Education 【 display / non-display 】

Education 【 display / non-display 】

• 2006

  -

  2010

  Sapporo Medical University   Graduate School of Medicine   博士課程 情報伝達医学専攻 中枢神経機能治療学  

• 1998

  -

  2004

  Sapporo Medical University   School of Medicine   医学科  

Degree 【 display / non-display 】

Degree 【 display / non-display 】

• 2010.03   札幌医科大学   博士

Research Experience 【 display / non-display 】

Research Experience 【 display / non-display 】

• 2018.12

  -

  Now

  札幌医科大学 脳神経外科学講座 助教  

• 2017.04

  -

  2018.03

  Kyoto University  

• 2018.04

  -

  2018.11

  市立札幌病院 脳神経外科 副医長  

• 2014.01

  -

  2017.03

  札幌医科大学 脳神経外科学講座 助教  

• 2013.12

  　

  　

  札幌医科大学 脳神経外科学講座 診療医  

Research Areas 【 display / non-display 】

Research Areas 【 display / non-display 】

• Life sciences   Neurosurgery  

Affiliation 【 display / non-display 】

Affiliation 【 display / non-display 】

• Sapporo Medical University   脳神経外科   助教  

Research Interests 【 display / non-display 】

Research Interests 【 display / non-display 】

• Intracranial aneurysm

• moyamoya disease

• brain

• サイトカイン

• cytokine receptors

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Papers 【 display / non-display 】

Papers 【 display / non-display 】

• Deep learning from head CT scans to predict elevated intracranial pressure.

  Ryota Sato, Yukinori Akiyama, Takeshi Mikami, Ayumu Yamaoka, Chie Kamada, Kyoya Sakashita, Yasuhiro Takahashi, Yusuke Kimura, Katsuya Komatsu, Nobuhiro Mikuni

  Journal of neuroimaging : official journal of the American Society of Neuroimaging    2024.10  [International journal]

  　View Summary

  BACKGROUND AND PURPOSE: Elevated intracranial pressure (ICP) resulting from severe head injury or stroke poses a risk of secondary brain injury that requires neurosurgical intervention. However, currently available noninvasive monitoring techniques for predicting ICP are not sufficiently advanced. We aimed to develop a minimally invasive ICP prediction model using simple CT images to prevent secondary brain injury caused by elevated ICP. METHODS: We used the following three methods to determine the presence or absence of elevated ICP using midbrain-level CT images: (1) a deep learning model created using the Python (PY) programming language; (2) a model based on cistern narrowing and scaling of brainstem deformities and presence of hydrocephalus, analyzed using the statistical tool Prediction One (PO); and (3) identification of ICP by senior residents (SRs). We compared the accuracy of the validation and test data using fivefold cross-validation and visualized or quantified the areas of interest in the models. RESULTS: The accuracy of the validation data for the PY, PO, and SR methods was 83.68% (83.42%-85.13%), 85.71% (73.81%-88.10%), and 66.67% (55.96%-72.62%), respectively. Significant differences in accuracy were observed between the PY and SR methods. Test data accuracy was 77.27% (70.45%-77.2%), 84.09% (75.00%-85.23%), and 61.36% (56.82%-68.18%), respectively. CONCLUSIONS: Overall, the outcomes suggest that these newly developed models may be valuable tools for the rapid and accurate detection of elevated ICP in clinical practice. These models can easily be applied to other sites, as a single CT image at the midbrain level can provide a highly accurate diagnosis.

  DOI PubMed

• An anatomo-functional study of the interactivity between the paracentral lobule and the primary motor cortex.

  Yusuke Kimura, Shoto Yamada, Katsuya Komatsu, Rei Enatsu, Ryota Sato, Chie Kamada, Ayaka Sasagawa, Tsukasa Hirano, Masayasu Arihara, Nobuhiro Mikuni

  Journal of neurosurgery     1 - 9  2024.05  [International journal]

