KEIO RESEARCHERS INFORMATION SYSTEM

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Papers 【 Display / hide 】

• Enhanced Precision in Personalized Intraoperative Monitoring of Facial Nerves: A Comparative Analysis of Functional MRI-Guided and Conventional Electrode Placement for Transcranial Motor-Evoked Potentials During Skull Base Surgery.

  Sayanagi T, Tamura R, Tomio R, Sogano J, Karatsu K, Ishikawa K, Kosugi K, Akiyama T, Ueda R, Toda M

  Operative neurosurgery (Hagerstown, Md.)  2026.03

  ISSN  2332-4252

  　View Summary

  BACKGROUND AND OBJECTIVES: – Facial nerve preservation is critical in skull base surgery. Transcranial facial motor-evoked potential (tfMEP) monitoring can be limited by interindividual primary motor cortex (M1) facial cortex variability and intraoperative perturbations. We evaluated a functional MRI (fMRI)–guided, neuronavigation-assisted montage to personalize stimulating electrode placement and reduce thresholds during cerebellopontine angle tumor surgery.METHODS: – In a prospective cohort (n = 20), tfMEPs were recorded simultaneously using 2 montages: (1) fMRI-guided electrode directly over the patient-specific M1 facial hotspot identified by preoperative task fMRI and (2) conventional C3/C4. Train-of-five stimulation elicited compound muscle action potentials from orbicularis oculi/oris. The primary end point was stimulation threshold (mA) to elicit >50 µV, measured at predefined stages (precraniotomy through closure). Secondary analyses assessed threshold changes after durotomy/cerebrospinal fluid (CSF) drainage and postoperative House–Brackmann (HB) grades.RESULTS: – fMRI-guided placement yielded lower baseline thresholds than conventional within patients (mean 65.5 vs 73.5 mA; Δ = −8.9 mA; P < .0001). The advantage persisted at closure (85.3 vs 96.3 mA; P < .0001). After durotomy/CSF drainage, thresholds increased modestly with both montages (+3.3 vs +4.0 mA; between-group P = .65). Monitoring feasibility was 100%, providing continuous data early in the case when direct nerve stimulation was not yet possible. At the latest follow-up, 17/20 (85%) had HB I and 3/20 (15%) HB II; no patient had permanent moderate/severe palsy.CONCLUSION: – Neuronavigation-assisted, fMRI-guided tfMEP reliably targets the individual M1 facial area and significantly lowers stimulation thresholds vs conventional C3/C4, without increasing susceptibility to threshold drift after CSF loss. This simple, adoptable workflow may enhance intraoperative decision making for facial nerve preservation. Larger multicenter studies are warranted to validate outcome prediction and refine threshold-based alarm criteria.

  • Access to Document (DOI)

• Combined presigmoid retrolabyrinthine and retrosigmoid approach for large vestibular schwannoma: a case report.

  Kojima M, Tamura R, Ishikawa K, Sayanagi T, Karatsu K, Ueda R, Toda M

  Frontiers in surgery 13   1817241 - 7 2026

  ISSN  2296-875X

  　View Summary

  Background – The retrosigmoid approach is widely used for vestibular schwannoma resection. If the tumor is large, significant cerebellar retraction may be required, which can cause cerebellar edema. The presigmoid retrolabyrinthine route preserves the labyrinth and reduces cerebellar retraction and manipulation but provides only a narrow surgical corridor. We report the use of a combined approach to safely resect a large vestibular schwannoma with brainstem compression while avoiding complete postoperative deafness. Methods – A 24-year-old man presented with a large right vestibular schwannoma causing considerable brainstem compression. A combined temporal–suboccipital craniotomy with near-total mastoidectomy was performed to expose the sigmoid sinus while preserving the labyrinth. Microsurgical dissection was performed via the retrosigmoid corridor, while a rigid endoscope inserted through the presigmoid route provided direct visualization of the brainstem side. Results – This dual-corridor, dual-visualization technique enabled safe subperineural tumor removal and identification of the facial nerve. Gross total resection was achieved, and the postoperative course was uneventful. At approximately 6 months postoperatively, facial nerve function remained normal (House–Brackmann grade I). Formal postoperative pure-tone audiometry demonstrated residual hearing on the operated side, predominantly in the low-frequency range. Although serviceable hearing was not preserved, complete postoperative deafness was avoided. Conclusion – In large vestibular schwannomas with vertical brainstem extension, retrosigmoid resection alone may require excessive cerebellar retraction. Adding a presigmoid retrolabyrinthine corridor improves brainstem access, minimizes cerebellar retraction and manipulation, and facilitates safe tumor removal. This combined approach is a practical strategy for patients with significant brainstem compression.

