for Stone Disease


Fig. 11.1

Example of video tower components including light source, processor, and recording devices



Historically, video systems were analogue and interfaced with fiber-optic or rod-lens endoscopes. The camera head would attach to the scope and then transmit the signal to the video processor. Camera heads could be used with a wide range of endoscopes and were not manufacturer specific (Fig. 11.2). The advantage of this system was that it allowed the user to not be limited to endoscopes from one manufacturer, but rather be able to select endoscopes from a variety of manufacturers to best fits ones needs. With the introduction of digital endoscopes, the video processors and endoscopes became tightly linked. Brand X’s endoscope will only connect with Brand X’s video processor. Therefore purchasing decisions, especially when selecting digital instruments, must take this into account.

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Fig. 11.2

Camera head used that is used with fiber-optic endoscopes


Numerous manufacturers produce video systems that are used in urology including Olympus (Tokyo, Japan), Karl Storz (Tuttlingen, Germany), Stryker (Kalamazoo, MI), and Richard Wolf (Knittlingen, Germany). All offer systems that are compatible with analogue (fiber-optic, rod-lens) endoscopes used in endourology. The manufacturers typically scale the systems to suit different price points. Differentiators would include the resolution of the camera head and display system, the type of light source (usually Xenon or LED), the features of the video processor, and whether a recording system is included. The cost of system can range from approximately $15,000 up to over $100,00 (US dollars). Currently Olympus, Storz, and Wolf all produce digital endoscopes for urology. It is important to remember that when selecting digital endoscopes that the video processor from the same manufacturer must be factored into the overall purchase cost.


Light Source


Lighting technology, similar to other industries, has evolved from halogen to xenon and now to light-emitting diode (LED) bulbs. Halogen light sources offer the benefit of lower cost bulbs as compared to xenon and LED, but at the expense of heat generation. The brighter the light, the greater the heat generated. Halogen lights also are not energy efficient, and the bulbs can require frequent replacement. Xenon light sources run cooler than halogen and produce stable light at warm color temperatures allowing for accurate color rendering during procedures. Xenon bulbs last four to five times longer than halogen bulbs and therefore require less frequent replacement. However, Xenon bulbs cannot be dimmed, and an actuator is used to reduce light output when needed. LED light sources are the most recent innovation. LED bulbs have the most consistent light output and longest run time by a wide margin when compared to xenon and halogen light. They are also the most energy efficient and usually run cooler. Although both xenon and LED light sources are currently available, LED will likely completely replace xenon in the future in urologic video systems [1].


Video Processors


The video processor is an essential component of the video system. The process converts the incoming video signal to a format that can be output at the native resolution of the video display. The processor, based on the settings, uses algorithms to attempt to enhance the image that is broadcast on the video display. Most urologists are familiar with the white balance function of the video processor. It is used to correct the color temperature so that the image displayed is not too blue or too yellow. The video processors usually have exposure modes that correct for bright or dark spots in the image. Different exposure modes can be set so that the image is adjusted with peak brightest versus average brightness. Smaller (spot) sampling can be set versus sampling the entire image. This is analogous to settings on a consumer SLR camera. If an image has hot spots, such as the light reflecting off a bright object, then the peak brightness setting tends to work best. However, if the image is more uniform, then I will usually select an averaging setting where the entire image is used to scale the exposure. Often the processor will have basic settings available directly on the front panel, but more advanced settings may be hidden in menu systems.


Some manufacturers have attempted to differentiate themselves by including advanced processing capabilities. One example of this is narrowband imaging (NBI), which is offered on some models of Olympus’ video processors. NBI is an optical technology that changes the spectrum of illumination from broadband blue, green, and red to narrowband blue and green [2]. Illumination of the 415 and 540 nm wavelength facilitates the visualization of the submucosal microvasculature and may aid in bladder tumor detection [3, 4]. Karl Storz offers a competing technology with their D-Light C Photodynamic Diagnostic (PPD) system which enables both white light and blue light (wavelength 360–450 nm) fluorescence cystoscopy (Fig. 11.3). Blue light cystoscopy (BLC) using hexaminolevulinate (HAL/Cysview/Hexvix) has been shown to increase detection rates of carcinoma in situ and papillary bladder lesions over white light cystoscopy alone [5]. While these settings are not used during stone procedures, they may add value to the purchase of a video system.

