Kazuhiro Yasuda

Oita University, Ōita, Ōita, Japan

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Publications (80)187.15 Total impact

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    ABSTRACT: Steady pressure automatically controlled endoscopy (SPACE) is a new modality that eliminates on-demand insufflation but enables automatic insufflation in the gastrointestinal tract. Though its use in porcine esophageal ESD was reported to be promising, its applicability and potential effectiveness to gastric procedures have not been evaluated. The aims were (1) to evaluate feasibility and safety of SPACE in the stomach, and (2) to assess its potential advantages over conventional endoscopy in preventing "blind insufflation"-related complications. A multicenter randomized preclinical animal study. Laboratories at three universities. Experiment 1: Gastric ESD was attempted in the swine (n = 17), under either SPACE or manual insufflation. Experiment 2: Gastroscopy was performed for 10 min in the perforated stomach (n = 10) under either SPACE or manual insufflation. Experiment 1: ESD time, energy device activation time, number of forceps exchanges, specimen size, en block resection rate, vital signs and any intraoperative adverse events. Experiment 2: Intra-gastric and intra-abdominal pressures, vital signs, and any adverse events. Experiment 1: Gastric ESD was completed in all animals. ESD time tended to be shorter in SPACE than in the control, though the difference was not significant (p = 0.18). Experiment 2: Although both intra-gastric and intra-abdominal pressures remained within preset values in SPACE, they showed excessive elevation in control. An animal study with small sample size. SPACE is feasible and safe for complicated and lengthy procedures such as gastric ESD, and is potentially effective in preventing serious consequences related to excessive blind insufflation.
    No preview · Article · Dec 2014 · Surgical Endoscopy
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    ABSTRACT: Advanced complex surgery performed with the natural orifice translumenal endoscopic surgery technique requires use of a multitasking platform. The aim of this study is to evaluate the basic functionality of a prototype multitasking platform "EndoSAMURAI" with the use of a biosimulation model and ex vivo porcine stomach. We compared the performance of basic surgical skill tasks between the EndoSAMURAI and standard laparoscopic instrumentation. Basic surgical tasks include cutting, dissection, and suturing and knot tying. Main outcome measurements were the time to complete each task and leak pressure to evaluate the quality of the suturing and knot tying. Although it took longer to perform all basic surgical tasks with the EndoSAMURAI than with laparoscopic instrumentation, all tasks could be performed precisely and with an accuracy comparable to that of the laparoscopic technique. Leak pressures of the gastric closure site between both techniques were also comparable.
    No preview · Article · Apr 2014 · Surgical laparoscopy, endoscopy & percutaneous techniques
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    ABSTRACT: Background and AimWe have focused on sodium alginate (SA) solution as a potential submucosal injection material for endoscopic submucosal dissection (ESD). A previous SA solution had high viscosity and problems such as difficult handling. After its properties were adjusted, SA solution was examined in vitro and its clinical safety was evaluated.Methods With 0.4% sodium hyaluronate (SH) solution as a control, catheter injectability and mucosa-elevating capacity of 0.3–0.8% SA solutions were evaluated. Next, 0.6% SA solution was used for ESD in 10 patients with early gastric cancer in a prospective clinical study.ResultsCompared with 0.4% SH solution, 0.6% SA solution exhibited no significant difference in catheter injectability but significant superiority in mucosa-elevating capacity. In the clinical study, no adverse events were observed in any patient.Conclusion The safety of 0.6% SA solution as a submucosal injection material was confirmed and it is suggested that its efficacy should be investigated in a larger number of cases.
