Naoya Kuwayama

Publications (58)63.74 Total impact

• Article: Effect of carotid endarterectomy on cognitive function in patients with asymptomatic carotid artery stenosis.

  Akiko Takaiwa, Naoya Kuwayama, Naoki Akioka, Kunikazu Kurosaki, Nakamasa Hayashi, Shunro Endo, Satoshi Kuroda
  [show abstract] [hide abstract]
  ABSTRACT: BACKGROUND: This study was conducted to determine if patients with asymptomatic carotid artery stenosis show cognitive function decline, and if they experience any changes in cognitive function after carotid endarterectomy (CEA). METHOD: Cognitive function was examined in 15 patients (12 males and three females, 70.0 ± 6.5 years) with asymptomatic carotid artery stenosis before and 3 months after CEA. Cognitive function was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), two subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R 2 subtests), and the Japanese version of National Adult Reading Test (JART). The patients' average scores were compared with the normal average by one-sample t-tests, and the before and after scores were compared with paired t-tests. Changes in each patient were calculated from difference before and after CEA using 95 % confidence intervals. RESULTS: Before surgery, patients showed significant cognitive decline in RBANS total scale and immediate memory, language, and attention. At 3 months after CEA, the total scale and the immediate memory were not significantly different from the normal average. The average total scale score, the immediate memory and attention, and the WAIS-R 2 subtests scores were increased after treatment. Changes in each patient were calculated from the scores before and after CEA. At 3 months after CEA, the rate of increase in RBANS scores were 60.0 % of the patients for immediate memory, 26.7 % for visuospatial/constructional, 33.3 % for language and attention, 26.7 % for delayed memory, 47.7 % for total scale and 26.7 % for WAIS-R 2 subtests. Thus, so-called asymptomatic patients exhibit mild cognitive impairment before surgery, but after CEA, patients recover normal memory abilities. CONCLUSIONS: Our findings of mild cognitive dysfunction in asymptomatic patients suggest that they might be symptomatic after all.
  Acta Neurochirurgica 01/2013; · 1.52 Impact Factor
• Article: Syringomyelia associated with paget disease of the skull.

  Satoshi Hori, Masanori Kurimoto, Kimiko Umemura, Hideo Hamada, Seiya Nagao, Nakamasa Hayashi, Naoya Kuwayama, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: A 38-year-old man presented with a rare case of syringomyelia associated with Paget disease of the skull. Syringosubarachnoid (SS) shunting was performed. We speculate that deformation of the skull secondary to Paget disease caused narrowing of the foramen magnum with progressive impairment of the cerebrospinal fluid circulation, which led to syringomyelia and neurological symptoms. SS shunting is safe, effective, and technically simple, so may be a useful initial treatment for syringomyelia associated with Paget disease of the skull.
  Neurologia medico-chirurgica 01/2013; 53(2):115-8. · 0.61 Impact Factor
• Article: Efficacy of Endovascular Revascularization in Elderly Patients with Acute Large Vessel Occlusion: Analysis from the RESCUE-Japan Retrospective Nationwide Survey.

  Yusuke Egashira, Shinichi Yoshimura, Nobuyuki Sakai, Naoya Kuwayama
  [show abstract] [hide abstract]
  ABSTRACT: BACKGROUND: The purpose of this study was to evaluate the efficacy of endovascular treatment (EVT) in elderly patients (≥75 years of age) with acute large-vessel occlusion (LVO). METHODS: A total of 229 patients with acute LVO treated by EVT in 2008 were registered from 68 medical centers in Japan. Among the total of 229 patients, 89 were elderly patients. We retrospectively investigated the treatment efficacy of EVT and patient outcome, and compared the parameters between the elderly and the nonelderly group. RESULTS: Recanalization after EVT was equally obtained in both groups (P = .71). There was no significant difference in the favorable outcome (modified Rankin Scale [mRS] 0-2) between the elderly and nonelderly groups (30.3% vs 33.6%; P = .61), whereas poor outcome (mRS 5 and 6) was observed more in the elderly group than in the nonelderly group (48.3% vs 32.1%; P = .01). In patients with any recanalization (Thrombolysis in Myocardial Infarction grading system 1-3), the rates of favorable outcome in both groups were similar (39.7% vs 42.6%; P = .71). In contrast, in patients without recanalization, there was a significant difference in the poor outcome between the elderly and the nonelderly groups (76.2% vs 46.7%; P = .046). Symptomatic intracranial hemorrhage occurred in 6.7% in the elderly group and in 11.4% in the nonelderly group (P = .23). CONCLUSIONS: The elderly population could achieve favorable outcomes comparable to the nonelderly population, especially when they achieve any recanalization by EVT. Elderly patients should not be excluded from recanalization therapy with EVT because of age.
  Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 12/2011;
• Article: Retrospective nationwide survey of acute stroke due to large vessel occlusion in Japan: a review of 1,963 patients and the impact of endovascular treatment.