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Fig. 11.3

Karl Storz Video System with Photodynamic Diagnostic system (PPD). (Courtesy of Karl Storz, Tuttlingen, Germany)


Endoscopes


Rigid Nephroscopes


Nephroscopes are primarily used during percutaneous nephrolithotomy (PCNL) but can also be adapted to be used for the treatment of bladder stones. Prior generation and many current nephroscopes use rod-lens technology, but some of the modern smaller caliber nephroscopes utilize fiber-optic bundles which allow for some flex of the scope without the resultant “half-moon” image that occurs when rod-lens-based scopes are bent. Nephroscopes are available in a range of diameters, lengths, and lens angles. Olympus, Karl Storz, and Richard Wolf all offer models of different lengths and diameters.


When selecting a nephroscope, the tract size used during a PCNL must be considered. For example, if a sheath with a 30 F inner diameter is used, then the nephroscope should be smaller than this, typically 24–26 F. This permits the nephroscope to pass easily through the sheath but still allows for some outflow of fluid around the scope during the procedure, thus facilitating low intrarenal pressures and maintaining adequate visualization. Manufacturers may offer the option of the offset of the eyepiece to be 45° versus 90°. My preference is a 90-degree offset as I find this makes the nephroscope easier to rotate while keeping the camera head in the correct orientation (Fig. 11.4). The length of the nephroscope may also vary between manufacturers. For example, Karl Storz offers their full size (24–26 Fr outer sheath) nephroscope in both a 19 and 24 cm length. My preference here is always the longer length. The longer length facilitates the use in obese patients or in patients with long percutaneous tracts. Longer nephroscopes can also be useful traversing within the kidney such as when trying to reach the lower pole through an upper pole tract. In addition, the longer nephroscopes can be used to approach bladder stones transurethrally and for tissue morcellation after holmium laser enucleation of the prostate (HoLEP). The Storz system has an adapter that allows the nephroscopes to be used with the outer sheath from the Storz resectoscope set. The allows for atraumatic passage into the bladder (Fig. 11.5).

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Fig. 11.4

Nephroscope with 90-degree offset eyepiece


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Fig. 11.5

Nephroscope connected to outer sheath of resectoscope set (standard lens with laser bridge also shown)


For smaller 24 Fr nephrostomy tracts, manufacturers offer a variety of slightly smaller and “slender” nephroscopes. Karl Storz manufactures an 18 Fr nephroscope with a 22 Fr outer sheath and is available with both a 45- and 90-degree offset eyepiece (Fig. 11.6). Similarly, Richard Wolf offers a universal nephroscope (“Model Dresden”) with a small sheath circumference of 20.8–24 Fr and a working channel of 10.5 Fr.

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Fig. 11.6

18 Fr “Slender” nephroscope with 22 Fr outer sheath. Used during PCNL with 24 Fr tract


Briefly, a digital nephroscope utilizing complementary metal–oxide–semiconductor (CMOS) technology was available. Dubbed the “Smith” digital nephroscope, it coupled with Gyrus ACMI’s Invisio Digital processor. It coupled two LED driver light carriers and a 1 mm digital camera, thereby eliminating the need for an external light source and camera head. This scope offered enhanced ergonomics with a pistol grip handle and is lightweight (470 g) [6]. However, after the acquisition of Gyrus ACMI by Olympus, the digital nephroscope production was ceased. To date, no replacement digital nephroscope has become available.


Since the initial reports of “mini-perc” by Jackman in 1998, PCNL with a reduced cross-sectional diameter tract (<20 Fr) has grown in popularity [7]. With reduced tract size, a requirement for the development of a smaller nephroscope occurred. Currently multiple manufacturers, including Olympus, Karl Storz, and Richard Wolf, produce small caliber nephroscopes that are suitable for mini-PCNL. However, where the products differentiate themselves is in what other equipment is part of the mini-PCNL set. For example, Karl Storz manufacturers the “Storz Modular Minimally Invasive PCNL System” (MIPS). This product includes the mini 12 Fr nephroscope, but also a series of one-step dilators (15, 16.5, 21 Fr) and reusable sheaths (16, 17.5, 22 F) (Fig. 11.7). The tightly integrated reusable system decreases the need for costly single-use disposable products. A limitation of the Storz mini-nephroscope is that the irrigation fluid is run through the 6.7 Fr working channel of the nephroscope and there is not an option to run the fluid through the outer sheath. When using larger instruments in the working channel, irrigation flows are greatly reduced. The Richard Wolf 15/18 Fr mini-PCNL system includes a 12 Fr nephroscope with a 12-degree lens that is coupled with an outer sheath measuring 15 or 18 Fr. In contrast to the Storz MIPS system, the outer sheath of Wolf’s system allows for irrigation fluid to be run through it, circumventing the issue with reduced flow with instruments in the working channel of the nephroscope. The Wolf system also offers 12 and 15 Fr dilators. Olympus offers a 15 Fr mini-nephroscope with a 7.5 Fr working channel. It includes a continuous irrigation sheath but does not include dilators.