    No preview · Article · Apr 2014 · Digestive Endoscopy
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    ABSTRACT: The rate and risk factors of recurrent or metachronous adenocarcinoma following endoscopic ablation therapy in patients with Barrett's esophagus (BE) have not been specifically reported. The aim of this study was to determine the incidence and predictors of adenocarcinoma after ablation therapy for BE high-grade dysplasia (HGD) or intramucosal carcinoma (IMC). This is a single center, retrospective review of prospectively collected data on consecutive cases of endoscopic ablation for BE. A total of 223 patients with BE (HGD or IMC) were treated by ablation between 1996 and 2011. Primary outcome measures were recurrence and new development of adenocarcinoma after ablation. Recurrence was defined as the presence of adenocarcinoma following the absence of adenocarcinoma in biopsy samples from two consecutive surveillance endoscopies. Logistic regression analysis was performed to assess predictors of adenocarcinoma after ablation. One hundred and eighty-three patients were included in the final analysis, and 40 patients were excluded: 22 for palliative ablation, eight lost to follow-up, five for residual carcinoma and five for postoperative state. Median follow-up was 39 months. Recurrence or new development of adenocarcinoma was found in 20 patients (11 %) and the median time to recurrence/development of adenocarcinoma was 11.5 months. Independent predictors of recurrent or metachronous adenocarcinoma were hiatal hernia size ≥ 4 cm (odds ratio 3.649, P = 0.0233) and histology (HGD/adenocarcinoma) after first ablation (odds ratio 4.141, P = 0.0065). Adenocarcinoma after endoscopic therapy for HGD or IMC in BE is associated with large hiatal hernia and histology status after initial ablation therapy.
    No preview · Article · Jan 2014 · Digestive Diseases and Sciences
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    Yuichi Endo · Kazuhiro Yasuda · Masafumi Inomata · Seigo Kitano
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    ABSTRACT: A man in his eighties complaining chiefly of abdominal pain and vomiting was referred to our hospital. He was diagnosed as having bowel obstruction and was treated conservatively with a long tube. Despite symptomatic improvement, the long tube did not progress more than 100 cm past the anal side of the ligament of Treitz. Contrast study by gastrografin showed intestinal tract compression on this side, and enhanced CT scan showed a lipid structure with internal heterogeneity and torsion of the surrounding vessels near the long tube's distal tip Small bowel volvuls was likely ; therefore, surgery was performed. Intraperitoneal laparoscopy revealed a 6-cm retroperitoneal tumor near the inferior pole of the left kidney and an internal hernia in the small intestine due to a cord that had been formed between the tumor and the mesenterium. After resecting the cord and reducing the internal hernia, we completed resection of the retroperitoneal tumor through a small 8-cm laparotomy wound made in the abdominal wall directly above the tumor. Histological findings showed the tumor to be a lipoma accompanied by hemorrhage.Bowel obstruction due to a retroperitoneal lipoma is rare, but if a fatty structure in the bowel obstruction is observed, the possibility of retroperitoneal lipoma must be considered. In such situations, laparoscopic observation is useful in determining the appropriate surgical procedure and accurate pathological state.
    Preview · Article · Jan 2014 · Nihon Rinsho Geka Gakkai Zasshi (Journal of Japan Surgical Association)
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    ABSTRACT: Natural orifice translumenal endoscopic surgery (NOTES) has gained much attention worldwide since the first report of transgastric peritoneoscopy in a porcine model in 2004. In this review, we summarize and highlight the current status and future directions of NOTES. Thousands of human NOTES procedures have been performed. The most common procedures are cholecystectomy and appendectomy, mainly performed through transvaginal access in a hybrid fashion with laparoscopic assistance, and the general complication rate is acceptable. Although much work is still needed to refine the techniques for NOTES, the development of NOTES has the potential to create a paradigm shift in minimally invasive surgery.
