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Dive into the research topics where Tomohiko Miyata is active.

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Featured researches published by Tomohiko Miyata.


Clinical Gastroenterology and Hepatology | 2004

Clinical outcomes of double-balloon endoscopy for the diagnosis and treatment of small-intestinal diseases.

Hironori Yamamoto; Hiroto Kita; Keijiro Sunada; Yoshikazu Hayashi; Hiroyuki Sato; Tomonori Yano; Michiko Iwamoto; Yutaka Sekine; Tomohiko Miyata; Akiko Kuno; Hironari Ajibe; Kenichi Ido; Kentaro Sugano

BACKGROUND & AIMS A specialized system for a new method for enteroscopy, the double-balloon method, was developed. The aim of this study was to evaluate the usefulness of this endoscopic system for small-intestinal disorders. METHODS The double-balloon endoscopy system was used to perform 178 enteroscopies (89 by the anterograde approach and 89 by the retrograde approach) in 123 patients. The system was assessed on the basis of the rates of success in jejunal and ileal insertion and the entire examination of the small intestine, diagnostic yields, ability to perform treatment, and complications. RESULTS Insertion of the endoscope beyond the ligament of Treitz or ileocecal valve was possible in all 178 procedures. It was possible to observe approximately one half to two thirds of the entire small intestine by each approach, and observation of the entire small intestine was possible in 24 (86%) of 28 trials. The source of bleeding was identified in 50 (76%) of 66 patients with GI bleeding, scrutiny of strictures was possible in 23 patients, and a tumor was examined endoscopically in 17 patients. Two complications (1.1%) occurred. Endoscopic therapies in the small intestine including hemostasis (12 cases), polypectomy (1 case), endoscopic mucosal resection (1 case), balloon dilation (6 cases), and stent placement (2 cases) were performed successfully. CONCLUSIONS Double-balloon endoscopy permits the exploration of the small intestine with a high success rate of total enteroscopy. The procedure is safe and useful, and it provides high diagnostic yields and therapeutic capabilities.


Clinical Gastroenterology and Hepatology | 2010

Long-term Outcome of Patients With Obscure Gastrointestinal Bleeding Investigated by Double-Balloon Endoscopy

Satoshi Shinozaki; Hironori Yamamoto; Tomonori Yano; Keijiro Sunada; Tomohiko Miyata; Yoshikazu Hayashi; Masayuki Arashiro; Kentaro Sugano

BACKGROUND & AIMS It is often difficult to determine the cause of obscure gastrointestinal bleeding (OGIB). We evaluated the diagnostic yield and long-term outcome of patients with OGIB by using double-balloon endoscopy (DBE). METHODS In this large, retrospective cohort study, DBE was performed in 200 consecutive patients with OGIB. Follow-up data were available from 151 patients for 29.7 months (range, 6-78 months), and clinical outcome was assessed. RESULTS DBE detected bleeding sources in 155 of 200 patients (77.5%). The most frequent source detected was small intestine ulcers/erosions (64 patients). Patients who underwent DBE within 1 month after the last episode of overt bleeding had a better yield of positive findings than those who did not (84%, 107/128 patients vs 57%, 24/42; P = .002). The overall rate of control of OGIB was 64% (97/151 patients). Patients with vascular lesions of the small intestine had a significantly lower rate of control of OGIB than those with other small intestine lesions (40%, 12/30 patients vs 74%, 52/70; P = .001). A requirement for a large transfusion before DBE (P = .012), multiple lesions (P = .010), and suspicious (not definite) lesions (P = .038) each significantly increased the likelihood of overt rebleeding in patients with vascular lesions of the small intestine. CONCLUSIONS DBE is useful for the diagnosis of patients with OGIB and should be performed as soon as possible after overt OGIB. Patients with vascular lesions of the small intestine should be followed with particular care.


Gastrointestinal Endoscopy | 2009

A comparison of conventional endoscopy, chromoendoscopy, and the optimal-band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps

Kazutomo Togashi; Hiroyuki Osawa; Koji Koinuma; Yoshikazu Hayashi; Tomohiko Miyata; Keijiro Sunada; Mitsuhiro Nokubi; Hisanaga Horie; Hironori Yamamoto

BACKGROUND The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye. OBJECTIVE To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy. DESIGN An open prospective study. SETTING Jichi Medical University, Japan. PATIENTS A total of 133 colonoscopy cases. MAIN OUTCOME MEASUREMENT A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification. RESULTS A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy. CONCLUSIONS Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.


