Koji Tokunaga

Okayama University, Okayama, Okayama, Japan

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Publications (140)168.53 Total impact

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    ABSTRACT: We describe a case of a very unusual complication following a coiling procedure in which the patient developed transient unique cerebral and cerebellar lesions. Lesions were examined not only by magnetic resonance imaging (MRI) but also by positron emission tomography-computed tomography (PET-CT) and proton magnetic resonance spectroscopy (1H-MRS). Case presentation A 33-year-old woman presented an incidental 3.7 × 3.3-mm unruptured cerebral aneurysm (CAn) in her basilar artery, which was successfully coiled with balloon assistance. A follow-up brain MRI at 1 and 2 months showed a gradual increase in several white matter hyperintense lesions in the left cerebellar, bilateral occipitotemporal and left parietoccipital lobe during fluid-attenuated inversion recovery (FLAIR). These were the only lesions associated with perfused CAn. However, the patient did not show any additional symptoms such as visual disturbance throughout the entire course. 11C-methionine-PET (MET-PET) showed an obvious increase in methionine uptake in the lesion corresponding to enhanced areas with gadolinium-enhanced MRI. MRS showed a decrease in the N-acetylaspartate/creatine (NAA/cr) ratio and a slight elevation of the choline/creatine (cho/cr) ratio and a lactate peak in the lesion. A follow-up MRI at 6 and 12 months showed a gradual decrease in the initial hyperintense lesions in FLAIR without any treatment. We present a case of an unusual complication after a coiling procedure. Although it is difficult to identify this etiology without a pathological examination, it is importance to increase awareness of such a potential complication arising from coiling procedures, because interventional procedures have become the first choice of treatment for cerebrovascular diseases in many countries.
    Preview · Article · Dec 2015 · BMC Neurology
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    Full-text · Dataset · Nov 2015
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    Full-text · Dataset · Nov 2015
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    ABSTRACT: Objectives: The aim of this study was to identify risk factors for rupture of unruptured cerebral aneurysms (UCAs) in elderly Japanese patients aged 70 years or older. Methods: The participants included all patients 70 years of age or older in 3 prospective studies in Japan (the Unruptured Cerebral Aneurysm Study of Japan [UCAS Japan], UCAS II, and the prospective study at the Jikei University School of Medicine). A total of 1,896 patients aged 70 years or older with 2,227 UCAs were investigated. The median and mean follow-up periods were 990 and 802.7 days, respectively. Results: The mean aneurysm size was 6.2 ± 3.9 mm. Sixty-eight patients (3.6%) experienced subarachnoid hemorrhage during the follow-up period. Multivariable analysis per patient revealed that in patients aged 80 years or older (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.16-3.49, p = 0.012), aneurysms 7 mm or larger (HR, 3.08; 95% CI, 1.35-7.03, p = 0.007 for 7-9 mm; HR, 7.82; 95% CI, 3.60-16.98, p < 0.001 for 10-24 mm; and HR, 43.31; 95% CI, 12.55-149.42, p < 0.001 for ≥25 mm) and internal carotid-posterior communicating artery aneurysms (HR, 2.45; 95% CI, 1.23-4.88, p = 0.011) were independent predictors for UCA rupture in elderly patients. Conclusions: In our pooled analysis of prospective cohorts in Japan, patient age and aneurysm size and location were significant risk factors for UCA rupture in elderly patients.
    Full-text · Article · Oct 2015 · Neurology
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    ABSTRACT: A 62-year-old man with high fever and in a state of disorientation was transferred to our hospital. One year before this transfer, he had undergone total arch replacement surgery for thoracic aortic dissection. On admission to our hospital, head MRI revealed multiple brain abscesses in the territory of the vertebral-basilar artery, and chest CT showed gas around the aortic graft, in particular, at the origin of the left subclavian artery. We diagnosed him with brain abscesses in the left vertebral-basilar artery resulting from an infected aortic graft. We immediately began administration of intravenous antibiotics. Although his blood, urine, and cerebrospinal fluid cultures were negative, fortunately, the brain abscesses and ectopic gas disappeared. Since reports of only antibiotic use for treating brain abscesses due to aortic graft infection are rare, the appropriate duration of antibiotic administration has not been established yet. Therefore, careful observation is required in this case.
    No preview · Article · Mar 2015 · No shinkei geka. Neurological surgery
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    ABSTRACT: Spinal hemangioblastomas are benign, and total surgical resection is the standard treatment method used. However, hypervascular tumors may have excessive operative blood loss if the tumors are divided. We encountered a case of cauda equina hemangioblastoma with extraordinary blood supply, which was treated with preoperative embolization. A 49-year-old woman with von Hippel-Lindau disease who had undergone multiple surgeries for intracranial/extracranial hemangioblastomas had lumbago and leg pain. Magnetic resonance images revealed intradural spinal tumors at the L4-S1 vertebral level, with remarkable gadolinium enhancement. The patient was referred to our hospital, after a plan of total resection had been abandoned elsewhere because of the high flow feeders and high pressure of the tumors. Preoperative embolization was performed with consequent disappearance of the arterial blood supply to the tumor. Two days later, the tumor was resected subtotally with reduced tension and a little blood loss. The patient’s symptoms resolved soon after surgery. Selective preoperative embolization for a spinal hemangioblastoma with a rich blood supply is a valid option as an adjuvant to the complete surgical resection of a tumor.
    Preview · Article · Jan 2015 · Spinal Surgery
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    ABSTRACT: In this article, we introduce cutting-edge knowledge pertaining to the pathophysiology of moyamoya disease from the viewpoint of angioarchitecture and genetic analysis. A complementary relationship among the anterior circulation(AC), the posterior circulation(PC)and the external carotid artery(ECA)system is involved in the pathophysiology of moyamoya disease. Suzuki’s grading is representative of the interaction between the AC and ECA, and it has traditionally played a leading role in evaluating disease progression. The interaction between the AC and PC is related to hemodynamic ischemia. There is a difference between pediatric and adult moyamoya patients in the interaction between the AC and PC. The analysis of the RNF213 gene is noteworthy as a new approach to understanding the pathophysiology of moyamoya disease. The prognosis and responsiveness to revascularization surgery can be predicted on the basis of genetic analysis. Although gene therapy for moyamoya disease is only now just in the basic experimental studies stage, it can be expected to emerge as an assisting modality for indirect revascularization surgery. © 2015 Japanese Congress of Neurological Surgeons. All rights reserved.
    Preview · Article · Jan 2015 · Japanese Journal of Neurosurgery
  • K Tokunaga · T Hishikawa · K Sugiu · I Date

