Initially developed as an extension of cystoscopy, ureteroscopy has become a major technique for the diagnosis and treatment of upper urinary tract disorders. At the end of the 1970s, the method was limited to the management of only a small number of lesions of the distal ureter ( ); today the entire upper urinary tract can be approached for diagnosis and treatment by using retrograde ureteroscopy. This progress is a result of the development of rigid and flexible ureteroscopes and of adequate accessory instruments. The first endoscopic explorations were performed by Bozzini in 1806, using small caliber cannulas, the light source being a candle ( ). It was only at the end of the nineteenth century that the first cystoscope with a warm light source was created by Nietze.
The first description of the retrograde endoscopic approach of the upper urinary tract came from Hugh H. Young ( Fig. 1.1 ) who, in 1912, explored the dilated distal ureter of a patient with posterior urethral valves using a 9.5 F pediatric cystoscope ( ). This method had obvious limitations, making it necessary to develop specific instruments that allowed for the easy approach of the upper urinary tract, including the pyelocaliceal system. Significant advances occurred half a century later, leading to the appearance of modern rigid ureteroscopes. The most important role was the development by Hopkins in 1960 of cylindrical lens systems that allowed for a significant increase of light transmission along endoscopes. This made possible the appearance of low-caliber rigid ureteroscopes.
The pioneering period in the field of optical fibers started in 1854 when John Tyndall ( Fig. 1.2 ), resuming one of Colladon’s experiments from 1841, demonstrated in London the possibility of guiding light through a curved jet of water, due to the phenomenon of total internal reflection. The first patent for the transmission of light through optical fibers was granted in 1972, legitimizing this scientific breakthrough that paved the way for the construction and development of flexible endoscopes.
The first flexible ureteroscopy was reported by Marshall in 1964 ( ). He used a 9 F instrument produced by “American Cystoscopes Makers Inc.,” without a working channel and active deflection possibilities, being a purely diagnostic procedure. Takagi in 1966 and then Bush also reported the successful achievement of ureteropyeloscopies using flexible instruments with the same technical characteristics as that of Marshall. Without a proper irrigation system, they used forced diuresis in order to obtain a clearer image of the endoscopic field ( ).
Further technical advances allowed for the development of ureteroscopes and the improvement of accessory instruments necessary for the endoscopic procedures in the upper urinary tract ( Fig. 1.3 ).
Rigid ureteroscopy entered current urological practice only at the end of the 1970s. and achieved the assessment of women’s distal ureter using a pediatric cystoscope. However, the reduced length of the instrument did not allow for its routine use. , in cooperation with Richard Wolf Instruments (Rosemont, IL), developed a ureteroscope with a length of 23 cm that allowed for the approach of the distal ureter, both in women and in men. The diameter of the ureteroscope’s sheath ranged from 13 F to 16 F and allowed the use of telescopes with 0–70° lenses. This diameter facilitated the use of accessory instruments with dimensions of over 5 F. On the other hand, the relatively large diameter of the endoscope continued to create difficulties in approaching the ureteral orifice and the intramural ureter. Subsequently, Karl Storz Instruments (Culver City, CA) and Richard Wolf Instruments developed a ureteroscope with a length of 40 cm and a caliber of 9–11 F. The development of these endoscopes marked the beginning of the modern era of ureteroscopy.
Until the 1980s, the design of the ureteroscope underwent continuous development; a reduced diameter and working channels allowed for the use of accessory instruments. With the advances regarding optical fibers technology and with the appearance of reduced diameter working instruments, the diameter of modern ureteroscopes was reduced to 6.9–9.4 F, with an integral sheath and two working channels of 2.1–5.4 F. These miniature semi-rigid ureteroscopes use 5° telescopic lenses and have a length of 33 cm and 41 cm, respectively. The reduced caliber facilitated the access to the upper urinary tract, reducing the aggression on the ureter ( ).
Until 1981, the treatment of ureteral lithiasis was represented by surgical ureterolithotomy or by endoscopic manipulation of stones under cystoscopic control. The disadvantages of these methods were represented by the morbidity of open surgery, respectively by the reduced success rate of “blind” extraction of stones. The first endoscopic extraction of ureteral stones under ureteroscopic control was achieved by . Initially, the technical and safety difficulties of the intervention prevented the widespread use of ureteroscopy, the major disadvantage being the dimensions of the instruments.
