Retrograde Ureteroscopy in the Treatment of Upper Urinary Tract Lithiasis

6.1 Generalities

Ureteral calculi were first mentioned by Ambroise Pare in 1564. He also described impaction of stones in both ureters as a cause of death ( ). Although ureteral calculi were subsequently mentioned by many authors, a successful intervention for extracting them was performed only after 200 years. In 1788, Desault designed an instrument used for incising the ureter and extracting the stone. In 1879, Thomas Emmet performed two interventions for the first time. In one case, he used a forceps to extract a stone from the ureteral orifice, while in another case he performed a transvaginal ureterolithotomy. Many types of approaches were used in the following period of time: transperitoneal, perineal, sacral, and vaginal. Different types of incisions were described according to the location of the lithiasis: Pfannenstiel- or Gibson-type incisions for distal ureteral calculi and subcostal incision for proximal ones. Many attempts were made to blindly extract calculi before cystoscopy was developed. The first manipulation of a ureteral stone was achieved by Gustav Kolisher. He located the stone situated several centimeters above the ureteral orifice using a catheter with a metallic end, through which he injected 30 cc of sterile oil ( ). The discovery of X-rays in 1895, together with the introduction of cystoscopy, paved the way for the use of endoscopic instruments for manipulating calculi ( ).

6.2 Indications

The purpose of the surgical treatment of upper urinary tract lithiasis is to completely extract the stone with minimal morbidity. Technological advances have essentially changed the treatment of this condition. Until the 1980s, open surgical ureterolithotomy and extraction of the stones with a basket catheter under fluoroscopic control were the only alternatives for their treatment. The development of minimally invasive therapeutic alternatives for urinary lithiasis is closely linked to the technological evolution in different fields including: optical fibers, imagistics, shock wave lithotripsy (SWL), and ultrasonic, electrohydraulic, or laser lithotripters. As a result of these advances, modern techniques for treating calculi were developed, including ureteroscopic extraction, percutaneous nephrolithotomy, and SWL. These led to the development of the therapeutic arsenal for ureteral calculi, regardless of their size or location. The term of endourology was broadened, including antegrade and retrograde techniques for urinary tract approach.

Extracorporeal lithotripsy, introduced into urological practice in 1982 by Chaussy, is currently one of the elective methods of treatment for upper urinary tract calculi ( ).

Theoretically, SWL is less invasive, the anesthetic requirement being limited, while instrumentation of patients is only necessary in a small number of cases. However, it is encumbered by a high rate of retreatment, requiring auxiliary procedures, which imply an additional morbidity.

The quite low success rate, as well as the problems that may occur when using this method, together with the advances regarding ureteroscopy, have recently made the latter become a first-line therapy for ureteral calculi, regardless of their location.

With the reduction of the caliber of semirigid ureteroscopes, the development of laser technology, and the introduction of increasingly better and reliable flexible ureteroscopes, the indications for ureteroscopic lithotripsy have broadened, including the approach of pyelocaliceal lithiasis.

Several authors currently consider that extracorporeal lithotripsy is reserved only for radiopaque reno-ureteral lithiasis, with a reduced hardness, nonimpacted, while retrograde ureteroscopy can be used for any type of stones. The major advantage of retrograde ureteroscopy compared to other techniques of intracorporeal lithotripsy is represented by the use of a natural pathway of approach.

In 2007, AUA and EAU reached a consensus regarding the therapeutic indications for ureteral lithiasis, individualized for the index patient and for those presenting a series of particularities. The guideline defines the index patient as follows: an adult person (with the exception of pregnant women) with noncystine/nonuric ureteral lithiasis, without kidney stones, with normal contralateral renal function, and with a medical and anatomical condition that allow any one of the treatment options to be undertaken.

For this type of patient, in the presence of ureteral calculi <10 mm and with an optimal control of symptoms, the first therapeutic option is represented by pharmacological therapy favoring spontaneous passage. Measures for the active removal of the calculi are recommended when the obstruction persists, when the stone does not progress, or when the patient presents persistent colicative pain that cannot be controlled by therapy. For calculi >10 mm, both SWL and ureteroscopy represent first-line therapeutical alternatives.

