**Modern Upper Urinary Tract Endoscopy**

Puru Naidu, Jessica Packer, Maheshi Samaraweera and John G. Calleary

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/52750

**1. Introduction**

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362 Endoscopy

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Upper urinary tract endoscopy has come a long way from the first endoscopic examination performed in 1912 by Young and McKay. They used a 9.5 F rigid cystoscope in a patient with a very dilated ureter [1]. Current semi-rigid and flexible instruments are purposely de‐ signed to allow diagnostic and effective therapeutic interventions with minimal associated morbidity. The timeline of this evolution is perfectly described elsewhere [2].This chapter summarises the instrumentation available to the modern urologist, the basic principles be‐ hind their use and the major clinical outcomes now expected from their use.

### **2. Technology**

This section will describe the endoscopes in modern use and the ancillary equipment we use for therapeutic indications. While some units still use a rigid ureteroscope these have been replaced in many units by semi-rigid and flexible ureteroscopes.

#### **2.1. Endoscopes**

#### *2.1.1. Semi-rigid*

The semi-rigid ureteroscope is the workhorse of endoscopic ureteric surgery. It was devel‐ oped from the larger rigid ureteroscope primarily because of concerns about the inability of the rigid scope to access the upper ureter without causing significant damage to the urothe‐ lium. The "flexibility" and reduced size are primarily due to the introduction of fibre-optics.

© 2013 Naidu et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The fibre-optic bundles (clad for image transmission, unclad for light transmission) are fixed at both ends which permits movement without loss of picture quality.

Semi-rigid ureteroscopes are very durable instruments. The biggest reason for failure is im‐ proper use or maintenance. Factors associated with failure are age, shaft design (tapered < stepped) length (long > short) and diameter (narrow > wider). While the instruments flexi‐ bility has increased its therapeutic potential, it also increases its susceptibility to breakage and deflections above 5cm are said to be particularly damaging to the instruments [3-4].

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 365

**Figure 3.** An Olympus flexible ureteroscope (single active deflection, one thumb handle) and Wolf semi-rigid uretero‐

The first flexible ureteroscope was introduced through a ureterotomy at open surgery in 1960 [5]. The first trans-urethral instrument was used in 1962 to treat a stone in the lower ureter. This instrument and its immediate successor were diagnostic instruments which could not be manoeuvred. In addition they required forced diuresis to keep the ureter pat‐ ent. A group from the University of Chicago pioneered the next major developments to in‐ corporate a deflecting tip. This instrument still required insertion into the ureter through a rigid channel but was the first flexible ureteroscope to resemble a modern instrument [6]. The same group were the first to trial an actively deflecting flexible ureteroscope and intro‐

The basic design of the instrument is similar to the semi-rigid instrument.Each uses non-co‐ herently arranged light bundles for light transmission (flexi uses 1-2 only) and coherently arranged bundles for image transmission (flexi uses one). Likewise there is a working chan‐ nel (one) which is usually 3.2 F diameter. In the flexible scope this is cylindrical and situated slightly off-center. This is because of the fibre-optics for image transmission.The degree of eccentricity of the working channel is greater with increasing diameter and results in a dis‐ proportionate larger loss of deflection when using instruments. A further loss of deflection ability comes from using "stiffer" instruments.The flexible ureteroscope is also hard wearing but rather than drawing its strength from steel column strength comes from composite poly‐

duced secondary passive deflection to produce the modern ureteroscope [7].

scope.

*2.1.2. Flexible ureteroscopy (figure 3)*

*2.1.2.1. Historical perspective*

*2.1.2.2. Modern design*

Modern scopes have either straight (Figure 1) or offset eyepiece. The only advantage of the off‐ set eyepiece is that it allows the use of larger therapeutic instruments.The shaft is usually ta‐ pered so that the distal diameter (4.5 – 9 F) is less than the proximal (6.5-15F). The difference between proximal and distal diameter varies between manufacturers but is of the order of 2-4 F. The scope length is described as being "short" at approximately 30 cm or long at 40+ cm. Short scopes are useful for the lower ureter in males and lower and upper ureter in females. The long ureteroscope is best for visualisation and treatment in the upper ureter.Within the metal‐ lic sheath are the fibre-optic bundles and either one or two working channels. If two channels are being used, one tends to be larger to allow instrumentation and either continued of irriga‐ tion or a second working instrument.The distal end tends to be ovoid (figure 2). A variety of ac‐ cessories are available to improve irrigation flow but the vast majority of procedures are done using gravity, either alone or using pressurised irrigation bags.

**Figure 1.** Headpiece of modern semi-rigid Ureteroscope. This model has a straight eyepiece with two working chan‐ nels each with a red rubber seal. In this model both channels are equal in diameter.

**Figure 2.** Distal tip of a semi-rigid ureteroscope showing the larger opening of the working channels (right side) com‐ pared to the optical opening. Note the stepped appearance as opposed to a more usually seen tapered tapered ap‐ pearance. The lens is angled at 5 degrees to allow visualisation of the working instruments as they exit the channel.

Semi-rigid ureteroscopes are very durable instruments. The biggest reason for failure is im‐ proper use or maintenance. Factors associated with failure are age, shaft design (tapered < stepped) length (long > short) and diameter (narrow > wider). While the instruments flexi‐ bility has increased its therapeutic potential, it also increases its susceptibility to breakage and deflections above 5cm are said to be particularly damaging to the instruments [3-4].

**Figure 3.** An Olympus flexible ureteroscope (single active deflection, one thumb handle) and Wolf semi-rigid uretero‐ scope.

### *2.1.2. Flexible ureteroscopy (figure 3)*

### *2.1.2.1. Historical perspective*

The fibre-optic bundles (clad for image transmission, unclad for light transmission) are fixed

Modern scopes have either straight (Figure 1) or offset eyepiece. The only advantage of the off‐ set eyepiece is that it allows the use of larger therapeutic instruments.The shaft is usually ta‐ pered so that the distal diameter (4.5 – 9 F) is less than the proximal (6.5-15F). The difference between proximal and distal diameter varies between manufacturers but is of the order of 2-4 F. The scope length is described as being "short" at approximately 30 cm or long at 40+ cm. Short scopes are useful for the lower ureter in males and lower and upper ureter in females. The long ureteroscope is best for visualisation and treatment in the upper ureter.Within the metal‐ lic sheath are the fibre-optic bundles and either one or two working channels. If two channels are being used, one tends to be larger to allow instrumentation and either continued of irriga‐ tion or a second working instrument.The distal end tends to be ovoid (figure 2). A variety of ac‐ cessories are available to improve irrigation flow but the vast majority of procedures are done

**Figure 1.** Headpiece of modern semi-rigid Ureteroscope. This model has a straight eyepiece with two working chan‐

**Figure 2.** Distal tip of a semi-rigid ureteroscope showing the larger opening of the working channels (right side) com‐ pared to the optical opening. Note the stepped appearance as opposed to a more usually seen tapered tapered ap‐ pearance. The lens is angled at 5 degrees to allow visualisation of the working instruments as they exit the channel.

at both ends which permits movement without loss of picture quality.

