Updated on 2026/03/24

写真a

 
Mihara Riku
 
Affiliation
Nippon Medical School Hospital, Department of Neurological Surgery, Assistant Professor
Title
Assistant Professor
External link

Papers

  • Preoperative Magnetic Resonance Imaging Findings in Patients with Tarsal Tunnel Syndrome and Postoperative Outcomes.

    Kyongsong Kim, Toyohiko Isu, Atsushi Sugawara, Kenta Koketsu, Minoru Ideguchi, Hiroyuki Dan, Riku Mihara, Yasuo Murai

    Neurologia medico-chirurgica   65 ( 9 )   407 - 412   2025.9

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    Tarsal tunnel syndrome is an entrapment neuropathy at the tarsal tunnel. The diagnosis and the prediction of the surgical outcome are difficult. We compared preoperative magnetic resonance imaging findings with the postoperative results. We examined preoperative magnetic resonance imaging findings in 38 consecutive patients with Tarsal tunnel syndrome (47 feet); their mean age was 73.8 years. We inspected the nerve width on the slice showing the most compressed nerve, and the hyperintensity of that nerve on preoperative T2* fat-suppressed axial magnetic resonance imaging images and examined the role of magnetic resonance imaging in the diagnosis and of the surgical outcomes in patients with Tarsal tunnel syndrome. Postoperatively, there was significant symptom improvement. On preoperative magnetic resonance imaging scans the mean width of the most compressed nerve was 0.99 ± 0.37 mm. There was no significant correlation between the preoperative symptom severity and postoperative symptom improvement. In 29 feet (61.7%) we observed hyperintensity of the compressed nerve. In all but one foot the hyperintense area was displayed on 3 axial slices adjacent to the strongest nerve compression point. There was no significant difference in the preoperative symptom severity in patients with (group 1, n = 29) or without hyperintensity (group 2, n = 18). The nerve width at the point of greatest compression was significantly thinner, and postoperative symptom improvement was significantly greater in group 1 patients. Although there was no correlation between the preoperative nerve compression severity and the surgical results, nerve hyperintensity on magnetic resonance imaging scans may help with the diagnosis of Tarsal tunnel syndrome.

    DOI: 10.2176/jns-nmc.2025-0115

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  • Effect of Perfusion CT on Time Required to Evaluate Indications for Thrombectomy for Acute Cerebral Infarction.

    Riku Mihara, Minoru Ideguchi, Kyongsong Kim, Kenta Koketsu, Yasuo Murai

    Journal of Nippon Medical School = Nippon Ika Daigaku zasshi   92 ( 1 )   97 - 103   2025

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    BACKGROUND: Rapid treatment of patients with emergency large vessel occlusion (ELVO) improves outcomes. With Vitrea software, the cerebral infarct size and penumbra can be quantified, and 4D images can be constructed quickly. We investigated the performance of Vitrea in ELVO patients. METHODS: To evaluate indications for mechanical thrombectomy, we performed plain brain CT, then MRI (group 1, n=30). In May 2022 we acquired perfusion CT scans with Vitrea after plain CT on the same equipment (group 2, n=27) and then compared time from onset to the end of mechanical thrombectomy. At 1 month post-treatment we recorded the neurological outcome by using the modified Rankin scale (mRS). We also compared the infarction areas identified with Vitrea and MRI the day after treatment using DWI-ASPECTS in 25 of 27 patients in group 2. We excluded 2 patients with basilar artery occlusion because this type of occlusion is not included in DWI-ASPECTS. RESULTS: There were no significant intergroup differences in patient characteristics, time from admission or puncture to re-canalization, and outcome 1 month after treatment. Vitrea overestimated the infarct area in 1 of 25 patients (4.0%). Times from admission to transit for examination, to the examination end, and time from admission to puncture, were significantly shorter in group 2. CONCLUSIONS: In ascertaining indications for thrombectomy in patients with acute cerebral stroke, perfusion CT with Vitrea shortened time to treatment. However, further investigation is needed to confirm the accuracy of Vitrea in determining the infarct area.

