Tatsuo Igarashi

Chiba University, Tiba, Chiba, Japan

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Publications (181)277.73 Total impact

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    ABSTRACT: Background: Laparoscopic and robot-assisted surgeries are performed under carbon dioxide insufflation. Switching from gas to an isotonic irrigant introduces several benefits and avoids some adverse effects of gas insufflation. We developed an irrigating device and apparatus designed for single-incision laparoscopic surgery and tested its advantages and drawbacks during surgery in a porcine model. Materials and methods: Six pigs underwent surgical procedures under general anesthesia. A 30-cm extracorporeal cistern was placed over a 5-6-cm abdominal incision. The abdomen was irrigated with warm saline that was drained via a suction tube placed near the surgical field and continuously recirculated through a closed circuit equipped with a hemodialyzer as a filter. Irrigant samples from two pigs were cultured to check for bacterial and fungal contamination. Body weight was measured before and after surgery in four pigs that had not received treatments affecting hemodynamics or causing diuresis. Results: One-way flow of irrigant ensured laparoscopic vision by rinsing blood from the surgical field. Through a retroperitoneal approach, cystoprostatectomy was successfully performed in three pigs, nephrectomy in two, renal excision in two, and partial nephrectomy in one, under simultaneous ultrasonographic monitoring. Through a transperitoneal approach, liver excision and hemostasis with a bipolar sealing device were performed in three pigs, and bladder pedicle excision was performed in one pig. Bacterial and fungal contamination of the irrigant was observed on the draining side of the circuit, but the filter captured the contaminants. Body weight increased by a median of 2.1% (range, 1.2-4.4%) of initial weight after 3-5 hours of irrigation. Conclusions: Surgery under irrigation is feasible and practical when performed via a cistern through a small abdominal incision. This method is advantageous, especially in the enabling of continuous and free-angle ultrasound observation of parenchymal organs. Adverse effects of abdominal irrigation need further assessment before use in humans.
    No preview · Article · Jan 2016 · Journal of Laparoendoscopic & Advanced Surgical Techniques
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    ABSTRACT: The purpose of this study is to design a new surgical scissors handle and determine its effectiveness with various usability indices. A new scissors handle was designed that retains the professional grip but has the shapes of the eye rings modified to fit the thumb and ring finger and finger rests for the index and little finger. The newly designed scissors and traditional scissors were compared by electromyography, subjective evaluation and task performance in experiments using cutting and peeling tasks. The newly designed scissors reduced muscle load in both hand during cutting by the closing action, and reduced the muscle load in the left hand during peeling by the opening action through active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load. The newly designed scissors used in this study demonstrated high usability. Practitioner Summary: A new scissors handle was designed that has the eye rings modified to fit the thumb and ring finger. The newly designed scissors reduced muscle load and enabled active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load.
    No preview · Article · May 2015 · Ergonomics
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    ABSTRACT: Single-agent interferon (IFN) is no longer regarded as a standard option for first-line systemic treatment of metastatic renal cell carcinoma (RCC) in Western countries. However, some patients with favorable-risk RCC may still achieve complete and long-lasting remission in response to IFN treatment. The present study compared favorable-risk Japanese patients with metastatic RCC Japanese patients who had been treated with IFN or tyrosine kinase inhibitor (TKI) therapy as a first-line systemic therapy. From 1995 to 2014, a total of 48 patients with favorable risk as defined by the Memorial Sloan Kettering Cancer Center criteria who did not receive adjuvant systemic therapy were retrospectively enrolled in this study. We assessed the tumor response rate, progression-free survival (PFS), and overall survival (OS). The objective response rate for first-line therapy was 29% in the IFN group and 47% in the TKI group, but this difference did not reach the level of statistical significance. Median OS for IFN and TKI was 71 and 47 months, respectively (p=0.014). Median first-line PFS for IFN and TKI was 20 and 16 months, respectively (no significant difference). First-line IFN therapy did not prove inferior to TKI therapy in terms of OS according to metastatic sites. IFN is associated with a survival benefit in Japanese patients with favorable-risk metastatic RCC in the era of targeted therapy. Further prospective study is needed.
    Full-text · Article · Mar 2015 · Korean journal of urology
  • Takuro Ishii · Kazuyoshi Nakamura · Yukio Naya · Tatsuo Igarashi
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    ABSTRACT: Abstract Introduction: Transurethral surgery is widely accepted as standard therapy for male urethral obstruction. The present study was undertaken to identify and select lesions to be managed by processing endoscopic images of the urethra for assisting less invasive therapy in patients with voiding dysfunction. Material and methods: Cystourethroscopic video files of 25 patients with lower urinary tract symptoms were recorded before and after administration of alpha-1 adrenoceptor antagonists. Each video frame was restored and tagged with information indicating the position in the panoramic image of the urethra. A three-dimensional virtual urethra was created to indicate critical lesions for voiding dysfunction, together with fluid dynamics simulation of urine flow. Results: The urine stream was depicted in the virtual urethras in 19 patients. Before therapy, 17 patients showed vortex formation that was diminished after therapy in nine patients with a significant relationship in improvement of relative energy loss of flow (p=0.025). The narrowing points proximal to the vortex, candidate of lesions, were identified in the panoramic image and linked to the endoscopic image. Discussion: Therapeutic designing for endoscopic management was possible in patients with voiding dysfunction based on computational fluid dynamics, and would be promising as "focal" therapy for aging males.
    No preview · Article · Oct 2014 · Minimally Invasive Therapy & Allied Technologies