    No preview · Article · Nov 2013 · Nippon Geka Gakkai zasshi
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    ABSTRACT: The routine use of postoperative adjuvant chemotherapy in patients with stage II colorectal cancer is not recommended. However, the incidence of tumor recurrence or distant metastasis in these patients is reported to be 25-35%. The identification of high-risk patients with stage II colorectal cancer remains difficult. Therefore, the aim of this study was to determine the risk factors that may help identify stage II colorectal cancer patients with unfavorable prognosis. Paraffin-embedded tissue samples from 109 patients with stage II colorectal cancer following curative operation were analyzed. Thirteen clinicopathological variables and 5 biological markers were assessed using immunohistochemistry, including p53 (tumor suppressor gene), CD10 (tumor invasion marker), CD34 (angiogenic marker), Ki-67 (cell proliferation index) and CAM 5.2 (marker of lymph node micrometastasis) and investigated for associations with disease-specific survival. Univariate analysis revealed bowel obstruction, lymph node micrometastasis and lymphatic invasion (P<0.01) to be highly significant factors for determining the 5-year disease-specific survival. By contrast, the multivariate analysis revealed lymph node micrometastasis and lymphatic invasion to be independent prognostic factors. Stage II colorectal cancer patients with lymph node micrometastasis and lymphatic invasion may therefore be suitable candidates for adjuvant chemotherapy to improve prognosis.
    Preview · Article · Jul 2013 · Molecular and Clinical Oncology
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    Preview · Article · May 2013 · Gastrointestinal Endoscopy
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    ABSTRACT: The aim of this study was to use the difficulty score for a laparoscopic cholecystectomy procedure to predict the surgical difficulty of single-port laparoscopic cholecystectomy. From January 2009 to April 2011, single-port laparoscopic cholecystectomy was performed in 30 patients at our institution. The patients were evaluated using the difficulty score and classified into 3 groups: low, intermediate, and high difficulty. All surgeries were successfully completed without conversion to conventional laparoscopic surgery. A strong relationship was observed between the increasing score and longer surgical time. The mean surgical time was longer and the amount of blood loss was greater in the intermediate-difficulty and high-difficulty groups than in the low-difficulty group. Moreover, the high-difficulty group had a higher rate of insertion of an additional trocar than the low-difficulty group. Thus, the difficulty of single-port laparoscopic cholecystectomy is well predicted using the difficulty score.
    No preview · Article · Dec 2012 · Surgical laparoscopy, endoscopy & percutaneous techniques
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    ABSTRACT: A patient with gastroduodenal obstruction caused by an unresectable gastroduodenal or periampullary cancer cannot ingest food and/or liquid. The patient's quality of life rapidly deteriorates, resulting in a dismal prognosis. Stomach-partitioning gastrojejunostomy has been previously reported, and here, we evaluate the laparoscopic procedure. We performed laparoscopic stomach-partitioning gastrojejunostomy in 18 patients with unresectable gastroduodenal or periampullary cancers. Data on operation time, blood loss, complications, and postoperative course were retrospectively collected. The mean operation time was 152 min, and conversion to open surgery was not required in any patients. Postoperative complications occurred in three patients (17%) and included cholangitis, anastomotic ulcer hemorrhage, and enterocolitis. The mean time to oral intake was 4.5 days, and the mean and median duration of oral intake were maintained for 133 and 88 days, respectively. Laparoscopic stomach-partitioning gastrojejunostomy is a safe and effective procedure that allows patients with gastroduodenal outlet obstruction to eat again and improve the quality of their remaining life.
    No preview · Article · Sep 2012 · Asian Journal of Endoscopic Surgery
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    ABSTRACT: Background: Natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed via transgastric, transvaginal, or transcolonic approaches. However, the transcolonic approach has potential disadvantages including intraperitoneal infection. To avoid such disadvantages, we applied the submucosal tunnel technique to transrectal peritoneal access in this study. Study aims are to clarify the technical feasibility of a submucosal tunnel method for transrectal abdominal access and to assess the healing process of the submucosal tunnel histopathologically. Methods: The study comprised six female pigs. The following procedures were performed: (1) The mucosa was cut after injection of sodium hyaluronate into the submucosa at the upper rectum. (2) Submucosal tunneling was performed by endoscopic submucosal dissection technique. (3) A small incision was made at the end of the tunnel. (4) After transrectal peritoneoscopy, the mucosal incision site was closed with endoclips. Results: Transrectal peritoneoscopy was successfully performed in all pigs. Necropsy revealed no findings of peritonitis. Histopathologic examination showed good healing of the submucosal tunnel. The wound healing process of the submucosal tunnel on postoperative day 7 was mainly in the inflammatory phase at the mucosal incision site, the proliferative phase at the submucosal tract, and the proliferative/remodeling phase at the seromuscular incision site. Conclusions: The submucosal tunnel technique appears to be useful and safe for transrectal peritoneal access because healing at the seromuscular incision site proceeded rapidly.