364 Endoscopy

using gravity, either alone or using pressurised irrigation bags.

nels each with a red rubber seal. In this model both channels are equal in diameter.

The first flexible ureteroscope was introduced through a ureterotomy at open surgery in 1960 [5]. The first trans-urethral instrument was used in 1962 to treat a stone in the lower ureter. This instrument and its immediate successor were diagnostic instruments which could not be manoeuvred. In addition they required forced diuresis to keep the ureter pat‐ ent. A group from the University of Chicago pioneered the next major developments to in‐ corporate a deflecting tip. This instrument still required insertion into the ureter through a rigid channel but was the first flexible ureteroscope to resemble a modern instrument [6]. The same group were the first to trial an actively deflecting flexible ureteroscope and intro‐ duced secondary passive deflection to produce the modern ureteroscope [7].

#### *2.1.2.2. Modern design*

The basic design of the instrument is similar to the semi-rigid instrument.Each uses non-co‐ herently arranged light bundles for light transmission (flexi uses 1-2 only) and coherently arranged bundles for image transmission (flexi uses one). Likewise there is a working chan‐ nel (one) which is usually 3.2 F diameter. In the flexible scope this is cylindrical and situated slightly off-center. This is because of the fibre-optics for image transmission.The degree of eccentricity of the working channel is greater with increasing diameter and results in a dis‐ proportionate larger loss of deflection when using instruments. A further loss of deflection ability comes from using "stiffer" instruments.The flexible ureteroscope is also hard wearing but rather than drawing its strength from steel column strength comes from composite poly‐ meric materials. They also come in variable lengths (54 – 70 cm) and are tapered with a dis‐ tal end of 4.9 – 11 F (most 5.3 – 8.7) and a proximal diameter of 5.8 – 11F(most 7.7-9.9).

the collecting system especially with an instrument in situ[4]. Pietrow et al have looked at factors to increase the lifespan of flexible instruments. The instrument should be stored with the headpiece upright and the tip dependent. At no time should the shaft be bent, as to do so risks damaging the light bundles. This damage is evident as black dots within the image. When inserting instruments it is best to ensure that the tip is straight and a laser should not be activated until the tip of the fibre is about two mm from the telescope. As repeated inser‐ tion can be damaging it is thought that access sheaths can prevent damage. The use of softer

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 367

These are the instruments and technology which turn the instrument from a diagnostic tool

There are four techniques for stone destruction in use in Urology. Of these two (laser and EHL) are most widely used in ureteric and intra-renal endoscopy.Electro-Hydrolic Litho‐ tripsy (EHL) uses the cavitation bubble produced by an electrically induced spark to destroy calculi. This is achieved by the expansion of the bubble resulting in a shock wave, followed by its collapse and rebound off any surface with which it comes into contact. Using a 5F probe up to 90% of ureteral calculi can be successfully treated. The advantage of this tech‐ nology is that it is relatively inexpensive with low running costs. The disadvantage is that, because of the uncontrollable nature of the shock wave, fragments are propelled forward. This is also the explanation for the ureteric perforation rates of up to 8.5% [10].For best re‐ sults the probe should be held at a minimum distance of 1 mm from the stone and 1-2 mm

Ultrasound, pneumatic and EHL sources are useful only for treating calculi. Hence for treat‐ ment of upper tract lesions or haemostasis for biopsy other technologies are required. Con‐ tact diathermy probes are available but are limited by size to treating ureteric and renal

The primary energy method used in endourological management of both stones and small volume upper tract TCC is LASER. While many laser types have been used the main laser used is the Holmium: YAG laser (figure 5). The primary reason for this is that it is the only laser capable of destroying any stone type. The Holmium is a solid state pulsed laser with a wavelength of 2100 nm and delivers the enrgy through quartz fibres. The fibres range in size from 200 – 1000 µm. In our unit we use a 270 and 365 µm fibre both of which can be used through a semi-rigid and flexible ureteroscope. Most lasers use an acoustic shock wave (sim‐ ilar to EHL) generated by vaporising the fluid in front of the fibre creating a gas bubble.The Holmium laser does produce vaporisation but its primary effect is photo-thermal thus effec‐ tively evaporating the stone or tissue [11]. This produces tiny fragments of approximately the same size as the fibre. This is in contra-distinction to other energy forms which produce uneven larger fragments. However retro-pulsion of fragments can occur being seen most

pelvic lesions. Their use with a flexible ureterorenoscope limits deflection.

wires (eg Nitinol) and smaller calibre laser fibres can also help [9].

**2.2. Ancillary technology**

into a potent therapeutic modality.

from the ureteroscope and urothelium.

*2.2.1. Tissue / stone destruction*

#### *2.1.2.3. Differences between semi-rigid and flexible ureteroscopes*

The essential difference between the two types of ureteroscope are in terms of optics and ability to deflect. The fibre-optic bundles are smaller in the flexible scope. This usually does not adversely impact on light intensity because of the higher refractive index of the bundles. The angle of view is altered by fitting the distal bundles with an angled lens. Usually this is up to 10° and allows visualisation of instruments as they exit the working channel. The depth of view is less in the flexible scope due to fibre-optic technology, this is compensated for by magnification and focusing. This is a feature common for all flexible endoscopy.

The major difference between the two types of ureteroscope is in the degree of movement available with the flexible instrument. The initial range of deflection was up to 170°. This was based on the measurement of the maximum uretero-infundibular angle [8]. The most modern ureteroscopes can deflect to 270° both sides.

Deflection is sub-divided into active and passive deflection.Active deflection is controlled by a lever mechanism just behind the eyepiece. The basic principle behind this is that moving wires which pass through the scopes cladding and which are fixed to the distal tip causes the scope to bend. Where one lever is present this is called primary active deflection. The most modern scopes have a second active deflection mechanism (figure 4). Passive deflec‐ tion is facilitated by a "softer" segment of the ureteroscope which on contact with the curves of the intra-renal collecting system allows the scope to be deflected. This allows inspection of and treatment in all parts of the collecting system.