    No preview · Article · Jul 2014 · Clinical Neuroradiology
  • Tomohito Hishikawa · Koji Tokunaga · Kenji Sugiu · Isao Date
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    ABSTRACT: Background: The object of this study was to compare the long-term outcomes in adult patients with moyamoya disease (MMD) with posterior circulation involvement (PCi) treated through surgical revascularization with those in adult patients without PCi. Methods: The records of 32 consecutive adult patients with ischemic-type MMD who were treated with revascularization were reviewed. Twelve of these patients (38 %) had PCi at initial onset. Clinical characteristics of the patients with PCi were compared to those without PCi. Neurological outcomes were assessed using the modified Rankin Scale (mRS) in the preoperative and postoperative follow-up periods. A five-year Kaplan-Meier stroke risk was calculated. Results: The frequency of presenting with infarction was significantly higher among patients with PCi than among those without PCi (p = 0.006). mRS scores in the preoperative period were significantly higher in patients with PCi than in patients without PCi (p = 0.0004). There were no significant differences in mRS scores between the preoperative and postoperative follow-up period in patients with PCi (p = 0.3), nor were there any between the preoperative and postoperative follow-up periods in patients without PCi (p = 0.2). The five-year Kaplan-Meier risk of surgical morbidity and ipsilateral stroke was 14.3 % in surgically treated hemispheres with PCi versus 14.9 % in surgically treated hemispheres without PCi (p = 0.96). Conclusions: PCi at initial onset was significantly correlated with poor outcome. Revascularization for the middle cerebral artery territory in patients with PCi was effective at preventing recurrent ischemic stroke.
    No preview · Article · May 2014 · Acta Neurochirurgica
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    ABSTRACT: Object: The effect on clinical outcomes of symptomatic vasospasm after aneurysmal subarachnoid hemorrhage (SAH) in patients over 80 years who underwent coil embolization was evaluated. Methods: Forty-four cases were reviewed and divided into two groups according to patient age: Group A, 79 years or younger, and Group B, 80 or older. Patient characteristics, prevalence of symptomatic vasospasm, modified Rankin Scale (mRS) scores at discharge and frequency of symptomatic vasospasm in patients with mRS scores of 3-6 were analyzed. Results: Thirty-two (73%) of the 44 cases were categorized as Group A and 12 (27%) as Group B. Group B had a significantly higher prevalence of symptomatic vasospasm compared to Group A (P=0.0040). mRS scores at discharge were significantly higher in Group B than in Group A (P=0.0494). Among cases with mRS scores of 3-6, there was a significantly higher frequency of symptomatic vasospasm in Group B than in Group A (P=0.0223). Conclusions: In our cohort of aneurysmal SAH patients treated by coil embolization, patients over 80 years of age were more likely to suffer symptomatic vasospasm, which significantly correlated with worse clinical outcomes, than those 79 years and under.
    Full-text · Article · Mar 2014
  • Koji Tokunaga · Tomohito Hishikawa · Kenji Sugiu · Isao Date