    DOI: 10.1272/jnms.JNMS.2025_92-115

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  • 灌流CTを用いた脳主幹動脈急性閉塞の治療選択と実施

    鶴谷 美紅, 三原 陸, 井手口 稔, 纐纈 健太, 國保 倫子, 尾関 友博, 團 裕之, 藤田 寛明, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   813 - 813   2024.11

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  • DECTによる脳塞栓症の血栓性状評価 電子密度とCT値

    團 裕之, 井手口 稔, 鶴谷 美紅, 藤田 寛明, 三原 陸, 尾関 友博, 國保 倫子, 纐纈 健太, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   815 - 815   2024.11

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  • 灌流CTの解析画像だけでは血栓回収術の適応を判断しきれず、MRIも必要とした症例

    三原 陸, 井手口 稔, 纐纈 健太, 團 裕之, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   585 - 585   2024.11

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  • 腫瘍塞栓時にOptimoをもちいたFlow controlが有用であった1症例

    井手口 稔, 鶴谷 美紅, 藤田 寛明, 三原 陸, 團 裕之, 尾関 友博, 國保 倫子, 纐纈 健太, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   481 - 481   2024.11

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  • 経過観察のみで自然消失した海綿静脈洞部硬膜動静脈瘻の一例

    藤田 寛明, 井手口 稔, 鶴谷 美紅, 團 裕之, 三原 陸, 尾関 友博, 國保 倫子, 纐纈 健太, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   631 - 631   2024.11

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  • 破裂微小脳動脈瘤に対する塞栓術後の攣縮予防治療による再開通が疑われた一例

    井手口 稔, 鶴谷 美紅, 藤田 寛明, 三原 陸, 團 裕之, 尾関 友博, 國保 倫子, 纐纈 健太, 金 景成, 村井 保夫

    日本脳神経血管内治療学会学術集会抄録集   40回   652 - 652   2024.11

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    Language:Japanese   Publisher:(一社)日本脳神経血管内治療学会  

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  • 【各神経ブロック,関節ブロックの実際】上臀皮神経・中臀皮神経ブロック

    團 裕之, 金 景成, 三原 陸, 藤田 寛明, 井須 豊彦

    脊椎脊髄ジャーナル   37 ( 7 )   523 - 528   2024.8

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    Language:Japanese   Publisher:(株)三輪書店  

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  • 【脳神経外科医の画像読影 とるワザとよむチカラ】脊髄・脊椎・末梢神経

    金 景成, 三原 陸, 團 裕之, 井須 豊彦

    脳神経外科速報   34 ( 4 )   398 - 404   2024.7

  • Identification and decompression of superior cluneal nerve implicated in low back pain. International journal

    Kenta Koketsu, Kyongsong Kim, Toyohiko Isu, Rinko Kokubo, Minoru Ideguchi, Riku Mihara, Yasuo Murai

    Acta neurochirurgica   166 ( 1 )   59 - 59   2024.2

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    INTRODUCTION: Low back pain (LBP) can be attributable to entrapment of the superior cluneal nerve (SCN) around the iliac crest. Surgical decompression is a useful treatment; however, finding all entrapped SCNs involved in patients with LBP can be difficult. We performed a retrospective study to help identify entrapped SCNs in the narrow surgical field. METHODS: We enrolled 20 LBP patient (22 sides) with SCN entrapment. They were 9 males and 11 females; their mean age was 72.5 years. We developed a 3-step procedure for successful SCN decompression surgery. In step 1, the thoracolumbar fascia is exposed and the SCN penetrating the fascia is released. In step 2, the fascia is opened and the SCN is released. In step 3, the fascia above the iliac crest is opened and the SCN is released. RESULTS: We successfully released 66 nerves; the average was 3.0 ± 0.8 (1-4) per patient. Step 1 detected 18 nerves (27.3%), step 2 identified 35 (53.0%), and in step 3, 13 (19.7%) were recognized. By tracing the thin nerves branching off the SCN, we found 7 nerves (10.6%). We performed 22 operations; step 1 identified 16 SCNs (72.7%), step 2 identified 21 (95.5%), and step 3 found 12 nerves (54.5%). CONCLUSIONS: The SCN is most readily identified upon opening of the thoracolumbar fascia. To identify as many SCN branches as possible, our 3-step method may be useful.

    DOI: 10.1007/s00701-024-05960-z

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  • Reliability of PainDETECT for Evaluating Low Back Pain Caused by Cluneal Nerve Entrapment.