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    ABSTRACT: Voiding dysfunction is a common disease among the elderly male population. However, few studies have elucidated the flow dynamics of the disease mechanism. We attempted to clarify the fluid dynamics of urine in the prostatic urethra (PU) in patients with bladder outlet obstruction (BOO), a common disease associated with voiding dysfunction. A model of normal PU and three phase models following the BOO progression were prepared using 3D CAD software tracing cystourethroscopic images. In fluid dynamics computation, the normal detrusor pressure was applied to the bladder side in each model. Results of fluid simulation were compared for flow trajectory line, fluid energy dynamics using Bernoulli's principle and pressure loss coefficient. In the BOO model, a large vortex was observed adjacent to the bladder outlet (BO) with increased hydraulic energy loss during the passage through the tract. In contrast, opening of the BO eliminated the vortex with reduction of hydraulic energy loss. These results corresponded with clinical data measured by catheterized pressure sensors inserted into the urethra, and those of urethral diameter measured by urethrography. Fluid dynamics simulation using CAD models can clarify the mechanism of voiding dysfunction in a less invasive and more acceptable way in patients with BOO.
    No preview · Article · May 2014 · Journal of Mechanics in Medicine and Biology
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    ABSTRACT: Voiding dysfunction is common in the aged male population. However, the obstruction mechanism in the lower urinary tract and critical points for obstruction remains uncertain. The aim of this paper was to develop a system to investigate the relationship between voiding dysfunction and alteration of the shape of the prostatic urethra by processing endoscopic video images of the urethra and analyzing the fluid dynamics of the urine stream. A panoramic image of the prostatic urethra was generated from cystourethroscopic video images. A virtual 3-D model of the urethra was constructed using the luminance values in the image. Fluid dynamics using the constructed model was then calculated assuming a static urethra and maximum urine flow rate. Cystourethroscopic videos from 11 patients with benign prostatic hyperplasia were recorded around administration of an alpha-1 adrenoceptor antagonist. The calculated pressure loss through the prostatic urethra in each model corresponded to the prostatic volume, and the improvements of the pressure loss after treatment correlated to the conventional clinical indices. As shown by the proposed method, the shape of the prostatic urethra affects the transporting urine fluid energy, and this paper implies a possible method for detecting critical lesions responsible for voiding dysfunction. The proposed method provides critical information about deformation of the prostatic urethra on voiding function. Detailed differences in the various types of relaxants for the lower urinary tract could be estimated.
    No preview · Article · Jan 2014 · IEEE Journal of Translational Engineering in Health and Medicine
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    ABSTRACT: Laparoscopic surgery remains a challenging procedure because visualization of the internal target organ cannot be achieved from the laparoscopic image. We have proposed a laparoscopic surgery support method relying on three-dimensional (3D) images reconstructed using a stereo laparoscope and a 3D ultrasound system. The aim of this study is to develop a visualization system providing depth information about blood vessels within the liver. The shape and depth information of blood vessels are then correctly superimposed on a 2D laparoscopic image on the basis following careful registration. The coordinates of the laparoscope and the ultrasound are registered by aligning the two 3D liver surface shapes obtained by a stereo laparoscope and an ultrasonic diagnostic equipment with a mechanically moved convex probe using multiple image processing techniques. Then, the shape and depth information within the liver are calculated, and color-coded blood vessel depth information is superimposed on the original 2D laparoscopic image. In a phantom experiment, the registered 3D images were the mean squared error (MSE) of 5.89 ± 3.11 mm. The 2D laparoscopic image was superimposed the color-coded depth of the blood vessels segmented from the 3D ultrasonic data. The calculation of depth information had the MSE of 1.88 ± 1.40 mm.
    No preview · Conference Paper · Jul 2013
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    ABSTRACT: Recently, a number of methods have been developed that make it possible to estimating elasticity and flexibility of lower urinary tract. However, those methods failed to estimate elasticity of bladder outlet directly. This paper describes a novel method for female bladder neck elasticity and flexibility estimation based on cystourethroscopic image. The first step is to extract edges from the original image based on Canny detector and morphological operations. The region of interest (ROI) was defined as the lowest part of the detected edge. The results of edge detection were compared with the original image in order to check the accuracy of proposed method. The deformation was defined as the vertical movement of certain points in which correspond to bladder neck outlet. Furthermore, the elasticity estimation may be acquired by taking the Fourier transform of the deformation wave. The experimental results indicate that this method is able to detect the deformation. By extracting the deformation, it is possible to define the vibration caused by intermittent irrigation. This vibration is expected to have correspondence to its elasticity and flexibility. Finally, directions for future work are suggested.
    No preview · Article · Mar 2013 · Journal of Medical Imaging and Health Informatics
  • Tatsuo Igarashi · Masayuki Teranuma · Takuro Ishii
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    ABSTRACT: A new surgical system that irrigates abdominal cavity during operation was introduced with special attention to overage of hemorrhage using an extracorporeal cisterna set on the small incision of the abdomen. Standard surgical maneuver was done successfully, including cutting, dissecting and cessation of hemorrhage. The article refers to present status about abdominal irrigation or lavage in various therapeutic modalities, its advantages and draw backs, and its impact in promoting new modality of surgeries.
    No preview · Article · Mar 2013 · Journal of Medical Imaging and Health Informatics
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    Satoki Zenbutsu · Tatsuo Igarashi · Tadashi Yamaguchi
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    ABSTRACT: Laparoscopic surgery is a challenging surgical operation because inside information about the target organ cannot be fully understood from the laparoscopic image. In this study, a fusion technique of surface information of a laparoscope and inside blood vessel information of ultrasound is proposed for guidance during laparoscopic surgery. The proposed technique can display the blood vessel depth inside of the target organ by projecting the ultrasonic image over a laparoscopic image. The registration of the laparoscopic and ultrasonic images is performed by registering the surface of the target organ, which is found in the ultrasonic volumetric data and stereoscopic images acquired by the stereo laparoscope. The performance of the proposed technique was evaluated experimentally using a tissue-mimicking phantom. The total computation time was 8.61 s on a personal computer (Xeon processor, 3 GHz CPU). The location of the blood vessel including depth information permits the visualization of risky areas during laparoscopic surgery.
    Full-text · Article · Mar 2013 · Journal of Medical Imaging and Health Informatics

