Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Hiroyuki Miyatani is active.

Publication


Featured researches published by Hiroyuki Miyatani.


Endoscopy | 2012

Endoscopic submucosal dissection for duodenal tumors: a single-center experience.

Satohiro Matsumoto; Hiroyuki Miyatani; Yukio Yoshida

The indications for endoscopic submucosal dissection (ESD) for duodenal tumors have not yet been established. We reviewed our experience of ESD performed for duodenal tumors. We analyzed the data of a total of 13 patients with 14 duodenal lesions (excluding papillary lesions) comprising 2 early cancers, 5 adenomas, and 7 neuroendocrine tumors, who were treated by ESD between 2005 and 2011. The mean tumor diameter was 12.7 ± 14.8 mm. En bloc resection was achieved in 85.7% of the cases. The procedure time was 89.1 ± 64.6 minutes. Intraoperative perforation occurred in three cases. The mean length of postoperative hospitalization was 8.4 ± 2.4 days. Because ESD for duodenal lesions was associated with a higher incidence of perforation than ESD for lesions in other locations (stomach, esophagus, and colon) reported previously, its use for duodenal lesions should be considered with caution.


World Journal of Gastrointestinal Endoscopy | 2015

Future directions of duodenal endoscopic submucosal dissection

Satohiro Matsumoto; Hiroyuki Miyatani; Yukio Yoshida

Endoscopic therapies for lesions of the duodenum are technically more difficult than those for lesions of the other parts of the gastrointestinal tract due to the anatomical features of the duodenum, and the incidence rate of complications such as perforation and bleeding is also higher. These aforementioned trends were especially noticeable for the case of duodenal endoscopic submucosal dissection (ESD). The indication for ESD of duodenal tumors should be determined by assessment of the histopathology, macroscopic morphology, and diameter of the tumors. The three types of candidate lesions for endoscopic therapy are adenoma, carcinoma, and neuroendocrine tumors. For applying endoscopic therapies to duodenal lesions, accurate preoperative histopathological diagnosis is necessary. The most important technical issue in duodenal ESD is the submucosal dissection process. In duodenal ESD, a short needle-type knife is suitable for the mucosal incision and submucosal dissection processes, and the Small-caliber-tip Transparent hood is an important tool. After endoscopic therapies, the wound should be closed by clipping in order to prevent complications such as secondary hemorrhage and delayed perforation. At present, the criteria for selection between ESD and EMR vary among institutions. The indications for ESD should be carefully considered. Duodenal ESD should have limitations, such as the need for its being performed by experts with abundant experience in performing the procedure.


Digestive Endoscopy | 2009

SLOW GROWING FLAT‐TYPE PRIMARY MALIGNANT MELANOMA OF THE ESOPHAGUS TREATED WITH CAP‐ASSISTED EMR

Hiroyuki Miyatani; Yukio Yoshida; Shinya Ushimaru; Noriyoshi Sagihara; Shigeki Yamada

We report a rare case of flat‐type primary malignant melanoma of the esophagus treated with endoscopic mucosal resection (EMR). A 64‐year‐old woman was referred for examination of a small pigmented lesion located in the mid esophagus. On endoscopy, the lesion exhibited almost no change in size over the year. Cap‐assisted EMR was performed en bloc. The histopathological findings showed atypical melanocyte proliferation in the basal layer, spindle cells, and epithelioid cell proliferation with nuclear enlargement and a few mitotic figures. Histopathological examination confirmed the diagnosis of primary malignant melanoma. Immunostaining for S‐100 protein and HMB‐45 antibody were positive, and the Ki‐67 index was low. The patient was discharged without additional surgical resection and/or chemotherapy. The patient had no symptoms and no signs of recurrence 20 months after EMR. There has been no report on a slow growing esophageal melanoma. It is difficult to estimate the malignant behavior of this case.


Gastrointestinal Endoscopy | 2011

Cicatricial stenosis after endoscopic submucosal dissection of esophageal cancer effectively treated with a temporary self-expandable metal stent

Satohiro Matsumoto; Hiroyuki Miyatani; Yukio Yoshida; Mitsuhiro Nokubi

Post-endoscopic submucosal dissection (ESD) cicatricial stenosis has become a clinical issue. In many cases, endoscopic esophageal dilation is performed in patients with post-ESD cicatricial stenosis. On the other hand, a number of recent studies have reported that stent placement is useful for the treatment of benign esophageal stenosis. 1 Here we report a case of cicatricial stenosis that failed to respond to conventional esophageal bougie dilation but was successfully dilated with a temporary self-expandable metal stent (SEMS).