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Fig. 11.7

Mini-nephroscope with one-step dilator and reusable sheath (Storz MIPS System)


Ureteroscopes



Semirigid


Semirigid ureteroscopes remain an essential component for endourologists to treat stones. They are usually utilized to treat stones in the ureter below the pelvic brim, but also in the mid- and upper ureter in females and occasionally males. Technology for semirigid ureteroscopes has been relatively stable over the past decade. The majority of the semirigid ureteroscopes are fiber-optic and therefore do not have the half-moon effect that a rod-lens-based scope would have when they are flexed. Semirigid ureteroscopes are available in different lengths, ranging from approximately 310 up to 450 mm depending on the make and model. The shorter ureteroscopes are easier to handle and are usually adequate to reach stones in the distal and mid-ureter in men, and throughout the entire ureter in women. The longer semirigid ureteroscopes can be used to reach the upper ureter in men and renal pelvis in both sexes, provided they can be passed without resistance.


There has been a trend toward miniaturization with semirigid ureteroscopes. Most modern semirigid ureteroscopes have a tip diameter of 7 Fr or less and then usually increase in diameter slightly through the shaft. Designs exist with either one large working channel (≈ 4.5 Fr) or two smaller channels (≈ 2–3 Fr) (Fig. 11.8). The advantage of the single channel is that a larger instrument can be accommodated, but irrigation flow may be compromised since the channel is shared. With two separate working channels, one is typically used for the instrument, while the second channel is dedicated for irrigation.

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Fig. 11.8

Examples of semirigid ureteroscopes with either one and two working channels and with offset and straight eyepieces. (© Karl Storz SE & Co. KG, Germany, with permission)


One other differentiating factor for semirigid ureteroscopes is an offset versus a straight lens configuration. An offset lens allows for a straight working channel that will accommodate a rigid instrument such as a pneumatic lithotripsy probe. However, if holmium:YAG laser lithotripsy is the preferred lithotrite, then the working channel does not need to be straight, and an offset lens is not required since the laser fiber is flexible. In my own practice, I find a semirigid ureteroscope with a straight lens more ergonomic to handle during procedures.


Miniaturization of semirigid ureteroscopes has occurred. Richard Wolf produces an ultrathin semirigid ureteroscope, dubbed the “needlescope” that has a 4.5 Fr tip and a shaft that increases to 6.5 Fr. This ureteroscope has a single 3.3 Fr working channel and is available in 315 and 430 mm lengths. The very small distal tip facilitates cannulation of the ureteral orifice and pre-dilation rarely needed. The smaller 3.3 Fr working channel can reduce irrigation flow when a large instrument is passed. For laser lithotripsy, a small caliber fiber with a ≤270 μm core is preferred versus a larger fiber with a 365 μm core. Although initially intended as a semi-ureteroscope for children, it has gained acceptance in treating adults as well. In our hands it has proven to be robust, despite the small size, and is our primary semirigid ureteroscope (Fig. 11.9).

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Fig. 11.9

Wolf semirigid “needlescope” ureteroscope with 4.5 Fr tip



Flexible Ureteroscopes


The advent of small caliber flexible ureteroscopes


coupled with the holmium:YAG laser resulted in a paradigm shift in the management of upper ureteral and renal stones [8, 9]. Shock wave lithotripsy had been the primary treatment option for stones <2.0 cm in the upper tract, but now flexible ureteroscopy with holmium:YAG laser lithotripsy became a viable alternative. After their introduction, flexible ureteroscope technology improved rapidly during the late 1990s and early 2000s resulting in smaller caliber, highly flexible instruments. At present, it is simplest to divide flexible ureteroscopes into several categories: first, fiber optic or digital optics and, second, single use or reusable.



