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Featured researches published by Tamotsu Miki.


Surgical Neurology | 1994

A case of lymphocytic hypophysitis with massive fibrosis and the role of surgical intervention

Hiroshi Nishioka; Hiroshi Ito; Tamotsu Miki; Kiyohiro Akada

Four weeks after a normal delivery, a 33-year-old woman was admitted to our hospital with visual disturbance, hypopituitarism, and diabetes insipidus. A homogeneously enhanced pituitary mass with suprasellar extension was observed. Presurgical steroid therapy was ineffective. A transsphenoidal approach revealed a firm white mass, which was histologically diagnosed as a lymphocytic hypophysitis with massive fibrosis. Lymphocytic hypophysitis shows a variety of clinical courses, and there are various problematic aspects concerning the histologic stage as well as the differential diagnosis. However, it is difficult to speculate concerning these without histologic studies. Cases with massive fibrosis, spontaneous resolution, or positive effects of steroids may be less likely.


Journal of Neurosurgery | 2011

Nationwide investigation of the current status of therapeutic neuroendoscopy for ventricular and paraventricular tumors in Japan: Clinical article

Nakamasa Hayashi; Hisayuki Murai; Shoichiro Ishihara; Takayuki Kitamura; Tamotsu Miki; Tomoru Miwa; Masakazu Miyajima; Kenichi Nishiyama; Takayuki Ohira; Shigeki Ono; Tomonari Suzuki; Shingo Takano; Isao Date; Naokatsu Saeki; Shunro Endo

OBJECT The authors report their investigation on the current status of neuroendoscopic biopsy for ventricular and paraventricular tumors as well as treatment for associated hydrocephalus in Japan. METHODS Patients who had undergone therapeutic neuroendoscopy between 2005 and 2009 were included in this study. The main items examined were age; sex; localization of tumor; pathological diagnosis using biopsy; the presence, treatment, and efficacy of treatment of associated hydrocephalus; perioperative complications; activities of daily living (ADL) before and after therapeutic neuroendoscopy; and the presence of dissemination during the postoperative course. RESULTS Seven hundred fourteen patients from 123 sites (462 male and 252 female patients, mean age 33.3 years) were enrolled. Localization of the tumor was mainly classified into the lateral ventricle in 91 patients, the third ventricle in 339, the fourth ventricle in 18, the suprasellar region in 75, and other paraventricular areas in 191 patients. The most commonly observed tumors were germ cell tumors in the third ventricle (177 cases [39%]), cystic lesions in the suprasellar region (56 cases [75%]), and astrocytic tumors in the thalamus-basal ganglia (71 cases [38%]). Although 641 (92.8%) of 691 patients could receive neuroendoscopic diagnosis using biopsy, the diagnosis obtained with endoscopic biopsy differed from the final diagnosis based on subsequent craniotomy in 18 patients and clinical course in 3 patients. Of these 21 patients, 7 had astrocytic tumors, 4 had pineal tumors, 6 had germ cell tumors, and 4 had other tumors. The final diagnostic accuracy rate was 89.7%. Associated hydrocephalus was observed in 517 patients (72.4%), of whom 316 and 39 underwent third ventriculostomy and fenestration of the septum, respectively. The response rates were 96.2% and 89.7%, respectively. Third ventriculostomy was required for recurrence of hydrocephalus in 41 patients (13.0%), and the long-term response rate was therefore 83.2% (263 of 316 patients). Perioperative complications other than fever, such as new onset of or progressive hydrocephalus, infection due to CSF leakage, and bleeding in the ventricle or tumor, were found in 81 patients (11.3%). The median Karnofsky Performance Scale score before endoscopic surgery was 80, but it increased to 90 after surgery. The score was thus significantly increased after surgery (p < 0.0001, Mann-Whitney U-test). Activities of daily living after surgery decreased due to perioperative complications in 15 patients (2.1%). The incidence of new dissemination after endoscopic biopsy was 6.8% and not high compared with routine surgical treatment. CONCLUSIONS The authors concluded that neuroendoscopic diagnosis using biopsy for ventricular and paraventricular tumors is adequately accurate and safe. It was demonstrated that endoscopic procedures play important roles not only in the treatment of hydrocephalus associated with intra- and paraventricular tumors but also in significantly improving ADL. Furthermore, the long-term outcome of endoscopic third ventriculostomy was clearly favorable.