  • Access to Document (DOI)

• A Single-center experience of subperineural resection of intracranial schwannomas and the clinical course following subtotal resection.

  Tomioka A, Tamura R, Sogano J, Karatsu K, Ishikawa K, Sayanagi T, Akiyama T, Ueda R, Toda M

  Frontiers in oncology 16   1830390 2026

  ISSN  2234-943X

  • Access to Document (DOI)

• Intraoperative Language mapping in a Japanese-English-French trilingual patient with a left Temporal lobe glioma: a case report.

  Yamamoto K, Tamura R, Ganaha S, Karatsu K, Ishizawa T, Kojima K, Ando M, Kosugi K, Kitamura Y, Ueda R, Ishikawa A, Imanishi T, Tsuji T, Toda M

  Brain structure & function 230 ( 9 ) 184 2025.11

  ISSN  1863-2653

  　View Summary

  Background: Awake surgery with intraoperative language mapping has become increasingly refined, allowing assessment not only of motor but also higher brain functions. Language remains the most critical function to evaluate and preserve. However, reports of multilingual patients undergoing such procedures are still limited, particularly those involving Japanese, a linguistically and structurally unique language. Case description: We present the case of a 32-year-old right-handed multilingual male (Japanese L1, English L2, French L3), a film director and actor, who underwent awake craniotomy for a recurrent low-grade glioma involving the left temporal lobe. Preoperative functional MRI confirmed left hemispheric language dominance across all three languages, although French and English showed broader activation than Japanese during semantic fluency tasks. During surgery, cortical mapping with object naming and reading tasks was performed in Japanese, English, and French. Naming errors were observed in the posterior superior temporal gyrus across all three languages, whereas semantic paraphasia in the posterior middle temporal gyrus and reading impairment in the posterior inferior temporal gyrus were specific to Japanese. Postoperative MRI revealed subtotal resection with preservation of language function. Histopathology confirmed astrocytoma, IDH-mutant, WHO grade 3. Conclusion: This case represents the first report of intraoperative language mapping in a Japanese–English–French trilingual patient, demonstrating both overlapping and language-specific cortical regions. The findings underscore the importance of individualized and multimodal language mapping in multilingual patients, particularly when typologically distant languages such as Japanese are involved.

  • Access to Document (DOI)

• Genetic and clinical characteristics of cranial nerve schwannoma harboring SH3PXD2A-HTRA1 fusion gene.

  Sogano J, Tamura R, Yo M, Nakamura K, Fukada I, Ueno T, Hino U, Tomioka A, Karatsu K, Nagao A, Ueda R, Nishihara H, Toda M

  Acta neuropathologica 150 ( 1 ) 31 2025.09

  ISSN  0001-6322

  　View Summary

  The SH3PXD2A-HTRA1 fusion gene has recently been identified in a subset of schwannomas, but its frequency and clinical significance remain unclear. This study aimed to investigate the prevalence and clinical relevance of this fusion gene in intracranial schwannomas, stratified by cranial nerve of origin. We retrospectively investigated the fusion gene in 237 intracranial schwannomas. Fusion detection was performed using reverse transcription polymerase chain reaction and confirmed by Sanger sequencing. Somatic NF2 status was evaluated using whole-genome sequencing or Merlin immunohistochemistry in fusion gene-positive cases. Clinical characteristics and postoperative tumor recurrence were compared between fusion gene-positive and fusion gene-negative tumors, and subgroup analyses were performed by cranial nerve of origin. The fusion gene was detected in 30 tumors (12.7%), with the highest frequency observed in trigeminal schwannomas (25.9%). Tumors classified as recurrent at baseline (odds ratio [OR], 3.74; P = 0.012), trigeminal nerve origin (OR, 2.88; P = 0.042), and intratumoral hemorrhage (OR, 18.61; P = 0.028) were significantly associated with fusion gene-positive tumors. In the trigeminal schwannomas, fusion gene-positive cases were significantly younger (P = 0.029). In the vestibular schwannomas, recurrence status was found to be independently associated with positive fusion gene status (OR, 4.53; P = 0.010). Furthermore, even after gross or nearly total resection, fusion gene-positive vestibular schwannomas exhibited a significantly higher incidence of recurrence after surgery (P = 0.046). Only 33% of fusion gene-positive tumors indicated somatic NF2 alteration. The SH3PXD2A-HTRA1 fusion gene may define a molecular subset of intracranial schwannomas with distinctive anatomical distribution and biological aggressiveness. It may contribute to tumorigenesis through an alternative pathway independent of NF2. Our findings provide a basis for future clinical investigations.

