endoscope
An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical device, which is used to look deep into the body by way of openings such as the mouth or anus. A typical endoscope applies several modern t ...
Etymologically
Etymology () The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the form of words ...
, the word could potentially refer to any bowel endoscopy ('' entero-'' + '' -scopy''), but idiomatically it is conventionally restricted to small bowel endoscopy, in distinction from
colonoscopy
Colonoscopy () or coloscopy () is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It can provide a visual diagnosis ( ...
Spiral enteroscopy
In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point.
Helices
Two major definitions of "spiral" in the American Heritage Dictionary are:Capsule endoscopy
As the small bowel can often be a source of pathology, endoscopy of the small bowel can be a useful diagnostic and therapeutic technique.
Esophagogastroduodenoscopy
Esophagogastroduodenoscopy (EGD) or oesophagogastroduodenoscopy (OGD), also called by various other names, is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum. It is considere ...
, also called upper endoscopy, gets as far as the first segment of the small bowel, the
duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine ...
, but the next two, the
jejunum
The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialised for the absorption by enterocytes of small nutrient molecules which have been previou ...
and
ileum
The ileum () is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine m ...
, require other methods. Visualization of the small bowel has long posed a challenge to
gastroenterologists
Gastroenterology (from the Greek gastḗr- “belly”, -énteron “intestine”, and -logía "study of") is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, ...
, due to the physical difficulty of reaching more
distal
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
regions of the small bowel. With the advent of the newer forms of enteroscopy, such as the double-balloon type, visualizing the entire tract is finally a practical reality in at least some cases, although it is still technically demanding.
Traditional gastroscopes can generally visualize the proximal and distal
duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine ...
in the hands of experienced endoscopists but are limited due to the length of the instrument. Pediatric colonoscopes or sometimes dedicated enteroscopes which are much longer than standard gastroscopes can visualize the proximal
jejunum
The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialised for the absorption by enterocytes of small nutrient molecules which have been previou ...
. This technique is referred to as push enteroscopy. Due to the length of the small bowel, averaging 4–6 meters in the adult, push enteroscopy is still not effective to adequately visualize large portions of the small intestine.
Wireless capsule endoscopy has proven to be the endoscopic investigation of choice for visualization of the entire small bowel. An 11 x 26 mm pill sized video camera is swallowed by the patient and approximately 8 hours of video is transmitted wirelessly to a receiver worn by the patient. The procedure is painless, well accepted by patients and offers a very high accuracy. It is limited by the inability to obtain
biopsies
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a di ...
, and is therefore considered a purely diagnostic tool.
Newer techniques, including single and double-balloon endoscopy have been developed to overcome some of these issues, but are limited by the length of the procedure, and the need for deep sedation or general
anesthesia
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), a ...
. Spiral enteroscopy is a novel technique that utilizes an overtube with raised spirals affixed on the enteroscope that is rotated to advance the enteroscope deep into the small bowel. Each of these 3 enteroscopy platforms offers similar accuracy and effectiveness but do not have widespread availability.