    Chiho Takada, Kyongsong Kim, Rinko Kokubo, Minoru Ideguchi, Riku Mihara, Kenta Koketsu, Yasuo Murai

    Journal of Nippon Medical School = Nippon Ika Daigaku zasshi   91 ( 3 )   328 - 332   2024

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    BACKGROUND: Superior/middle cluneal nerve entrapment (CN-E) is an elicitor of low back pain (LBP). The painDETECT questionnaire is used to characterize CN-E symptoms. METHODS: Nineteen consecutive patients with LBP caused by CN-E (superior CN-E = 7; middle CN-E = 12) participated in a Japanese language painDETECT questionnaire survey before surgery. A score of 12 or lower was recorded as 'neuropathic component unlikely', a score of 19 or higher as 'neuropathic pain likely', and scores between 13 and 18 as 'neuropathic pain possible'. LBP severity was recorded on a numerical rating scale, the Roland-Morris Disability Questionnaire, and the EuroQol-5 dimension-5 level. RESULTS: The mean painDETECT score was 11.8 and did not significantly differ between the superior CN-E and middle CN-E groups. We classified low back pain as unlikely to have a neuropathic component in 13 patients, as likely to have a neuropathic component in 2 patients, and as possibly neuropathic in 4 patients. There was no significant difference in the pain level of patients with scores of ≤12 and ≥13 on painDETECT. All patients reported trigger pain; the positive rate was high for electric shock pain, radiating pain, and pain attacks and low for a burning or tingling sensation, pain elicited by a light touch, and pain caused by cold or hot stimulation. CONCLUSION: The painDETECT questionnaire may not reliably identify LBP caused by superior/middle CN-E as neuropathic pain. A diagnosis of LBP due to CN-E must be made carefully because symptoms resemble nociceptive pain.

    DOI: 10.1272/jnms.JNMS.2024_91-312

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  • 脳神経外科医による末梢神経の外科 学会発表から見る最近のトレンド

    團 裕之, 金 景成, 井須 豊彦, 國保 倫子, 森本 大二郎, 三原 陸, 森田 明夫

    脳神経外科速報   33 ( 6 )   e8 - e14   2023.11

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  • 破裂瘤同定に苦慮した多発脳動脈瘤を伴うくも膜下出血の1例

    三原 陸, 井手口 稔, 金 景成, 纐纈 健太, 尾関 友博, 團 裕之, 森田 明夫

    脳神経外科速報   33 ( 6 )   e15 - e22   2023.11

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    症例は48歳女性で、前日からの頭痛を主訴とした。頭部CTでくも膜下出血を脳底槽からシルビウス裂に認め、やや左優位であった。脳血管撮影では右内頸動脈・左内頸動脈・左中大脳動脈・左前大脳動脈に多発脳動脈瘤を認めた。造影MRIによるvessel wall imagingで破裂瘤は右内頸動脈前壁動脈瘤の可能性が高いと判断し、同日開頭クリッピング術を行ったが、術中破裂所見は認めず動脈瘤を切除した。翌日に左側開頭クリッピング術を行い、左前大脳動脈瘤を破裂瘤と判断し、中内脳動脈瘤と左内頸動脈瘤もクリッピングした。初回手術7日後に脳血管撮影にて各動脈瘤の消失を確認し、遺残した高次脳機能障害のリハビリテーション目的に第76病日に転院した。切除した右内頸動脈瘤の病理所見では脳動脈瘤壁に炎症細胞の浸潤および毛細血管の増生を認め、造影された原因と考えられた。

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  • 脳神経外科医による末梢神経の外科 学会発表から見る最近のトレンド

    團 裕之, 金 景成, 井須 豊彦, 國保 倫子, 森本 大二郎, 三原 陸, 森田 明夫

    脳神経外科速報   33 ( 6 )   e8 - e14   2023.11

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  • Experience using gentian violet-free dyes for tissue visualization. International journal

    Fumihiro Matano, Yasuo Murai, Yohei Nounaka, Tadashi Higuchi, Riku Mihara, Koshiro Isayama, Akio Morita

    Journal of neurological surgery. Part A, Central European neurosurgery   2023.9

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    Gentian violet ink is used as a skin marker in various surgical procedures, including neurosurgery. The dye is also used to visualize the edges of blood vessels during bypass surgery. However, gentian violet ink carries the risks of carcinogenicity and venous injury, which causes microvascular thrombosis. Objective The objective of this study was to compare the gentian violet-free dye C.I. Basic Violet 4 (BV4) and gentian violet. The usefulness, in terms of color, and the formation of microvascular thrombosis in anastomosis were compared. Methods We used the gentian violet-free dye in 20 cases involving 3 vascular anastomoses. The bone cutting lines on the bone surface, superior temporal artery, and middle cerebral artery were drawn using BV4 and gentian violet ink. Results The colors of BV4 and gentian violet ink were similar. No thrombus formation was observed at the vascular anastomosis when using BV4. Conclusion BV4 can be used similarly to gentian violet ink. No adverse effects such as thrombus formation in microvascular anastomosis were experienced using BV4.

