Over the past several decades, flexible endoscopy has shifted the management of numerous gastrointestinal diseases from the surgeon to the endoscopist. What had started as a diagnostic discipline has now become one of advanced therapeutic potential. The concept of performing endoscopic surgery has become a reality with the advancement of endoluminal therapies for neoplasia, gastroesophageal (GE) reflux, motility disorders like achalasia and gastroparesis, and obesity. With advanced endoscopic tools at our disposal, endoscopic therapies are increasingly used as rescue therapies as well, especially after foregut surgical interventions. This chapter will address the indications and techniques for upper and lower flexible endoscopy as well as the recent advances in interventional endoscopy.
The flexible endoscope was initially developed in 1957 as an imaging device dependent on the delivery of light and transmission of the image along multiple bundles of chemically treated glass fibers. The fiberoptic bundle is 2 to 3 mm wide and is composed of 20,000 to 40,000 individual fine glass fibers, each approximately 10 μm in diameter.1 When using a fiberoptic endoscope, the endoscopist views the image through the eyepiece at the instrument head, or alternatively, a video camera can be affixed to the eyepiece to transmit the image to a video monitor. The majority of endoscopes in use today are videoscopic, although in many parts of the world, fiberoptic systems are still the standard. In these videoscopic systems, the visualized image is created from reflections onto a charge coupled device (CCD), which is a chip mounted at the end of the endoscope, rather than via the fiberoptic bundles. The CCD chip has thousands of pixels (light-sensitive points), which directly increase image resolution.2
In narrow-band imaging (NBI) endoscopy, filtered light is used to preferentially enhance the mucosal surface, especially the network of superficial capillaries. NBI is often combined with magnification endoscopy. Both adenomas and carcinomas have a rich network of underlying capillaries and enhance on NBI, thereby appearing dark brown against a blue-green mucosal background.3 The use of white light as well as NBI has enabled endoscopists to provide an immediate assessment of small colonic lesions without histopathologic evaluation.4 Gastric mucosal abnormalities are also differentiated by NBI with and without magnification endoscopy.5 NBI can also differentiate squamous from nonsquamous epithelium to help identify Barrett’s esophagus (Figs. 5-1 and 5-2).
Standard white light versus narrow-band imaging of the distal esophagus in patients with Barrett esophagus.
Differentiation of the squamous and columnar mucosa is easily seen in the narrow-band image.
Flexible endoscopes are being created in a wide variety of lengths and diameters, with an assortment ...