  Shinichi Yoshimura, Yusuke Egashira, Nobuyuki Sakai, Naoya Kuwayama
  [show abstract] [hide abstract]
  ABSTRACT: The purpose of this study was to clarify the clinical impact of endovascular treatment (EVT) on acute cerebral large vessel occlusion using a nationwide survey of Japan conducted in 2009. Patients admitted within 24 h after stroke onset were registered retrospectively. Treatment selection, methods, and clinical results were analyzed. A total of 1,963 patients (855 women, 1,108 men) treated in 2008 were registered from 68 medical centers in Japan. Mean age on admission was 74.1 ± 12.2 years (range 7-100 years). The first treatment was conservative therapy in 68%, intravenous tissue plasminogen activator (IV-tPA) in 21%, EVT in 9%, and combined IV-tPA + EVT in 2%. EVT mainly comprised angioplasty, intra-arterial thrombolysis and/or the combination of both. Patients treated ≤3 h after onset (1,286 cases) showed better clinical outcomes with combined IV-tPA + EVT than with conservative therapy, and significant differences in outcomes were seen for patients with occlusion of the basilar artery (p < 0.01) or middle cerebral artery (p < 0.01), but not the internal carotid artery. At >3 h after onset (677 patients), no IV-tPA was performed, and EVT was performed in 11%. Among the patients treated by EVT, there were significant differences in clinical outcome between complete recanalization (TIMI grade 3) and partial/no recanalization (TIMI grade 0-2) (p < 0.001; OR 5.98; 95% CI 3.27-10.96) and between any recanalization (TIMI grade 1-3) and no recanalization (TIMI grade 0) (p < 0.001; OR 36.15; 95% CI 4.88-267.53). This nationwide survey showed the efficacy of EVT with IV-tPA in patients with occlusion of the basilar or middle cerebral artery, but not of the internal carotid artery. The effects of new endovascular devices should be clarified in the near future.
  Cerebrovascular Diseases 08/2011; 32(3):219-26. · 2.72 Impact Factor
• Article: Flow-sensitive alternating inversion recovery (fair) imaging for retrograde cortical venous drainage related to intracranial dural arteriovenous fistula.

  Kyo Noguchi, Naoya Kuwayama, Michiya Kubo, Yuichi Kamisaki, Keisuke Kameda, Gakuto Tomizawa, Hideto Kawabe, Hikaru Seto
  [show abstract] [hide abstract]
  ABSTRACT: To evaluate the hypothesis that flow-sensitive alternating inversion recovery (FAIR) magnetic resonance (MR) imaging can detect retrograde cortical venous drainage (RCVD) in patients with intracranial dural arteriovenous fistula (DAVF). Seven patients with angiographically confirmed DAVF with RCVD and two DAVF patients without RCVD underwent examinations with conventional MR imaging and FAIR, five of these seven patients with RCVD also underwent examination with dynamic susceptibility contrast (DSC) MR imaging. The ability of FAIR to depict prominent cerebral veins was evaluated, and FAIR was compared with the relative cerebral blood volume (rCBV) maps created with DSC. In all DAVF patients with RCVD, FAIR clearly showed prominent veins on the surface of the brain in affected hemisphere, and FAIR corresponded well with the areas of increased rCBV. In all DAVF patients without RCVD, FAIR showed no prominent veins. FAIR can detect RCVD in patients with DAVF.
  Neuroradiology 03/2011; 53(3):153-8. · 2.82 Impact Factor
• Article: "Kissing" aneurysms of the internal carotid artery treated by coil embolization.