**Figure 4.** Cartoon depicting deflection in a flexible ureteroscope. The softer segment (\*\*) is represented in red and is the point at which the flexible ureteroscope "bends" on contact with the urothelium. The single \* represents the point of primary active deflection and the double \*\* represents the point of secondary active deflection.

Not surprisingly the flexible ureteroscope does not have the same longevity as the semi-rig‐ id ureteroscope and the cost of repair is about twice that of a semi-rigid ureteroscope. The risk factors for damage are increasing length and decreasing diameter of flexible uretero‐ scope, instrument or laser damage to the working channel or overzealous deflection within the collecting system especially with an instrument in situ[4]. Pietrow et al have looked at factors to increase the lifespan of flexible instruments. The instrument should be stored with the headpiece upright and the tip dependent. At no time should the shaft be bent, as to do so risks damaging the light bundles. This damage is evident as black dots within the image. When inserting instruments it is best to ensure that the tip is straight and a laser should not be activated until the tip of the fibre is about two mm from the telescope. As repeated inser‐ tion can be damaging it is thought that access sheaths can prevent damage. The use of softer wires (eg Nitinol) and smaller calibre laser fibres can also help [9].

### **2.2. Ancillary technology**

meric materials. They also come in variable lengths (54 – 70 cm) and are tapered with a dis‐ tal end of 4.9 – 11 F (most 5.3 – 8.7) and a proximal diameter of 5.8 – 11F(most 7.7-9.9).

The essential difference between the two types of ureteroscope are in terms of optics and ability to deflect. The fibre-optic bundles are smaller in the flexible scope. This usually does not adversely impact on light intensity because of the higher refractive index of the bundles. The angle of view is altered by fitting the distal bundles with an angled lens. Usually this is up to 10° and allows visualisation of instruments as they exit the working channel. The depth of view is less in the flexible scope due to fibre-optic technology, this is compensated for by magnification and focusing. This is a feature common for all flexible endoscopy.

The major difference between the two types of ureteroscope is in the degree of movement available with the flexible instrument. The initial range of deflection was up to 170°. This was based on the measurement of the maximum uretero-infundibular angle [8]. The most

Deflection is sub-divided into active and passive deflection.Active deflection is controlled by a lever mechanism just behind the eyepiece. The basic principle behind this is that moving wires which pass through the scopes cladding and which are fixed to the distal tip causes the scope to bend. Where one lever is present this is called primary active deflection. The most modern scopes have a second active deflection mechanism (figure 4). Passive deflec‐ tion is facilitated by a "softer" segment of the ureteroscope which on contact with the curves of the intra-renal collecting system allows the scope to be deflected. This allows inspection

**Figure 4.** Cartoon depicting deflection in a flexible ureteroscope. The softer segment (\*\*) is represented in red and is the point at which the flexible ureteroscope "bends" on contact with the urothelium. The single \* represents the point

Not surprisingly the flexible ureteroscope does not have the same longevity as the semi-rig‐ id ureteroscope and the cost of repair is about twice that of a semi-rigid ureteroscope. The risk factors for damage are increasing length and decreasing diameter of flexible uretero‐ scope, instrument or laser damage to the working channel or overzealous deflection within

of primary active deflection and the double \*\* represents the point of secondary active deflection.

*2.1.2.3. Differences between semi-rigid and flexible ureteroscopes*

366 Endoscopy

modern ureteroscopes can deflect to 270° both sides.

of and treatment in all parts of the collecting system.

These are the instruments and technology which turn the instrument from a diagnostic tool into a potent therapeutic modality.

### *2.2.1. Tissue / stone destruction*

There are four techniques for stone destruction in use in Urology. Of these two (laser and EHL) are most widely used in ureteric and intra-renal endoscopy.Electro-Hydrolic Litho‐ tripsy (EHL) uses the cavitation bubble produced by an electrically induced spark to destroy calculi. This is achieved by the expansion of the bubble resulting in a shock wave, followed by its collapse and rebound off any surface with which it comes into contact. Using a 5F probe up to 90% of ureteral calculi can be successfully treated. The advantage of this tech‐ nology is that it is relatively inexpensive with low running costs. The disadvantage is that, because of the uncontrollable nature of the shock wave, fragments are propelled forward. This is also the explanation for the ureteric perforation rates of up to 8.5% [10].For best re‐ sults the probe should be held at a minimum distance of 1 mm from the stone and 1-2 mm from the ureteroscope and urothelium.

Ultrasound, pneumatic and EHL sources are useful only for treating calculi. Hence for treat‐ ment of upper tract lesions or haemostasis for biopsy other technologies are required. Con‐ tact diathermy probes are available but are limited by size to treating ureteric and renal pelvic lesions. Their use with a flexible ureterorenoscope limits deflection.

The primary energy method used in endourological management of both stones and small volume upper tract TCC is LASER. While many laser types have been used the main laser used is the Holmium: YAG laser (figure 5). The primary reason for this is that it is the only laser capable of destroying any stone type. The Holmium is a solid state pulsed laser with a wavelength of 2100 nm and delivers the enrgy through quartz fibres. The fibres range in size from 200 – 1000 µm. In our unit we use a 270 and 365 µm fibre both of which can be used through a semi-rigid and flexible ureteroscope. Most lasers use an acoustic shock wave (sim‐ ilar to EHL) generated by vaporising the fluid in front of the fibre creating a gas bubble.The Holmium laser does produce vaporisation but its primary effect is photo-thermal thus effec‐ tively evaporating the stone or tissue [11]. This produces tiny fragments of approximately the same size as the fibre. This is in contra-distinction to other energy forms which produce uneven larger fragments. However retro-pulsion of fragments can occur being seen most with larger fibres. Like EHL, the holmium laser can damage urothelium and perforate the ureter. However this requires direct contact with the urothelium as because of its high ab‐ sorption in water the laser energy penetrates no more than 1 mm into hydrated tissue. It has been estimated that this contact time is of the order of two seconds [12].