    DOI: 10.1055/a-2175-3295

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  • Subcutaneous Emphysema of the Orbit after Nose-Blowing

    Riku Mihara, Yasuo Murai, Shun Sato, Fumihiro Matano, Akio Morita

    REPORTS   5 ( 2 )   2022.6

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    Orbital emphysema after nose-blowing is an uncommon condition and can appear without a trigger. Herein, we reported a case of orbital emphysema after nose-blowing and performed a literature review. A 68-year-old man fell and sustained an injury near his left orbit. No symptoms were noted. He noticed a left periorbital swelling after blowing his nose. Through computed tomography examination, he was diagnosed with subcutaneous emphysema. There are no previous reports that have reviewed the clinical features, need for surgery, and severity of symptoms of subcutaneous emphysema after nasal swallowing due to different factors. We retrospectively analyzed a cohort of 48 cases by searching PubMed to clarify these issues. Regarding the emphysema trigger, 21 cases had an injury or had previously undergone surgery. In 34 cases, conservative treatment was required, while surgery was selected in the acute phase in 6 cases and after the acute phase as a radical cure in 8 cases. Reduced visual acuity, diplopia, exophthalmos, facial hypoesthesia, and color disorders were noted and were more common among surgical cases. The literature review revealed no association between fracture location and the need for surgery; furthermore, surgery was less required in non-trauma cases, excluding osteoma, than in trauma cases (p = 0.0169). Our study reveals that a strict follow-up examination of visual symptoms is necessary for the first 2 days in cases of subcutaneous emphysema caused by nose blowing after facial trauma.

    DOI: 10.3390/reports5020021

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  • 上矢状静脈洞の左右、さらにテント下に及んだ急性硬膜外血腫の一例

    能中 陽平, 村井 保夫, 三原 陸, 五十嵐 豊, 樋口 直司, 横堀 将司, 森田 明夫

    日本脳神経外傷学会プログラム・抄録集   45回   190 - 190   2022.1

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Misc.

  • 特発性脊髄くも膜下出血の1例

    國保倫子, 三原陸, 團裕之, 井手口稔, 金景成, 村井保夫

    日本脊髄外科学会プログラム・抄録集   40th   2025

  • 脊髄・脊椎・末梢神経—特集 脳神経外科医の画像読影 : とるワザとよむチカラ

    金 景成, 三原 陸, 團 裕之, 井須 豊彦

    脳神経外科速報 : 臨床医の人生に伴走するlifetime journal   34 ( 4 )   398 - 404   2024.7

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    Language:Japanese   Publisher:大阪 : メディカ出版  

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    Other Link: https://ndlsearch.ndl.go.jp/books/R000000004-I033631540

  • 灌流CTによる急性脳主幹動脈閉塞に対する治療選択の決定

    三原 陸, 金 景成, 纐纈 健太, 井手口 稔, 村井 保夫

    脳血管内治療   8 ( Suppl. )   S692 - S692   2023.11

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    Language:Japanese   Publisher:(NPO)日本脳神経血管内治療学会  

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  • 4D flow MRIをもちいた硬膜動静脈瘻術前の検討

    井手口 稔, 金 景成, 三原 陸, 尾関 友博, 纐纈 健太, 村井 保夫

    脳血管内治療   8 ( Suppl. )   S198 - S198   2023.11

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  • 当施設のMeVOに対する血栓溶解療法と血栓回収療法の治療成績

    青木 大征, 井手口 稔, 三原 陸, 尾関 友博, 纐纈 健太, 金 景成, 村井 保夫

    脳血管内治療   8 ( Suppl. )   S662 - S662   2023.11

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  • 院内発症と病院外発症における急性血栓回収療法治療予後の検討

    井手口 稔, 金 景成, 三原 陸, 尾関 友博, 纐纈 健太, 村井 保夫

    脳血管内治療   8 ( Suppl. )   S669 - S669   2023.11

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