Neuroradiology | 1999

Rathke's cleft cyst with pituitary apoplexy: case report

Hiroshi Nishioka; Hiroshi Ito; Tamotsu Miki; Takao Hashimoto; H. Nojima; H. Matsumura

Abstract We report a Rathkes cleft cyst which presented as pituitary apoplexy, a rare presentation. A 46-year-old woman suffered sudden headache and visual loss. T1-weighted MRI 3 weeks after this apoplectic episode demonstrated a cystic lesion between the anterior and posterior lobes of the pituitary, with some high-signal material layering in it. The mass showed spontaneous regression on an image 3 weeks later. Trans-sphenoidal surgery confirmed the diagnosis of a Rathkes cleft cyst with a haematoma within it.


International Journal of Radiation Oncology Biology Physics | 2012

Preliminary Results of Fractionated Stereotactic Radiotherapy After Cyst Drainage for Craniopharyngioma in Adults

Naoto Kanesaka; Ryuji Mikami; Hidetsugu Nakayama; Sachika Nogi; Yu Tajima; Nobuyuki Nakajima; Jun Wada; Tamotsu Miki; Jou Haraoka; Mitsuru Okubo; Shinji Sugahara; Koichi Tokuuye

PURPOSE To retrospectively evaluate the effectiveness of fractionated stereotactic radiotherapy (FSRT) for craniopharyngioma. METHODS AND MATERIALS Between 1999 and 2005, 16 patients with craniopharyngioma were referred to Tokyo Medical University Hospital. They received FSRT alone after histologic confirmation by needle biopsy and underwent cyst drainage via endoscopy. The median prescription dose fraction was 30 Gy in six fractions. All patients except 1 were followed up until December 2009 or death. RESULTS The median follow-up period was 52 months (range, 4-117 months). Of the 17 patients, 3 experienced recurrence 4 to 71 months after FSRT. The 3-year local control rate was 82.4%. One patient died of thyroid cancer, and the 3-year survival rate was 94.1%. Eight patients had improved visual fields at a median of 2.5 months after FSRT, but hormonal functions did not improve in any patient. CONCLUSIONS FSRT after cyst drainage seems to be safe and effective for patients with craniopharyngiomas, and it may be a safe alternative to surgery.


Brain Tumor Pathology | 2009

Radiopathological characteristics of cerebellar malignant glioma in adults

Jiro Akimoto; Shinjiro Fukami; Masateru Tsutsumi; Takao Hashimoto; Tamotsu Miki; Jo Haraoka; Motoshige Kudo

Our aim was to extract the radiopathological features of cerebellar malignant glioma in adults from the four cases we encountered. All four cases (two men and two women, aged 52–80 years; mean age, 67 years) had a floating sensation or vertigo at the onset of their disease. Initially, these patients were given a diagnosis of cerebellar infarction or cavernous angioma, or had faint abnormalities in the cerebellum that were overlooked. These patients were followed up for 2–14 months (mean, 6 months), and the tumor was detected when their clinical symptoms deteriorated. The tumor was located in the hemisphere in one patient and in the vermis in three patients. MRI revealed ring-like enhancement in two patients and nodular enhancement in two patients. All patients underwent subtotal tumor resection, followed by postoperative radiochemotherapy. However, three patients died at 16 to 44 months (mean, 28 months), and cerebrospinal fluid (CSF) dissemination was observed in three patients. Two cases were classified as WHO grade III and two as WHO grade IV. The pathological features were typical of malignant glioma, partially presenting the features of low-grade glioma, such as pilocytic, astrocytic, or oligodendroglial components. Nuclear pleomorphism and vascular endothelial proliferation were prominent, and micronecrosis was relatively less evident. The MIB-1 index was 12%–40%, and most of the patients were p53 protein positive. At the onset of cerebellar malignant glioma, diagnostic imaging shows few signs of brain tumor. Thereafter, tumors grow in a short period of time, following a rapid clinical course. Because cerebellar malignant glioma is a rare disease, it is difficult to differentiate it from metastatic brain tumors and primary central nervous system lymphoma by preoperative imaging. Some patho logical features suggesting malignant transformation from low-grade glioma were detected.