Flexible Fiber-optic Ureteroscopes


Fiber-optic ureteroscopes were the first flexible ureteroscopes widely used in the treatment of stones [8]. Initially technology advanced rapidly, but the development of flexible fiber-optic ureteroscopes has slowed recently. However, they remain a valuable device, and all of the major scope manufacturers continue to produce flexible ureteroscopes. The smaller caliber and tip designs of the flexible fiber-optic ureteroscopes make them the best option for difficult-to-reach tight calyces [10]. Although these scopes share many similarities, there are some subtle differences (Table 11.1).


Table 11.1

Flexible digital ureteroscopes currently on the market

















































































 

Karl Storz


Flex-Xc


Richard Wolf


Cobra Vision


Richard Wolf


Boa Vision


Olympus


URF-V3


Boston Scientific


LithoVue


Distal tip


8.5 Fr


5.2 Fr


6.6 Fr


8.5 Fr


7.7 Fr


Sheath diameter


8.5 Fr


9.9 Fr


8.7 Fr


8.4 Fr


9.5 Fr


Recommended UAS


10/12


11/13


10/12


10/12


11/13


Number of working channels


1


2


1


1


1


Working channel


3.6 Fr


3.6 Fr/2.4 Fr


3.6 Fr


3.6 Fr


3.6 Fr


Angulation UP


270°


270°


270°


275°


270°


Angulation DOWN


270°


270°


270°


275°


270°


Working length


700 mm


680 mm


680 mm


670 mm


≈ 680 mm


Viewing angle


90°


90°


90°


80°


90°



UAS ureteral access sheath


Karl Storz currently produces the Flex-X2S fiber-optic ureteroscope, which is the successor to the prior Flex-X2 and before that the Flex-X. The Flex-X2S has a 7.5 Fr tip size that expands to 8.5 Fr along the shaft. It has 270° of primary deflection both upward and downward with an 88° field of view and 3.6 Fr working channel. The tip of the working channel of the scope is lined by LaserliteTM, a durable material designed to resist damage when the laser is fired inadvertently with the tip of the fiber within the distal working channel. The primary difference between the Flex-X2 and the newer Flex-X2S is that the newer scope has double the number of fiber-optic bundles, increasing from 4000 to 8000. This results in a sharper image with less of the honeycomb effect that can be seen when fewer fiber-optic bundles are employed. Another unique aspect of the Flex-X2S is that it is available in two different shaft lengths. The standard length is 670 mm and would be used for standard adult flexible ureteroscopy. A shorter option at 450 mm is also available and is geared toward pediatric procedures. However, the 450 mm shaft length also works well for antegrade ureteroscopy during a percutaneous procedure.


Olympus recently released its latest generation flexible ureteroscope, the URF-P7. This ureteroscope incorporates many of the features of its predecessor, the URF-P6, but with a design that focused on increased durability and stronger deflection mechanism. It incorporates a 4.9 Fr tip the quickly tapers to a 7.95 Fr shaft. The working channel is 3.6 Fr and the working length is 670 mm. The manufacturer reports 275° of upward and downward deflection. While long-term durability studies are needed to validate the manufacturers claim, this scope incorporates many changes designed to prevent the problems with locking deflection that had been reported in the prior generation of Olympus ureteroscopes [11]. The tapered tip design does facilitate passage directly without the need to place it over a guidewire. This tapered tip design has facilitated office ureteroscope for the surveillance of the upper tract transitional cell carcinoma in select patients [12].


Richard Wolf offers both a single-channel and a unique dual-channel flexible fiber-optic ureteroscope. The single-channel model is named the “Viper” and has a standard 3.6 Fr working channel, 270° of upward and downward deflection, a 680 mm working length, and a tip size of 6 Fr that increases to a shaft diameter of 8.8 Fr. This permits the use in a small diameter 10/12 Fr ureteral access sheath. The dual-channel model, called the “Cobra”, has two working channels, each with 3.3 Fr. The tip of fiber-optic Cobra is 6 Fr but increases to 9.9 Fr through the shaft. This increase in overall diameter is the trade-off for having the two working channels. However, the design permits the passage of a stone basket or laser fiber through one channel and thus does not limit irrigation through the second channel. Further creative uses might entail passing a laser fiber through one channel and a stone basket through the second channel. This ureteroscope also maintains the same 270° of bidirectional deflection at the Viper (Fig. 11.10).