    No preview · Article · Jun 2012 · Surgical Endoscopy
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    ABSTRACT: Introduction. Usefulness of submucosal tunneling for transgastric approach with clip closure of the mucosal incision in natural orifice translumenal endoscopic surgery (NOTES) has been described. Although the narrow longitudinal submucosal tunnel itself is considered good for wound approximation and healing, no reports have evaluated the sealing effect in this technique. This study was aimed at evaluating the technical feasibility of a submucosal tunnel technique for transgastric peritoneal access without mucosal closure. Methods. Transgastric peritoneoscopy using submucosal tunneling with endoscopic submucosal dissection without mucosal closure was performed on six 40- to 45-kg female pigs. Measures included (a) evaluation of technical feasibility, (b) clinical monitoring for 7 days, (c) necropsy findings, and (d) pathological examination. Results. NOTES transgastric peritoneoscopy was successfully performed in all pigs, and all recovered well clinically. Necropsy findings revealed no peritonitis, confirming completeness of gastric closure in 5 of the 6 pigs. One pig in which the submucosal layer of the tunnel was injured during dissection from the muscular layer showed local peritonitis. Pathological examination at the submucosal site tunnel showed wound healing with focal transmural fibrosis and inflammatory cell infiltration in 5 pigs, whereas the pig with peritonitis had a large mucosal defect with necrotic tissue, abscess formation, and focal transmural fibrosis. Conclusions. The submucosal tunnel technique without mucosal closure is safe and effective for transgastric peritoneal access and subsequent closure, when the endoscopists' learning curve is accomplished and the submucosal tunnel is produced without damaging of mucosa. It is necessary to use devices such as mucosal clips or tissue anchors in order to achieve adequate healing of mucosal defect.
    No preview · Article · Feb 2012 · Surgical Innovation
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    ABSTRACT: Although the laparoscopic approach is accepted for the treatment of colon cancer, its value for low rectal cancer is unknown. We sought to evaluate the technical feasibility of laparoscopic low anterior resection (Lap-AR) by determining short-term clinical outcomes and identifying the corresponding predictive factors. A retrospective single-institution study was carried out on 82 patients in whom Lap-AR had been attempted for rectal cancer during the period spanning April 2001 to December 2009. Patient characteristics, operative outcomes, and postoperative morbidities and mortalities were analyzed. The median operative time and the intraoperative blood loss were 300 minutes and 72.5 g, respectively. Overall morbidity and mortality rates were 11.0% and 0%, respectively. Complications included wound infection (6.1%, n=5), anastomotic leakage (1.2%, n=1), ileus (1.2%, n=1), and pneumonia (2.4%, n=2). A multivariate analysis indicated that the important risk factor associated with an operative time of >300 minutes was the T factor, and the risk factor associated with intraoperative blood loss was a body mass index (BMI) of >25 kg/m(2). Lap-AR is a technically feasible, safe, and effective method for treating patients with rectal cancer. A BMI>25 kg/m(2) and the T factor related to operative blood loss and operative time, respectively. Assessment of high BMI and, in particular, advanced tumor depth, should alert surgeons to the increased technical difficulty of Lap-AR.