  Chiaki Takahashi, Michiya Kubo, Soushi Okamoto, Nobuhisa Matsumura, Yukio Horie, Nakamasa Hayashi, Naoya Kuwayama, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: A 62-year-old female complaining of sudden severe headache was referred to our stroke center in consultation. Computed tomography showed diffuse spread of thick subarachnoid hemorrhage to the basal cistern and both sylvian fissures, and digital subtraction angiography showed kissing aneurysms arising in the left lateral and occipital directions in the C(1) portion of the internal carotid artery (ICA). The anterior choroidal artery was situated between the two aneurysms, and another small branch originating from the dome of the distal aneurysm was confirmed as a duplicated middle cerebral artery (MCA). Endovascular treatment was successfully performed to spare the two vessels involved. This case of kissing aneurysms and ICA-duplicated MCA is very rare, and presents difficulties for both surgical and endovascular treatments.
  Neurologia medico-chirurgica 01/2011; 51(9):653-6. · 0.61 Impact Factor
• Article: Usefulness of computed tomography angiography for the detection of high-risk aortas for carotid artery stenting.

  Hiromichi Yamamoto, Naoya Kuwayama, Nakamasa Hayashi, Michiya Kubo, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery.
  Neurologia medico-chirurgica 01/2011; 51(11):756-61. · 0.61 Impact Factor
• Article: Periprocedural cilostazol treatment and restenosis after carotid artery stenting: the Retrospective Study of In-Stent Restenosis after Carotid Artery Stenting (ReSISteR-CAS).

  Hiroshi Yamagami, Nobuyuki Sakai, Yuji Matsumaru, Chiaki Sakai, Yutaka Kai, Kenji Sugiu, Toshiyuki Fujinaka, Yasushi Matsumoto, Shigeru Miyachi, Shinichi Yoshimura, Toshio Hyogo, Naoya Kuwayama, Akio Hyodo
  [show abstract] [hide abstract]
  ABSTRACT: Restenosis after carotid artery stenting (CAS) is a critical issue. Cilostazol can reduce restenosis after interventions in coronary or femoropopliteal arteries. We investigated whether periprocedural cilostazol treatment was related to the incidence of in-stent restenosis (ISR) or target vessel revascularization (TVR) after CAS. The study group comprised 553 of 580 patients who underwent CAS between April 2003 and August 2006 and were followed for 30 months after the procedure. ISR was defined as stenosis of at least 50% detected on angiography or ultrasonography. TVR was defined as revascularization of the treated carotid artery. During CAS, 207 patients (37.4%) were treated with cilostazol. Over 30 months, ISR occurred in 23 patients (4.2%), TVR occurred in 16 patients (2.9%), and either ISR or TVR occurred in 25 patients (4.5%). The incidence of ISR or TVR was significantly lower in the cilostazol-treated group than in the untreated group (1.4% vs 6.4%; log-rank P = .006). In a multivariate analysis, cilostazol treatment (hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.08-0.95; P = .041) and stent diameter (HR, 0.73/1-mm increase; 95% CI, 0.54-0.99; P = .044) were independent factors for the occurrence of ISR or TVR. The incidence of a composite of events, including thromboembolism, hemorrhage, death, and TVR, tended to be lower in the cilostazol-treated group than in the untreated group (15.0% vs 19.9%; log-rank P = .17). Periprocedural cilostazol treatment was associated with lower rates of ISR and retreatment after CAS. A prospective randomized controlled trial is needed to clarify the effect of cilostazol on ISR after CAS.
  Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 09/2010; 21(3):193-9.
• Article: Consequences of preoperative evaluation of patterns of drainage of the cavernous sinus in patients treated using the anterior transpetrosal approach.