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Fig. 11.10

Example of 270° of bidirectional deflection that modern flexible ureteroscopes can obtain. (© Karl Storz SE & Co. KG, Germany, with permission)



Flexible Digital Ureteroscopes


With manufacturers incorporating digital image sensors in flexible ureteroscopes, the digital era of flexible ureteroscopes began [13]. Current digital ureteroscopes use one of two different types of imaging chips, either the less commonly used charge-coupled device (CCD) or the more common complementary metal–oxide–semiconductor (CMOS). Both of these devices function by converting photons into electrons [14]. The digital signal is carried through the scope along wires and then converted by the image processor into the displayed image on the monitor. CMOS-based systems require less energy, run at lower temperatures, process images quicker, and are less expensive to produce as compared to CCD based. CCD is however a more mature technology and less affected by signal noise [15]. With continual improvement in technology, the expectation is further improvement in image quality, and reduction in size will occur. This is one of the fastest progressing areas of endourologic equipment.


Digital ureteroscopes offer some advantages over fiber-optic models. The “chip-on-the-tip” design eliminates the need for a separate bulky camera head that is required with fiber-optic scopes in order to display the image on the video monitor. The results in a more ergonomic setup by being lighter and less cumbersome to handle. There are no focusing dials as the digital instruments have a fixed focal length, further simplifying operation. The lighter digital ureteroscopes may result in less hand fatigue, especially during longer procedures. Reducing the number of cords from two (camera and light cord) to one helps to prevent entanglement and clutter. However, as previously discussed, each brand of digital ureteroscope requires a manufacturer-specific video processor, and therefore switching from one manufacturer to another is not simply a process of switching scopes but also requires switching video processors. With fiber-optic ureteroscopes this is simpler, as the camera head can be moved from one scope to another independent of the manufacturer.


Karl Storz manufactures the Flex-Xc, a CMOS-based flexible digital ureteroscope. It has a single 3.6 Fr working channel and a 700 mm shaft length. It is capable of 270° of bidirectional deflection with a 90° field of view. It has a built-in LED bulb for illumination. After its initial introduction, the CMOS chip was upgraded in a revision from 240 × 240 pixels to 460 × 400 pixels. The Flex-Xc has been demonstrated in bench evaluation to be highly maneuverable and out maneuvered other digital ureteroscopes in a bench model [16] (Fig. 11.11).

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Fig. 11.11

Storz Flex-Xc digital ureteroscope. (© Karl Storz SE & Co. KG, Germany, with permission)


The latest generation Olympus flexible ureteroscope is the CMOS-based URF-V3. It has a 8.5 distal end outer diameter, a 3.6 Fr working channel, and a length of 670 mm. It provides 275° of bidirectional deflection and has a similar revised deflection mechanism as the URF-P7 designed to be more robust and avoid the prior reported problems with locked deflection [11]. At present, no clinical data regarding performance is available, but it appears to be a promising scope design and of the prior generation URF-V2.


Richard Wolf produces two flexible digital ureteroscopes, the Boa vision and the Cobra vision. The Boa vision, similar to the fiber-optic Viper, has a single 3.6 Fr working channel. It has a 6.6 Fr stainless steel tip that increases in diameter to an 8.7 Fr shaft. It has a 680 mm working length with 270° of bidirectional deflection. Like the Storz Flex-Xc, it has an integrated LED light (Fig. 11.12a). In contrast, the Cobra vision has two working channels of 3.6 and 2.4 Fr (Fig. 11.12b). The digital Cobra vision has a 5.2 Fr tip that increases to a shaft size of 9.9 Fr. It also has a 680 mm working length, 270° of bidirectional deflection, and an integrated LED light.

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Fig. 11.12

(a) Tip of single-channel Wolf Boa vision digital ureteroscope. (b) Tip of dual-channel Wolf Cobra vision digital ureteroscope. (© Richard Wolf, Knittlingen, Germany, with permission)



Fiber-optic Versus Digital Ureteroscopes


There are multiple factors to consider when comparing fiber-optic with flexible digital ureteroscopes including imaging quality, size, maneuverability, durability, and cost. With continual innovation and introduction of new products, it is a moving target to perform direct comparisons between models, but some generalizations can be made. Multiple studies have demonstrated improved image quality when comparing fiber-optic to flexible digital ureteroscopes. In one study, the Karl Storz flexible fiber-optic ureteroscope 11274AA was compared to the Olympus URF-V, a first-generation CCD-based digital ureteroscope. The authors performed 44 consecutive procedures with these two ureteroscopes; the first 22 were with the Karl Storz fiber-optic and the later 22 with the Olympus digital. The digital URF-V scored higher in a subjective measure of maneuverability and visibility. The authors also noted greater clarity, superior magnification, and a lack of a moiré effect. The digital scope was able to visualize the entire collecting system in 90.9% of cases versus 81.8% for the fiber-optic scope [17]. Humphreys reported that with the use of digital ureteroscopes pathology such as Randall’s plaques within the renal papilla, which could not have been previously visualized with fiber-optic scopes, could now be seen [13].


