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Yamashita, Hiromasa*; Oka, Kiyoshi; Yamanaka, Noriaki*; Seki, Takeshi; Kim, K.*; Kuwana, Kenta*; Masamune, Ken*; Naganawa, Akihiro*; Dohi, Takeyoshi*; Chiba, Toshio*
Nihon Reza Igakkai-Shi, 33(2), p.122 - 130, 2012/08
no abstracts in English
Oka, Kiyoshi; Seki, Takeshi; Naganawa, Akihiro*; Yamashita, Hiromasa*; Kim, K.*; Chiba, Toshio*
Minimally Invasive Therapy and Allied Technologies, 19(2), p.94 - 99, 2010/04
Times Cited Count：6 Percentile：30.06(Surgery)We developed a new laser device using a composite-type optical fiberscope for laser surgery to treat twin-twin transfusion syndrome. The composite-type optical fiberscope (2.2 mm in external diameter) consists of a centrally located single fiber for laser treatment (0.1mm in diameter) and its surrounding fibers for diagnosis. This fiberscope enables transmission of 40-W Yb fiber laser. The Yb fiber laser can be focused to 10 mm focal length using two lenses on the tip of the fiberscope. In this research, we emitted the laser to in vivo porcine mesenteric vessel with blood flow both with an established laser fiber of 0.6-mm diameter (0.6-mm normal fiber) and with our composite-type optical fiberscope to compare the cautery performance of those devices.
Seki, Takeshi*; Oka, Kiyoshi; Naganawa, Akihiro*; Yamashita, Hiromasa*; Kim, K.*; Chiba, Toshio*
Minimally Invasive Therapy and Allied Technologies, 18(6), p.350 - 355, 2009/12
Times Cited Count：3 Percentile：16.09(Surgery)Fetoscopic laser photocoagulation of chorionic plate anastomosing vessels (FLPC) applies to the treatment of previable fetuses with severe twin-twin transfusion syndrome (TTTS). However, there has not been an established method to confirm that the blood flow is blocked. For this issue, we have developed a composite-type optical fiberscope (2.2 mm in diameter). This fiberscope enables transmission of 50 W Yb fiber laser which can be focused to 10 mm focal length using two lenses on the fiberscope tip. In this study, we combined the fiberscope and a laser blood-flow meter, and irradiated cautery laser to porcine mesenteric vein with measuring blood flow at the same time. From the experimental results, we could quantitatively measure the blood flow before and after laser irradiation, and confirm the blood flow blocking with our system.
Oka, Kiyoshi; Naganawa, Akihiro*; Yamashita, Hiromasa*; Nakamura, Tetsuya*; Chiba, Toshio*
Lecture Notes in Computer Science 5128, p.251 - 259, 2008/00
We present our new laser device for prospective human fetoplacental surgery including that of twin-twin transfusion syndrome. We developed acomposite-type optical fiberscope (2.2-mm in diameter) that enables transmission of 40-W Yb fiber laser light alongside of coaxial fetoscopic images. Using a laser condensing lens on the fiberscope tip, Yb fiber laser light can be focused 10-mm off. Using porcine liver tissue, despite changes in delivered laser energy, the diameter and depth of cauterized areas remained constant when the liver position agreed with the laser focal point, although the laser output altered the extent of tissue ablation. In conclusion, the performance of the fiberscope can be well controlled with accurate and efficient ablation of the target tissue. This Yb fiber laser fiberscope is expected to work much better if mounted on a miniature bending manipulator and if provided with additional functions (realtime distance and blood flow measurements).
Oka, Kiyoshi; Yamashita, Hiromasa*; Nakamura, Tetsuya*; Ueda, Hirohisa*; Chiba, Toshio*
no journal, ,
In fetoscopic laser photocoagulation of placental communicating vessels (FLPC) for twin-to-twin transfusion syndrome (TTTS), there are several technical issues. These include; (1) laser light diffusion that reduces the energy density over the placental surface, (2) unknown distances between the placental surface and laser fiber tip, (3) difficulties in assessing actual flow of the targeted blood vessels, and (4) difficulties in controlling laser light direction for perpendicular irradiation. To settle these problems, we successfully developed a new small composite-type optical fiberscope. In this report, we present our experimental outcomes to assess its clinical availability/feasibility for clinical TTTS laser surgery.
Oka, Kiyoshi; Nakamura, Tetsuya*; Ueda, Hirohisa*; Toriya, Tomoaki*; Tsumanuma, Koji*; Naganawa, Akihiro*; Watanabe, Shinsuke*; Ishiyama, Akihiko*; Yamashita, Hiromasa*; Chiba, Toshio*
no journal, ,
no abstracts in English
Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi; Yamashita, Hiromasa*; Chiba, Toshio*
no journal, ,
We developed a new laser device using the composite-type optical fiberscope for laser surgery for twin-twin transfusion syndrome. A composite-type optical fiberscope (2.2 mm in diameter) consists of a centrally located single fiber for laser treatment and its surrounding fibers for diagnosis. This fiberscope enables transmission of 50-W Yb fiber laser. The Yb fiber laser can focus laser to 10 mm focal length using two lenses on tip of the fiberscope. In this paper, we describe the experimental results of temperature control during blood-flow interception of porcine mesenteric venous flow and measure blood flow before and after laser irradiation for evaluation blood flow interception.
