During the last half century, two achievements can be considered as major advances in the field of gastroenterology: the adaptation of fiberoptics to gastrointestinal endoscopy, and, as a consequence, the discovery of Helicobacter pylori [1,2]. Indeed, the role of H. pylori would not have been suspected without the pathologic and microbiologic study of biopsy material obtained with the endoscope. Attempts to inspect in vivo the internal cavities of the human body are probably as ancient as medicine itself. The challenge was to find a safe source of light that would not generate heat that could damage tissues.

The precursors

As early as the end of the 18th century, the Lichtleier, an ancestor of the modern proctoscope, paved the way with a system of lenses illuminated by candlelight. The name “endoscope” was coined as early as 1853 by A.J. Desormeaux for an instrument used in urology [3] while the first “gastroscope” was developed in Erlangen by A. Kussmaul [4]. These instruments were hampered by the fact that they could not direct enough light to the targeted site. With the invention of the electric bulb, a better insight became possible, but these instruments could not be used for prolonged periods of time because of the heat generated by the light bulb.

In 1881, Mikulicz performed the first gastroscopy in a human being using a rigid instrument of 65 cm long and 14 mm diameter [5]. This angulated instrument compensated for the anatomical angulations of the human esophagus and was equipped with a water circulation system to cool the light bulb and channels for the light source and to introduce air.

In 1932, the first semiflexible gastroscope was developed by instrument maker and technician George Wolf and gastroenterologist Rudolf Schindler who is widely rated as “the father of gastroscopy.” This instrument allowed a greater range for examination, facilitating diagnosis and endoscopic treatments.

We cannot leave the discussion of semiflexible gastroscopy without mentioning one of the most decorated American gastroenterologists, Walter L. Palmer, who brought a new level of understanding to the diagnosis and treatment of digestive diseases, particularly peptic ulcer, gastrointestinal cancer, and ulcerative colitis. In 1934, he facilitated the release of Dr. Schindler from a Nazi concentration camp where he was held because of his part‐Jewish blood. Eventually, Dr Schindler immigrated to the US. In 1941 he founded the Gastroscopic Club, now the American Society for Gastrointestinal Endoscopy, and became its first president.

The fiberscope

The development of fiberoptics led to the birth of modern gastrointestinal endoscopy.

In the hybrid semiflexible gastroscope built by the German instrument maker Storz in 1966, lenses were used for visualization while the electric light bulb was replaced by optical fibers made of either glass or plastic. Plastic fibers were more flexible and durable than glass; however, glass optical fibers could be manufactured with diameters smaller than their plastic counterparts, and the quality of light transmission was superior in glass optical fibers. The next improvements in fiberoptic technology were due to optical engineers who considered the possibility of fiberoptics transmitting not only light but also images. In 1954, two articles were published in the same issue of Nature, a brief note by van Heel on the “transport of images” and an extensive article on a flexible fiberscope by Harold Hopkins of London and his co‐worker Narinder Singh Kapany [6]. Thanks to the collaboration between Basil Hirschowitz and the physicist Larry Curtiss who succeeded (with the aid of Corning Glass) in producing high‐quality fiberoptics, clinical application of fiberoptics to gastrointestinal endoscopy became possible and was reported in Gastroenterology in 1958 [7].

Prototype fiberscopes were made by American Cystoscope Makers (ACMI) in 1960 and a commercial model was produced in 1961 with the first color images published in the Lancet [8]. Because of the high prevalence of gastric cancer in Japan, the Machida Company developed fiberendoscopy and soon the technicians at Olympus, led by the engineer Kawahara, produced many fine models of high optical quality with side‐ and front‐viewing capabilities [9].

Following the adaptation of fiberoptics for medical instruments, endoscopy of the GI tract became a routine diagnostic and therapeutic tool in many gastroenterology units throughout the world. In the early 1970s, the curiosity of a few pediatric gastroenterologists and surgeons was stimulated by the growing interest in endoscopy and its diagnostic success in adult gastroenterology. At that time, gastrointestinal endoscopy in children was performed with the standard adult gastroscopes, bronchoscopes and prototypes of pediatric fiberscopes which were available in a few pediatric hospitals in Europe, United States and Japan [9–14].