A newer approach is to inject a liquid polymer above the stone which on exposure to body temperature solidifies. This forms a seal or plug which prevents migration. Once the stone is destroyed cold saline irrigation is used which liquefies the gel. The polymers construction is such that any residual gel is degraded and gone from the ureter by two hours. The only

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 369

These come in multiple shapes and sizes with the primary aim of grasping or trapping the stone fragments. This allows physical removal of the fragments. Graspers tend to have three prongs which facilitates extraction of "larger" fragments. They tend to have a co-axial de‐ sign with inner and outer sheaths. Retrieval is facilitated by advancing the inner sheath. Bas‐ kets are designed to trap multiple small fragments within their Nitinol wires. There are various designs with varying features aimed at improving the stone free rate post lithotrip‐ sy. Tipless designs are said to reduce the risk of urothelial perforation. A recent trend is the basket in which laser lithotripsy can be performed with the laser fibre being introduced

**Figure 7.** A re-usable ureteroscopic biopsy forceps (left) and a tri-radiate grasper (Captura, Cook medical)

These instruments are a standard part of the endourologists arsenal. They are used for for‐ eign body removal in the case of a migrated JJ stent. Also they are useful for biopsy of intraureteric lesions for histological evaluation. However because of size constraints resultant from the dimensions of the ureteroscope, they are very small and the biopsy sample attained is often too small for analysis. A solution to this was developed by Cook. They backloaded a larger biopsy forceps (Bigopty) through the ureteroscope and then connected it to the biopsy handle. The biopsy forceps thus enters the ureter before the ureteroscope and hence can be

commercially available model is the Backstop from Boston Scientific.

through the hollow shaft (eg Cook Flat wire stone extractor).

*2.2.3. Baskets and graspers*

*2.2.4. Biopsy forceps*

of greater size (figure 8).

**Figure 5.** A holmium laser in use on an intra-renal stone at semi-rigid ureteroscopy.

#### *2.2.2. Anti-migration devices*

As indicated above one of the biggest problems withtreating stones in the ureter is retropul‐ sion. There have been a number of approaches to reducing this migration. The most com‐ mon approach is to place a device beyond the stone in a closed manner. Once past the stone the device is deployed to form a barrier to retrograde stone passage.The most used exam‐ ples of this are the Stone cone © (Boston Scientific) (figure 6) and the N-Trap (Cook Medi‐ cal). The Stone Cone is a Nitinol based wire with a length which is softer and forms a conical shaped when deployed. It is straightened by passing it over a wire and assumes its natural shape once the wire is removed. The N-Trap when deployed from its access sheath forms a basket. Laser lithotripsy is then performed and any fragments which migrate upwards do so into the Cone/Basket. At the end of the lithotripsy procedure, the Cone/Basket is gently re‐ moved under vision with the ureteroscope. Both devices are designed to release a stone fragment when a threshold level of pressure is reached. This prevents larger fragments im‐ pacting in the ureter at attempted removal.

**Figure 6.** The Stone Cone (Boston Scientific) in its "cone" shape prior to use.

A newer approach is to inject a liquid polymer above the stone which on exposure to body temperature solidifies. This forms a seal or plug which prevents migration. Once the stone is destroyed cold saline irrigation is used which liquefies the gel. The polymers construction is such that any residual gel is degraded and gone from the ureter by two hours. The only commercially available model is the Backstop from Boston Scientific.

#### *2.2.3. Baskets and graspers*

with larger fibres. Like EHL, the holmium laser can damage urothelium and perforate the ureter. However this requires direct contact with the urothelium as because of its high ab‐ sorption in water the laser energy penetrates no more than 1 mm into hydrated tissue. It has

As indicated above one of the biggest problems withtreating stones in the ureter is retropul‐ sion. There have been a number of approaches to reducing this migration. The most com‐ mon approach is to place a device beyond the stone in a closed manner. Once past the stone the device is deployed to form a barrier to retrograde stone passage.The most used exam‐ ples of this are the Stone cone © (Boston Scientific) (figure 6) and the N-Trap (Cook Medi‐ cal). The Stone Cone is a Nitinol based wire with a length which is softer and forms a conical shaped when deployed. It is straightened by passing it over a wire and assumes its natural shape once the wire is removed. The N-Trap when deployed from its access sheath forms a basket. Laser lithotripsy is then performed and any fragments which migrate upwards do so into the Cone/Basket. At the end of the lithotripsy procedure, the Cone/Basket is gently re‐ moved under vision with the ureteroscope. Both devices are designed to release a stone fragment when a threshold level of pressure is reached. This prevents larger fragments im‐

been estimated that this contact time is of the order of two seconds [12].

**Figure 5.** A holmium laser in use on an intra-renal stone at semi-rigid ureteroscopy.

*2.2.2. Anti-migration devices*

368 Endoscopy

pacting in the ureter at attempted removal.

**Figure 6.** The Stone Cone (Boston Scientific) in its "cone" shape prior to use.

These come in multiple shapes and sizes with the primary aim of grasping or trapping the stone fragments. This allows physical removal of the fragments. Graspers tend to have three prongs which facilitates extraction of "larger" fragments. They tend to have a co-axial de‐ sign with inner and outer sheaths. Retrieval is facilitated by advancing the inner sheath. Bas‐ kets are designed to trap multiple small fragments within their Nitinol wires. There are various designs with varying features aimed at improving the stone free rate post lithotrip‐ sy. Tipless designs are said to reduce the risk of urothelial perforation. A recent trend is the basket in which laser lithotripsy can be performed with the laser fibre being introduced through the hollow shaft (eg Cook Flat wire stone extractor).

**Figure 7.** A re-usable ureteroscopic biopsy forceps (left) and a tri-radiate grasper (Captura, Cook medical)

#### *2.2.4. Biopsy forceps*

These instruments are a standard part of the endourologists arsenal. They are used for for‐ eign body removal in the case of a migrated JJ stent. Also they are useful for biopsy of intraureteric lesions for histological evaluation. However because of size constraints resultant from the dimensions of the ureteroscope, they are very small and the biopsy sample attained is often too small for analysis. A solution to this was developed by Cook. They backloaded a larger biopsy forceps (Bigopty) through the ureteroscope and then connected it to the biopsy handle. The biopsy forceps thus enters the ureter before the ureteroscope and hence can be of greater size (figure 8).

does not work then the next step is dilatation of the ureteric orifice and should that fail then a JJ stent is placed. This results in dilation by loss of peristalsis. Interval ureteroscopy can

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 371

**Figure 9.** Use of a ureteric catheter (white tube) to facilitate entry into the left ureteric orifice in a man with a median

A longer ureteroscope is needed in males due to the combination of the longer urethra, the relatively immobile prostatic urethra and the better development of the Psoas muscle. The latter factor can make it difficult to negotiate the ureteroscope beyond the iliac vessels. A second wire can sometimes help straighten a tortuous ureter. However, excessive force should be avoided because of the risk to the ureter (mucosal damage, perforation) and to the