  　View Summary

  OBJECTIVE: The purpose of this study was to understand the anatomical and functional connections between the paracentral lobule (PCL) and the primary motor cortex (M1) of the human brain. METHODS: This retrospective study included 16 patients who underwent resection of lesions located near M1. Nine patients had lesions in the dominant hemisphere. Tractography was performed to visualize the connectivity between two regions of interest (ROIs)-the convexity and the interhemispheric fissure-that were shown by functional MRI to be activated during a finger tapping task. The number, mean length, and fractional anisotropy (FA) of the fibers between the ROIs were estimated. During surgery, subdural electrodes were placed on the brain surface, including the ROIs, using a navigation system. Cortico-cortical evoked potentials (CCEPs) were evoked by applying electrical stimuli to the hand region of M1 using electrodes placed on the convexity and were measured with electrodes placed on the interhemispheric fissure. To verify CCEP bidirectionality, electrical stimuli were applied to electrodes on the interhemispheric fissure that showed CCEP responses. Correlations of CCEP amplitudes and latencies with the number, mean length, and mean FA value obtained from tractography were determined. The correlations between these parameters and perioperative motor functions were also analyzed. RESULTS: Fibers of 14 patients were visualized by diffusion tensor imaging (DTI). Unidirectional CCEPs between the PCL and M1 were measurable in all 16 patients, and bidirectional CCEPs between them were measurable in 14 patients. There was no significant difference between the two directions in the maximum CCEP amplitude or latency (amplitude, p = 0.391; latency, p = 0.583). Neither the amplitude nor latency showed any apparent correlation with the number, mean length, or mean FA value of the fibers obtained from tractography. Pre- and postoperative motor function of the hands was not significantly correlated with CCEP amplitude or latency. The number and mean FA value of fibers obtained by DTI, as well as the maximum CCEP amplitude, varied between patients. CONCLUSIONS: This study demonstrated an anatomical connection and a bidirectional functional connection between the PCL, including the supplementary motor area, and M1 of the human brain. The observed variability between patients suggests possible motor function plasticity. These findings may serve as a foundation for further studies.

  DOI PubMed

• [Usefulness of Preoperative Simulation: Skull Base Approach].

  Masahiko Wanibuchi, Toru Hirano, Toshihiro Takami, Shinji Kawabata, Motomasa Furuse, Naosuke Nonoguchi, Masahiro Kameda, Ryo Hiramatsu, Ryokichi Yagi, Gen Futamura, Masao Fukumura, Takuya Kosaka, Yusuke Fukuo, Katsuya Komatsu, Nobuhiro Mikuni

  No shinkei geka. Neurological surgery   52 ( 2 ) 320 - 326  2024.03  [Domestic journal]

  　View Summary

  Preoperative simulation images creates an accurate visualization of a surgical field. The anatomical relationship of the cranial nerves, arteries, brainstem, and related bony protrusions is important in skull base surgery. However, an operator's intention is unclear for a less experienced neurosurgeon. Three-dimensional(3D)fusion images of computed tomography and magnetic resonance imaging created using a workstation aids precise surgical planning and safety management. Since the simulation images allows to perform virtual surgery, a déjà vu effect for the surgeon can be obtained. Additionally, since 3D surgical images can be used for preoperative consideration and postoperative verification, discussion among the team members is effective from the perspective of surgical education for residents and medical students. Significance of preoperative simulation images will increase eventually.

  DOI PubMed

• Combined endoscopic endonasal and transcranial approach for internal carotid artery aneurysms: usefulness and safety of endonasal proximal control.

  Ryota Sato, Yukinori Akiyama, Takeshi Mikami, Yuka Kawata, Chie Kamada, Yusuke Kimura, Katsuya Komatsu, Nobuhiro Mikuni

  Neurosurgical review   46 ( 1 ) 283 - 283  2023.10  [International journal]

  　View Summary

  It is necessary to secure both the proximal and distal sides of the parent artery to prevent premature rupture when clipping cerebral aneurysms. Herein, we describe four cases in which the proximal internal carotid artery (ICA), affected by a paraclinoid aneurysm, was secured using an endoscopic endonasal approach. We used various tools, including a surgical video, cadaver dissection picture, artist's illustration, and intraoperative photographs, to elucidate the process. No patient experienced postoperative complications at our institution. Compared to the cervical or cavernous ICA, the ICA adjacent to the clivus (paraclival ICA) can be anatomically safely and easily exposed using an endoscopic endonasal approach because there is no need to consider cerebrospinal fluid leakage or hemorrhage from the cavernous sinus. Securing the proximal side of the parent artery using an endoscopic endonasal approach may be a viable method for clipping selected ICA aneurysms, such as paraclinoid aneurysms especially for upward or outward aneurysms of the C2 portion.

