The development of flexible colonoscopy followed the introduction of the flexible gastroscope by a few years. The ability to look into the colon extended the view from the rigid sigmoidoscope throughout the entire large bowel.

In the beginning, it was thought that colonoscopy would not be possible by pushing an instrument through the length of the colon from an external position outside the anus. Original attempts at colonic intubation were aided by pulling backward on a swallowed long string that passed through the entire intestinal tract to which a gastroscope was tied. Attempts were also made at positioning the flexible colonoscope through a rigid sigmoidoscope, but none of the methods were accepted.

Dr Bergin Overholt made a latex cast of the sigmoid colon using a rapidly solidifying latex enema in order to understand the convoluted course of the sigmoid colon, and did the first colonoscopy.

Improvements in technology and technical skill advanced the capability of examining further and further into the large bowel, with the early attempts aided by fluoroscopic examination of the abdomen during instrumentation procedures.

A better understanding of intraluminal anatomy led to the discontinuation of reliance on fluoroscopy, and with advances in technique, colonoscopy rapidly became the preferred imaging modality for the large bowel, displacing almost completely the barium enema.

The indications for colonoscopy are myriad, while screening and cancer prevention are becoming the most frequent indication for this examination.

Prior to the development of flexible endoscopy, when a gastroenterologist visualized a polyp on rigid sigmoidoscopy, they would call a surgeon to remove the polyp. Gastroenterologists were not trained in the removal of polyps, although surgeons, even in their residency training, were adept at polypectomy. It was natural therefore for a surgeon to develop techniques of polypectomy through the flexible colonoscope.

The first application of colonoscopic polypectomy was introduced by Dr Hiromi Shinya in New York City using a home-made wire passed through a thin plastic catheter. An assistant hand-held the connection between the active cord of an electrosurgical unit and a hemostat clamped on the wire after the polyp was encircled. Over the next few years, rapid developments occurred so that polypectomy is now a standard therapeutic application in the large bowel.

Almost all polyps can be removed, and submucosal injections of various solutions have made resection of large polyps easier and safer. There is little controversy about the indications for and against the need for surgery when a polyp contains invasive cancer, and these concepts have become well accepted over the past several years. The role for colonoscopy in lower GI bleeding and in inflammatory bowel disease has evolved largely due to the work of investigators in these fields who have written these chapters.

Colonoscopy is now a discipline that is neither a medical or surgical tool, but addresses a broad range of medicine including internal medicine, gastroenterology, surgery, pathology, radiology, pediatrics, and molecular biology. The future will see other developments in instrumentation, techniques, and applications. The chapters reproduced in this e-book are representative of the textbook Colonoscopy: Principles and Practice published by Blackwell Publishing, Ltd, in 2004 with 54 chapters edited by Jerome D. Waye, Douglas K. Rex, and Christopher B. Williams.

Copyright © Blackwell Publishing, 2004