**Figure 10.** View from a ureteroscope as it is being inserted into the left ureteric orifice between two guidewires (rail‐

then be performed after approximately two weeks.

lobe of prostate and a high bladder neck.

ureteroscope because of shear forces.

roading)

**Figure 8.** Bigopty (Cook Medical), a backloaded ureteric biopsy forceps,capable of taking large biopsy samples.

### **3. Ureteroscopy technique**

All uretersocopy is preceded by a careful cystoscopy. A negative MSU or treatment with culture appropriate antibiotics is mandatatory. Active infection is the only absolute contraindication to ureteroscopy. Relative contra-indications are ongoing anti-coagulation therapy or bleeding diatheses. Appropriate antibiotic prophylaxis is given at induction of anaesthe‐ sia. This has been shown to reduce infection rates from 13 to 2% [13].Ureteroscopy is usually under a general / spinal anaesthetic with the patient in the lithotomy position but can also be performed in the flank or prone positions.Some authors suggest that the ipsilateral leg be straightened to facilitate ureteral entry.A careful cystoscopy prevents bleeding from the bladder neck which can impair vision and identifies situations where ureteral access is more difficult such as the man with a median lobe or high bladder neck. The primary aim of the cystoscopy is to insert a 0.035 to 0.038 inches guidewire ("floppy" end first) into the relevant ureteric orifice which facilitates the safe introduction of the semi-rigid ureteroscope. This is placed into the renal pelvis under fluoroscopy so that the floppy end is seen to be coiled. This wire is typically called the "safety" wire. Should this prove difficult, the bladder should be emptied and a further attempt made. If it still proves difficult a ureteric catheter can be used to straighten the intra-mural ureter (figure 9). This usually allows the wire to pass. The bladder is emptied on completion to avoid distortion of the ureteric orifice and minimise kinking of the intra-mural ureter.

#### **3.1. Semi-rigid ureteroscopy (AUA and EAU guidelines, ref 14-15)**

The initial step is introducing the ureteroscope into the ureteric orifice. The tip of the scope can be passed under a "safety" guidewire to facilitate entry. If this does not permit entry then the scope should be rotated. Should this fail a second wire can be introduced and the tip of the scope passed between the two wires. This is called "rail-roading" (figure 10). If this does not work then the next step is dilatation of the ureteric orifice and should that fail then a JJ stent is placed. This results in dilation by loss of peristalsis. Interval ureteroscopy can then be performed after approximately two weeks.

**Figure 8.** Bigopty (Cook Medical), a backloaded ureteric biopsy forceps,capable of taking large biopsy samples.

All uretersocopy is preceded by a careful cystoscopy. A negative MSU or treatment with culture appropriate antibiotics is mandatatory. Active infection is the only absolute contraindication to ureteroscopy. Relative contra-indications are ongoing anti-coagulation therapy or bleeding diatheses. Appropriate antibiotic prophylaxis is given at induction of anaesthe‐ sia. This has been shown to reduce infection rates from 13 to 2% [13].Ureteroscopy is usually under a general / spinal anaesthetic with the patient in the lithotomy position but can also be performed in the flank or prone positions.Some authors suggest that the ipsilateral leg be straightened to facilitate ureteral entry.A careful cystoscopy prevents bleeding from the bladder neck which can impair vision and identifies situations where ureteral access is more difficult such as the man with a median lobe or high bladder neck. The primary aim of the cystoscopy is to insert a 0.035 to 0.038 inches guidewire ("floppy" end first) into the relevant ureteric orifice which facilitates the safe introduction of the semi-rigid ureteroscope. This is placed into the renal pelvis under fluoroscopy so that the floppy end is seen to be coiled. This wire is typically called the "safety" wire. Should this prove difficult, the bladder should be emptied and a further attempt made. If it still proves difficult a ureteric catheter can be used to straighten the intra-mural ureter (figure 9). This usually allows the wire to pass. The bladder is emptied on completion to avoid distortion of the ureteric orifice and minimise

The initial step is introducing the ureteroscope into the ureteric orifice. The tip of the scope can be passed under a "safety" guidewire to facilitate entry. If this does not permit entry then the scope should be rotated. Should this fail a second wire can be introduced and the tip of the scope passed between the two wires. This is called "rail-roading" (figure 10). If this

**3. Ureteroscopy technique**

370 Endoscopy

kinking of the intra-mural ureter.

**3.1. Semi-rigid ureteroscopy (AUA and EAU guidelines, ref 14-15)**

**Figure 9.** Use of a ureteric catheter (white tube) to facilitate entry into the left ureteric orifice in a man with a median lobe of prostate and a high bladder neck.

A longer ureteroscope is needed in males due to the combination of the longer urethra, the relatively immobile prostatic urethra and the better development of the Psoas muscle. The latter factor can make it difficult to negotiate the ureteroscope beyond the iliac vessels. A second wire can sometimes help straighten a tortuous ureter. However, excessive force should be avoided because of the risk to the ureter (mucosal damage, perforation) and to the ureteroscope because of shear forces.

**Figure 10.** View from a ureteroscope as it is being inserted into the left ureteric orifice between two guidewires (rail‐ roading)

### **3.2. Flexible ureteroscopy (AUA and EAU guidelines ref 14-15)**

Most flexible ureteroscopy is preceded by a semi-rigid examination of the ureter. This amongst other things dilates the ureteric orifice as well as allowing placement of a second guidewire. This second wire usually straightens out the ureter. There are two schools of thought on flexible ureteroscopic technique. One will introduce the flexible scope into the urethra and either beside or loaded along the guidewire into the ureteric orifice. The other will use a ureteric access sheath to allow repeated easy access to the ureter. A ureteric sheath (figure) is placed over a stiff guidewire under screening to the lower or mid ureter depend‐ ing on the level at which the operator needs to work. The flexible ureteroscope is then placed through the sheath directly into the ureter. Where repeated insertions/removals are necessary, the access sheath reduces instrumentation time. The advantage of using the sheath is that it may reduce the intra-renal pressure during prolonged stone procedures hence minimising the risk of nephron loss.Once in the collecting system, the flexible uretero‐ scope can be manoeuvred to directly visualise all calyces. This is by a combination of torqu‐ ing (twisting) the scope itself and active and passive deflection. Visualisation of the calyces is helped by retrograde contrast injection and radiological screening, thus outlining the whole system.