    No preview · Article · Feb 2012 · Surgical laparoscopy, endoscopy & percutaneous techniques
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    ABSTRACT: Sodium alginate is used clinically in the treatment of peptic ulcer disease. Because of its viscosity, sodium alginate could possibly become a new submucosal injection material for use in endoscopic resection. We evaluated the feasibility of endoscopic submucosal dissection (ESD) using sodium alginate. The lesion-lifting properties of sodium alginate were examined in porcine stomachs and were compared with those of normal saline solution and sodium hyaluronate solution. After confirming the proper concentration of sodium alginate, ESD using sodium alginate was performed in 11 patients with gastric mucosal cancer or adenoma. The lesion-lifting properties of sodium alginate and clinical outcomes were assessed. The thickness of the submucosal elevation created by 3% sodium alginate in porcine stomach was equivalent to that of sodium hyaluronate. ESD using sodium alginate was completed successfully in all patients without adverse effects except in 1 patient in whom transient shrinkage of the gastric wall disappeared spontaneously after approximately 30 minutes. The mean tumor size was 15.3 mm. En bloc resection and a negative resection margin were obtained in all. Histopathologic examination revealed that all tumors were confined to the mucosal layer except for 1 that was confined to the submucosal layer without lymphovascular invasion, and there were no adverse effects such as tissue damage. No patient required additional treatment, and none showed recurrence during a median follow-up period of 28 months. Small sample size. This preliminary study suggests that sodium alginate might be a novel, safe submucosal injection material for use in endoscopic resection. Further investigation of the properties of sodium alginate is warranted.
    No preview · Article · Nov 2011 · Gastrointestinal endoscopy
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    ABSTRACT: Few long-term results of laparoscopic resection for gastrointestinal stromal tumors (GISTs) of the stomach have been established to evaluate technical safety and oncologic feasibility. Between April, 1998 and October, 2008, data of 18 patients who underwent laparoscopic resection of GISTs of <5 cm in diameter were reviewed. There were 10 men and 8 women with average age of 66.5 years. Estimated blood loss was minimal, and average operation time was 99.2 ± 30.5 minutes. There were no major intraoperative complications or conversions to open approach. Oral feeding started 2 to 4 days after operation, and the mean hospital stay was 10.1 ± 5.5 days. There were no major postoperative complications except for 1 patient who suffered from aspiration pneumonia. Tumor size was 3.7 ± 1.1 cm (range, 1.5 to 7.0 cm), and all patients had free surgical margins. During long-term follow-up (average 54.6 mo), no complications occurred except for liver metastasis in only 1 patient who was responding well to imatinib therapy. Laparoscopic wedge resection of GISTs of <5 cm in diameter is a safe and oncologically feasible technique offering good long-term outcomes.
    No preview · Article · Aug 2011 · Surgical laparoscopy, endoscopy & percutaneous techniques
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    ABSTRACT: Issues surroundings the safety and efficacy of palliative laparoscopic resections for patients with stage IV colorectal cancer have not been explicitly examined in the literature. We describe our experience with laparoscopic procedures for patients with stage IV incurable symptomatic colorectal cancer and compare perioperative outcomes with a contemporaneous group of patients who underwent conventional open procedures. We retrospectively reviewed data from laparoscopic resections performed in patients for symptomatic stage IV colorectal cancer between 1999 and 2009. Data regarding patient demographics, perioperative morbidity and mortality, intraoperative blood loss, operative time, length of postoperative hospital stay, and time from surgery to chemotherapy were assessed. A total of 29 patients were identified and of these patients, 11 (38%) underwent palliative laparoscopic resections and 18 (62%) underwent conventional open resection for stage IV colorectal cancer. In comparing laparoscopic to conventional procedures, the length of postoperative hospital stay in the laparoscopic resection group was significantly shorter than that in the open resection group (median, 17 vs. 20 d, P<0.05). Significant differences were present between the 2 groups when following features were compared: leukocyte on day 1 (median, 7.87 vs. 8.70 × 10/L) and day 3 (median, 6.40 vs. 7.80 × 10/L), albumin level on day 7 (median, 38.0 vs. 29.8 g/L), and C-reactive protein level on day 7 (median, 0.6 vs. 2.8 mg/dL). There were no significance differences between the 2 groups in intraoperative blood loss (median, 105 vs. 155 mL), operative time (median, 271.5 vs. 187.5 min), time to intake of solid food (median, 4 vs. 4 d), the rate of postoperative complications, perioperative mortality, or a duration from surgery to chemotherapy (median, 22 vs. 28 d). Palliative laparoscopic resection is a safe and feasible option with acceptable morbidity and mortality in patients with stage IV colorectal cancer. Importantly, in this group of difficult-to-treat patients, our results compare favorably with those from previously published reports on open procedures.