Gastrointestinal Endoscopy | 2010

Safety and efficacy of double-balloon enteroscopy in pediatric patients

Naoyuki Nishimura; Hironori Yamamoto; Tomonori Yano; Yoshikazu Hayashi; Masayuki Arashiro; Tomohiko Miyata; Keijiro Sunada; Kentaro Sugano

BACKGROUND Although double-balloon enteroscopy (DBE) is performed increasingly often in adults, few findings are available on the use of DBE in pediatric patients in the published literature. OBJECTIVES The aim of our study was to evaluate the safety and efficacy of DBE in pediatric patients. DESIGN A retrospective database review. SETTING AND PATIENTS A database analysis was performed on all pediatric patients (18 years old or younger) who underwent DBE at the Jichi Medical University Hospital between September 2000 and October 2008 selected from a total of 825 patients. MAIN OUTCOME MEASUREMENTS Clinical utility and safety of DBE in pediatric patients. RESULTS A total of 92 procedures were performed in 48 patients (27 male, 21 female) with a median age (range) of 12.2 (4-18) years. DBE was performed with the patients under general anesthesia in 43 procedures and under moderate sedation in 49 procedures. The most common indication for DBE was treatment of a stricture of a biliary anastomosis after living-donor liver transplantation with establishment of Roux-en-Y hepaticojejunostomy (23 patients). Endoscopic retrograde cholangiography using DBE was performed, and endoscopic therapy could be performed successfully in 13 (56%) patients. The second most common indication was obscure GI bleeding (10 patients); the lesions responsible for the bleeding were found in 7 (70%) patients. Other indications included surveillance and treatment of hereditary polyposis syndromes (5 patients), abdominal pain (4 patients), and inflammatory bowel disease (2 patients). The overall diagnostic yield was 65% (31 of the 48 patients). Postpolypectomy bleeding occurred in 1 case, but no other complications such as perforation and pancreatitis were observed. LIMITATIONS Small number of patients, participation bias, and single centers experience. CONCLUSIONS DBE is a safe and clinically useful endoscopic procedure in pediatric patients.


Inflammopharmacology | 2007

Double balloon endoscopy in two hundred fifty cases for the diagnosis and treatment of small intestinal disorders.

H. Kita; Hironori Yamamoto; Tomonori Yano; Tomohiko Miyata; Michiko Iwamoto; Keijiro Sunada; Masayuki Arashiro; Yoshikazu Hayashi; Kenichi Ido; Kentaro Sugano

Abstract.Double balloon endoscopy is based on a new insertion mode in which two balloons at the distal ends of both an endoscope and an overtube are operated in combination. We have performed 419 enteroscopic examinations in 250 patients using the Fujinon double balloon endoscopy system between September 2000 and October 2005. Total enteroscopy was successfully achieved by the combination of both oral and anal approaches in 55 out of 71 cases in whom total enteroscopy was intended. Of 250 patients, ulcerative and/or erosive lesions were found in 49 cases and tumors/polyps were found in 49 cases. We also found 26 cases of vascular lesion, including angiodysplasia. Endoscopic treatments, including hemostasis using either clipping devices or electro coagulation, polypectomy, endoscopic mucosal resection, balloon dilation, and stent placement was successfully carried out. Double balloon enteroscopy is both feasible and useful technique for the diagnosis as well as treatment of small intestinal disorders.


Gastrointestinal Endoscopy | 2011

Nonsurgical management of small-bowel polyps in Peutz–Jeghers syndrome with extensive polypectomy by using double-balloon endoscopy

Hirotsugu Sakamoto; Hironori Yamamoto; Yoshikazu Hayashi; Tomonori Yano; Tomohiko Miyata; Naoyuki Nishimura; Hakuei Shinhata; Hiroyuki Sato; Keijiro Sunada; Kentaro Sugano

BACKGROUND The major problem in the management of Peutz-Jeghers syndrome (PJS) is small-bowel polyps, which can cause intussusception and bleeding. Double-balloon endoscopy (DBE) enables endoscopic resection of small-bowel polyps. OBJECTIVE The aim of this study was to determine the efficacy and safety of endoscopic management of small-bowel polyps in PJS patients by using DBE. DESIGN Retrospective chart review. SETTING Single university hospital. PATIENTS Consecutive patients with PJS who underwent multiple sessions of DBE for evaluation or treatment of small-bowel polyps between September 2000 and April 2009. INTERVENTIONS Endoscopic resection of small-bowel polyps in PJS patients was performed by using DBE. MAIN OUTCOME MEASUREMENTS Efficacy, safety, and long-term laparotomy rate after the procedures were evaluated. RESULTS Fifteen patients (10 men, mean age 34.0 ± 15.8 years) underwent DBE for a mean 3.0 ± 1.0 sessions. The mean numbers of resected polyps larger than 20 mm significantly decreased as sessions advanced (first, 3.6; second, 1.3; third, 0.7; fourth, 0.4; and fifth, 1.0; P = .02). The mean maximum sizes of resected polyps also significantly decreased at each session: 33, 19, 12, 17, and 30 mm (P = .01). One patient had a perforation, but was managed conservatively. Other complications were pancreatitis (n = 2) and bleeding (n = 2). Only 1 patient underwent surgery for intussusception during the study period. LIMITATIONS This was a small single-center retrospective study of short duration. CONCLUSIONS Endoscopic management of small-bowel polyps in PJS patients by using DBE is safe and effective and avoids urgent laparotomy.