During the middle and late 1970s, several publications demonstrated the safety, diagnostic and therapeutic value of pediatric GI endoscopy, contributing to our knowledge of many GI diseases in infants and children [15–23]. Although the literature was not readily accessible, similar skills were developing in Eastern Europe and Russia [24–27]. Less than 10 years after its introduction in pediatric gastroenterology, endoscopy was the subject of several books in Spanish, German, and English [28–30]. By middle and late 2000s, an extensive knowledge of pediatric GI endoscopy was summarized in additional books [31–23].

Today, training in pediatric gastroenterology is not complete without acquiring competence in diagnostic upper gastrointestinal endoscopy and colonoscopy and basic therapeutic endoscopic GI procedures [34]. Diagnostic endoscopy has become a routine part of pediatric gastroenterology, combining the advantage of direct visual observation of the GI tract with target mucosal biopsy and therapeutic procedures.

The arsenal of accessory instruments has been diversified and very much improved whether dealing with foreign body extraction, diathermic loops for polypectomy, sclerotherapy needles and bands (silicon or latex) for variceal eradication, dilation bougies and pneumatic balloons, hemostatic clipping devices and electro‐ and photocoagulation devices for hemorrhagic lesions, and gastrostomy kits. The reliable use of these tools needs constant maintenance by skilled staff and good training to guarantee a safe procedure.

Training

The great progress of the video endoscopic equipment has rendered teaching and training a simpler task through participation of the trainee in the procedure. A growing number of “train the trainer” courses has also been implemented worldwide, with focused programs in Australia, United Kingdom, and Canada. Computerized programs and simulators have been developed and are very useful to familiarize the trainee with the space distribution of organs and to learn to exert the right movements of the endoscope to reach the targeted organ or perform a delicate therapeutic procedure [35–38].

Also, several good “hands‐on” courses with live demonstrations and training on porcine models have been developed in Belgium, France, Italy, the Netherlands, UK and United States. Finally, the trainee should complete their training in a reputed pediatric center, large enough to get the necessary experience and with support from an experienced pediatric gastroenterologist.

Evolution

The improvements that have occurred in instruments, sedation and anesthesia during the last 40 years have transformed pediatric endoscopy and gastroenterology. Pediatric gastroenterologists are now able to perform difficult diagnostic and therapeutic procedures that used to be left to the adult endoscopist, such as endoscopic ultrasonography. These procedures likely need to be concentrated in referral tertiary hospitals that can afford the costly equipment and specialized staff. These highly specialized units can safely count on such facilities as surgical and intensive care assistance, in case of adverse events because one should always bear in mind that endoscopy is an invasive procedure with inevitable risks. The constant progress in instrument quality has considerably enhanced the diagnostic power of endoscopy. Several instrument makers have implemented optical zooms but also more sophisticated methods such as dyeless virtual chromoendoscopy, Olympus Narrow Band Imaging (NBI®), Fujinon Flexible Spectral Imaging Color Enhancement (FICE®) and Pentax™ i‐Scan®.

Mechanical improvements have enhanced the maneuverability of the endoscopes, for instance the adjustable stiffness of colonoscopes that facilitates access to the whole colon, insertion into the ileocecal valve and exploration of the terminal ileum. Exploration of the upper GI tract beyond the proximal jejunum and the terminal ileum is also possible with the double balloon enteroscope [39], which permits not only visualization of small bowel lesions but also biopsies and polypectomy. The most spectacular progress has been the wireless video capsule endoscopy (WCE) which allows exploration of the complete small bowel [40,41] matched with an array of enteroscopes which can traverse the deepest parts of the small intestine to complement findings seen on the WCE.

Conclusion

Endoscopy is undoubtedly an invasive technique and invasiveness is not welcomed in pediatrics. However, there is no doubt that GI endoscopy has a promising future in the field of therapeutic and interventional endoscopy with more improvements to come.

Gastrointestinal endoscopy in children has evolved from a rather confidential tool in the early 1970s, available to very few pediatric gastroenterologists with special skills and curiosity, to a routine diagnostic technique present in almost all pediatric gastroenterology units throughout the world. The stimulating adventure granted to the early “discoverers” has been replaced by less thrilling but probably more useful procedures since continuous improvement of the instruments allows deeper and more audacious therapeutic procedures.