What is endoscopy?

Indications and Procedures

Early endoscopes were simply rigid hollow tubes with a light source. They were inserted into body orifices, such as the anus or the mouth, to allow the physician to look directly at structures and processes within. Modern instruments are more sophisticated. They often use fiber optics in flexible cables to penetrate deep into body structures. For example, one form of colonoscope can be threaded though the entire lower intestine, allowing the physician to search for pathologies all the way from the anus to the cecum of the colon (large intestine).

There are eight basic types of endoscope: gastroscope, colonoscope, bronchoscope, cystoscope, laparoscope, colposcope, arthroscope, and amnioscope. Their primary uses are diagnostic; however, they can be fitted with special instruments to perform many different tasks, including taking bits of tissue for biopsy and carrying out surgical procedures.

Uses and Complications

The gastroscope and its variants are used to inspect structures of the gastrointestinal system. The name of one class of procedure gives an idea of how sophisticated the gastroscope has become: esophagogastroduodenoscopy. As the term implies, this technique can be used to investigate the esophagus (the tube leading to the stomach), the stomach itself, and the intestines all the way into the duodenum (the first link of the small intestine). Furthermore, in a procedure called "endoscopic retrograde cholangiopancreatography," the endoscope can be used to investigate processes in the gallbladder, the cystic duct, the common hepatic duct, and the common bile duct. By far the most common use of the gastroscope is in the diagnosis and management of esophageal and stomach problems. The gastroscope is used to confirm the suspicion of stomach ulcers and other gastroesophageal conditions and to monitor therapy.

The colonoscope and its variants are critical in the diagnosis of diseases in the lower intestine and in some aspects of therapy. The long, flexible fiber-optic tube can be threaded through the anus and rectum into the S-shaped sigmoid colon
(flexible fiber-optic sigmoidoscopy). The tube can be made to rise up the descending colon, across the transverse colon, and down the ascending colon to the cecum. With the colonoscope, the physician can discover abnormalities such as polyps, diverticula, and blockages and the presence of cancer, Crohn’s disease, ulcerative colitis, and many other diseases. The physician can also use the colonoscope to remove polyps; this is the major therapeutic use of colonoscopy.

Like most other forms of endoscopy, bronchoscopy is used for both diagnosis and treatment. The bronchoscope allows direct visualization of the trachea
(the tube leading from the throat to the lungs) and the bronchi (the two main air ducts leading into the lungs). It will show certain forms of lung cancer, various infectious states, and other pathologies. The bronchoscope can also be used to remove foreign objects, excise local tumors, remove mucus plugs, and improve bronchial drainage.

The cystoscope is used for visual inspection of the urethra and bladder. The bladder stores urine; the urethra is the tube through which it is eliminated. Cystoscopy
discovers many of the conditions that can afflict these organs: obstruction, infection, cancer, and other disorders.

The laparoscope is used to look into the abdominal cavity for evidence of a wide variety of conditions. It can inspect the liver, help evaluate liver disease, and take tissue samples for biopsy. Laparoscopy
can confirm the diagnosis of ectopic pregnancy (a condition in which a fetus develops outside the uterus, usually in one of the Fallopian tubes). It can confirm the presence or absence of abdominal and female reproductive cancers and diagnose disease conditions in the gallbladder, spleen, peritoneum (the membrane that surrounds the abdomen), diaphragm, ovaries, and uterus, as well as give some views of the small and large intestine. Importantly, the laparoscope is commonly used to remove gallbladders (cholecystectomy
). This procedure is far less traumatic than the old surgery, often permitting release of the patient a day or two after the operation rather than requiring weeks of recuperation. Likewise, many other surgeries, such as appendectomies, gastric bypasses, hysterectomies, and colectomies, are also now performed laparoscopically.

The colposcope is used to inspect vaginal tissue and adjacent organs. Common reasons for colposcopy include abnormal bleeding and suspicion of tumors.

Arthroscopy
, the investigation of joint structures by endoscopy, is now the most common invasive technique used on patients with arthritis or joint damage. In addition to viewing the area, the arthroscope can be fitted with various instruments to perform surgical procedures.

The term “amnioscope” comes from the amnion, the membrane that surrounds a fetus. This type of endoscope is used to enter the uterus and inspect the growing fetus in the search for any visible abnormalities.

Endoscopy is one of the most useful and most used techniques for diagnosis because it permits the investigation of many internal body organs without surgery. It is extraordinarily safe in the hands of experienced practitioners and is relatively free of pain and discomfort for patients, although there are risks of bleeding, pain, infection, and rarely, perforation of the tissue wall. In addition, specialized endoscopes are assuming greater roles in therapy. Many procedures that once involved major surgery can now be conducted through endoscopy, saving the patient pain, trauma, and expense.

Perspective and Prospects

Endoscopes have become highly sophisticated instruments with enormous range throughout the body and enormous potential. Colonoscopy, for example, promises to revolutionize the treatment of cancerous and precancerous polyps by helping physicians attain a clearer understanding of the polyp-to-cancer progression. The laparoscope has revolutionized gallbladder removal, as the arthroscope has revolutionized joint surgery. The gastroscope gives the physician new security and control in the management of gastrointestinal conditions, and the bronchoscope facilitates many lung procedures.

Similarly throughout the entire range of endoscopy, new opportunities are opening and leading to significant improvements in therapy, and these improvements will continue. Wireless electronic and video techniques are being introduced into endoscopy, and this new technology promises to widen the applications and therapeutic range of endoscopy still further.

Bibliography

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Litin, Scott C., ed. Mayo Clinic Family Health Book. 4th ed. New York: HarperResource, 2009.

Scott-Conner, Carol E. H., ed. The SAGES Manual: Fundamentals of Laparoscopy, Thoracoscopy, and GI Endoscopy. 2d ed. New York: Springer, 2006.