Journal of Gastroenterology | 2009

Nonsteroidal anti-inflammatory drug-induced small-bowel lesions identified by double-balloon endoscopy: endoscopic features of the lesions and endoscopic treatments for diaphragm disease

Yoshikazu Hayashi; Hironori Yamamoto; Hiroki Taguchi; Keijiro Sunada; Tomohiko Miyata; Tomonori Yano; Masayuki Arashiro; Kentaro Sugano

BackgroundNonsteroidal anti-inflammatory drugs (NSAIDs) occasionally induce small-bowel injury. However, the clinical features have only been partially clarified. The aim of this study was to clarify the clinical features of the disease and evaluate the effectiveness of endoscopic balloon dilation therapy for diaphragm disease, using double-balloon endoscopy (DBE).MethodsThis is a retrospective case study using our DBE database. Our inclusion criteria required patients to meet all the following criteria: (1) history of NSAID use; (2) endoscopic findings of erosion and/or ulcer and/or typical diaphragm-like strictures; (3) improvement in clinical findings (signs and symptoms) and/or endoscopic findings by cessation of NSAIDs, except for diaphragm disease; and (4) exclusion of other causes (e.g., malignant tumor, inflammatory bowel disease, and infectious disease). The clinical records of patients were investigated.ResultsEighteen patients were included. Sixteen patients showed ulcerative lesions, and the remaining 2 patients showed diaphragm diseases. For localized lesions, 12 patients evidenced lesions in the ileum, 5 patients had lesions in the duodenum and/or jejunum, and 1 had lesions in both intestines. The ulcerative lesions were multiple with various morphologies that were located unrelated to mesenteric or antimesenteric sides. The endoscopic balloon dilations were performed safely, and all patients improved with regard to their symptoms.ConclusionsSymptomatic NSAID-induced small-bowel injuries exhibit a variety of patterns of ulcerative lesions as observed in the ileum in many cases. The endoscopic balloon dilation appears to be a safe and effective treatment for diaphragm disease.


Journal of Gastroenterology | 2004

Gastrointestinal stromal tumor in the jejunum: diagnosis and control of bleeding with electrocoagulation by using double-balloon enteroscopy.

Makoto Nishimura; Hironori Yamamoto; Hiroto Kita; Tomonori Yano; Keijiro Sunada; Tomohiko Miyata; Takeshi Sugimoto; Satoru Iino; Yutaka Sekine; Michiko Iwamoto; Nobuki Ohnishi; Akiko Kuno; Hirohide Ohnishi; Shinji Sakurai; Kenichi Ido; Kentaro Sugano

A 43-year-old man presented with gastrointestinal bleeding. A tumor with central ulceration was observed in the jejunum, with the use of a new enteroscopy system called “double-balloon enteroscopy”. Bleeding after biopsy sampling of the tumor was controlled endoscopically by using electrocoagulation. Histological findings of the biopsy specimens were consistent with gastrointestinal stromal tumor, and this was surgically resected. Double-balloon enteroscopy was useful for the diagnosis as well as the control of bleeding in this patient.


Digestive Endoscopy | 2004

Successful treatment with balloon dilatation using a double‐balloon enteroscope for a stricture in the small bowel of a patient with Crohn's disease

Keijiro Sunada; Hironori Yamamoto; Hiroto Kita; Tomonori Yano; Tomohiko Miyata; Yutaka Sekine; Akiko Kuno; Nobuki Onishi; Michiko Iwamoto; Atsuhiro Sasaki; Kenichi Ido; Kentaro Sugano

The requirement for endoscopic access to a stricture is a major limitation of the endoscopic dilatation for the treatment of strictures in the gastrointestinal tract. We have developed the double‐balloon enteroscopy method that enables visualization of the entire small bowel. In addition, double‐balloon enteroscopy has a potential for the interventional therapy including dilatation of strictures. We present here a case of jejunal strictures in a 47‐year‐old woman with Crohns disease successfully treated with a balloon catheter in combination with double‐balloon enteroscopy. Balloon dilation with double‐balloon enteroscopy is a promising method for the treatment of small bowel strictures in Crohns disease.


Journal of Gastroenterology and Hepatology | 2008

Endoscopic observation of Meckel's diverticulum by double balloon endoscopy: Report of five cases

Satoshi Shinozaki; Hironori Yamamoto; Hirohide Ohnishi; Hiroto Kita; Tomonori Yano; Michiko Iwamoto; Tomohiko Miyata; Yoshikazu Hayashi; Keijiro Sunada; Kenichi Ido; Norio Takayashiki; Kentaro Sugano

Background and Aim:  Most cases of Meckels diverticula are asymptomatic, however, some cases presented with gastrointestinal (GI) bleeding. It is often difficult to determine whether Meckels diverticulum is a source of obscure GI bleeding. Double balloon endoscopy allows endoscopic access to the entire small intestine. The aim of this study was to compare endoscopic findings of three hemorrhagic and two non‐hemorrhagic Meckels diverticula in patients with obscure GI bleeding using this novel technique.

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Keijiro Sunada

Jichi Medical University

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Kentaro Sugano

Jichi Medical University

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Tomonori Yano

Jichi Medical University

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Kenichi Ido

Jichi Medical University

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Hiroyuki Sato

Jichi Medical University

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