The development of ureteroscopes with a length of 50 cm allowed the retrograde approach up to the level of the pyelocaliceal system. This development was produced by Karl Storz Endoscopy, and was based on the research conducted together with Perez-Castro Ellendt and Martinez-Pineiro ( ). These represented the basis for the subsequent evolution and progress of ureteroscopes with different lengths (25–54 cm), optical systems, and diameters (9–16 F).
The technical difficulties in achieving a rigid ureteroscopic approach are determined by the need for ureteral dilation and by the impediments in advancing the instruments along the ureter, in overcoming the sinuosities, and the areas with a reduced caliber. The modalities for overcoming these impediments represented the object of many studies regarding how to facilitate advancing the rigid ureteroscope into the middle ureter, especially in men. The attempt to solve these problems, as well as the desire to retrogradely approach the entire upper urinary tract, led to the introduction of semirigid and flexible ureteroscopes into current practice ( ). Their use implied the progress of accessory instruments, with the development of extracting forceps, basket catheters, and lithotripsy probes with calibers of 1.9–2 F.
In the early 1980s, at Chicago University, Bagley, Huffman, and Lyon started the development of the flexible ureteroscope, adding three essential technical features: the working channel, the irrigation system, and active deflection ( ).
In 1990, flexible ureteroscopes had a 10 F diameter, a standard working channel of 3.6 F, and a unidirectional active deflection. Today, due to the miniaturization of optical fibers, the average dimensions of the instruments have been reduced to 7.5 F; the deflection system has also been enhanced, with the increase of amplitude and even the presence of two active areas.
With the technological development, the indications for the ureteroscopic approach have also been diversified. Thus, in 1982 Goodman described the retrograde ureteroscopic approach as a conservative method for treating upper urinary tract urothelial tumors ( ).
Together with the development of endoscopes, a similar evolution of the energy sources was recorded. The first attempt of intracorporeal lithotripsy belongs to who used a 0.8 kHz ultrasonic lithotripter. In 1955, Coates managed to obtain a partial fragmentation of stones using a 15 kHz device ( ). In 1983, Huffman reported the use of ultrasonic lithotripsy during ureteroscopic interventions ( ).
The elecrohydraulic lithotripter was invented by Yutkin in 1955, at Kiev University. However, the political situation at that moment initially limited its use to within the East-European Bloc only ( ). In 1985, Green and Lytton reported the use of electrohydraulic lithotripsy in the ureteroscopic treatment of ureteral lithiasis ( ), while Begun, in 1988, used this method during flexible ureteroscopy.
described the Swiss lithoclast, a pneumatic lithotripsy device whose development was based on the principles stated by Heurteloup in 1932 for bladder stones fragmentation ( ). The main disadvantage of this type of safe and efficient lithotripsy is the impossibility of using it on the increasingly popular flexible ureteroscopes. In 1994, Grasso and Loisides published the experimental results of a pneumatic lithotripter with nitinol flexible probes ( ). attempted the lithotripsy of a bladder stone using a ruby laser. Initially used by Watson in 1984, pulsed-dye laser was the first type of laser that positioned itself as a source of energy for lithotripsy ( ). Subsequently, other lasers were developed and used: Alexandrite, Nd:YAG, Ho:YAG, etc. The first description of the potential for using the Ho:YAG laser in urology belongs to Johnson, in 1992 ( ). The first results of this type of laser in intracorporeal lithotripsy were published in 1995, demonstrating its efficacy and safety ( ).
The development of accessory instruments was dictated by the features of the endoscopes and energy sources. In 1983, Huffman introduced the balloon dilation of the ureteral orifice. published the first results of nitinol basket catheters, while in 2001, Dretler described a new instrument, the so-called “stone cone” or “Dretler cone,” designed to prevent the ascent of ureteral lithiasic fragments during lithotripsy ( ).
Two other historical landmarks that should not be overlooked are the first upper urinary tract photographic image obtained by Takagi in 1968, and the first video recording of the upper urinary tract by Takayasu in 1970 ( ) ( Table 1.1 ).