The increased hardness of cystine stones and, implicitly, the reduced success rates of SWL in these patients require retrograde ureteroscopy with intracorporeal lithotripsy (Ho:YAG, ultrasonic, or pneumatic) as the first therapeutic alternative. In patients with uric lithiasis, chemolysis associated with pharmacological expulsive therapy is a viable option. Ureteroscopy is a very efficient method for treating patients with this type of lithiasis, who are not candidates for pharmacological therapy ( ).

For septic patients with lithiasic ureteral obstruction, emergency decompression of the urinary tract will be performed (percutaneous nephrostomy and JJ catheter stenting), and the definitive treatment will be performed after reequilibration.

Semirigid or flexible ureteroscopic approach is preferred to SWL in patients who require complete extraction of the stones: pilots, personnel on long-distance ships, female patients who wish to become pregnant in the near future, and patients who are going to travel to countries with a less developed medical infrastucture ( ). Last but not least, the choice of a therapeutic alternative depends on the technical endowment of the urological department, as well as on the patient’s option.

6.2.1 Indications of Ureteroscopy in the Treatment of Ureteral Lithiasis

The essential element in the management of ureteral calculi is represented by the choice of the optimal therapeutic alternative.

Although the initial experience concerning rigid ureteroscopy led to favorable results regarding distal ureteral lithiasis, the success rate for middle and proximal ureteral calculi was low. The miniaturization of rigid ureteroscopes, the introduction of semirigid ureteroscopes and subsequently of flexible ones, and the use of better lithotripters improved the retrograde endoscopic approach of proximal calculi ( ).

As opposed to rigid or semirigid ureteroscopy, the flexible one has limited indications for the approach of pelvic ureteral calculi, due to the difficulties in maneuvering at this level, this method proving its efficiency especially in the treatment of iliac or lumbar ureteral calculi ( ).

However, flexible ureteroscopy should be seen as a method that is complementary to the rigid or semirigid one for ureteral lithiasis. It can prove to be essential in certain circumstances, when semirigid retrograde approach is inefficient, impossible, or contraindicated: patients with urinary derivations ( Figs 6.1–6.3 ), important ureteral sinuosities, large prostatic adenomas, etc.

6.2.2 Indications of Ureteroscopy in the Treatment of Pyelocaliceal Lithiasis

The modern therapeutic options for pyelocaliceal calculi are represented by SWL, flexible ureteroscopy, and percutaneous nephrolithotomy, the therapeutic strategy being individualized according to the particularities of each case.

SWL is the elective method in the treatment of pyelocaliceal lithiasis with sizes of less than 20 mm. However, for calculi with certain chemical compositions (cystine, calcium oxalate monohydrate, etc.), extracorporeal lithotripsy has a modest success rate ( ).

Flexible ureteroscopy is indicated in patients with SWL-resistant lithiasis, especially with sizes of less than 2 cm, those with large calculi benefiting from the percutaneous approach.

Also, SWL has a modest success rate in patients with lower caliceal lithiasis, due to the difficult evacuation of the lithiasic fragments. In these cases, flexible retrograde approach may be the first therapeutic alternative ( ).

Patients with renal lithiasis and skeletal anomalies, morbid obesity, hemorrhagic diathesis, and kidney malformations, in whom percutaneous approach and/or SWL are contraindicated or very difficult to perform, are also candidates for flexible retrograde ureteroscopic approach ( ).

This method can also be an alternative in the treatment of intradiverticular lithiasis ( ).

6.2.1 Indications of Ureteroscopy in the Treatment of Ureteral Lithiasis

The essential element in the management of ureteral calculi is represented by the choice of the optimal therapeutic alternative.