of four weeks. The stent causes ureteric dilation and ureteroscopy can usually be completed at the time of stent removal. In the situation where a stone laden basket will not negotiate a narrowed area then it should be gently moved back up to dilated ureter and opened. This will release some fragments and permit a further attempt at removal. If this fails it means that the fragments are too large and further laser lithotripsy is warranted. If the basket will not open then it can be disassembled and laser lithotripsy performed to the fragments with‐ in the basket.If either avulsion or intussusception is suspected then an immediate retrograde examination is performed. If the renal collecting system is not outlined with contrast then the diagnosis is confirmed. Drainage of the collecting system is mandatatory and this is usu‐ ally with a percutaneous nephrostomy. Open surgery is required and the technique used

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 373

Between 1200 and 1400 per 100,000 people will develop urinary stones each year with a male:female ratio of 3:1.The majority of stones are composed of calcium oxalate, often mixed with calcium phosphate, in both adults and children. The acute presentation is usually un‐ mistakable with the classical history of loin to groin colicky pain. Evaluation with non-con‐ trast CT is advisable for diagnosis. The immediate management usually involves analgesia and treatment of any infection present, and then determining definitive management [14]. Stones smaller than 5 mm will generally pass, but larger stones often require urological in‐ tervention [16]. For the purpose of this chapter, the management of upper urinary tract stones will be explored and outlined with the emphasis being on endourological manage‐

The options available for the management of upper urinary tract stones include observation, Extra-Corporeal Shock wave Lithotripsy (ESWL), Ureteroscopy, Percutaneous Nephro-lith‐ otomy (PCNL),laparoscopy and rarely open surgical removal. The appropriate modality for each individual patient will depend on the interaction between stone (size, location, appear‐ ance of the stone on imaging, composition),anatomical abnormalities, the presence of infec‐ tion and concomitant co-morbidities which may affect the decision regarding appropriate anaesthetic time.There also is an increasing trend toward intervention because of technologi‐ cal improvements and a growing dissatisfaction with the overall success rates with extracor‐

Most stones less than 5mm in size will pass spontaneously.European Association of Urology guidelines state that active stone removal is recommended for renal stones >6-7mm in size [14]. However, those of less than 6mm in size, if symptomatic, can be considered for treat‐

will depend on the site and extent of injury.

**4. Upper tract stones**

**4.1. Introduction**

ment.

**4.2. Management**

ment [14-15].

poreal shock wave lithotripsy [17].

### **3.3. Complications of ureteroscopy (specific to ureteroscopy)**

Ureteroscopy is performed in the lithotomy position. This position increases the risk of DVT and for this reason most endourologists use compression boots. The risk is small with mod‐ ern series reporting a risk of 0.2%. The other risk of positioning is damage to nerves such as the common peroneal through inadequate padding. Thankfully the risk is very small and the damage is usually temporary.

Ureteric complications range in severity from bleeding to complete avulsion. Bleeding is usually self limiting and occurs following instrumentation. Its reported in 0-2.1 % of series and usually does not prevent procedure completion. The majority will settle with an indwel‐ ling JJ stent/ ureteric catheter for at most two weeks. More significant ureteric damage re‐ sults in either a tear or perforation. A tear is defined as a breach in the urothelium. It is best to move any stone away fro the tear into dilated ureter to prevent further damage. Again they usually respond to a short period of stenting. Ureteric perforation occurs in one to five percent of modern studies. The rate is decreasing due to increasing experience and (more significantly) smaller calibre instruments.Stenting is the mainstay of management and it is in this situation that the safety wire really helps. The stent can be placed over the safety wire which has been pre-positioned into the renal pelvis. If the patient does not settle or develops an infected urinoma then a percutaneous nephrostomy may have to be placed.It is excep‐ tional to require open repair of a perforation.

Ureteric intussusception (urothelium only, muscle in place) and avulsion are the most se‐ vere forms of ureteric injury. Both are due to overly aggressive attempts to remove stone fragments or to forcing a ureteroscope through a narrowed ureteric segment. The golden rule is to stop and re-evaluate. In the case of a ureter which will not accept a scope then the narrowed are can be dilated under radiological screening or a JJ stent can be left for a period of four weeks. The stent causes ureteric dilation and ureteroscopy can usually be completed at the time of stent removal. In the situation where a stone laden basket will not negotiate a narrowed area then it should be gently moved back up to dilated ureter and opened. This will release some fragments and permit a further attempt at removal. If this fails it means that the fragments are too large and further laser lithotripsy is warranted. If the basket will not open then it can be disassembled and laser lithotripsy performed to the fragments with‐ in the basket.If either avulsion or intussusception is suspected then an immediate retrograde examination is performed. If the renal collecting system is not outlined with contrast then the diagnosis is confirmed. Drainage of the collecting system is mandatatory and this is usu‐ ally with a percutaneous nephrostomy. Open surgery is required and the technique used will depend on the site and extent of injury.

### **4. Upper tract stones**

### **4.1. Introduction**

**3.2. Flexible ureteroscopy (AUA and EAU guidelines ref 14-15)**

**3.3. Complications of ureteroscopy (specific to ureteroscopy)**

whole system.

372 Endoscopy

the damage is usually temporary.

tional to require open repair of a perforation.

Most flexible ureteroscopy is preceded by a semi-rigid examination of the ureter. This amongst other things dilates the ureteric orifice as well as allowing placement of a second guidewire. This second wire usually straightens out the ureter. There are two schools of thought on flexible ureteroscopic technique. One will introduce the flexible scope into the urethra and either beside or loaded along the guidewire into the ureteric orifice. The other will use a ureteric access sheath to allow repeated easy access to the ureter. A ureteric sheath (figure) is placed over a stiff guidewire under screening to the lower or mid ureter depend‐ ing on the level at which the operator needs to work. The flexible ureteroscope is then placed through the sheath directly into the ureter. Where repeated insertions/removals are necessary, the access sheath reduces instrumentation time. The advantage of using the sheath is that it may reduce the intra-renal pressure during prolonged stone procedures hence minimising the risk of nephron loss.Once in the collecting system, the flexible uretero‐ scope can be manoeuvred to directly visualise all calyces. This is by a combination of torqu‐ ing (twisting) the scope itself and active and passive deflection. Visualisation of the calyces is helped by retrograde contrast injection and radiological screening, thus outlining the

Ureteroscopy is performed in the lithotomy position. This position increases the risk of DVT and for this reason most endourologists use compression boots. The risk is small with mod‐ ern series reporting a risk of 0.2%. The other risk of positioning is damage to nerves such as the common peroneal through inadequate padding. Thankfully the risk is very small and

