endoscopy

endoscopy, medical examination of the interior of the body, usually through a natural body opening, by the insertion of a flexible, lighted optical shaft or open tube. Instruments used include the endoscope, a flexible tube for examination of the esophagus, stomach, and duodenum, and the bronchoscope, a flexible tube for examination of the bronchial tubes. These are passed through the mouth into the respective organs. The examinations are usually performed in a hospital or a physician’s office with local anesthesia. The colonoscope, a flexible tube used for examination of the colon, and the proctosigmoidoscope, a similar instrument used for examination of the rectum and lower colon, are passed through the anal orifice; mild sedation and pain medication are typically administered during these procedures. The cystoscope, a lighted rod, is passed through the urethra for examination of the bladder with local, spinal, or general anesthesia. Today these procedures are generally accompanied by the use of camera or video technology in order to collect images of the tissues being examined. In addition, endoscopes may be designed with digital modifications that facilitate the visualization of tissues.

Three endoscopic procedures require incisions for the introduction of the lighted shaft. The thoracoscope permits examination of the chest cavity and surface of the lungs through a small incision between the ribs. The peritoneoscope allows examination of the abdominal cavity and lower surfaces of the liver and gallbladder through a small incision in the abdominal wall. The culdoscope permits examination of the female pelvic organs through a small vaginal incision.

Fibre-optic endoscopes are pliable, highly maneuverable instruments that allow access to channels in the body that older, semirigid instruments cannot access at all or can access only at great discomfort to the patient. Composed of multiple hairlike glass rods bundled together, these instruments can be more easily bent and twisted, and the intense light enables the endoscopist to see around corners as well as forward and backward. Accessories can be added to the instrument that make it possible to obtain cell and tissue samples, excise polyps and small tumours, and remove foreign objects.

Although fibre-optic endoscopes can be used to visualize the stomach and duodenum, they are unable to reach farther into the small intestine. As a result, examination of the small intestine may require the use of wireless capsule endoscopy (video capsule endoscopy), which consists of a pill-sized camera that is swallowed. The camera transmits data to sensors that are attached to the abdomen with adhesive, and a data recorder that stores image information collected by the camera is attached to a belt worn around the waist. In most cases, the sensors and belt are worn for a period of eight hours, during which time the camera capsule obtains images of nearly the entire length of the small intestine. The images stored in the data recorder are downloaded onto a computer for analysis. The capsule eventually travels the length of the gastrointestinal tract and is excreted in a bowel movement.