Although the initial experience concerning rigid ureteroscopy led to favorable results regarding distal ureteral lithiasis, the success rate for middle and proximal ureteral calculi was low. The miniaturization of rigid ureteroscopes, the introduction of semirigid ureteroscopes and subsequently of flexible ones, and the use of better lithotripters improved the retrograde endoscopic approach of proximal calculi ( ).

As opposed to rigid or semirigid ureteroscopy, the flexible one has limited indications for the approach of pelvic ureteral calculi, due to the difficulties in maneuvering at this level, this method proving its efficiency especially in the treatment of iliac or lumbar ureteral calculi ( ).

However, flexible ureteroscopy should be seen as a method that is complementary to the rigid or semirigid one for ureteral lithiasis. It can prove to be essential in certain circumstances, when semirigid retrograde approach is inefficient, impossible, or contraindicated: patients with urinary derivations ( Figs 6.1–6.3 ), important ureteral sinuosities, large prostatic adenomas, etc.

6.2.2 Indications of Ureteroscopy in the Treatment of Pyelocaliceal Lithiasis

The modern therapeutic options for pyelocaliceal calculi are represented by SWL, flexible ureteroscopy, and percutaneous nephrolithotomy, the therapeutic strategy being individualized according to the particularities of each case.

SWL is the elective method in the treatment of pyelocaliceal lithiasis with sizes of less than 20 mm. However, for calculi with certain chemical compositions (cystine, calcium oxalate monohydrate, etc.), extracorporeal lithotripsy has a modest success rate ( ).

Flexible ureteroscopy is indicated in patients with SWL-resistant lithiasis, especially with sizes of less than 2 cm, those with large calculi benefiting from the percutaneous approach.

Also, SWL has a modest success rate in patients with lower caliceal lithiasis, due to the difficult evacuation of the lithiasic fragments. In these cases, flexible retrograde approach may be the first therapeutic alternative ( ).

Patients with renal lithiasis and skeletal anomalies, morbid obesity, hemorrhagic diathesis, and kidney malformations, in whom percutaneous approach and/or SWL are contraindicated or very difficult to perform, are also candidates for flexible retrograde ureteroscopic approach ( ).

This method can also be an alternative in the treatment of intradiverticular lithiasis ( ).

6.3 Rigid and semirigid retrograde ureteroscopy technique

Semirigid ureteroscopes are currently used more and more frequently, being less traumatic than the rigid ones and better than the flexible ones ( ). Their external diameter is approximately equal to that of rigid ureteroscopes, but the endoscopic field remains round all the time, even if the instrument is flexed more than 4 cm, due to the fact that the light is transmitted through optical fibers similar to those used in the case of flexible ureterorenoscopes.

Rigid or semirigid ureteroscopy also presents a series of other important advantages compared to the use of the flexible instrument. Thus, the durability and reduced costs represent arguments in its favor. Also, the caliber of the working channel of the ureteroscopes allows the use of a large variety of auxiliary instruments, ensuring a better irrigation and visibility.

These advantages are counterbalanced by the difficulties in approaching the proximal ureter (especially in men) and the pyelocaliceal system, as well as by the high risk of intraoperative incidents and complications.

6.3.1 Preliminary Measures

The preliminary measures have in mind patient selection, preoperative preparation, anesthesia, the steps preceding the actual intervention, and patient positioning on the operating table.

6.3.1.1 Patient Selection

Prior anamnestic assessment may provide important data regarding associated diseases, as well as any previous interventions that may make the ureteroscopic approach more difficult.

The preoperative clinical and paraclinical examinations are essential for preparing and planning the endoscopic intervention. Retrograde ureteroscopy is difficult in patients in whom the standard lithotomy position cannot be ensured due to skeletal deformations. The presence of a prostatic median lobe or a large cystocel may also determine difficulties in achieving a rigid or semirigid retrograde ureteroscopic approach.

Preoperative imaging explorations include ultrasonography of the urinary tract, simple renovesical radiography, and intravenous urography.