  Nakamasa Hayashi, Hikari Sato, Yoshifumi Tsuboi, Shoichi Nagai, Naoya Kuwayama, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: Extradural procedures in an anterior transpetrosal approach (ATPA) may interrupt the route of drainage from the superficial middle cerebral veins (SMCVs) and the cavernous sinus (CS) to the pterygoid venous plexus at the temporal skull base. Patterns of drainage of the SMCV and the CS and the results of surgery were examined in 12 patients with petroclival lesions treated using the ATPA between 2000 and 2008. The angiographic patterns of drainage of the SMCV were examined in 22 sides of the 12 patients. The SMCV drained into the sphenoparietal sinus in 12 sides, the sphenobasal veins in 4 sides, and the cortical veins in 6 sides. The patterns of drainage of the CS were examined on 12 sides in which the SMCV drained into the sphenoparietal sinus. The CS drained into the inferior petrosal sinus (IPS) in 7 sides and equally into the pterygoid plexus and IPS in 3 sides. The CS drained mainly into the pterygoid plexus in 2 sides of 2 patients, who both suffered temporal lobe swelling postoperatively. The pattern of venous drainage of the CS must be considered in planning surgical approaches to petroclival lesions. In patients with a well-developed pterygoid plexus, surgical interruption of this drainage route may be a cause of injury of the temporal lobe.
  Neurologia medico-chirurgica 01/2010; 50(5):373-7. · 0.61 Impact Factor
• Article: Thoracic vertebral cavernous hemangioma in a schizophrenic patient--case report.

  Masanori Kurimoto, Kyo Noguchi, Shoichi Nagai, Takashi Asahi, Naoya Kuwayama, Nakamasa Hayashi, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: A 55-year-old man presented with gait disturbance, incontinence, and back pain. He had a medical history of schizophrenia for the past 35 years. Computed tomography (CT) and magnetic resonance imaging suggested thoracic vertebral hemangioma. Dynamic CT incidentally detected a hepatic hemangioma. Laminectomy of T3 and T4, resection of the epidural hemangioma, and rigid instrumentation between T1 and T6 using rod and hook systems were performed. Postoperatively, his symptoms completely disappeared and the histological diagnosis was capillary hemangioma. Schizophrenic patients have diminished sensitivity to pain or other symptoms, so neurological symptoms may become severe. However, early and appropriate treatment can result in satisfactory neurological outcome. The patient had a rare association of vertebral hemangioma and hepatic hemangioma, which may be a chance occurrence.
  Neurologia medico-chirurgica 01/2010; 50(6):485-7. · 0.61 Impact Factor
• Article: Distribution of internal elastic lamina and external elastic lamina in the internal carotid artery: possible relationship with atherosclerosis.

  Toru Masuoka, Nakamasa Hayashi, Emiko Hori, Naoya Kuwayama, Osamu Ohtani, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: The intracranial internal carotid artery (ICA) is a muscular artery and lacks external elastic lamina (EEL). Stenosis of the intracranial ICA is relatively uncommon, but the most common site is the cavernous portion. The characteristics of the arterial wall structures were examined using serial 3-mm sections of 32 intracranial ICAs obtained from 50 cadavers to identify where the EEL disappeared. The portions of the ICA where the intima exhibited thickening were also determined. Both the internal elastic lamina (IEL) and EEL were observed in all 32 specimens of the petrous portion of the ICA. Only the IEL was observed in all 32 specimens of the intradural portion of the ICA. The EEL had disappeared in 31 of the 32 specimens of the horizontal segment of the cavernous portion of the ICA. Intimal thickening of the ICA was observed in 23 of 32 ICA specimens, and frequently appeared in the horizontal segment of the cavernous portion of the ICA. The EEL disappeared in the cavernous portion of the ICA, which is the most common site of stenosis of the intracranial ICA. Change in the elasticity of the arterial wall in the cavernous portion may be an important factor in the process of atherosclerosis in the intracranial ICA.
  Neurologia medico-chirurgica 01/2010; 50(3):179-82. · 0.61 Impact Factor
• Article: Retrospective survey of endovascular treatment for ruptured intracranial aneurysm in Japan: Retrospective Endovascular Subarachnoid Aneurysm Treatment (RESAT) study.

