Yazawa, Masaki

写真a

Affiliation

School of Medicine, Department of Plastic and Reconstructive Surgery （Shinanomachi）

Position

Associate Professor

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Career 【 Display / hide 】

  • 1996.04
    -
    1998.06

    慶應義塾大学医学部研修医（形成外科）

  • 1998.07
    -
    1999.05

    社会保険埼玉中央病院医員（外科）

  • 1999.06
    -
    2000.04

    佐野厚生総合病院医員（外科）

  • 2000.05
    -
    2002.02

    慶應義塾大学助手（医学部形成外科学）

  • 2002.03
    -
    2006.03

    栃木県立がんセンター医員（形成外科）

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Academic Background 【 Display / hide 】

  • 1990.04
    -
    1996.03

    Keio University, 医学部

    University, Graduated

  • 1996.04
    -
    2004.03

    Keio University, 大学院医学研究科博士課程, 外科系形成外科学

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • 博士（医学）（甲）取得（第２２０５号）, Keio University, 2004.02

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Licenses and Qualifications 【 Display / hide 】

  • 医師免許, 1996.05

  • 日本医師会認定産業医, 2003.09

  • 日本形成外科学会専門医, 2004.03

  • 日本頭蓋顎顔面外科学会専門医, 2015.01

  • 日本形成外科学会皮膚腫瘍外科指導専門医, 2015.04

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Papers 【 Display / hide 】

  • Chest wall reconstruction using the pectoralis major flap with dual-partitioned partially cut ribs

    Uchikawa-Tani Yumiko, Yazawa Masaki, Konno Eri, Kishi Kazuo

    JPRAS Open 5   7 - 12 2015.09

    　View Summary

    <p>In some cases, skeletal and soft issue elements are required for chest wall reconstruction. Although muscle flaps and ribs are commonly used for achieving ideal reconstruction, deformation and loss of bone strength are unavoidable in such cases. In the present report, we describe a technique for chest wall reconstruction that can help avoid such donor site deformity. A 59-year-old woman with metastasis of a malignant mixed tumor in the parotid gland underwent resection from the sternoclavicular joint to the first and second ribs, including the manubrium and part of the sternum body. To achieve chest wall reconstruction, we used a pectoralis major flap along with two dual-partitioned ribs. In this modified procedure, instead of simply using the flaps with the whole ribs (which is common), we only used the anterior cortical portion of the ribs. This helped preserve the chest wall strength and prevented deformity at the donor site. At 7 months after surgery, the cut ribs in the reconstructed area and the original donor site appeared stable, without any complications, on computer tomography. Although the thickness of the bone used was half of that used with the conventional method, the skeletal strength was sufficient for her daily activities. Our modified method requires some additional effort for cutting the ribs, but the rest of the procedure involves the use of a conventional, simple rib-muscle flap. With this method, donor site deformity can be prevented, and the procedure can not only be adapted for chest wall reconstruction but also for other skeletal reconstructions that require the use of ribs.</p>

  • Mesh-like incisions are a simple and effective modification of the traditional components separation technique

    Uchikawa-Tani Yumiko, Yazawa Masaki, Kishi Kazuo

    JPRAS Open 5   41 - 45 2015.09

    　View Summary

    <p>The components separation technique (CST) was first described in 1990 and involves elevating the external oblique muscle and medially advancing the muscle complex to close abdominal wall defects. Because this procedure is straightforward and does not require prosthetic materials to repair the defect, many surgeons have adopted it. However, some patients who undergo this technique develop Spigelian herniation or "lateral bulging", which is a projection deformity of the lateral abdominal wall. These patients may require prosthetic reinforcement to strengthen the abdominal wall due to the relaxing incision that is made during the CST. In this report, we describe a simple modification to improve the relaxing incision by substituting several short incisions for the traditional single, long incision in the external oblique fascia. These short incisions create a mesh-like pattern in the fascia, which preserves the strength of the lateral abdominal wall and may help prevent Spigelian herniation or lateral bulging. Although the separation of the external oblique muscle from the internal oblique muscle is slightly cumbersome compared to the traditional CST, the plane is avascular and sparsely connected, which allows separation using a finger or tools in our modified technique. Further studies are needed to confirm whether this technique is effective for large defects, although this simple modification may preserve the strength of the lateral abdominal wall without the need for prosthetic materials.</p>

  • Advantages of superficial femoral vein grafts for carotid artery reconstruction following carotid artery resection in the treatment of head and neck cancer