World Journal of Gastrointestinal Endoscopy | 2016

Risk factors for postoperative bleeding after gastric endoscopic submucosal dissection in patients under antithrombotics

Yuji Shindo; Satohiro Matsumoto; Hiroyuki Miyatani; Yukio Yoshida; Hirosato Mashima

AIM To evaluate the risk factors for postoperative bleeding after gastric endoscopic submucosal dissection (ESD) based on the latest guidelines. METHODS A total of 262 gastric neoplasms were treated by ESD at our center during a 2-year period from October 2012. We analyzed the data of these cases retrospectively to identify the risk factors for post-ESD bleeding. RESULTS Of the 48 (18.3%) cases on antithrombotic treatment, 10 were still receiving antiplatelet drugs perioperatively, 13 were on heparin replacement after oral anticoagulant withdrawal, and the antithrombotic therapy was discontinued perioperatively in 25 cases. Postoperative bleeding occurred in 23 cases (8.8%). The postoperative bleeding rate in the heparin replacement group was 61.5%, significantly higher than that in the non-antithrombotic therapy group (6.1%). Univariate analysis identified history of antithrombotic drug use, heparin replacement, hemodialysis, cardiovascular disease, diabetes mellitus, elevated prothrombin time-international normalized ratio, and low hemoglobin level on admission as risk factors for post ESD bleeding. Multivariate analysis identified only heparin replacement (OR = 13.7, 95%CI: 1.2-151.3, P = 0.0329) as a significant risk factor for post-ESD bleeding. CONCLUSION Continued administration of antiplatelet agents, based on the guidelines, was not a risk factor for postoperative bleeding after gastric ESD; however, heparin replacement, which is recommended after withdrawal of oral anticoagulants, was identified as a significant risk factor.


World Journal of Gastroenterology | 2013

Hemorrhagic gastric and duodenal ulcers after the Great East Japan Earthquake Disaster

Kenichi Yamanaka; Hiroyuki Miyatani; Yukio Yoshida; Shinichi Asabe; Toru Yoshida; Misaki Nakano; Shin Obara; Hidehiko Endo

AIM To elucidate the characteristics of hemorrhagic gastric/duodenal ulcers in a post-earthquake period within one medical district. METHODS Hemorrhagic gastric/duodenal ulcers in the Iwate Prefectural Kamaishi Hospital during the 6-mo period after the Great East Japan Earthquake Disaster were reviewed retrospectively. The subjects were 27 patients who visited our hospital with a chief complaint of hematemesis or hemorrhagic stool and were diagnosed as having hemorrhagic gastric/duodenal ulcers by upper gastrointestinal endoscopy during a 6-mo period starting on March 11, 2011. This period was divided into two phases: the acute stress phase, comprising the first month after the earthquake disaster, and the chronic stress phase, from the second through the sixth month. The following items were analyzed according to these phases: age, sex, sites and number of ulcers, peptic ulcer history, status of Helicobacter pylori (H. pylori) infection, intake of non-steroidal anti-inflammatory drugs, and degree of impact of the earthquake disaster. RESULTS In the acute stress phase from 10 d to 1 mo after the disaster, the number of patients increased rapidly, with a nearly equal male-to-female ratio, and the rate of multiple ulcers was significantly higher than in the previous year (88.9% vs 25%, P < 0.005). In the chronic stress phase starting 1 mo after the earthquake disaster, the number of patients decreased to a level similar to that of the previous year. There were more male patients during this period, and many patients tended to have a solitary ulcer. All patients with duodenal ulcers found in the acute stress phase were negative for serum H. pylori antibodies, and this was significantly different from the previous years positive rate of 75% (P < 0.05). CONCLUSION Severe stress caused by an earthquake disaster may have affected the characteristics of hemorrhagic gastric/duodenal ulcers.


Therapeutics and Clinical Risk Management | 2009

Cecal perforation with an ascending colon cancer caused by upper gastrointestinal endoscopy

Hiroyuki Miyatani; Yukio Yoshida; Hirokazu Kiyozaki

Colonic perforation caused by upper gastrointestinal (GI) endoscopy is extremely rare. A 69-year-old woman was referred to our hospital because of abdominal fullness. Colonoscopy could be performed only up to the hepatic flexure due to an elongated colon and residual stools. Because her symptoms improved, upper GI endoscopy was performed 11 days later. The patient developed severe abdominal pain two hours after the examination. Abdominal X-ray and computed tomography showed massive free air. Immediate laparotomy was performed for the intestinal perforation. After removal of stool, a perforation site was detected in the cecum with an invasive ascending colon cancer. Therefore, a right hemicolectomy, ileostomy, and transverse colostomy were performed. Although she developed postoperative septicemia, the patient was discharged 38 days after admission. Seven months postoperatively, the patient died of lung, liver, and brain metastases. Even in cases with a lesion that is not completely obstructed, it is important to note that air insufflations during upper GI endoscopy can perforate the intestinal wall in patients with advanced colon cancer.