  Nobuyuki Sakai, Waro Taki, Shinichi Yoshimura, Toshio Hyogo, Masayuki Ezura, Yasushi Matsumoto, Yasushi Ito, Hiroshi Abe, Makoto Sonobe, Shigeki Kobayashi, [......], Tomoaki Terada, Masaki Komiyama, Toshiyuki Fujinaka, Kenji Sugiu, Koichi Sato, Ichiro Nakahara, Kiyoshi Kazekawa, Masaru Hirohata, Akio Hyodo, Chiaki Sakai
  [show abstract] [hide abstract]
  ABSTRACT: Annual retrospective surveys of 20 to 31 medical centers performing endovascular treatment of cerebral aneurysms in Japan from 1997 to 2008 were performed to analyze technical and clinical outcomes of endovascular treatment for ruptured cerebral aneurysm. Patients treated with dome embolization using bare platinum coils within 14 days after onset were retrospectively selected, and clinical features, and technical and clinical outcomes at discharge were studied. Retrospective Endovascular Subarachnoid Aneurysm Treatment (RESAT) 1 covers patients treated from 1997, when the Guglielmi detachable coil was introduced, to 2002, just after International Subarachnoid Aneurysm Trial was reported. RESAT 2 to RESAT 7 were conducted annually between 2003 and 2008. Among 5,624 patients with ruptured aneurysms treated within 14 days after onset, 4,782 patients were treated by dome embolization using platinum detachable coils. The patients in this large retrospective survey included 35.8% aged over 70 years, 36.6% with posterior circulation aneurysms, and 29.3% with poor grades (Hunt and Kosnik grades IV and V). The proportion of patients aged over 70 years tended to increase each year from 33.4% in RESAT 1 to 39.8% in RESAT 7, and the proportion of those with posterior circulation aneurysms decreased from 44.2% in RESAT 1 to 23.8% in RESAT 7 (p<0.001). Overall technical success was obtained in 4,666 patients (97.6%), and favorable clinical outcome (good recovery and moderate disability) at discharge was obtained in 88.0% of grade I-III cases and 73.6% of grade I-V cases. Procedure-related morbidity was 2.9% and mortality was 0.8%. Despite this survey involving high proportions of aged, posterior circulation, and poor-grade patients, the technical success rate and immediate clinical results were relatively favorable. The patient prognosis and aneurysm changes must be investigated over a longer period, together with the effects of the introduction of new endovascular devices for cerebral aneurysms.
  Neurologia medico-chirurgica 01/2010; 50(11):961-5. · 0.61 Impact Factor
• Article: Cerebral venous sinus thrombosis revealed by digital subtraction angiography in a 69-year-old man with papilledema

  Masayoshi Toge, Seiji Hayasaka, Yoriko Hayasaka, Michiya Kubo, Naoya Kuwayama
  [show abstract] [hide abstract]
  ABSTRACT: A 69-year-old man complained of mild headache and abnormal visual fields in both eyes. Two months after the onset of these symptoms, the patient exhibited good central vision, abnormal visual fields, and papilledema. Enhanced computed tomography and magnetic resonance angiography of the brain showed no abnormality. Neurologic study showed no localizing signs, but increased intracranial pressure with normal composition of the cerebrospinal fluid. Digital subtraction angiography revealed thrombosis of the superior sagittal sinus. The patient was treated with heparin and acetazolamide. Thereafter, his intracranial pressure and papilledema decreased. Ophthalmologists and neurosurgeons should be aware that old cerebral sinus thrombosis may require digital subtraction angiography for diagnosis.
  07/2009; 28(4):147-153.
• Article: Changes in cognitive function during the 1-year period following endarterectomy and stenting of patients with high-grade carotid artery stenosis.

