symptoms showed progressive worsening during the first 2 days after onset with a concurrent increase in left cerebral hemisphere deep white matter ischemic lesions. Hemodynamic instability was considered the cause of stroke progression, and an emergent revascularization surgery (superficial temporal artery-middle cerebral artery [STA-MCA] bypass) was performed. This resulted in improvement of the neurological symptoms and a good clinical outcome. Acute STA-MCA bypass may be an effective treatment option in select pediatric patients with intracranial carotid artery dissection whose symptoms progress regardless of maximal medical treatment.