Okubo, Toshiki

写真a

Affiliation

School of Medicine, Department of Orthopaedic Surgery ( Shinanomachi )

Position

Instructor
Scopus Paper Info  
Paper Count: 57 Citation Count: 500 h-index: 7

Click to view the Scopus page. The data was downloaded from Scopus API in March 08, 2026, via http://api.elsevier.com and http://www.scopus.com .

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Career 【 Display / hide 】

  • 2009.04
    -
    2010.03

    Tokyo Dental Collage Ichikawa General Hospital, 初期臨床研修医

  • 2010.04
    -
    2011.03

    Keio University Hospital, 初期臨床研修医

  • 2011.04
    -
    2011.06

    Department of Orthopaedics Surgery, Keio University School of Medicine

  • 2011.07
    -
    2012.09

    Department of Orthopaedics Surgery, Nasu Red Cross Hospital

  • 2012.10
    -
    2014.03

    Department of Orthopaedics Surgery, Tokyo Dental Collage Ichikawa General Hospital

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Research Keywords 【 Display / hide 】

  • Regenerative medicine

  • Pain control

  • Spine and spinal cord

  • Regeneration of spinal cord

  • Spinal cord injury

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Papers 【 Display / hide 】

  • Inferior Outcomes of Posterior Correction and Fusion Surgery for Adults With Residual Lenke Type 5 Adolescent Idiopathic Scoliosis: A Comparative Study With Adolescents

    Shibata R., Suzuki S., Takeda K., Iga T., Okubo T., Ozaki M., Tsuji O., Nagoshi N., Matsumoto M., Nakamura M., Watanabe K.

    Global Spine Journal 16 ( 2 ) 1059 - 1066 2026.03

    ISSN  21925682

    　View Summary

    Study Design: Retrospective cohort study. Objective: This study aimed to determine whether the outcomes of posterior correction and fusion surgery (PSF) in patients with residual adolescent idiopathic scoliosis (AIS) during adulthood (Lenke type 5 AdIS) are inferior to those in patients with AIS treated during adolescence. Methods: We retrospectively evaluated 48 patients with type 5 AdIS who underwent PSF after 20 years old. As controls, we selected 67 patients with type 5 AIS who underwent PSF before 18 years old. Both groups were matched based on the preoperative thoracic and thoracolumbar/lumbar Cobb angles, resulting in 33 patients in each group. We compared preoperative and postoperative radiographic parameters and SRS-22 scores between the 2 groups. Results: Preoperatively, the AdIS group had significantly lower flexibility index (59.0% ± 13.0% vs 66.6% ± 16.7%; P = 0.01). The preoperative SRS-22 scores for pain and mental health domain were significantly worse in the AdIS group (pain, 3.9 ± 0.8 vs 4.3 ± 0.7, P < 0.01; mental health, 3.6 ± 0.8 vs 4.2 ± 0.6, P < 0.01). The AdIS group had significantly more fused vertebrae and longer intraoperative time than the AIS group. Postoperatively, lumber Cobb angle (16.1° ± 5.6° vs 8.6° ± 4.0°, P < 0.01) and correction rate were both less favorable in the AdIS group. Both pain and mental health scores remained significantly worse in the AdIS group (pain: AdIS, 4.3 ± 0.6 vs AIS, 4.7 ± 0.3; P < 0.01; mental health: AdIS, 4.1 ± 0.7 vs AIS, 4.5 ± 0.5; P = 0.02). Conclusion: Patients with type 5 AdIS had a similar correction of the major curve as those with AIS; however, the surgery was more invasive, with inferior postoperative clinical outcomes, than those with AIS. These findings suggest that the surgical timing should be carefully considered in patients with type 5 AIS to optimize outcomes.

  • Ten-Year Clinical Outcomes After Decompression Surgery for Lumbar Spinal Stenosis: The Impact of Preoperative Modic Changes

    Watanabe K., Fujii T., Michikawa T., Iga T., Okubo T., Takeda K., Suzuki S., Ozaki M., Tsuji O., Nagoshi N., Matsumoto M., Nakamura M.