Ureteric complications range in severity from bleeding to complete avulsion. Bleeding is usually self limiting and occurs following instrumentation. Its reported in 0-2.1 % of series and usually does not prevent procedure completion. The majority will settle with an indwel‐ ling JJ stent/ ureteric catheter for at most two weeks. More significant ureteric damage re‐ sults in either a tear or perforation. A tear is defined as a breach in the urothelium. It is best to move any stone away fro the tear into dilated ureter to prevent further damage. Again they usually respond to a short period of stenting. Ureteric perforation occurs in one to five percent of modern studies. The rate is decreasing due to increasing experience and (more significantly) smaller calibre instruments.Stenting is the mainstay of management and it is in this situation that the safety wire really helps. The stent can be placed over the safety wire which has been pre-positioned into the renal pelvis. If the patient does not settle or develops an infected urinoma then a percutaneous nephrostomy may have to be placed.It is excep‐

Ureteric intussusception (urothelium only, muscle in place) and avulsion are the most se‐ vere forms of ureteric injury. Both are due to overly aggressive attempts to remove stone fragments or to forcing a ureteroscope through a narrowed ureteric segment. The golden rule is to stop and re-evaluate. In the case of a ureter which will not accept a scope then the narrowed are can be dilated under radiological screening or a JJ stent can be left for a period Between 1200 and 1400 per 100,000 people will develop urinary stones each year with a male:female ratio of 3:1.The majority of stones are composed of calcium oxalate, often mixed with calcium phosphate, in both adults and children. The acute presentation is usually un‐ mistakable with the classical history of loin to groin colicky pain. Evaluation with non-con‐ trast CT is advisable for diagnosis. The immediate management usually involves analgesia and treatment of any infection present, and then determining definitive management [14]. Stones smaller than 5 mm will generally pass, but larger stones often require urological in‐ tervention [16]. For the purpose of this chapter, the management of upper urinary tract stones will be explored and outlined with the emphasis being on endourological manage‐ ment.

#### **4.2. Management**

The options available for the management of upper urinary tract stones include observation, Extra-Corporeal Shock wave Lithotripsy (ESWL), Ureteroscopy, Percutaneous Nephro-lith‐ otomy (PCNL),laparoscopy and rarely open surgical removal. The appropriate modality for each individual patient will depend on the interaction between stone (size, location, appear‐ ance of the stone on imaging, composition),anatomical abnormalities, the presence of infec‐ tion and concomitant co-morbidities which may affect the decision regarding appropriate anaesthetic time.There also is an increasing trend toward intervention because of technologi‐ cal improvements and a growing dissatisfaction with the overall success rates with extracor‐ poreal shock wave lithotripsy [17].

Most stones less than 5mm in size will pass spontaneously.European Association of Urology guidelines state that active stone removal is recommended for renal stones >6-7mm in size [14]. However, those of less than 6mm in size, if symptomatic, can be considered for treat‐ ment [14-15].

### *4.2.1. Non invasive treatment of upper tract stones*

ESWL is entirely non invasive, and it uses super sonic waves to fragment stones into small pieces that can be easily passed. Shortly after its introduction in 1983, it became widely ac‐ cepted as the first line treatment modality for the majority of stones and rapidly replaced invasive surgical options. ESWL is effective for most renal stones less than 2 cm in size and ureteric stones less than 1 cm in size [18].In patients with normal anatomy, and with non lower pole renal stones < 20mm in size, ESWL is recommended as first line treatment. Lower pole stones have a higher failure rate with ESWL and so other treatment modalities should be sought ( see below). In one study which compared stone free rates of ureteral stones of variable sizes and locations which were treated by ureteroscopy or extra-corporeal shock wave lithotripsy, ESWL was associated with a success rate of 64% ( up to two treatments), as compared to 96% for ureteroscopy in a single treatment [17].

rates were superior in the PCNL group, the semi rigid ureteroscopy provides advantages for operating times, haemoglobin loss, post-operative visual analogue scoring by patients and reduced hospital stay [20]. The situation is slightly more complex in lower pole stones as the

ureteroscopy)

Modern Upper Urinary Tract Endoscopy http://dx.doi.org/10.5772/52750 375

ureteroscopy)

Ureteroscopy

ESWL

Ureteroscopy (retrograde or antegrade) or ESWL

Ureteroscopy or ESWL

**Stones <1cm in size Stones 1-2cm in size Stones >2cm in size**

**Table 1.** European Association of Urology (EAU) recommendations for the treatment of Renal stones.

Treatment for renal calculi in the inferior calyx is also very dependent on size:

**Stones <1cm in size Stones 1-2cm in size Stones >2cm in size** ESWL Favourable factors for ESWL? Endourology ( PCNL or

**Location Stone size 1st choice 2nd choice**

ESWL

The management of ureteric calculi is also dependent on the size of the stone involved. The table below outlines the European Urological Association guidelines for Stone management

> Ureteroscopy (retrograde or antegrade) or ESWL

The European Association of Urology and the American Urological Association guidelines Panel have published stone free rates for different treatment modalities within their nephro‐ lithiasis guidelines.In a cohort comparison group (early 1980s vs 1992) the success of ure‐

Ureteroscopy or ESWL Ureteroscopy

Flexible ureteroscopy ESWL PCNL Laparoscopy

Flexible ureteroscopy No -> Endourology

>10mm

>10mm

**Table 3.** EAU recommendations for the treatment of Ureteric stones

PCNL Yes -> ESWL or endourology

**Table 2.** EAU recommendations for the treatment of Lower pole stones.

ESWL ESWL or endourology Endourology (PCNL / flexible

following table shows.

**Ureteric Calculi**

dependent on size of stone:

Proximal ureter <10mm

Distal ureter <10mm

**The outcomes of ureteroscopy**

It is important to highlight that certain stone composition such as cystine or phosphate stones may be resistant to fragmentation.There are also multiple other contra indications to the use of ESWL which include pregnancy, bleeding diatheses, severe obesity, anatomical obstruction distal to the stone.

#### *4.2.2. Invasive treatment of upper tract stones*

Larger stones, particularly those composed of cystine or struvite, can be approached via es‐ tablishing percutaneous access to the collecting system through a small flank incision. This would allow direct visualization and intra-corporeal lithotripsy for stone disruption, and re‐ moval of fragments known collectively as Percutaneous nephrolithotomy (PCNL).

PCNL has high success rates of around 90% however there are risks onvolved, and major intra-operative or post operative complication rates are often reported as 0.03% to 10% [19]. However, ureteroscopy is fast becoming the main form of treatment for upper urinary tract stone management and this is what will be discussed for the purpose of this chapter.