NeuroImage | 2007

Surface rendering-based virtual intraventricular endoscopy: Retrospective feasibility study and comparison to volume rendering-based approach

Nobuyuki Nakajima; Jun Wada; Tamotsu Miki; Jo Haraoka; Nobuhiko Hata

OBJECTIVE Virtual endoscopic simulations using volume rendering (VR) have been proposed as a tool for training and understanding intraventricular anatomy. It is not known whether surface rendering (SR), an alternative to VR, can visualize intraventricular and subependymal structures better and thus making the virtual endoscope more useful for simulating the intraventricular endoscopy. We sought to develop SR-virtual endoscopy and compared the visibility of anatomical structures in SR and VR using retrospective cases. MATERIALS AND METHODS Fourteen patients who underwent endoscopic intraventricular surgery of third ventricle enrolled the study. SR-virtual endoscopy module was developed in open-source software 3D Slicer and virtual endoscopic scenes from the retrospective cases were created. VR virtual endoscopy of the same cases was prepared in commercial software. Three neurosurgeons scored the visibility of substructures in lateral and third ventricle, arteries, cranial nerves, and other lesions Results: We found that VR and SR-virtual endoscopy performed similarly in visualization of substructures in lateral and third ventricle (not significant statistically). However, the SR was statistically significantly better in visualizing subependymal arteries, cranial nerves, and other lesions (p<0.05, respectively). CONCLUSIONS We concluded that SR-virtual endoscopy is a promising tool to visualize critical anatomical structures in simulated endoscopic intraventricular surgery. The results lead us to propose a hybrid technique of volume and surface rendering to balance the strength of surface rendering alone in visualizing arteries, nerves and lesions, with fast volume rendering of third and lateral ventricles.


Journal of Clinical Neuroscience | 1998

Evaluation of traumatic subarachnoid haemorrhage on computed tomography

Tamotsu Miki; Yusuke Ikeda; Osamu Utsugi; Hiroshi Ito

Traumatic subarachnoid haemorrhage (TSAH) is a computed tomography (CT) scan finding frequently found in the acute phase of brain injury. However, the clinical evaluation of TSAH is controversial. The subjects in the present series consisted of 46 patients in whom the initial CT scan within 6 h after injury revealed a high density area in the subarachnoid space. The subjects were divided into three types: type 1 n = 10) had massive haemorrhage in the basal cisterns; type II (n = 9) had localized haemorrhage in the basal cisterns; and type III (n = 27) had localized haemorrhage in the cortical sulci or Sylvian fissure. The clinical and neuroradiological findings as well as the outcome of these three types of TSAH are discussed. The results of our study showed that TSAH observed at an acute stage of head trauma was associated with a great variety of intracranial pathological changes. Type I cases had either good or poor outcome, and diffuse brain injury was predominant in patients with poor outcome. The outcome was generally good in type II and III cases.


BMJ Open | 2017

Do failures in non-technical skills contribute to fatal medical accidents in Japan? A review of the 2010–2013 national accident reports

Masashi Uramatsu; Yoshikazu Fujisawa; Shinya Mizuno; Takahiro Souma; Akinori Komatsubara; Tamotsu Miki