    No preview · Article · Jan 2014 · No shinkei geka. Neurological surgery
  • Koji Tokunaga · Tomohito Hishikawa · Kenji Sugiu · Isao Date
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    ABSTRACT: Our treatment modalities and techniques for intracavernous large or giant internal carotid artery (ICA) aneurysms have been changed based on past clinical experience. We report clinical results and pitfalls of bypass surgery for intracavernous ICA aneurysms. This study included unruptured symptomatic 37 intracavernous ICA aneurysms in 36 patients. Treatment methods were selected based on the anatomical features of the aneurysm and neurological/hemodynamic conditions during balloon test occlusion (BTO). Eleven aneurysms were treated without bypass surgery. Low flow bypass (STA-MCA anastomosis) was performed for 18 aneurysms, and eight aneurysms were treated with high flow bypass. A saphenous vein graft was originally used for high flow bypass, but it was changed with a radial artery because of the problem of long-term patency. ICA occlusion was accomplished by ligation of the cervical ICA alone in the early cases until we encountered a case with brain infarction due to emboli from the aneurysm after ICA ligation. Accordingly, ICA occlusion was performed by endovascular internal trapping two days after bypass surgery. There was, however, a case of graft thrombosis before ICA occlusion. We now occlude ICA by surgical trapping between the neck and the intracranial ICA immediately after revascularization. No patients had permanent ischemic neurological deficits due to cerebral hypoperfusion after ICA occlusion. Our treatment algorithm based on BTO was reliable. When the patients undergo bypass surgery, we perform ICA occlusion by surgical trapping between the neck and the intracranial portion.
    No preview · Article · Jan 2014 · Surgery for Cerebral Stroke
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    ABSTRACT: We developed the Japanese Registry of Neuroendovascular Therapy 2 (JR-NET2) database and used the information for a retrospective, nation-wide multicenter, observational study to clarify the clinical characteristics, current status of procedures, and outcome of patients treated by neuroendovascular therapy in Japan. In this report, we analyzed the clinical characteristics of dural arteriovenous fistulas (dAVFs) in the JR-NET2 database. All patients with dAVFs treated with endovascular therapy in 150 Japanese hospitals were included. Patient characteristics, clinical presentations, and imaging characteristics were analyzed. A total of 1,075 patients with dAVFs underwent 1,520 endovascular procedures. Of 1,075 patients, 45% were men and 55% were women. The mean age was 65 ± 13 years. The most frequent location of dAVFs was the cavernous sinus (43.6%), followed by the transverse-sigmoid sinus (TSS) (33.4%). Twelve percent of the patients had intracranial hemorrhage, 9% had venous infarction, and 3% had convulsion. The statistically significant independent risk factors of intracranial hemorrhage were TSS, superior sagittal sinus (SSS), tentorium, anterior cranial fossa, cranio-cervical junction, cortical venous reflux (CVR), and varix. Risk factors of venous infarction were age older than 60 years, male sex, TSS, SSS, and CVR. Risk factors of convulsion were male sex, SSS, and CVR. This is the largest nationwide report, to date, of the clinical characteristics of dAVFs treated by neuroendovascular therapy. CVR was a major risk factor of aggressive symptoms.
    No preview · Article · Dec 2013 · Neurologia medico-chirurgica
  • M Nakagawa · K Sugiu · K Tokunaga · C Sakamoto · K Fujiwara
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    ABSTRACT: Aim: Some of cases suffering from subarachnoid hemorrhages (SAHs) in grade V on World Federation of Neurologic Surgeons (WFNS) grading can gain a good prognosis. The outcome of patients of SAH in grade V on WFNS grading in their institute was here investigated. Methods: Between April 2007 and July 2012, consecutive 37 patients had SAH diagnosed on CT scan and were classified in grade V on WFNS grading in Kosei General Hospital. There were seventeen male and twenty female patients. We were assigned to patients with spontaneous respiration and without oculomotor palsy (N group, N.=11), and patients with oculomotor palsy (O group, N.=26). Patients were evaluated by mRS. Results: The prognosis in N group was significantly better than in O group (P<0.001). Conclusion: Surgical treatments should be considered for SAH patients without oculomotor palsy. It is necessary to make subgroups in grade V on WFNS grading in order to decide operative indication and evaluate the treatment results of SAH in grade V.