    Yokoyama Junkichi, Yazawa Masaki, Yoshimoto Hitoshi, Matsuo Seigo, Ohba Shinichi

    Acta Oto-Laryngologica 135 （ 3 ） 302 - 306 2015.03

    ISSN  0001-6489

    　View Summary

    <p>Conclusion: Reconstruction of the carotid artery using the superficial femoral vein (SFV) is very effective due to the ease in harvesting the vessel and its optimal size and length for carotid artery replacement. Objectives: To evaluate the effectiveness of carotid artery reconstruction using the SFV. Methods: Ten patients with malignant tumors involving the carotid artery underwent carotid artery resection followed by reconstruction with the SFV. The SFV between the deep femoral vein and branches to the great saphenous vein and deep femoral vein at the popliteal region was used as a reconstructive vessel. Results: The mean length and diameter of the grafted SFVs were 13.9 cm and 11.2 mm, respectively. The mean time for acquisition of SFV was 18 min. Ultrasonography measurements indicated that the mean lumen diameter of the common carotid artery was 8.37 mm. None of the patients experienced any permanent neurologic complications. The 2-year and 5-year overall survival rates were 60% and 40%, respectively. En bloc resection of the cancer and involved carotid artery followed by reconstruction with the SFV provides effective locoregional control. Our results indicated no postoperative vascular graft thrombosis and no donor site complications.</p>

  • Basic study of soft tissue augmentation by adipose-inductive biomaterial

    Yazawa Masaki, Mori Taisuke, Nakayama Yasuhide, Kishi Kazuo

    Journal of Biomedical Materials Research - Part B Applied Biomaterials 103 （ 1 ） 92 - 96 2015.01

    ISSN  1552-4973

    　View Summary

    <p>Reconstructive surgery for tumor resection, trauma, and congenital anomaly involves volume augmentation with autologous tissue transfer. However, a healthy region is damaged as a donor site, and the autologous tissue is transferred like a patchwork to the recipient site. We have attempted to induce adipogenesis activity in artificial biomaterial that is injectable with an injection needle for soft tissue augmentation. First of all, the optimal dose of pioglitazone hydrochloride was examined with adipo-precursor cells in terms of the proliferator-activated receptor-g mRNA expression levels affected by reagent in vitro. Then, salmon collagen with pioglitazone was adjusted in terms of the dose and the salmon collagen was injected into mouse back using an injection needle in vivo. At 4 weeks after implantation, the pioglitazone collagen gel was substituted by mature adipocytes in comparison with the case for control collagen gel without pioglitazone. These results are indicative of the possibility of promoting adipogenesis using collagen with pioglitazone as an adipose-inductive substance.</p>

  • Anatomic basis of anorectal reconstruction by dynamic graciloplasty with pudendal nerve anastomosis

    Hikosaka Makoto, Yazawa Masaki, Sakuma Hisashi, Uchikawa Yumiko, Takayama Masayoshi, Kishi Kazuo

    Diseases of the Colon and Rectum 58 （ 1 ） 104 - 108 2015

    ISSN  0012-3706

    　View Summary

    <p>BACKGROUND: Dynamic graciloplasty has been proposed for anal reconstruction, but this method has 2 major drawbacks. First, an electrical device is required for control of the gracilis. The anastomosis with the pudendal nerve will provide more physiological control. Second, the limitation in the mobility of the muscle flap results in wrapping the anal canal with the muscle's distal portion, which is tendonlike and inelastic. Enhancing the mobility of the muscle flap will enable wrapping with the proximal, muscle-like, and extensible portion, possibly providing better sphincteric function. However, the basis for such an operative method is lacking. OBJECTIVE: The aim of this study is to provide the basis for the refined method of anal sphincter reconstruction by dynamic graciloplasty with pudendal nerve anastomosis and to verify the feasibility of lengthening the nerve to the gracilis muscle flap by dissecting into the muscle belly, detaching the gracilis muscle from its origin, and enhancing the mobility of the muscle flap. STUDY DESIGN: This is a retrospective, descriptive study. METHODS: The results from the anatomical study on 9 cadavers are reported. RESULTS: Tension-free anastomosis of the pudendal nerve and nerve to the gracilis was successfully performed in all the 9 cases: in 2 cases, by lengthening the nerve. The detachment of the muscle origin improved the mobility of the muscle flap, and the more proximal portion could be used for wrapping the anal canal, as confirmed in 4 cases. LIMITATIONS: The limited number of cases was a shortcoming of this study. CONCLUSIONS: By lengthening the nerve to the muscle, the gracilis can be used for anal sphincter reconstruction with pudendal nerve anastomosis, negating the need for an electrical device. By detaching the origin of the gracilis muscle, its proximal portion can be used to wrap the anal canal, possibly enabling a longer functional canal with stronger constricting force and better vascularity. These modifications to past methods may improve fecal continence after the operation.</p>