  Akiko Takaiwa, Nakamasa Hayashi, Naoya Kuwayama, Naoki Akioka, Michiya Kubo, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: In patients with severe carotid artery stenosis, cognitive decline and changes in cognitive function before to after treatment have been noted, though the true effects of treatment in such patients remain unclear. A convenient and repeatable neuropsychological test battery is needed for such patients. In 26 patients with severe carotid artery stenosis treated by carotid endarterectomy (CEA) and stenting (CAS), cognitive function was examined before and 1 week, 3 months, 6 months, and 1 year after treatment. RBANS and MMSE were selected as a test battery, and changes in test scores and long-term results of revascularization were evaluated. RBANS was useful and suitable for neuropsychological testing in such patients, and yielded the following results: (1) Patients before treatment had, on average, RBANS scores rated low average, with mild but relatively diffuse cognitive impairment; (2) RBANS scores were increased significantly at 3 months after CEA and CAS, and cognitive improvement was maintained over 1 year; and (3) scores were decreased temporarily at 1 week after CEA, but not after CAS. Patients with severe carotid artery stenosis exhibited mild decline in cognitive function, which was improved after CEA and CAS. RBANS is a suitable test battery for this type of patient.
  Acta Neurochirurgica 07/2009; 151(12):1593-600. · 1.52 Impact Factor
• Article: [Classification and diagnosis of intracranial dural arteriovenous fistulas].

  Naoya Kuwayama
  [show abstract] [hide abstract]
  ABSTRACT: Intracranial dural arteriovenous fistulas (DAVFs) are abnormal connections between the dural arteries and dural veins in the cranial dura mater. These fistulas involve the cavernous sinus, transverse-sigmoid sinus, superior sagittal sinus, inferior/superior petrosal sinus, sphenoparietal sinus, anterior cranial base, tentorium, craniocervical junction, and anterior condylar confluence. Presently, there are several classifications according to the venous restrictive condition. These classifications are useful in both determining the hemodynamic status of the patient and in formulating treatment strategies. The clinical signs and symptoms of these fistulas essentially result from hypertensive venopathy with or without venous hemorrhages. Patients with aggressive course are characterized by retrograde leptomeningeal venous drainage and veneous restrictive lesions. Besides location specific symptoms, intracranial venous hypertension is a key mechanism mimicking benign intracranial hypertension. Angiographic evaluation of the impairment in cerebral venous drainage is important as well as evaluating the angioanatomical features of the feeding and draining vessels and of the fistula sites. The characteristic findings of modern diagnostic tools such as CT scan, MRI, and conventional angiography are also described in this study.
  Brain and nerve = Shinkei kenkyū no shinpo 09/2008; 60(8):887-95.
• Article: A development of atheromatous plaque is restricted by characteristic arterial wall structure at the carotid bifurcation.

  Emiko Hori, Nakamasa Hayashi, Hideo Hamada, Toru Masuoka, Naoya Kuwayama, Yutaka Hirashima, Hideki Origasa, Osamu Ohtani, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: It is said atheromatous plaque is located very focally, but there have been few reports regarding this matter. Various aspects of the pathogenesis of the development of atheromatous plaque at the carotid bifurcation have previously been discussed. We have noted the correlation of plaque localization with characteristics of the cervical carotid artery wall. Morphological and histopathologic changes in the carotid bifurcation were examined in 72 cadaver cases with or without atheromatous plaque. We determined the level at which the wall structure changed to muscular artery from elastic artery and analyzed its influence on the development of atheromatous plaque. Atheromatous plaques at the distal site of the ICA extended within 0 to 37 mm from the carotid bifurcation. The proximal side of the CCA more than 5 mm away from the bifurcation was elastic artery, whereas the distal side of the ICA more than 15 mm from the bifurcation was muscular artery. The area of the carotid bifurcation between elastic artery and muscular artery was a transitional zone. Approximately 80% of them were located within 15 mm, and these areas were coincident with the transitional zone. Most atheromatous plaque was located in the transitional zone. The arterial wall structure is related to the development of atheromatous plaque at the cervical carotid bifurcation.
  Surgical Neurology 07/2008; 69(6):586-90; discussion 590-1. · 1.67 Impact Factor
• Article: Giant plexiform neurofibroma and suboccipital meningocele manifesting as segmental neurofibromatosis.