  DOI PubMed

• Microbleeds Due to Reperfusion Enhance Early Seizures after Carotid Ligation in a Rat Ischemic Model.

  Takuro Saito, Takeshi Mikami, Tsukasa Hirano, Hiroshi Nagahama, Rei Enatsu, Katsuya Komatsu, Satoshi Okawa, Yukinori Akiyama, Nobuhiro Mikuni

  Neurologia medico-chirurgica   63 ( 6 ) 228 - 235  2023.06  [Domestic journal]

  　View Summary

  Impaired reperfusion in ischemic brain disease is a condition that we are increasingly confronted with owing to recent advances in reperfusion therapy. In the present study, rat models of reperfusion were investigated to determine the causes of acute seizures using magnetic resonance imaging (MRI) and histopathological specimens. Rat models of bilateral common carotid artery ligation followed by reperfusion and complete occlusion were created. We compared the incidence of seizures, mortality within 24 h, MRI, and magnetic resonance spectroscopy (MRS) to evaluate ischemic or hemorrhagic changes and metabolites in the brain parenchyma. In addition, the histopathological specimens were compared with those observed on MRI. In multivariate analysis, the predictive factors of mortality were seizure (odds ratios (OR), 106.572), reperfusion or occlusion (OR, 0.056), and the apparent diffusion coefficient value of the striatum (OR, 0.396). The predictive factors of a convulsive seizure were reperfusion or occlusion (OR, 0.007) and the number of round-shaped hyposignals (RHS) on susceptibility-weighted imaging (SWI) (OR, 2.072). The incidence of convulsive seizures was significantly correlated with the number of RHS in the reperfusion model. RHS on SWI was confirmed pathologically as microbleeds in the extravasation of the brain parenchyma and was distributed around the hippocampus and cingulum bundle. MRS analysis showed that the N-acetyl aspartate level was significantly lower in the reperfusion group than in the occlusion group. In the reperfusion model, RHS on SWI was a risk factor for convulsive seizures. The location of the RHS also influenced the incidence of convulsive seizures.

  DOI PubMed

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Misc 【 display / non-display 】

Misc 【 display / non-display 】

• Intraoperative Mapping and Monitoring for Rootlets of the Lower Cranial Nerves Related to Vocal Cord Movement.

  Masahiko Wanibuchi, Yukinori Akiyama, Takeshi Mikami, Katsuya Komatsu, Toshiya Sugino, Kengo Suzuki, Aya Kanno, Shunya Ohtaki, Shouhei Noshiro, Nobuhiro Mikuni

  Neurosurgery   78 ( 6 ) 829 - 34  2016.06  [International journal]

  　View Summary

  BACKGROUND: Damage to the motor division of the lower cranial nerves that run into the jugular foramen leads to hoarseness, dysphagia, and the risk of aspiration pneumonia; therefore, its functional preservation during surgical procedures is important. Intraoperative mapping and monitoring of the motor rootlets at the cerebellomedullary cistern using endotracheal tube electrodes is a safe and effective procedure to prevent its injury. OBJECTIVE: To study the location of the somatic and autonomic motor fibers of the lower cranial nerves related to vocal cord movement. METHODS: Twenty-four patients with pathologies at the cerebellopontine lesion were studied. General anesthesia was maintained with fentanyl and propofol. A monopolar stimulator was used at amplitudes of 0.05 to 0.1 mA. Both acoustic and visual signals were displayed as vocalis muscle electromyographic activity using endotracheal tube surface electrodes. RESULTS: The average number of rootlets was 7.4 (range, 5-10); 75% of patients had 7 or 8 rootlets. As many as 6 rootlets (2-4 in most cases) were responsive in each patient. In 23 of the 24 patients, the responding rootlets congregated on the caudal side. The maximum electromyographic response was predominantly in the most caudal or second most caudal rootlet in 79%. CONCLUSION: The majority of motor fibers of the lower cranial nerves run through the caudal part of the rootlets at the cerebellomedullary cistern, and the maximal electromyographic response was elicited at the most caudal or second most caudal rootlet. ABBREVIATION: EMG, electromyographic.