    No preview · Article · Dec 2013 · Journal of neurosurgical sciences
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    ABSTRACT: Embolization of intracranial tumor is widely performed in Japan, mainly before neurosurgical resection. A retrospective, multicenter, observational study in Japan was conducted to clarify the nature, frequency, and risk factors of complications in intracranial tumor embolization. Patients were derived from the Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2). A total of 20,854 patients were enrolled in JR-NET2, of which 1,018 patients (4.88 %) with intracranial tumors underwent embolization. The primary end point was the proportion of patients with a modified Rankin scale (mRS) score of 0-2 (independency) at 30 days. The secondary end point was the occurrence of complications related to the procedures. The risk factors of the occurrence of complications were studied. The proportion of patients with mRS scores ≤2 at 30 days after procedure was 91.3 %. Complications occurred in 15 of the 1,012 patients (1.48 %). Multivariate analysis showed that embolization for tumors other than meningioma (OR, 4.626; 95 % CI, 1.347-14.59; p = 0.0105) was significantly associated with the development of complications. The frequency of complications after intracranial tumor embolization was relatively low in this large Japanese cohort. Embolization for tumors other than meningioma was the only significant risk factor for the occurrence of complications.
    No preview · Article · Nov 2013 · Neuroradiology
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    ABSTRACT: Traumatic brain injury (TBI) sustained in a traffic accident or a fall is a major cause of death that affects a broad range of ages. The aim of this study was to investigate the therapeutic effects of intra-arterial transplantation of mesenchymal stem cells (MSCs) combined with hypertonic glycerol (25%) or mannitol (25%) in a TBI model of rats. TBI models were produced with a fluid percussion device. At 24hours after TBI, MSCs (1×10(6) cells/100μl) with glycerol or mannitol were administered via the right internal carotid artery. Rats were evaluated behaviorally and immunohistochemically, and hyperpermeability of the blood-brain barrier (BBB) induced by hypertonic solutions was explored. Compared to PBS or glycerol, the administration of mannitol resulted in increased BBB disruption. The mannitol-treated rats showed significant improvement in motor function. Intra-arterial transplantation of MSCs caused no thromboembolic ischemia. Immunohistochemically, more MSCs were observed in the injured brain tissues of mannitol-treated rats than in glycerol or PBS-treated rats at 24hours after transplantation. Intra-arterial transplantation of MSCs combined with mannitol is an effective treatment in a TBI model of rats. This technique might be used for patients with diseases of the central nervous system including TBI.
    No preview · Article · Sep 2013 · Neuroscience Letters
  • Tomohito Hishikawa · Koji Tokunaga · Kenji Sugiu · Isao Date
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    ABSTRACT: Object: There is no description of the change in the posterior cerebral artery (PCA) in the diagnostic criteria of moyamoya disease (MMD). However, PCAs are often involved in the clinical setting, and an understanding of the significance of PCA lesions is therefore of great importance when evaluating the disease progression and predicting prognosis. The aim of this study was to assess the difference in posterior circulation involvement in pediatric and adult patients with MMD. Methods: The records of 120 consecutive patients with MMD were reviewed. The clinical manifestations at diagnosis were evaluated on the basis of symptoms and CT and MRI findings. The degree of steno-occlusive internal carotid artery (ICA) lesions and the existence of steno-occlusive PCA lesions were evaluated by observing a total of 240 ICAs and PCAs on angiography. Angiographic correlation between anterior and posterior circulation was assessed in pediatric and adult patients with MMD. Results: Seventeen (26%) of 66 pediatric patients and 18 (33%) of 54 adult patients exhibited steno-occlusive PCA lesions. There was no significant difference in the prevalence of PCA lesions between pediatric and adult patients with MMD (p = 0.36). The prevalence of infarction in pediatric and adult patients with PCA involvement was significantly higher than that in pediatric and adult patients without PCA involvement (p = 0.0003 and p = 0.003, respectively). There was no significant difference