  Masanori Kurimoto, Yasushi Mizumaki, Osamu Fukuda, Nakamasa Hayashi, Naoya Kuwayama, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: A 34-year-old woman presented with segmental neurofibromatosis manifesting as a soft lump with a large café-au-lait macule on her occipital region and neck. Magnetic resonance imaging showed a thick skin tumor in the occipital region and posterior neck, and a suboccipital meningocele which seemed to have no association with her symptoms. Biopsy lead to a histological diagnosis of giant plexiform neurofibroma. During biopsy, massive local bleeding occurred and hemostasis was achieved by electrocautery and meticulous suture ligation. The postoperative course was uneventful and observation was continued for both the giant plexiform neurofibroma and the meningocele.
  Neurologia medico-chirurgica 07/2008; 48(6):271-4. · 0.61 Impact Factor
• Article: Involvement of meteorological factors and sex in the occurrence of subarachnoid hemorrhage in Japan.

  Kimiko Umemura, Yutaka Hirashima, Masanori Kurimoto, Naoya Kuwayama, Michiya Kubo, Hideki Origasa, Masaru Doshi, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: The sex difference in the seasonal occurrence of subarachnoid hemorrhage (SAH) and the association of meteorological factors in Japan were analyzed in 1006 consecutive patients with SAH in Toyama, Japan from 1996 to 2000. The study investigated whether these meteorological factors could explain the seasonality of the incidence of SAH in each sex. Seasonal variation of SAH occurrence peaked in spring in men, but peaked in spring and winter in women. The difference between maximum temperature and minimum temperature was the greatest on the day previous to SAH occurrence in multiple individuals in men, whereas mean humidity was the greatest on that day in women. Interestingly, the difference between maximum temperature and minimum temperature peaked in spring and mean humidity in winter from the meteorological data over the 5 years. The relationship between humidity and occurrence of SAH may explain the sex difference of the incidence of aneurysmal SAH. The humidity change may be a specific and additional meteorological factor for the incidence of SAH in women.
  Neurologia medico-chirurgica 04/2008; 48(3):101-7. · 0.61 Impact Factor
• Source

  Available from: 160.26.199.7

  Article: Basal encephalocele associated with hypoplasia of the internal carotid artery.

  Shinsaku Hasegawa, Nakamasa Hayashi, Michiya Kubo, Hideo Hamada, Naoya Kuwayama, Hideo Shojaku, Takuya Akai, Shunro Endo
  [show abstract] [hide abstract]
  ABSTRACT: A 22-year-old woman presented with a basal encephalocele associated with hypoplasia of the internal carotid artery (ICA) manifesting as a 6-year history of decreased vision in the right eye. She underwent encephalo-arterio-synangiosis under a diagnosis of hypoplasia of the ICA at age 6 years. Magnetic resonance imaging showed the encephalocele medial to the right temporal lobe. Frontotemporal craniotomy was performed for resection of the encephalocele and repair of the defect of the skull base. The pathogeneses of these developmental anomalies were probably related to developmental failure of the embryonic primordium during the 4th and 10th weeks.
  Neurologia medico-chirurgica 01/2008; 47(12):572-5. · 0.61 Impact Factor
• Article: A case of iatrogenic cerebral infarction demonstrated by postmortem cerebral angiography.

  Yutaka Tajima, Rie Takagi, Yoshihiko Kominato, Naoya Kuwayama
  [show abstract] [hide abstract]
  ABSTRACT: A 37-year-old man with a meningioma compressing the right frontal lobe underwent preoperative embolization of the feeding vessels from the right meningeal artery. Although the first challenge was apparently successful, an excess amount of embolization agent was accidentally injected during the next procedure. X-ray monitoring demonstrated flow of contrast medium into the right internal carotid, anterior and middle cerebral arteries, and then the patient suddenly developed left hemiparesis, nausea, and deep coma. He died 48 days after the embolization treatment without improvement of the coma. A medicolegal autopsy was performed to determine whether malpractice had occurred during the embolization procedure. An internal examination demonstrated massive necrosis of the cerebral hemispheres and lobar pneumonia with abscess in the lungs. Due to the extensive brain necrosis, it was impossible to carry out ordinary macroscopic examination to identify the precise site of the craniocerebral vessel occlusion. Postmortem angiography was therefore performed, and this successfully revealed occlusion of the right internal carotid artery. In this case, postmortem angiography played a key role in identification of the intracranial vascular lesion that was responsible for the iatrogenic cerebral infarction.
  Legal Medicine 12/2007; 9(6):326-9.