Objectives We sought to clarify how large a proportion of fatal medical accidents can be considered to be caused by poor non-technical skills, and to support development of a policy to reduce number of such accidents by making recommendations about possible training requirements. Design Summaries of reports of fatal medical accidents, published by the Japan Medical Safety Research Organization, were reviewed individually. Three experienced clinicians and one patient safety expert conducted the reviews to determine the cause of death. Views of the patient safety expert were given additional weight in the overall determination. Setting A total of 73 summary reports of fatal medical accidents were reviewed. These reports had been submitted by healthcare organisations across Japan to the Japan Medical Safety Research Organization between April 2010 and March 2013. Primary and secondary outcome measures The cause of death in fatal medical accidents, categorised into technical skills, non-technical skills and inevitable progress of disease were evaluated. Non-technical skills were further subdivided into situation awareness, decision making, communication, team working, leadership, managing stress and coping with fatigue. Results Overall, the cause of death was identified as non-technical skills in 34 cases (46.6%), disease progression in 33 cases (45.2%) and technical skills in two cases (5.5%). In two cases, no consensual determination could be achieved. Further categorisation of cases of non-technical skills were identified as 14 cases (41.2%) of problems with situation awareness, eight (23.5%) with team working and three (8.8%) with decision making. These three subcategories, or combinations of them, were identified as the cause of death in 33 cases (97.1%). Conclusions Poor non-technical skills were considered to be a significant cause of adverse events in nearly half of the fatal medical accidents examined. Improving non-technical skills may be effective for reducing accidents, and training in particular subcategories of non-technical skills may be especially relevant.


Endocrine Pathology | 1995

Lymphocytic adenohypophysitis associated with Rathke’s cleft cyst

Hiroshi Nishioka; Hiroshi Ito; Tamotsu Miki; Jun Wada; Toshiaki Sano

During the 8th month of her first pregnancy, a 40-year-old female suffered from visual disturbances. After treatment of pericarditis, which appeared 1 month after a normal delivery, she was referred to the neurosurgical department. She showed bitemporal hemianopsia, disturbance of visual acuity, and hypopituitarism. Initial computed tomography (CT) image showed a solid pituitary mass with suprasellar extension. However, 2 months later, the CT image changed to an enlarged partially cystic lesion. Transsphenoidal exploration of the sella demonstrated lymphocytic adenohypophysitis coexistent with Rathke’s cleft cyst. To our knowledge, such an association has never been reported previously. Presurgical diagnosis of lymphocytic adenohypophysitis still remains difficult and surgical intervention is necessary for definitive diagnosis. However, special attention is needed for the histological diagnosis of this lesion, particularly in clinically atypical cases.


Brain Tumor Pathology | 2004

Clinical diagnosis of gliomatosis cerebri: report of three cases.

Jiro Akimoto; Hiroshi Nishioka; Tamotsu Miki; Jo Haraoka; Motoshige Kudo

Distinction of gliomatosis cerebri (GC), a rare entity characterized by a widespread infiltration of the brain by tumor, from diffuse glioma is a difficult clinical problem. Most previously reported cases of GC have been autopsy cases because of the lack of objective and quantitative clinical diagnostic criteria. In order to better define this entity, we report the neuroradiological and pathological findings of three cases of GC. Three patients (one man and two women, aged 46–71 years) presented with symptoms of mild increased intracranial pressure, cognitive impairment, or seizure. Magnetic resonance imaging (MRI) was done with T1-weighted images after gadolinium injection, and with T2 -weighted images and fluid attenuated inversion recovery (FLAIR) in all cases. Histological confirmation of glial proliferation was obtained in all cases by craniotomy. The topography of the tumoral infiltration was characteristic, involving mainly the white matter, basal ganglia, thalamus, and commissural fibers. More than two cerebral lobes were affected. Contrast enhancement was absent, and mass effects were minimal compared with the extent of tumoral infiltration, but one patient presented with a small frontal enhanced mass during the clinical course. The pathological analyses demonstrated infiltration of the brains by variably differentiated neoplastic glial cells with destruction of the myelin sheath, but the involved axis cylinder and neuronal cells were preserved. Diagnosis of GC should be faithful to the pathological diagnosis criteria of Scheinker and Evans, and therefore the precise assessment of MRI findings according to these criteria is required for clinical, antemortem diagnosis of GC.

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Jo Haraoka

Tokyo Medical University

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Jiro Akimoto

Tokyo Medical University

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Jun Wada

Tokyo Medical University

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Hiroshi Ito

Boston Children's Hospital

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Nobuyuki Nakajima

Brigham and Women's Hospital

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Hiroshi Mori

Jikei University School of Medicine

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