Transnasal gastroscopy

Our center utilizes transnasal upper gastrointestinal (GI) endoscopy (nasal gastric camera).

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When hearing "gastric camera," many people instinctively feel it sounds painful and unpleasant. The discomfort associated with transoral endoscopy occurs because the endoscope presses against the base of the tongue, triggering a pharyngeal reflex. For sensitive patients, this induces a gagging reflex similar to vomiting.

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In contrast, transnasal endoscopy does not press against the base of the tongue with the endoscope, so it rarely causes vomiting due to the pharyngeal reflex. Another major advantage of the transnasal insertion method is that patients can converse normally during the exam, allowing them to undergo the procedure in a relaxed state.

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Furthermore, with transoral endoscopy, it is necessary to thoroughly numb the pharyngeal area with a local anesthetic beforehand to suppress the gagging reflex. In highly sensitive patients, the procedure is sometimes performed under general anesthesia or sedatives to render the patient unconscious. Generally, in American hospitals, gastric endoscopy is performed using this latter method, meaning the effects of the anesthesia linger for a while afterward, leaving the patient groggy and unable to drive on the day of the exam. On the other hand, transnasal endoscopy usually only requires thoroughly numbing the nasal cavity and administering medication to prevent bleeding in the nose, making it possible in most cases. For the purpose of screening asymptomatic patients, it places minimal burden on the body, making it a highly desirable examination method. Since the development of transnasal gastroscopies, an increasing number of facilities conducting ningen dock (comprehensive medical exams) in Japan have replaced barium swallow X-rays—which expose patients to significant radiation—with gastric endoscopies.

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Up until now, barium swallow exams were primarily performed in Japan for the early detection of gastric cancer. Compared to endoscopy, barium exams are certainly simpler to perform and less costly. However, whether an early-stage gastric cancer can be detected using barium depends entirely on the technique of taking and reading the X-ray images. Japan is the country where the double-contrast imaging method was developed, and the techniques for taking and reading barium X-rays in Japan are the best in the world. In Japan, barium exams performed by veteran physicians and technicians meticulously examine subtle disruptions in the gastric mucosal structure, greatly contributing to the early detection of gastric cancer and the reduction of gastric cancer mortality rates. In contrast, the incidence rate of gastric cancer in the U.S. is overwhelmingly lower than in Japan, and barium exams themselves are rarely performed, meaning their quality unfortunately falls far short of Japan's standards.

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What about gastroscopy? The strength of a gastric camera is its ability to directly view the condition of the esophageal, gastric, and duodenal mucosa from the inside with the naked eye. It can clarify changes in color tone and the presence of bleeding, which are difficult to discern with barium X-rays. Not only can it detect lesions with raised or depressed surfaces, such as polyps and ulcers, but it can also detect completely flat lesions through changes in color tone. Another major advantage of gastroscopy is the ability to take tissue samples (biopsies) for pathological testing if a suspicious lesion is found. Needless to say, barium exams—which expose patients to a significant amount of radiation—are particularly undesirable for women who may become pregnant in the future.

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The models introduced at our clinic are Pentax's ultra-slim electronic scopes, EG16-K10 and EG-1580K, as well as Olympus's GIF-180N, the world's smallest-diameter electronic gastric camera. With outer diameters as small as 5.4mm, 5.1mm, and 4.9mm respectively, transnasal examinations are possible for almost all patients. If suspicious findings are present, tissue tests can be performed as needed. If insertion through the nose proves difficult, it is possible to switch to transoral insertion. Even in this case, because the camera itself is extremely thin, patients can undergo the transoral procedure much more comfortably than with conventional, thicker cameras. The video images taken during the exam are digitized and recorded onto a hard drive. Following the gastroscopy at our clinic, patients review the footage of their own stomach and duodenum alongside the physician while listening to their explanations.

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While it is true that gastroscopy is slightly more uncomfortable than a barium exam, we actively recommend the higher-quality, information-rich gastroscopy for the early detection of gastric and esophageal cancer.