  • Access to Document (DOI)

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Biomarkers for evaluation of clinical activity of VEGFR-targeted vaccines against malignant brain tumor patients

  Ueda, Ryo

  科学研究費補助金研究成果報告書 2023

• iPS cells producing retroviral replicating vector for malignant glioma

  Ueda, Ryo

  科学研究費補助金研究成果報告書 2023

• Biomarkers for evaluation of clinical activity of VEGFR-targeted vaccines against malignant brain tumor patients

  Ueda, Ryō

  科学研究費補助金研究成果報告書 2020

• Biomarkers for evaluation of clinical activity of VEGFR-targeted vaccines against malignant glioma patients

  Ueda, Ryo

  科学研究費補助金研究成果報告書 2017

• Immunotherapy targeting brain tumor stem cell antigen and niche

  Ueda, Ryo

  科学研究費補助金研究成果報告書 2014

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Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• 【脳神経外科医のための疾患・症状別当直マニュアル】知っておきたい外来対応(疾患・症状編)　めまい・ふらつきを訴える患者

  植田 良, 戸田 正博

  脳神経外科速報 ((株)メディカ出版)  32 ( 2 ) 234 - 238 2022.03

  ISSN  0917-1495

• Pipeline留置後に脳内多発性造影病変を認めた1例

  山田 浩貴, 秋山 武紀, 中屋 雅人, 富岡 あず菜, 植田 良, 戸田 正博

  脳血管内治療 ((NPO)日本脳神経血管内治療学会)  6 ( Suppl. ) S279 - S279 2021.11

  ISSN  2423-9119

• 脳・頭頸部腫瘍塞栓術における難易度のgradingの試み

  秋山 武紀, 水谷 克洋, 高橋 里史, 植田 良, 戸田 正博

  脳血管内治療 ((NPO)日本脳神経血管内治療学会)  6 ( Suppl. ) S21 - S21 2021.11

  ISSN  2423-9119

• 経鼻内視鏡下頭蓋底手術における鼻中隔粘膜弁の再挙上

  小澤 宏之, 関水 真理子, 中村 伸太郎, 御子柴 卓弥, 永井 遼斗, 渡部 佳弘, 植田 良, 戸田 正博, 小川 郁

  日本耳鼻咽喉科学会会報 ((一社)日本耳鼻咽喉科学会)  124 ( 4 ) 641 - 641 2021.04

  ISSN  0030-6622

• 【頭蓋底腫瘍の治療オプション-開頭手術・内視鏡手術・放射線治療】傍鞍部〜蝶形骨縁(髄膜腫)部位による症状と手術適応

  植田 良, 戸田 正博

  Clinical Neuroscience ((株)中外医学社)  39 ( 4 ) 441 - 443 2021.04

  ISSN  0289-0585

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Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• グリオーマ患者血清IgG抗体に認識される精巣組織由来グリオーマ抗原の単離と解析

  植田良，戸田正博，吉田一成，河上裕，河瀬斌

  [Domestic presentation]  第61回日本脳神経外科学会総会, 

  2002.10

  , 

  Oral presentation (general)

• Serological identification of SOX D group proteins as highly immunogenic cancer-testis antigen in glioma

  Ueda Ryo, Toda Masahiro, Kawase Takeshi, Kawakami Yutaka

  [International presentation]  American Association for Cancer Research. Annual Meeting, 