  DOI PubMed

• arterial spin labeling法による髄膜腫内血流の評価

  鰐渕 昌彦, 小松 克也, 秋山 幸功, 長濱 宏史, 三國 信啓

  脳循環代謝 ( 日本脳循環代謝学会 )  27 ( 1 ) 183 - 183  2015.10

• Radical removal of recurrent malignant meningeal tumors of the cavernous sinus in combination with high-flow bypass.

  Masahiko Wanibuchi, Yukinori Akiyama, Takeshi Mikami, Satoshi Iihoshi, Kei Miyata, Yoshifumi Horita, Toshiya Sugino, Katsuya Komatsu, Kengo Suzuki, Ken Yamashita, Nobuhiro Mikuni

  World neurosurgery   83 ( 4 ) 424 - 30  2015.04  [International journal]

  　View Summary

  BACKGROUND: Meningiomas or solitary fibrous tumors arising from the cavernous sinus (CS) are usually treated with radiosurgery to control growth. Surgical removal of cavernous tumors is indicated only for tumors extending outside the CS. However, even after adequate treatment, the tumor may exhibit recurrence or malignant transformation. We report a treatment option for recurrent meningeal tumors of the CS. METHODS: In 4 patients with CS tumors that exhibited regrowth after multiple operations and radiosurgery, radical removal in combination with high-flow bypass was performed, and a vascularized muscle flap was used for reconstruction. One patient had a radiation-induced atypical meningioma, 2 patients had transformed atypical meningiomas, and 1 patient had a frequently recurring solitary fibrous tumor. RESULTS: No local recurrence was observed in any patients during a follow-up period of 13-41 months. In all patients, a Karnofsky performance scale score of >80 on admission was maintained at >70 at the final follow-up evaluation. CONCLUSIONS: Radical removal in combination with high-flow bypass provides favorable results and maintains quality of life in patients with recurrent CS meningeal tumors.

  DOI PubMed

• Radical removal of recurrent malignant meningeal tumors of the cavernous sinus in combination with high-flow bypass.

  Masahiko Wanibuchi, Yukinori Akiyama, Takeshi Mikami, Satoshi Iihoshi, Kei Miyata, Yoshifumi Horita, Toshiya Sugino, Katsuya Komatsu, Kengo Suzuki, Ken Yamashita, Nobuhiro Mikuni

  World neurosurgery ( ELSEVIER SCIENCE INC )  83 ( 4 ) 424 - 30  2015.04  [Refereed]  [International journal]

  　View Summary

  BACKGROUND: Meningiomas or solitary fibrous tumors arising from the cavernous sinus (CS) are usually treated with radiosurgery to control growth. Surgical removal of cavernous tumors is indicated only for tumors extending outside the CS. However, even after adequate treatment, the tumor may exhibit recurrence or malignant transformation. We report a treatment option for recurrent meningeal tumors of the CS. METHODS: In 4 patients with CS tumors that exhibited regrowth after multiple operations and radiosurgery, radical removal in combination with high-flow bypass was performed, and a vascularized muscle flap was used for reconstruction. One patient had a radiation-induced atypical meningioma, 2 patients had transformed atypical meningiomas, and 1 patient had a frequently recurring solitary fibrous tumor. RESULTS: No local recurrence was observed in any patients during a follow-up period of 13-41 months. In all patients, a Karnofsky performance scale score of >80 on admission was maintained at >70 at the final follow-up evaluation. CONCLUSIONS: Radical removal in combination with high-flow bypass provides favorable results and maintains quality of life in patients with recurrent CS meningeal tumors.

  DOI PubMed

Research Projects 【 display / non-display 】

Research Projects 【 display / non-display 】

• 線維芽細胞に着目したくも膜炎症の分子機構の解明と新たな脳保護薬の開発

  基盤研究(C)

  Project Year :

  2020.04

  -

  2023.03

   