    Global Spine Journal 16 ( 2 ) 918 - 927 2026.03

    ISSN  21925682

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    Study Design: Retrospective Cohort Study. Objective: Modic changes (MCs) have been associated with low back pain; however, their prognostic value in surgical outcomes—particularly in patients with lumbar spinal stenosis (LSS) treated with decompression alone—remains unclear. Few studies have investigated the progression and long-term clinical impact of MCs. This study aimed to evaluate the 10-year progression of MCs and their association with clinical outcomes following posterior decompression surgery for LSS. Methods: This study included 62 patients who underwent posterior decompression for LSS and completed a 10-year follow-up with MRI and clinical assessments. MCs and disc degeneration were evaluated using standardized MRI criteria. Japanese Orthopaedic Association (JOA) scores and recovery rates were assessed preoperatively and at follow-up. Outcomes were compared between Modic-negative patients and those with preoperative Modic Type 1 or Type 2 changes. Analysis of covariance adjusted for confounding variables. Results: The prevalence of MCs increased from 37.1% preoperatively to 74.2% at 10 years. Type 1 changes were dynamic, often progressing to Type 2 or 3. Type 2 changes were more stable and associated with significantly lower postoperative JOA scores and recovery rates compared to Modic-negative or Type 1 patients (P < 0.05), after adjustment for age, sex, sagittal alignment parameters, and disc degeneration. Type 2 MCs were also linked with minimal improvement in back pain. Conclusion: Modic changes, particularly Type 2, are associated with inferior long-term outcomes. These findings suggest that Modic Type 2 may serve as a prognostic marker of advanced degeneration and may be associated with reduced recovery following decompression surgery.

  • Clinical characteristics and surgical outcomes of intradural spinal metastases: a comparative analysis between intramedullary and extramedullary lesions

    Okubo T., Nagoshi N., Iga T., Takeda K., Ozaki M., Suzuki S., Matsumoto M., Nakamura M., Watanabe K.

    Journal of Neuro Oncology 176 ( 3 )  2026.02

    ISSN  0167594X

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    Purpose: Intradural spinal metastases, including intramedullary (IM) and intradural extramedullary (IDEM) lesions, are rare manifestations of advanced systemic malignancy, and the role of surgery remains controversial. This study aimed to clarify how anatomical compartments influence surgical intent, feasibility, and postoperative neurological outcomes. Methods: We retrospectively reviewed fifteen consecutive patients who underwent surgery for intradural spinal metastases between 2010 and 2024. Lesions were classified as IM (n = 6) or IDEM (n = 9). Clinical presentation, operative characteristics, extent of resection, and adjuvant therapy were evaluated. Neurological function was assessed using the modified McCormick scale (MMCS) before and after surgery. Results: IM lesions were more frequently associated with severe preoperative neurological impairment and were predominantly located in the thoracic spine, whereas IDEM lesions were distributed across cervical, thoracic, and lumbar levels. Gross total resection was achieved more often in IDEM lesions (44.4%) than in IM lesions (16.7%). Postoperatively, neurological function improved in 5 patients (33.3%), remained stable in 6 (40.0%), and deteriorated in 4 (26.7%). Although improvement occurred in both groups, IDEM lesions more often achieved a favorable final functional status (MMCS grades I–II), whereas IM lesions frequently showed limited functional recovery. No perioperative complications were observed. Conclusions: Surgical intervention for intradural spinal metastases may be considered selectively as part of a multidisciplinary palliative strategy focused on neurological function. Anatomical compartment influences surgical feasibility, intent, and achievable outcomes. IDEM lesions may allow resection with functional recovery in selected patients, whereas IM lesions generally require a conservative, function-preserving approach with clearly defined goals.

  • Identification of Risk Factors for Long-Term Surgical Outcomes Following Laminoplasty for Cervical Ossification of the Posterior Longitudinal Ligament

    Otomo N., Nagoshi N., Yamane J., Kono H., Miyamoto A., Takeda K., Yamamoto T., Shibata R., Nishimura S., Kamata Y., Daimon K., Okubo T., Kobayashi Y., Iga T., Suzuki S., Ozaki M., Matsumoto M., Nakamura M., Watanabe K.

