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Dive into the research topics where Ryuhei Okada is active.

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Featured researches published by Ryuhei Okada.


Journal of Gastrointestinal and Digestive System | 2017

Observation of the Pharynx to the Cervical Esophagus Using Trans-nasal Endoscopy with Image-enhanced Endoscopy for Early Detection of Head and Neck Cancers

Kenro Kawada; Takuya Okada; Taro Sugimoto; Kazuya Yamaguchi; Yuudai Kawamura; Toshihiro Matsui; Masafumi Okuda; Taichi Ogo; Yuuichiro Kume; Andres Mora; Akihiro Hoshino; Yutaka Tokairin; Yasuaki Nakajima; Ryuhei Okada; Yusuke Kiyokawa; Fuminori Nomura; Yosuke Ariizumi; Takahiro Asakage; Takashi Ito; Tatsuyuki Kawano

Introduction: We started endoscopic treatment for superficial pharyngeal cancer in 1996, and thus far, 97 lesions of 77 cases of superficial head and neck cancer have been detected using trans-oral endoscopy. However, some areas are difficult to observe with trans-oral endoscopy because of the gag reflex. We have therefore applied transnasal endoscopy for observing of the pharynx to the cervical esophagus. Methods: To avoid overlooking cancers located at the floor of the mouth, soft palate and uvula, we first observe the oral cavity. After administering local anesthesia to the nose without sedation, the endoscope is inserted through the nose. When the tip of the endoscope reaches caudal to the uvula, the patient opens his or her mouth wide, sticks the tongue forward as far as possible and makes a makes a vocalization like “ayyy”. The endoscopist then makes the endoscope take a U-turn and observes the oropharynx, particularly radix linguae. To examine the hypopharynx and the orifice of the esophagus, the patient is asked to blow hard and puff their cheeks while the mouth remains closed. This approach provides a much better view of the orifice of the esophagus than is possible with trans-oral endoscopy with deep sedation. Results: In this study, we detected 22 superficial cancers of the oral cavity. Previous efforts to detect such cancers using trans-oral endoscopy have failed. In addition, we were never able to detect early cancers located at base of tongue in the past, but since implementing the intra-oropharyngeal U-turn method, we have detected more than 10 cases. We were also never able to detect early cancers located at the pharyngoesophageal junction in the past, but since implementing the modified Valsalva maneuver, we have detected more than 20 cases. Between 2008 and 2016, a total of 164 cases of 227 lesions of superficial head and neck cancer were detected by trans-nasal endoscopy, which is more than twice as many as were detected with conventional screening. Mucosal redness, white deposits or loss of a normal vascular pattern and proliferation of vascular pattern such as small dots or salmon roe with a close-up view of it are important characteristics to diagnose superficial pharyngeal cancer. Moreover, a brownish area using image-enhanced endoscopy is useful for early diagnosis. With adequate extension of the pharyngeal mucosa using the Valsalva maneuver, observing the protruded areas should prove useful for diagnosing the depth of invasion. Conclusions: Observing the pharynx to the cervical esophagus using trans-nasal endoscopy with imageenhanced endoscopy is useful for early detection of head and neck cancers.


Case reports in otolaryngology | 2017

Case of Superficial Cancer Located at the Pharyngoesophageal Junction Which Was Dissected by Endoscopic Laryngopharyngeal Surgery Combined with Endoscopic Submucosal Dissection

Kenro Kawada; Tatsuyuki Kawano; Taro Sugimoto; Kazuya Yamaguchi; Yuudai Kawamura; Toshihiro Matsui; Masafumi Okuda; Taichi Ogo; Yuuichiro Kume; Yutaka Nakajima; Andres Mora; Takuya Okada; Akihiro Hoshino; Yutaka Tokairin; Yasuaki Nakajima; Ryuhei Okada; Yusuke Kiyokawa; Fuminori Nomura; Takahiro Asakage; Ryo Shimoda; Takashi Ito

Aims. In order to determine the indications of transoral surgery for a tumor located at the pharyngoesophageal junction, the trumpet maneuver with transnasal endoscopy was used. Its efficacy is reported here. Material and Methods. An 88-year-old woman complaining of dysphagia, diagnosed with cervical esophageal cancer, and hoping to preserve her voice and swallowing function was admitted to our hospital. Conventional endoscopy showed that the tumor had invaded the hypopharynx. When inspecting the hypopharynx and the orifice of the esophagus, we asked the patient to blow hard and puff her cheeks with her mouth closed (trumpet maneuver). After the trumpet maneuver, the pharyngeal mucosa was stretched out. The pedicle of the tumor arose from the left-anterior wall of the pharyngoesophageal junction, so we decided to perform endoscopic resection. Result. Under general anesthesia, the curved laryngoscope made it possible to view the whole hypopharynx, including the apex of the piriform sinus and the orifice of the esophagus. The cervical esophageal cancer was pulled up to the hypopharynx. Under collaboration between a head and neck surgeon and an endoscopist, the tumor was resected en bloc by endoscopic laryngopharyngeal surgery combined with endoscopic submucosal dissection. Conclusion. Transnasal endoscopy using the trumpet maneuver is useful for a precise diagnosis of the pharyngoesophageal junction. Close collaboration between head and neck surgeons and endoscopists can provide good results in treating tumors of the pharyngoesophageal junction.


