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Retrograde Ureteroscopy in Upper Urinary Tract Lithiasis
alternative. Inferior caliceal lithiasis constitutes an elective indication Figure 3: Retrograde Flexible Ureteroscopic Approach
for the flexible retrograde approach (see
of an Inferior Caliceal Calculus
Figure 3). Although the
success rate of SWL procedures can reach 92%, for calculi in this
location it may decrease to only 41%.
17
The most important advantages of retrograde ureteroscopy in
comparison with other intra-corporeal lithotripsy techniques are
represented by the natural tract approach, as well as the possibility of
complete clearance. By improving the accessibility to the entire
urinary tract, retrograde ureteroscopy may be performed in an
increasing number of patients with malformations or urinary
diversions. The influence of pyelocaliceal anatomy on the success
rate of the retrograde flexible approach is still under debate. However,
this influence is less significant in comparison with that over the
success rate of SWL. It is even more reduced for the new endoscopes
with double active or ‘exaggerated deflection’.
18
Figure 4: Retrograde Flexible Ureteroscopic Approach
to a Middle Caliceal Diverticulum
A method for optimising the flexible ureteroscopic approach in cases
of inferior caliceal lithiasis was represented by lithotripsy after stone
dislodgement to more accessible areas of the pyelocaliceal system. In
calculi smaller than 10mm, Schuster et al. reported a success rate of
77% for cases of in situ lithotripsy in comparison with 89% of patients
in whom the dislodgement technique was performed. For calculi
between 10 and 20mm, the success rates were 29 and 100%,
respectively.
19
Kourambas et al. applied this technique only in cases in
which in situ lithotripsy was impossible, thus increasing the success
rate from 83 to 90%.
20
As far as the pyelocaliceal diverticulae are concerned, currently there
is a large variety of surgical options available for this specific
pathology: open procedures, the retrograde uretero-renoscopic
Figure 5: Holmium-doped:Yttrium–Aluminium–Garnet
approach,
21,22
percutaneous direct or indirect access
23–25
and the
Lithotripsy of Ureteral Lithiasis
laparoscopic approach.
26
Indications for the retrograde ureteroscopic
treatment are limited to the symptomatic diverticulae not larger than
1.5cm in size, with or without intra-diverticular lithiasis, and especially
for those in an anterior position that are difficult to approach
percutaneously
27
(see Figure 4).
New Trends in Ureteroscopic Equipment
Flexible uretero(reno)scopes continue to evolve and improve rapidly,
with new models being introduced each year, some by companies
not previously known to manufacture endoscopes. Difficulties
occurred during attempts to explore certain areas of the
pyelocaliceal system (and especially the inferior calyx), which
enforced improvements to the active deflection system and the
optical system. One of the major requirements was to create models
with two active deflections, ensuring a superior manoeuvrability and in the active deflection amplitude (up to 270º in both directions) and
enabling the approach of lesions that are sometimes inaccessible to range (the so-called ‘exaggerated deflection’). Similarly, the new
single-deflection endoscopes.
28
models of flexible ureteroscopes from Olympus (Olympus, Melville,
New York) and Richard Wolf (Richard Wolf, Knittlingen, Germany)
The first such flexible ureteroscope was ACMI DUR-8 Elite (ACMI offered amplitudes of over 270º of the active deflections.
Corporation, Southborough, Massachusetts), which, in addition to the
upward/downward deflection of 170/180º of the DUR-8 model, Despite new designs with increased deflection and smaller calibres,
allowed a secondary downward active deflection of 130º to be durability was not compromised. Digital video semi-rigid or flexible
obtained. This secondary deflection is achieved by activating a ureteroscopes have recently been introduced. These instruments
second mobile lever placed on the opposite side of the body to the provide the current gold standard image for ureteroscopy, and
flexible endoscope. The Karl Storz company (Karl Storz Endoscopy, involve the incorporation of a charged coupled device (CCD) or a
Tuttlingen, Germany) followed a different concept of improving the complementary metal-oxide semiconductor (CMOS) chip in the
manoeuvrability of the endoscope. Subsequently, the Flex-X distal tip of the endoscope (the so-called ‘chip on a stick’ or ‘chip on
(11278AU1) and the Flex-X2 Storz models benefited from an increase the tip’ technologies). Digital video-ureteroscopes are coupled to
EUROPEAN UROLOGICAL REVIEW 75
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