  2002.07

  , 

  Oral presentation (general)

• 精巣組織由来のグリオーマ抗原遺伝子の単離

  植田良，戸田正博，吉田一成，河上裕，河瀬斌

  [Domestic presentation]  第6回Waterfront Neurosurgical Conference, 

  2002.07

  , 

  Oral presentation (general)

• 精巣組織由来の新規グリオーマ抗原の単離

  植田良，戸田正博，吉田一成，河上裕，河瀬斌

  [Domestic presentation]  第23回ニューロオンコロジーの会, 

  2002.07

  , 

  Oral presentation (general)

• Serological identification of SOX6 as highly immunogenic cancer-testis antigen in glioma

  植田良，戸田正博，吉田一成，河瀬斌，河上裕

  [Domestic presentation]  第8回基盤的癌免疫研究会, 

  2002.07

  , 

  Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• 難治性脳腫瘍血管を標的としたペプチドワクチン療法の新規治療効果予測因子の検証

  2024.04

  -

  2027.03

  基盤研究(C), Principal investigator

• 難治性脳腫瘍新生血管を標的としたペプチドワクチン療法の臨床効果予測因子の検証

  2021.04

  -

  2024.03

  Keio University, Grant-in-Aid for Scientific Research (C), No Setting

  　View Summary

  本研究では、難治性脳腫瘍に対するペプチドワクチン療法臨床試験被験者の様々な検体を用いて個々の患者における正・負の免疫動態を総合的に評価し、①同ペプチドワクチン療法の効果が期待できる症例の選出方法開発（免疫療法の有効性を予測するための免疫バイオマーカー探索）、②免疫バイオマーカーにより同免疫療法と抗がん剤との組み合わせなどの免疫制御法の改良技術を評価する。本研究成果は、本治療に対する治療反応性予測を可能にし、治療成績向上につながる可能性がある。また、脳腫瘍免疫および脳腫瘍血管新生・浸潤性における新たな機構の解明につながり、治療困難な脳腫瘍の治療成績の改善に貢献することが期待される。

• 悪性脳腫瘍に対するウイルス搭載iPS細胞を用いた新規治療の開発

  2021.04

  -

  2024.03

  Keio University, Grant-in-Aid for Scientific Research (B), No Setting

  　View Summary

  悪性神経膠腫（グリオーマ）は、グリオーマ幹細胞（GSC）の存在により、強い浸潤性お
  よび治療抵抗性を示す。本研究では、治療抵抗性・浸潤性GCSに追従するiPS細胞由来神経
  幹細胞を、自殺遺伝子搭載複製型ウイルスの”producing cell” かつ“delivery vehicle”として用いる革新的な新規治療法を開発する。

• 悪性脳腫瘍新生血管を治療標的としたペプチドワクチン療法の有効性予測因子の解明

  2018.04

  -

  2021.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

• Biomarkers for evaluation of clinical activity of VEGFR-targeted vaccines against malignant glioma patients

  2015.04

  -

  2018.03

  Keio University, UEDA RYO, TODA MASAHIRO, Grant-in-Aid for Scientific Research (C), No Setting

  　View Summary

  Evaluation of immunological biomarkers may lead to better understanding of the critical immune response indicators that may help to predict clinical responses of cancer immunotherapy. We characterized status of immune cells, cytokines, chemokines, and other immunosuppressive molecules in malignant glioma patients who received vaccinations of VEGF receptor (VEGFR)-derived peptides. Peripheral blood samples from patients who demonstrated positive radiologic response or stable disease revealed superior VEGFR-specific CTL reactivity and lower level of serum VEGF compared to samples from other patients with progressing malignant glioma. Plasma IL-8 level was negatively correlated with overall survival. These data indicate that these parameters may be potential immune-biomarkers for evaluation of clinical activity of VEGFR-targeted vaccines.

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• LECTURE SERIES, NEUROSURGERY

  2026

• CLINICAL CLERKSHIP IN NEUROSURGERY

  2026

• LECTURE SERIES, NEUROSURGERY

  2025

• CLINICAL CLERKSHIP IN NEUROSURGERY

  2025

• LECTURE SERIES, NEUROSURGERY

  2024

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