    Global Spine Journal 16 ( 1 ) 446 - 455 2026.01

    ISSN  21925682

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    Study Design: Retrospective multi-institutional study. Objectives: Although previous studies have evaluated the surgical outcomes of laminoplasty in patients with cervical ossification of the posterior longitudinal ligament (OPLL), the long-term results remain unclear. The purpose of this study is to assess outcomes more than 10 years post-surgery and identify to identify factors that affect the long-term prognosis. Methods: Eighty-four OPLL patients with more than a minimum of 10-year follow-up after surgery were divided into a good group with more than 50% improvement of the recovery rate of the cervical Japanese Orthopaedic Association (JOA) score, and a poor group with less than 50% improvement. The demographic data and radiographic parameters of cervical spinal alignment were compared, and significant poor prognostic factors were evaluated by multivariate logistic regression. Results: Four preoperative factors showed significant differences between 2 groups: the presence of type 2 diabetes (P = 0.012), the baseline JOA scores (P = 0.001), the narrowest segment in the cervical (P < 0.001) and the presence of T2-weighted high signal on MRI (P = 0.030). Logistic regression analysis identified 3 of 4 factors were significantly associated with postoperative poor outcomes: the presence of type 2 diabetes (P = 0.011), the baseline JOA scores (P = 0.022), and the presence of T2-weighted high signal on MRI (P = 0.035). Conclusion: This study identified three risk factors associated with poor long-term surgical outcomes following laminoplasty for cervical OPLL. These findings could be significant indicators for predicting long-term outcomes in cervical OPLL patients.

  • Comparative analysis of MRI features and surgical outcomes between intramedullary and extramedullary schwannomas in the spinal cord

    Kitagawa T., Nagoshi N., Hase M., Okubo T., Iga T., Takeda K., Ozaki M., Suzuki S., Tsuji O., Matsumoto M., Nakamura M., Watanabe K.

    Spinal Cord 63 ( 11 ) 607 - 612 2025.11

    ISSN  13624393

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    Study Design: A retrospective comparative study. Objectives: To clarify the distinctive magnetic resonance imaging (MRI) features and surgical outcomes of intramedullary schwannoma (IMS) compared to extramedullary schwannoma (EMS) in the spinal cord. Setting: Hospital in Tokyo, Japan. Methods: 19 cases each of IMS and EMS were matched by propensity score from a cohort of spinal cord tumor patients treated between 2008 and 2022. Preoperative MRI images were meticulously analyzed for general values and distinctive features at the tumor-spinal cord interface. Surgical outcomes were assessed based on neurological function, visual analogue scale (VAS), and recurrence rates. Results: IMS and EMS exhibited similar MRI intensity patterns on T1- and T2-weighted images, but differed significantly in features surrounding the tumor, such as rough boarder (IMS: 78.9%, EMS: 5.3%, P value < 0.001) and peritumoral edema (IMS: 57.9%, EMS: 10.5%, P value = 0.005). Postoperatively, IMS cases showed substantial neurological improvement, with no recurrences following gross total resection (GTR). However, residual pain at the segmental level persisted more commonly in IMS compared to EMS (postoperative VAS, IMS: 45.0 ± 34.3, EMS: 19.7 ± 26.8, P value = 0.017). Conclusions: The distinct MRI features identified, particularly the observation of the border with the spinal cord, offer valuable insights for differentiating IMS from EMS preoperatively. Although IMS results in improved neurological function with no recurrence following GTR, attention must be given to residual pain.

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Reviews, Commentaries, etc. 【 Display / hide 】

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Awards 【 Display / hide 】

  • EUROspine-JSSR traveling fellowship

    2025

    Type of Award： Other

  • 東京都医師会 医学研究賞奨励賞

    2018

    Type of Award： Award from publisher, newspaper, foundation, etc.

  • Cervical Spine Research Society (CSRS) 2018 1st place Basic Science Research Award

    2018

    Type of Award： Award from international society, conference, symposium, etc.

  • International spinal cord society (ISCoS) 2018 Postdoctoral Fellow Award

    2018

    Type of Award： Award from international society, conference, symposium, etc.

  • International Society for Stem Cell Research (ISSCR) Travel Award

    2017

    Type of Award： Award from international society, conference, symposium, etc.

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