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

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Presentations 【 Display / hide 】

  • 多血小板血漿の創傷治癒への応用

    Ogata Hisao, Yazawa Masaki, Kimura Akiko, Nakajima Tatsuo, Watanabe Naohide, Mori Taisuke

    第9回ケロイド・肥厚性瘢痕研究会, 

    2003.03
    , 

    Oral presentation (general)

  • 多血小板血漿の臨床応用−問題点と今後の展望−

    Yazawa Masaki, Ogata Hisao, Kimura Akiko, Nakajima Tatsuo, Mori Taisuke, Watanabe Naohide

    第7回慶應義塾大学医学部形成外科学教室同門会学術集会, 

    2003.02
    , 

    Oral presentation (general)

  • 大きな前方口蓋瘻孔を伴った顎裂に対し歯槽骨骨延長を行った一例

    Sakamoto Teruo, IッShiki Yasunari, Ogata Hisao, Nakajima Tatsuo, Kaneko Tsuyoshi, Satou Hiroko, Yazawa Masaki

    第7回慶應義塾大学医学部形成外科学教室同門会学術集会, 

    2003.02
    , 

    Oral presentation (general)

  • Basic studies on the clinical applications of platelet-rich plasma

    Yazawa Masaki, Ogata Hisao, Nakajima Tatsuo, Watanabe Naohide, Mori Yasumasa

    The International Meeting of the Tissue Engineering Society international, 

    2002.12
    , 

    Poster presentation

  • 多血小板血漿の皮膚創傷治癒に関する基礎的検討

    Kimura Akiko, Ogata Hisao, Nakajima Tatsuo, Yazawa Masaki, Watanabe Naohide, Mori Taisuke

    第11回日本形成外科学会基礎学術集会, 

    2002.10
    , 

    Oral presentation (general)

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

  • 脂肪誘導機能付加生体材料による組織欠損補填療法の開発

    2011.04
    -
    2013.03

    文部科学省, 科学研究費・若手研究（Ｂ）, Research grant, No Setting

  • 自己細胞由来血小板成長因子によるパーソナル治療剤の開発

    2013.04
    -
    2016.03

    文部科学省, 科学研究費・基盤研究（Ｃ）, Research grant, Principal investigator

  • 血小板創製技術の医療応用

    2015.04
    -
    2016.03

    日本医療研究開発機構, 橋渡し研究加速ネットワークプログラム・シーズＢ, Research grant, Coinvestigator(s)

  • 自己細胞由来誘導性血小板成長因子剤によるパーソナル治療

    2016.04
    -
    2019.03

    文部科学省, 科学研究費・基盤研究（Ｃ）, Research grant, Principal investigator

  • 血小板創製技術の医療応用

    2016.04
    -
    2017.03

    日本医療研究開発機構, 橋渡し研究加速ネットワークプログラム・シーズＢ, Research grant, Coinvestigator(s)

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Awards 【 Display / hide 】

  • 第1回日本再生医療学会優秀演題賞

    Yazawa Masaki, 2002.04, 第1回日本再生医療学会, 濃厚血小板液とその担体としてのフィブリン糊に関する実験的研究

  • 第１回日本再生医療学会　優秀演題賞

    2002.04

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Courses Taught 【 Display / hide 】

  • LECTURE SERIES, PLASTIC AND RECONSTRUCTIVE SURGERY

    2024

  • CLINICAL CLERKSHIP IN PLASTIC AND RECONSTRUCTIVE SURGERY

    2024

  • LECTURE SERIES, PLASTIC AND RECONSTRUCTIVE SURGERY

    2023

  • INTRODUCTION TO CLINICAL CLERKSHIPS

    2023

  • CLINICAL TRAINING IN DIAGNOSIS

    2023

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Courses Previously Taught 【 Display / hide 】

  • 形成外科学：悪性腫瘍切除後再建（頭蓋・頭頸部）

    Keio University

    2015.04
    -
    2016.03
    , 

    Full academic year, Lecture

  • 形成外科学：マイクロサージャリー・顔面神経麻痺

    Keio University

    2015.04
    -
    2016.03
    , 

    Full academic year, Lecture

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