  三上 毅, 鈴木 比女, 秋山 幸功, 三國 信啓, 小松 克也, 平野 司

  　View Summary

  臨床データから得られた知見として、慢性脳虚血性疾患に対する開頭血行再建術で得られたくも膜と脳脊髄液を使用した。対象群として開頭による非虚血性疾患で得られた前頭葉皮質血管(M4)直上のくも膜を使用した。これまでの研究成果としては、くも膜の厚さは年齢や疾患が影響しており、厚いくも膜では内層に線維芽細胞やマクロファージが増勢し、VEGFαやTGFβなどの炎症マーカーが増加していた。また、くも膜内の線維化や慢性炎症が確認されていることを基に、免疫組織学的に線維化に関わる炎症マーカーや間葉系幹細胞の存在、血管新生の有無を確認した。虚血性疾患において、強い炎症反応が認められており、疾患による影響もみられることがわかった。 また、実験動物として両側総頸動脈閉塞による認知症モデルによる評価を行った。8週のWister kyotoラットにおいて、両側総頚動脈閉塞モデルを作成し、頚動脈閉塞後4週間目に実験用7.0TMRIで脳小血管病性変化を計測した。また、電気生理学的な影響を測定するため、Pinnacle Technology社の大脳皮質脳波測定システムで、てんかん波や高次脳機能を反映するβ波やγ波などの高周波帯域のパワースペクトラム解析を行った。虚血によるてんかん原生が非常に強く影響を及ぼしていることを見出すとともに、MRI及び電気生理学的な虚血の影響を推し量れるシステムを確立した。また、両側頚動脈閉塞と再灌流の電気生理学的変化や組織変化、MRI画像変化の違いを検討し、組織学的変化が及ぼす電気生理学的異常について検討中である。

• analysis of molecular mechanism of invasion in malignant gliomas and development of a novel treatment by inhibition of glioma cell migrations

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2017.04

  -

  2020.03

   

  Wanibuchi Masahiko

  　View Summary

  Gliomas account for 24.1% of primary brain tumors. It is difficult to cure the disease with multimodality treatment combined with surgery, chemotherapy, and radiotherapy. The 5-year survival rate of glioblastoma which is the most malignant type of gliomas is only 10.1%. The reason for the poor prognosis is the invasive capacity, however, the factors and mechanisms of invasion or migration is still unknown.In this study, we found several factors which related to the prognosis of gliomas such as ACTC1 (actin alpha cardiac muscle 1), SERPINEA1, IL13 receptor alpha 2. Among these, ACTC1 was also closely related to the invasion of malignant gliomas. In addition, timelapse study of U87 malignant glioma cell line revealed gene knockdown of ACTC1 using by siRNA resulted in the inhibition of migration of glioma cells. The present study demonstrated that targeting of migration capacity of glioma cells may lead to the improvement of prognosis of malignant gliomas.

• Pathophysiology of oscillation in ischemic condition

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2016.04

  -

  2019.03

   

  Mikami Takeshi

  　View Summary

  To evaluate the neurofunction and effectiveness of revascularization, electrocorticography was evaluated in moyamoya disease. The average spectral power ratio of the beta band per total band in moyamoya disease before bypass was lower than that of control, and the significance disappeared after bypass surgery. The spectral power levels of the beta band and gamma band were increased in moyamoya disease after bypass surgery. Using rat model, similar result could be obtained in ischemic condition. Then, an effective neuromodulation is developing with neuro-stimulation.

• Prevention of neointimal hyperplasia induced by an endovascular stent via intravenous infusion of mesenchymal stem cells

  Grant-in-Aid for Scientific Research (C)

  Project Year :

  2016.04

  -

  2019.03

   

  Katsuya Komatsu

  　View Summary

  In-stent restenosis causes recurrent ischemic events. Neointimal hyperplasia induced by an inflammatory response to the stent strut may be a possible mechanism of in-stent restenosis. Intravenous infusion of mesenchymal stem cells (MSCs) has been reported to show therapeutic efficacy for cerebral stroke presumably by an anti-inflammatory effect. This study aimed to determine whether MSCs can reduce or prevent neointimal hyperplasia induced by an endovascular stent. We deployed two types of stents using an animal model. Stents were implanted in the common carotid artery (CCA), and superficial cervical artery (SCA). Infused MSC immediately after deployment of stents prevented in-stent stenosis of CCA and SCA. Intravenous infusion of MSCs inhibited the inflammatory reaction to an implanted stent strut, and prevented progressive neointimal hyperplasia in the stented CCA and SCA. Thus, MSC treatment could attenuate the recurrence of cerebral ischemic events after stenting.