Where Next for the Endoscope?

Ricardo A. Natalin; Jaime Landman

In This Article

History of Endoscopic Urology

The concept of examining the body's interior and its organs dates back to ancient times. The Hippocratic Corpus records perhaps the first successful rudimentary efforts at endoscopy, which used a rectal speculum. Although various historic references to devices and examination techniques to study the human body can be found, most historians consider the first modern attempts at endoscopy to have been initiated by Philipp Bozzini (1773–1809; Figure 1a), who in 1806 introduced his 'Lichtleiter', or light conductor, in an effort to study hollow organs and human body cavities (Figure 1b). The Lichtleiter was constructed with angled mirrors positioned to project the image of internal structures to the human eye. The device incorporated a single candle as a light source to illuminate the body interior, and double aluminum tubes to be inserted into the body orifice that was being studied. The Lichtleiter is considered the first known endoscope in modern medicine.[1] Its urologic utility was limited, however, as it allowed inspection of only a small area of the bladder mucosa and the poor extracorporeal lighting compromised efficient organ evaluation.

Figure 1.

Bozzini and his Lichtleiter. a | Philipp Bozzini (1773–1809). b | The Lichtleiter or light conductor.

A French urologist, Pierre Salomon Segalas (1792–1875), improved the Lichtleiter in 1826 by adding an extra candle as a light source and making a new cannulated catheter that drained the bladder and facilitated its inspection. This device was constructed from a gum elastic material in order to improve the safety and comfort of the procedure. Despite some improvement, this 'speculum urethra-cystique'[2] similarly failed to enable effective inspection of the bladder.

The term 'endoscope' is credited to the French urologist Antonin Jean Désormeaux (1815–1894), and was introduced in 1853 to describe a device based on Bozzini's Lichtleiter. Désormeaux replaced the candle with a bright flame achieved by burning a solution of 96% alcohol with turpentine, which produced a beam of light that could be focused, enhancing the endoscopic examination. Désormeaux also reconfigured the mirror angles used in the system so that the light could be concentrated more precisely, which enabled better visualization of the region reached by the reflected light beam.[1] Désormeaux performed the first successful endoscopic surgery when he reported the endoscopic excision of a urethral papilloma and urethral strictures—procedures made possible by the superior visualization of his system.[3] Despite this improvement, Désormeaux's endoscope still lacked sufficient illumination and was only able to inspect a field millimeter by millimeter.

Recognizing the limitations of existing endoscopes, Maximilian Nitze (1848–1906) made two brilliant modifications to create what many historians consider to be the first successful contemporary endoscope (Figure 2). In 1876, Nitze augmented his device with prisms and lenses, which permitted transurethral visualization of the bladder with a wide field of view. Additionally, he introduced the first intracorporeal light source at the tip of the instrument, using a water-cooled electric platinum filament lamp.[4] Nitze's cystoscope was initially cumbersome to use owing to the complicated and elaborate water-cooling system. Additionally, insertion of the endoscope was difficult, and the device produced an inverted image. Despite these drawbacks, however, the device proved to be very functional as it enabled visualization of the bladder interior. Nitze not only revolutionized endoscopy, but his cystoscope clearly paved the way for minimally invasive surgery.[5] In 1910, Christian Jacobaeus used the Nitze cystoscope to perform the first endoscope-guided laparoscopy.[4]

Figure 2.

Nitze's cystoscope.

The invention, in 1878, of the vacuum lamp—a carbon filament confined in a vacuum glass—led to production of the mignon lamp, a small vacuum lamp that fitted perfectly at the end of a cystoscope. In 1883, David Newman was the first to adapt the incandescent electric bulb for use with the cystoscope. This modification greatly simplified the cystoscope and reduced the cost of its manufacture, which brought it into widespread use.

Urologic endoscopic treatment was vastly enhanced by the development of the resectoscope in 1926 by Maximilian Stern (1877–1946). In 1931, incorporation of a moving cutting loop into the resectoscope made this instrument suitable for use in transurethral resection procedures. These procedures soon became standard for most cases of benign prostatic hyperplasia and superficial bladder tumors.[6]

Another significant advance in endoscopy was the introduction of the zoom lens and rod-lens system, commonly referred to as the Hopkins telescope after the physicist Harold Hopkins. The use of glass fibers (fiberoptics), first for illumination and later for flexible optics, further advanced endoscopy. The introduction of coherent glass fiber bundles, and their ability to carry true video images, allowed for the creation of the first flexible endoscopes.[7] French researchers pioneered the use of video cameras in endoscopy in 1956, which improved ergonomics, enhanced safety and increased success rates.[8] In 1963 the first use of a flexible-fiber ureterorenoscope was reported.[9]

Nowadays, a wide variety of urinary tract disorders are successfully treated in a minimally invasive manner owing to the endoscope and related technologies (Table 1). Fiberoptic technology is widespread, but remains a 'fragile' modality with distinct imaging limitations that are intrinsically insurmountable.