  • No preview · Article · Mar 2013 · Journal of Medical Imaging and Health Informatics
  • Takuya Akagi · David Gomez · Jose Gonzalez · Tatsuo Igarashi · Wenwei Yu

    No preview · Chapter · Jan 2013
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    Tatsuo Igarashi

    Preview · Article · Dec 2012 · International Journal of Urology
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    Tatsuo Igarashi

    Preview · Article · Jun 2012 · International Journal of Urology
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    ABSTRACT: To examine the efficacy of an alpha-1 blocker and its correlation to structural alteration of the prostatic urethra and the loss of energy in the urine flow using a virtual urethra processed from an endoscopic video image. Video images of the prostatic urethra were recorded during cystourethroscopy in 11 patients with benign prostatic hyperplasia (BPH) before and after treatment with an alpha-1 blocker, naftopidil. The three-dimensional (3D) structure of the prostatic urethra was reproduced from video files. Fluid dynamic analysis and hydraulic energy calculations were performed using the "virtual" 3D urethral images. In 9 of 11 patients studied, an 11% improvement in the loss of energy (range, 1%-82%) was seen. Alpha-1 blocker treatment mediated the disappearance or decrease of the bulky vortex formation in seven patients, which led to an improved urinary stream. A positive correlation was found between improved energy loss and residual urine volume (P=0.0312). Alpha-1 blocker therapy led to a decreased energy loss in the urine flow in the prostatic urethra in relation to the improvement of clinical symptoms. The cystourethroscopy could be a tool to assess the urethral resistance in patients with BPH using image processing methodology.
    No preview · Article · Apr 2012 · Journal of endourology / Endourological Society