in the distribution of infarction areas between pediatric and adult patients with PCA involvement (p = 0.62). On the basis of the staging system used, steno-occlusive lesions in ICAs ipsilateral to PCAs with lesions were in significantly advanced stages compared with lesions in ICAs ipsilateral to PCAs without lesions in both pediatric and adult cases (p < 0.0001 and p = 0.0008, respectively). Pediatric patients had less advanced steno-occlusive lesions in ICAs ipsilateral to PCAs with lesions compared with adults (p < 0.05). Conclusions: The clinical significance of posterior circulation involvement in MMD was similar between pediatric and adult patients. The only significant difference was that less advanced ICA lesions could complicate posterior circulation involvement in pediatric patients.
    No preview · Article · Aug 2013 · Journal of Neurosurgery
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    ABSTRACT: Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors. Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed. Stent volume gradually increased in each case and had increased by 1.04-1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P < 0.05). A 3D-CT examination is useful for precisely measuring stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period.
    No preview · Article · Jul 2013 · Neuroradiology
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    ABSTRACT: Aneurysms at the vertebrobasilar junction are often found with basilar artery(BA)fenestration. We encountered 10 consecutive cases of aneurysms associated with BA fenestration. The purpose of this study is to describe the frequency, clinical features, and outcome of these aneurysms treated by endovascular procedure. The incidence of these aneurysms in our series was 1.9%. All aneurysms were successfully treated by coil embolization. Half of them were treated by using simple technique, and the other half were treated by using adjunctive techniques such as balloon remodeling technique. 70% of these cases were ruptured, and all except one case showed good recovery at the time of discharge. We found 63 reported cases of this aneurysm in the literature between 2000 and 2012. 57 out of 63 aneurysms were treated by endovascular means with good clinical results. The usefulness of endovascular procedure is reported to be superior to surgical clipping because of their anatomical complexity and the difficulty of surgical exposure for clipping. We conclude that outcome of these aneurysms is favorable and endovascular procedure has become their standard treatment for these aneurysms.
    No preview · Article · Jul 2013 · No shinkei geka. Neurological surgery
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    ABSTRACT: We report here a case of cervical carotid artery aneurysm. This 37-year-old male suffered from acute neck swelling when he was taking lunch after physical work. Ultrasonography demonstrated a cervical pseudoaneurysm and a jet flow, which was blowing into the dome from the carotid artery. Angiogram revealed an aneurysm with a diameter of 3cm at the bifurcation of the common carotid artery. Coil embolization using double-catheter technique was performed and complete occlusion of the aneurysm was obtained without any complications. The patient returned to his normal life. Cervical carotid artery aneurysms are rare and they induce pain by swelling in the neck, hoarseness, swallowing disturbance, hemorrhage, and cerebral ischemia due to embolism. In case of a cervical carotid artery aneurysm, safe and effective treatments are required and endovascular treatment should be considered. Although stent-assisted coil embolization or covered-stent placement were reported as an effective treatment for cervical aneurysms, coil embolization without using a stent was performed in this particular patient who is a young, blue-collar worker because the avoidance of long-term anti-platelet therapy was desirable. Preoperative evaluation is important to select adequate treatment.
    No preview · Article · Jun 2013 · No shinkei geka. Neurological surgery

Publication Stats

904 Citations
168.53 Total Impact Points

Institutions

  • 1994-2015
    • Okayama University
      • Department of Neurological Surgery
      Okayama, Okayama, Japan
    • Kagawa Prefectural Central Hospital
      Takamatu, Kagawa, Japan
  • 2014
    • Okayama City Hospital
      Okayama, Okayama, Japan
  • 2005
    • Hiratsuka Kyosai Hospital
      Hiratuka, Kanagawa, Japan
  • 2004
    • University of Geneva
      • Division of Radio-oncology
      Genève, Geneva, Switzerland
  • 1999
    • Okayama Rosai Hospital
      Okayama, Okayama, Japan