Auris Nasus Larynx | 2014

Successful management of hypoparathyroidism following total thyroidectomy with vitamin D3 alone

Masami Suzuki; Atsunobu Tsunoda; Takeshi Kudo; Ryuhei Okada; Minoru Toyoda

OBJECTIVE To assess the efficacy and safety of a single administration of vitamin D3 for postoperative hypoparathyroidism. PATIENTS AND METHODS Twelve patients with postoperative hypoparathyroidism were enrolled for this study. They had taken calcium and vitamin D3 orally after the surgery and had shown no symptoms of hypoparathyroidism. Then, all patients had changed their regimen to a single administration of vitamin D3 (1α(OH)D3) with monitoring of serum calcium, urine calcium (u-Ca) and creatinine (u-Cre). The dose of vitamin D3 was started at 2.0μg/day and appropriately adjusted to maintain the ratio of u-Ca and u-Cre (u-Ca/u-Cre) at less than 0.3. The physical findings were carefully checked and the serum intact-parathyroid was also estimated. Those data and physical findings were monitored for at least two years. RESULT The maintenance dose of vitamin D3 varied from 0.5 to 3.5μg/day, and the mean dose was 2.04μg/day. All patients tolerated changes of regimen without any symptoms of hyper-/hypocalcemia. CONCLUSION A single administration of vitamin D3 is not only safe but also an easy and cost-effective regimen. This also makes drug control easy and worthwhile both for patients and clinicians. LEVEL OF EVIDENCE 2c.


Anatomical Science International | 2014

Origin, course and distribution of the nerves to the posterosuperior wall of the external acoustic meatus

Juri Kiyokawa; Kumiko Yamaguchi; Ryuhei Okada; Taketoshi Maehara; Keiichi Akita


Nippon Jibiinkoka Gakkai Kaiho | 2012

[Thiel's method of embalming and its usefulness in surgical assessments].

Ryuhei Okada; Atsunobu Tsunoda; Naoko Momiyama; Naomi Kishine; Ken Kitamura; Seiji Kishimoto; Keiichi Akita


Open Journal of Clinical Diagnostics | 2013

Measurement of shear wave velocities coupled with an evaluation of elasticity using ARFI elastography in diagnosis of papillary thyroid carcinoma

Ryuhei Okada; Masami Suzuki; Koji Takeuchi; Hiroyuki Horikoshi; Atsunobu Tsunoda


Open Journal of Gastroenterology | 2018

A Case of Simultaneous Triple Primary Cancers of the Hypopharynx, Esophagus, and Stomach Which Were Dissected by Endoscopic Laryngo-Pharyngeal Surgery Combined with Endoscopic Submucosal Dissection

Kenro Kawada; Taro Sugimoto; Ryuhei Okada; Kazuya Yamaguchi; Yuudai Kawamura; Masafumi Okuda; Yuuichiro Kume; Andres Mora; Tairo Ryotokuji; Takuya Okada; Akihiro Hoshino; Yutaka Tokairin; Yasuaki Nakajima; Yusuke Kiyokawa; Fuminori Nomura; Yoshuke Ariizumi; Shohei Tomii; Takashi Ito; Takahiro Asakage; Yusuke Kinugasa; Tatsuyuki Kawano


Toukeibu Gan | 2017

The effects of transoral surgery for the recurrent hypopharyngeal cancer after radiation therapy with cetuximab

Fuminori Nomura; Taro Sugimoto; Kenro Kawada; Takuro Sumi; Yousuke Ariizumi; Yusuke Kiyokawa; Akihisa Tasaki; Ryuhei Okada; Natsuko Hattori; Tatsuyuki Kawano; Seiji Kishimoto; Takahiro Asakage


Practica oto-rhino-laryngologica | 2017

A Case of Osteosarcoma of the Temporal Region Arising in Fibrous Dysplasia

Yusuke Kiyokawa; Yousuke Ariizumi; Fuminori Nomura; Akihisa Tasaki; Ryuhei Okada; Atsunobu Tsunoda; Seiji Kishimoto; Takahiro Asakage


Journal of Otolaryngology-ENT Research | 2017

The Usefulness of an Intra-Oropharyngeal U-turn Method using Trans-Nasal Endoscopy for Detecting Superficial Squamous Cell Carcinoma of the Base of the Tongue

Kenro Kawada; Tatsuyuki Kawano; Takuya Okada; Kazuya Yamaguchi; Yuudai Kawamura; Toshihiro Matsui; Masafumi Okuda; Taichi Ogo; Yuuichiro Kume; Yutaka Nakajima; Andres Mora; Akihiro Hoshino; Yutaka Tokairin; Yasuaki Nakajima; Ryuhei Okada; Yusuke Kiyokawa; Fuminori Nomura; Yosuke Ariizumi; Taro Sugimoto; Takahiro Asakage; Takashi Ito

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Takahiro Asakage

Tokyo Medical and Dental University

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Fuminori Nomura

Tokyo Medical and Dental University

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Yusuke Kiyokawa

Tokyo Medical and Dental University

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Kenro Kawada

Tokyo Medical and Dental University

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Masami Suzuki

Takeda Pharmaceutical Company

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Taro Sugimoto

Tokyo Medical and Dental University

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Tatsuyuki Kawano

Tokyo Medical and Dental University

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Akihiro Hoshino

Tokyo Medical and Dental University

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Atsunobu Tsunoda

Tokyo Medical and Dental University

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Kazuya Yamaguchi

Tokyo Medical and Dental University

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