  • No preview · Article · Feb 2012 · European Urology Supplements
  • Tetsuro Onishi · Hiroyoshi Suzuki · Tatsuo Igarashi
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    ABSTRACT: We present a patient showing favourable response after combination treatment with interferon-α (IFN- α) and cyclooxygenase-2 (Cox-2) inhibitor (celecoxib) against metastatic renal cell carcinoma (RCC). The patient underwent left radical nephrectomy for RCC on 18th April, 2005. On follow-up computed tomographic scan, mediastinal metastasis was detected 3 years after nephrectomy, and metastasectomy was performed. The histological features were clear cell carcinoma as was the primary RCC, and immunohistochemical analysis revealed negative for Cox-2 staining both the primary and metastatic lesions. Aiming at the treatment of residual mediastinal RCC, the patient started to receive IFN-α, and this cytokine therapy lasted for 1 year and 2 months. Nevertheless, the outcome was progression of disease (PD), namely, new lung field lesions were observed. A different type of IFN-α treatment also resulted in PD. Based upon these results, a combination of IFN-α and Cox-2 inhibitor was newly adopted for treatment. After the combination therapy for 3 months, 68.75% of metastases disappeared. We concluded that Cox-2 inhibitor is a potent medicine in combination with IFN-α for metastatic lung tumour from RCC.
    No preview · Article · Jan 2012 · Hinyokika kiyo. Acta urologica Japonica

  • No preview · Article · Jan 2012
  • Takuro Ishii · Satoki Zenbutsu · Tatsuo Igarashi

    No preview · Conference Paper · Jan 2012
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    ABSTRACT: Recent surgical techniques have been advancing under endoscopic view and insufflation of carbon dioxide gas to expand the abdominal cavity. Isotonic fluid could be one candidate for expanding cavities to facilitate surgical maneuvering. We tested the feasibility and drawbacks of replacement of irrigating materials using a porcine model (water-filled laparoendoscopic surgery [WAFLES]). Laparoscopic cholecystectomy was performed in two porcine models using instillation of sorbitol solution as irrigant. Solution irrigation was performed through one of four ports, with drainage via another port. Conventional forceps equipped with a monopolar electrode for electrocautery, laparoscope, video processor, ultrasound, and transducer for measuring intraabdominal pressure were used. Laparoscopic cholecystectomy was successfully undertaken with the following benefits: (1) clear observation of the dissecting plane throughout maneuvering; (2) control of oozing and spilled bile by irrigation and suction; and (3) ultrasonographic and laparoscopic images can be obtained simultaneously without any restriction to probe location. However, two disadvantages should be noted: (1) difficulties in managing floating organs and (2) interruption of vision by blood. WAFLES provides some benefits for endoscopic surgery with proper devices, including apparatuses for irrigation and suction. Efficient irrigation and selection of proper irrigant and apparatuses are required to establish an acceptable procedure.
    No preview · Article · Dec 2011 · Journal of Laparoendoscopic & Advanced Surgical Techniques

Publication Stats

2k Citations
277.73 Total Impact Points


  • 1984-2016
    • Chiba University
      • • Department of Urology
      • • Graduate School of Engineering
      • • Division of Artificial Systems Science
      • • Research Center for Frontier Medical Engineering
      • • Graduate School of Medicine
      Tiba, Chiba, Japan
  • 2009
    • Seirei Sakura Citizen Hospital
      Сакура, Chiba, Japan
  • 2008
    • National Defense Medical College
      • Division of Urology
      Tokorozawa, Saitama, Japan
  • 2000-2008
    • Chiba University Hospital
      Tiba, Chiba, Japan
  • 1987-2005
    • Asahi General Hospital
      Asahi, Chiba, Japan
  • 2002
    • Kyushu University
      Hukuoka, Fukuoka, Japan
  • 2001
    • Keio University
      • Department of Urology
      Edo, Tokyo, Japan
  • 1986
    • Toyama Medical and Pharmaceutical University
      Тояма, Toyama, Japan