Stone-free rates (SFR) were compared between fiber-optic and flexible digital ureteroscopes in several studies. One study compared the Olympus URF-P5 fiber-optic ureteroscope to the digital URF-V and evaluated stone-free outcomes 1 month after flexible ureteroscopy. The SFR was comparable at 88% and 86%, respectively, but the operative times were somewhat longer with the fiber-optic ureteroscope taking an average of 53.8 min versus 44.5 min for the digital ureteroscope [18]. In another study, the Karl Storz Flex-X2 was compared to the Gyrus/ACMI DUR-D and reported similar findings. The stone clearance rates were 88.2% and 85.7%, respectively, but again the fiber-optic instrument took slightly longer to perform the procedure at a mean of 46.5 min versus 38.3 min for the digital device [19]. While it is not entirely clear why the digital ureteroscopes had shorter procedure lengths, possibilities include that the better visualization allows for more accurate targeting of the stone and that the improved ergonomics may allow the surgeon to work in a more time-efficient manner.



Limitations of Flexible Digital Ureteroscopes


While flexible digital ureteroscopes appear to have some clear advantages, there are also some drawbacks. The digital image can be disrupted during laser lithotripsy due to the wave produced from the photoacoustic effect of the holmium:YAG laser. This is seen as lines and artifacts passing through the image on the video monitor. To counter this effect manufacturers have begun to place shock-absorbing devices at the tip of the scope where the image sensor is located [20]. While this may have reduced the effect, in my experience it can still be seen even with current generation digital ureteroscopes when the laser fires close to the tip of the scope. Advancing the laser fiber further out from the tip of the scope, and thus increasing the distance between the point where the acoustic shock wave is generated and the image sensor, helps to reduce the effect. A good guideline is to keep the fiber advanced far enough that it occupies one quarter of the screen as reported by Talso [21].


Current generation flexible digital ureteroscopes have larger shaft diameters, and in some cases tip diameters, in comparison to flexible digital ureteroscopes (Table 11.2). This is primarily a limitation of the size of the digital image sensor. The larger size can limit access through a tight ureteropelvic junction (UPJ) or narrow infundibulum. In one report using the Olympus URF-V, the target stone could not be reached in approximately 10% of the procedures, but when the surgeon switched to the smaller fiber-optic URF-P5, the target was reached in all of the procedures [15]. In a bench study using the K-Box (Porges-Coloplast, Humlebæk, Denmark), fiber-optic ureteroscopes had better end-tip deflection by a median of 21° when compared to digital ureteroscopes with the exception of the digital Flex-Xc [16]. This can be a factor when trying to enter a calyx that requires a high degree of angulation. Future advances in miniaturization that allow for a smaller diameter and more compact tip designs will help to overcome these shortcomings. In the interim, it is best to have a fiber-optic backup flexible ureteroscope available if digital ureteroscopes are used as the primary instrument. If the target cannot be reached with the digital ureteroscope, then trying the fiber-optic model is prudent.


Table 11.2

Flexible fiber-optic ureteroscopes currently on the market












































































 

Karl Storz


Flex-X2


Olympus


URF-P6


Richard Wolf


Viper


Richard Wolf


Cobra


Distal tip


7.5 Fr


4.9 Fr


6 Fr


6 Fr


Sheath diameter


8.5 Fr


7.95 Fr


8.8 Fr


9.9 Fr


Smallest UAS it fits


9.5/11.5


9.5/11.5


9.5/11.5


11/13


Number of working channels


1


1


1


2


Working channel


3.6 Fr


3.6 Fr


3.6 Fr


3.3 Fr × 2


Angulation UP


270°


275°


270°


270°


Angulation DOWN


270°


275°


270°


270°


Fits other camera systems


Yes


Yes


Yes


Yes


Working length


670 mm


670 mm


680 mm


680 mm


Viewing angle


88°


90°


90°


90°



UAS ureteral access sheath

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Oct 20, 2020 | Posted by in UROLOGY | Comments Off on for Stone Disease
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