Clinical Medicine Insights: Gastroenterology | 2009

Endoscopic Needle Knife Precut Papillotomy for Inaccessible Bile Duct Following Failed Pancreatic Duct Access

Hiroyuki Miyatani; Yukio Yoshida

Aims To evaluate the safety, effectiveness, success rate and complications of needle knife precut papillotomy for inaccessible bile duct after failed pancreatic ducts access. Methods Selective common bile duct cannulation was required for 582 patients from November 2004 to May 2008. Precut sphincterotomy was performed in 28 patients (16 male, 12 female; mean age 71). When standard bile duct cannulation was unsuccessful after more than 20 minutes, the bile duct was considered inaccessible. Group A consisted of patients where pancreatic duct access was possible and transpancreatic papillary septotomy was performed (20 patients). If pancreatic duct cannulation also failed, needle knife precut method was performed and these patients belonged to group B (8 patients). The success and complication rates of the two groups were compared using the Chi-square test. Results The success rates were 85% and 87.5% respectively. Of the 28 patients in group A, 6 had mild to moderate pancreatitis and one patient had mild bleeding. The complication rates were 35% and 0% respectively and the differences were not significant. Conclusion Needle knife precut papillotomy is useful and acceptable in patients after failed pancreatic duct access.


Clinical and Experimental Gastroenterology | 2017

Tacrolimus versus anti-tumor necrosis factor agents for steroid-refractory active ulcerative colitis based on the severity of endoscopic findings: a single-center, open-label cohort study

Satohiro Matsumoto; Haruna Kawamura; Takeshi Nishikawa; Noriyoshi Sagihara; Hiroyuki Miyatani; Hirosato Mashima

Background and aims At Saitama Medical Center, for remission induction in active ulcerative colitis (UC) patients with endoscopic evidence of severe disease, we tend to preferentially use tacrolimus (TAC) over anti-tumor necrosis factor (TNF)-α agents. We conducted this study to evaluate the validity of our therapeutic strategies. Patients and methods This retrospective study was conducted in 52 steroid-refractory active UC patients with a Clinical Activity Index (CAI) score of ≥7 who were receiving remission induction therapy with TAC or anti-TNF-α agents. The patients were divided into a TAC treatment group (TAC group, n = 29) and an anti-TNF-α agent treatment group (anti-TNF group, n = 23). The CAI, Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and incidence of events (relapse, hospitalization and surgery) were retrospectively analyzed. Results At treatment initiation, the CAI score was 12.6 in the TAC group and 11.5 in the anti-TNF group (P = 0.09), while the corresponding values of the UCEIS were 6.5 and 5.1, respectively (P = 0.0035). The clinical remission rate at 12 weeks was 55% (65% when only the subgroup that received rapid induction therapy was included in the analysis) in the TAC group and 57% in the anti-TNF group, with no significant difference. The cumulative event-free rates at 1, 6 and 12 months were 65.5%, 39.4%, and 39.4%, respectively, in the TAC group and 95.7%, 77.2% and 71.7%, respectively, in the anti-TNF group (P = 0.0037). Conclusion Rapid induction therapy with TAC tended to be selected for active UC patients with endoscopic evidence of severe disease, and the present study supported the validity of this therapeutic approach. However, transition to the remission-maintenance phase was more favorable in the anti-TNF group.


Radiology Case Reports | 2012

Secondary aortoduodenal fistula without gastrointestinal bleeding directly detected by CT and endoscopy

Takaaki Iwaki; Hiroyuki Miyatani; Yukio Yoshida; Tomohisa Okochi; Osamu Tanaka; Hideo Adachi

We describe a 50-year-old man with a secondary aortoduodenal fistula who presented with high fever and right leg pain one year after undergoing an aortoiliac bypass with a polyester graft. Gangrene had developed in the right ankle, and contrast-enhanced computed tomography (CT) revealed that the graft had penetrated the third duodenal segment and obstructed the right graft limb. Esophagogastroduodenoscopy confirmed that the graft had perforated the duodenum. A preoperative diagnosis of aortoenteric fistula can be very difficult. In spite of the lack of gastrointestinal bleeding in this case, we directly diagnosed secondary aortoduodenal fistula preoperatively using computed tomography and esophagogastroduodenoscopy. Secondary aortoenteric fistulae should be suspected when a patient with an aortic prosthesis shows symptoms in the lower limb.

Collaboration


Dive into the Hiroyuki Miyatani's collaboration.

Top Co-Authors

Avatar

Yukio Yoshida

Jichi Medical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takaaki Iwaki

Jichi Medical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Hideaki Honda

Jichi Medical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Takeharu Asano

Jichi Medical University

View shared research outputs
Researchain Logo
Decentralizing Knowledge