    No preview · Article · Jun 2011 · Surgical laparoscopy, endoscopy & percutaneous techniques
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    ABSTRACT: Pre-operative chemoradiotherapy (CRT) is an important neoadjuvant therapy for locally advanced rectal cancer. In the present study, we investigated the factors that influence the efficacy of pre-operative CRT in locally advanced rectal cancer. We divided 50 patients with locally advanced rectal carcinoma treated with pre-operative CRT into two groups according to the grade of tumor response to pre-operative CRT: low-sensitivity group and high-sensitivity group. As candidates for the prediction of sensitivity to pre-operative CRT, clinicopathological factors and 12 biomarkers, including factors related to tumor growth, cell cycle, apoptosis, tumor stroma and cancer stem cells, were examined immunohistochemically in 48 resected specimens. Thirty-one tumors showed high sensitivity and 19 showed low sensitivity to pre-operative CRT. The status of stem cell-related factors, CD133 and CD24, was significantly associated respectively with sensitivity to pre-operative CRT (P=0.003, P=0.029). In 10 tumors positive for both CD133 and CD24, low sensitivity to CRT was found in 9 (90%), whereas in 16 tumors negative for both CD133 and CD24, low sensitivity was found in 3 (19%). Other pathological parameters were not associated with tumor response to pre-operative CRT. In conclusion, overexpression of cancer stem cell-related factors, CD133 and CD24, is associated with the sensitivity of locally advanced rectal cancer to pre-operative CRT.
    Preview · Article · May 2011 · Experimental and therapeutic medicine

  • No preview · Article · Apr 2011 · Gastrointestinal Endoscopy
  • Kazuhiro Yasuda · Hidefumi Shiroshita · Seigo Kitano

    No preview · Article · Jan 2011
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    ABSTRACT: A few studies have addressed the physiology related to a basic natural-orifice transluminal endoscopy surgery (NOTES) procedure, such as transgastric peritoneoscopy, but the physiologic impact of more complex NOTES procedures has not been previously examined. To evaluate the cardiopulmonary and immunologic effects of transvaginal NOTES cholecystectomy compared with laparoscopic cholecystectomy. Survival experiments in 10 40-kg female pigs assigned to transvaginal cholecystectomy and laparoscopic cholecystectomy groups. Transvaginal cholecystectomy was performed with the assistance of a needlescopic device, and laparoscopic cholecystectomy was performed in the standard manner. Cardiopulmonary and immunologic parameters in the transvaginal cholecystectomy group were compared with those in the laparoscopic cholecystectomy group. Cardiopulmonary parameters included heart rate, blood pressure, saturation pulse oximetry, intratracheal pressure, and arterial blood gases. Immunologic parameters included white blood cell count, tumor necrosis factor-α, interleukin-1β, and interleukin-6. All procedures were performed successfully without complications. Although operation times were longer for transvaginal cholecystectomy than for laparoscopic surgery, cardiopulmonary changes were similar and stable in both groups. White blood cell count, interleukin-1β, and interleukin-6 did not differ between the 2 groups, and the increase in tumor necrosis factor α after transvaginal cholecystectomy was significantly smaller on postoperative day 1 than after laparoscopic cholecystectomy (133.4 pg/mL vs 200.4 pg/mL; P < .05). Animal model and small sample size. Transvaginal cholecystectomy resulted in cardiopulmonary stability and well preserved immune function similar to those of laparoscopic cholecystectomy, suggesting that NOTES may be less invasive than laparoscopic surgery.
    No preview · Article · Dec 2010 · Gastrointestinal endoscopy

Publication Stats

2k Citations
187.15 Total Impact Points


  • 1999-2014
    • Oita University
      • • Faculty of Medicine
      • • Department of Gastroenterological Surgery
      • • First Department of Surgery
      Ōita, Ōita, Japan
  • 2006
    • National Hospital Organization Beppu Medical Center
      Бэппу, Ōita, Japan