#### *4.2.3. Selecting the treatment for a patient with stone management*

#### **Intra-renal calculi**

Different stone sizes respond better to different therapies and success rates are variable for the size of stone. The European Urological Association recommends the following manage‐ ment plan for kidney stones in the renal pelvis or upper/middle calyx, categorised according to size:

Flexible ureteroscopy is used less as a first line treatment for stones > 1.5cm in size. However with ongoing improvements in newer generation flexible ureteroscopes, there is an increas‐ ing trend toward ureteroscopy and laser lithotripsy for intr-renal calculi of all sizes and compositions. In the available literature, there are very few reported studies on the use of semi rigid ureteroscopy to treat renal stones. A prospective analysis performed by Bryniar‐ ski and co-workers assessed the safety of PNCL and retrograde intrarenal surgery use semi rigid ureteroscopy for the management of renal stones of >2cm in size. Although stone free rates were superior in the PCNL group, the semi rigid ureteroscopy provides advantages for operating times, haemoglobin loss, post-operative visual analogue scoring by patients and reduced hospital stay [20]. The situation is slightly more complex in lower pole stones as the following table shows.


**Table 1.** European Association of Urology (EAU) recommendations for the treatment of Renal stones.

Treatment for renal calculi in the inferior calyx is also very dependent on size:


**Table 2.** EAU recommendations for the treatment of Lower pole stones.

#### **Ureteric Calculi**

*4.2.1. Non invasive treatment of upper tract stones*

374 Endoscopy

compared to 96% for ureteroscopy in a single treatment [17].

*4.2.3. Selecting the treatment for a patient with stone management*

obstruction distal to the stone.

**Intra-renal calculi**

to size:

*4.2.2. Invasive treatment of upper tract stones*

ESWL is entirely non invasive, and it uses super sonic waves to fragment stones into small pieces that can be easily passed. Shortly after its introduction in 1983, it became widely ac‐ cepted as the first line treatment modality for the majority of stones and rapidly replaced invasive surgical options. ESWL is effective for most renal stones less than 2 cm in size and ureteric stones less than 1 cm in size [18].In patients with normal anatomy, and with non lower pole renal stones < 20mm in size, ESWL is recommended as first line treatment. Lower pole stones have a higher failure rate with ESWL and so other treatment modalities should be sought ( see below). In one study which compared stone free rates of ureteral stones of variable sizes and locations which were treated by ureteroscopy or extra-corporeal shock wave lithotripsy, ESWL was associated with a success rate of 64% ( up to two treatments), as

It is important to highlight that certain stone composition such as cystine or phosphate stones may be resistant to fragmentation.There are also multiple other contra indications to the use of ESWL which include pregnancy, bleeding diatheses, severe obesity, anatomical

Larger stones, particularly those composed of cystine or struvite, can be approached via es‐ tablishing percutaneous access to the collecting system through a small flank incision. This would allow direct visualization and intra-corporeal lithotripsy for stone disruption, and re‐

PCNL has high success rates of around 90% however there are risks onvolved, and major intra-operative or post operative complication rates are often reported as 0.03% to 10% [19]. However, ureteroscopy is fast becoming the main form of treatment for upper urinary tract

Different stone sizes respond better to different therapies and success rates are variable for the size of stone. The European Urological Association recommends the following manage‐ ment plan for kidney stones in the renal pelvis or upper/middle calyx, categorised according

Flexible ureteroscopy is used less as a first line treatment for stones > 1.5cm in size. However with ongoing improvements in newer generation flexible ureteroscopes, there is an increas‐ ing trend toward ureteroscopy and laser lithotripsy for intr-renal calculi of all sizes and compositions. In the available literature, there are very few reported studies on the use of semi rigid ureteroscopy to treat renal stones. A prospective analysis performed by Bryniar‐ ski and co-workers assessed the safety of PNCL and retrograde intrarenal surgery use semi rigid ureteroscopy for the management of renal stones of >2cm in size. Although stone free

moval of fragments known collectively as Percutaneous nephrolithotomy (PCNL).

stone management and this is what will be discussed for the purpose of this chapter.

The management of ureteric calculi is also dependent on the size of the stone involved. The table below outlines the European Urological Association guidelines for Stone management dependent on size of stone:


**Table 3.** EAU recommendations for the treatment of Ureteric stones

#### **The outcomes of ureteroscopy**

The European Association of Urology and the American Urological Association guidelines Panel have published stone free rates for different treatment modalities within their nephro‐ lithiasis guidelines.In a cohort comparison group (early 1980s vs 1992) the success of ure‐ teroscopic procedures rose from 86% to 96%. In addition, they observed an overall decrease in complications (20% to 12%) in ureteroscopy and 6.6% to 1.5% in ureteroscopic laser litho‐ tripsy [21]. Partly, this was thought to be due to greater surgeon experience and that this is significantly correlated to higher success and lower complication rates in ureteroscopic laser lithotripsy with holmium laser [21].

### **Renal Calculi**

The success rates (stone free or insignificant fragments) reported with PCNL are greater than 90% for renal stones >2cm. However, major complications during or after PCNL occur at reported rates of 0.03 % to 10% [22]. The success rates of retrograde intra-renal surgery have been reported as 75-95% for intra-renal stones >2cm after the first or second treatment, whereas the major or minor complications vary from 1.5 % to 12% [23].This is less frequent than rates in PCNL procedures. Major complications in ureteroscopy such as ureteric perfo‐ ration or avulsion are extremely rare.

### **Ureteric Calculi**

One study of a two year experience, highlighted that the success rates following ESWL were heavily influenced by stone size.The overall stone free success rate was 74.7% with one ses‐ sion. However, as the size of the stone increased, the success rate reduced. For stones <1cm the success ratewas 83.6%and when the stone size > 1cm the success rate reduced to 42.1%. The stone free rates also varied according to the site of the stone - 72.4% (proximal), 70% (mid ureter), and 82% (distal) after a single session [14-15].

In ureteroscopy, an overall stone –free rate of 87.8% was obtained irrespective of the size of the stone (88.9% for <1cm and 86.6% for >1cm). The success rates did slightly vary in relation to the stone site. The stone-free rates were 75% (proximal), 94.6% (mid ureter) and 84.6% (distal) [24].

The American Urological Association recent 2012 guidelines have published stone free rates for Shock Wave lithotripsy and ureteroscopy for the treatment of ureteric calculi and these are outlined in the tables below:
