The primary aim of glioma surgery is to achieve a balance between maximum tumor removal and minimal functional morbidity. The advent of awake surgery has greatly increased the number of patients with tumors in or around the eloquent language areas undergoing extensive removal. Preoperative anatomical evaluation modalities, such as diffusion tensor imaging (DTI) tractography or color mapping, are used to visualize the subcortical neuronal network in the white matter. This structural information can help predict further tumor extension and neuronal damage adjacent to the surrounding area of tumor. To achieve successful functional evaluation and maximum tumor removal without surgical complication, we must be well aware of the symptomatic evaluation following electrical stimulation. In the white matter, identifying the short association fibers and the long association fibers involving the association with language function are the key for successful resection. In our report, an overview of the anatomical structures and the clinical symptoms related to the language area encounterd in glioma removal surgery are reported.

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  Ongoing developments in endoscopic surgery continue to provide further indications for treating various skull base lesions. Recently, the usefulness of photodynamic diagnosis has been recognized in brain tumor resection and vascular surgery. Although those modalities give operators additional information such as tumor extension or vascular patency under microscope, its efficacy in endoscopic surgery is not confirmed. The authors applied the indocyanine green (ICG) fluorescence endoscopy in endoscopic endonasal skull base surgery and successfully recorded ICG fluorescence from sellar dura, pituitary, and surrounding structures in 30 consecutive patients. Also we could distinguish sellar tumor from pituitary gland or stalk. There were no complications that resulted from the use of ICG or the fluorescent light source. ICG fluorescence endoscopy shows promise as an intraoperative modality that can help preserve the normal pituitary function while avoiding dangerous dissection which may contribute to further develop the fluorescence endoscopic resection technique.

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  In endoscopic endonasal transsphenoidal surgery, it is essential to determine the precise anatomical relationship of the sellar or parasellar tumor with the internal carotid artery and the optic nerve prior to surgery in order to preserve the important structures and to avoid surgical complications. Computed tomography (CT) using a 64-detector row scanner and magnetic resonance imaging (MRI) using a 3.0 tesla system were used to create CT/MRI fusion images. Three orthogonal multiplanar reconstruction images including volume rendering (VR) and virtual endoscopy (VE) were created using a work station by radiological technologists in a 3-dimensional laboratory established in our hospital. The fusion images were then uploaded to a picture archiving communication system (PACS).
  When using system, the anatomical relationship between tumors and adjacent structures was clearly demonstrated. Additionally, the VR and VE images allow surgeons to make precise presurgical plans and conduct virtual operations. Furthermore, because the images can be observed anytime on PACS in the hospital, CT/MRI fusion images in endonasal transsphenoidal surgery contribute as very useful tools not only for the education of trainees and medical students but also for obtaining informed consent from patients and their families.

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  The transnasal transsphenoidal surgery (TSS) for anterior skull base lesions was a revolutionary operation started in 1900's, but was out of use in the pre-antibiotics era because of its high morbidity and mortality. However, TSS was re-introduced and developed applying microscope since 1960's and endoscope in 1990's. A visualization using high definition type (HD) endoscope contributed to the further development of TSS with the aid of its higher resolution (1,920×1,080=2,073,600 pixel). HD endoscope enables us to distinguish the tumor from surrounding structures more clearly and preserve better pituitary function. In this paper, we describe our recent experience in TSS for anterior skull base tumors using HD endoscope and its advantages.

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  Cavernous malformations are well known to somehow become more active after the first bleeding or initial seizure event. However, the real natural history of symptomatic cavernous malformations remains unclear, and the lack of information has obscured the treatment results.
  An investigation of the natural history of symptomatic cavernous malformations (s-CM) and the results of surgery was performed by distributing a questionnaire to large neurosurgical institutes across Japan. Data on 49 cases treated conservatively and 29 cases of surgery were collected. The distribution of patient age, sex and lesion location were comparable, however, the size of the lesion was larger in surgery group.
  Progression free survival, as determined using the Kaplan-Meier method, showed a marked difference in hemorrhage rate, which was greatly superior in the surgery cases. The annual rate of hemorrhage, as calculated from birth until the first event, was almost equal (1.7 and 1.8% in the conservative and surgical groups, respectively). However, rebleedings occurred in many of the conservatively treated cases, among whom the annual rate of hemorrhage was 10.2%/year after the first event and 19.7% after the second event. The high annual hemorrhage rate tends to persist at least for 5 years after the first event. In the surgical group, the rate was only 2.7%/year after the first event and after the surgery. Nevertheless, the neurological outcomes at the time of the last follow-up were quite similar in both groups, chiefly because of the complications that occurred as a result of surgical manipulations to the brainstem and basal ganglia.
  Cavernous malformations apparently become active after the first and second events have occurred. It is important to keep in mind that annual hemorrhage rates of 10%/year/case after the first event, and 20%/year/case after the second event are important part of the natural history of s-CM. Thus, the treatment results can be compared with these established rates of hemorrhage.

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  Central post-stroke pain (CPSP) is the most difficult type of central neuropathic pain to control with medical treatment. Pregabalin is recommended as the first-line drug for central neuropathic pain by the medical guidelines of various countries. The mechanism of action for pregabalin is considered to involve binding to α2-δ subunits of voltage-gated calcium channels. Pregabalin has been approved for peripheral neuropathic pain since 2010 and for central neuropathic pain since 2013 in Japan. This study evaluated the efficacy and safety of pregabalin for CPSP.
  We retrospectively reviewed 20 cases of CPSP that received pregabalin medication primarily (hemorrhage, n=14 ; infarction, n=6 ; mean age, 63.8±8.8 years). Pain levels were assessed twice as follows using a visual analog scale (VAS) : before pregabalin medication began, and after reaching maintenance dose.
  Pregabalin medication showed pain reduction in 11 of 20 cases (55.0%). VAS scores improved from pre-medication (mean, 8.2±1.3) to post-medication (mean, 6.7±2.3) (p=0.018), and the VAS improvement rate was 18.7±25.5%. In the 11 cases with reduced pain, the maintenance dose of pregabalin was 252±127 mg/day, and the dose at the onset of effect was 163±74 mg/day. Side effects were observed in 11 of 20 cases (severe, n=5 ; moderate, n=3 ; mild, n=3). Mean age according to severity of side effects was : severe, 68.2±7.0 years ; moderate, 61.3±14.2 years ; and mild, 56.0±5.3 years.
  Pregabalin medication was effective for reducing pain in patients with CPSP. Elderly individuals should start pregabalin medication at a low dose because side effects appear more frequently with increasing age.

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  We report a case of posterior reversible encephalopathy syndrome (PRES) during the subacute period of subarachnoid hemorrhage (SAH). An 84-year-old female with a ruptured basilar top aneurysm underwent successful embolization. Administration of antihypertensive drugs was discontinued to avoid hypotension during the period of vasospasm. On day 17 post embolization, her consciousness level deteriorated, and her MRI showed vasogenic edema in the bilateral occipital lobes. Under the diagnosis of PRES, antihypertensive therapy was resumed, and her symptoms and MRI findings improved.
  Thirteen cases of PRES after SAH have been reported, and it has been suggested that endothelial cell dysfunction due to primary brain damage due to SAH and hypertension during the period of vasospasm induces PRES. Though the occurrence of PRES after SAH is rare, neurosurgeons should be aware of this potential complication during the subacute period of SAH, because complete resolution of this syndrome is attainable with appropriate blood pressure control.

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