Preoperative intravenous urography or retrograde ureteropyelography allow for the specification of the position and size of the stone, the degree of obstructive suffering of the affected renal unit, and the anatomy of the urinary tract below and above the stone, as well as some congenital (ureteral bifidities or duplicities) or acquired conditions (ureteral stenoses or retroperitoneal fibrosis) that may make the retrograde endoscopic approach more difficult. This information is useful in estimating the intervention’s degree of difficulty, guiding the planning of the procedural tactics and its associated risks.

The urine must be sterile. Preoperative urinary infection requires adequate treatment. In case of a positive uroculture, targeted antibiotic therapy should precede the intervention by 48–72 h. Acute pyelonephritis contraindicates retrograde ureteroscopy. In this situation, ureteroscopy will be preceded by the clinical resolution of the septic status by ensuring the drainage of the renal unit by percutaneous nephrostomy or ureteral stenting and antibiotic treatment according to the antibiogram.

Even in the absence of a urinary infection, parenteral antibiotic prophylaxis is indicated immediately preoperatively or 12 h before the intervention.

Assessment of coagulation plays an essential role, not only in choosing the therapeutic modality and the instruments, but also in anticipating an increased risk of intraoperative bleeding, with a consecutive reduction of visibility. Oral anticoagulation treatment must be replaced before the intervention with administration of low molecular weight heparin, with predictable and easier to correct effects.

6.3.1.2 Patient Positioning

The patient should be placed on the endoscopy table in the standard lithotomy position, with the lower limb contralateral to the approached ureter in hyperabduction and in a lower position ( Fig. 6.4 ).

This position allows the ureteroscope to be guided in the direction of the intramural trajectory of the ureter, while the movements of the surgeon are not limited by the contralateral lower limb. Sometimes, the intervention can be performed in better conditions if the surgeon places himself outside this lower limb.

Some authors prefer lowering the ipsilateral lower limb, the ureteroscopic approach being facilitated by raising the respective hemitrigone, with the modification of the position of the ureteral orifice in a straight line and horizontal in relation with the bladder neck.

6.3.1.3 The Endourologic Equipment

Performing any endoscopic procedure requires preparing an adequate working table containing frequently used instruments and equipment.

Thus, the following are necessary: cystoscope, rigid, semirigid, or flexible ureteroscopes of different sizes and adequate auxiliary instruments, different guidewires (with curved or straight soft end, hydrophilic guidewire), ureteral catheters, stents, ureteral dilators, basket catheters, and energy generators (ultrasonic, electrohydraulic, pneumatic, or laser). The presence of these instruments determines a reduction of delays, of the operating time, and of the anesthetic risk.

6.3.1.4 Anesthesia

The type of anesthesia used for the treatment of ureteral lithiasis depends both on the technological level and on the type of available anesthetic technique. Both have evolved considerably over the last few years. Before the introduction of extracorporeal lithotripsy and of ureteroscopy, surgical ureterolithotomy required the use of general anesthesia. Ureteroscopy was initially performed exclusively under general or spinal anesthesia due to the high-caliber ureteroscopes that were used and to the necessity of dilating the ureteral orifice ( ).

The arguments in favor of general anesthesia are represented by the control of breathing, avoiding the patient’s movement, or coughing, which may produce lesions of the upper urinary tract. However, a review of the data in the literature did not show significant differences regarding the incidence of iatrogenic lesions during retrograde ureteroscopy with or without general anesthesia.

There are situations in which general anesthesia cannot be induced due to cardiovascular or respiratory conditions. In these cases, regional blockade should also include the fibers of the sympathetic nerves at the T8 level that transmit pain.

The use of regional anesthesia has seen a decline due to the period of time necessary for inducing anesthesia and the increased recovery period in the postoperative unit. The quicker induction of spinal anesthesia compared to the epidural one, together with the localized blockade, are arguments in favor of its use. Also, this type of anesthesia is indicated in pregnant women due to the reduced transfer of drugs toward the fetus. However, in patients with severe cardiovascular diseases, epidural anesthesia is preferred. In these situations, the degree and extent of the anesthetic blockade are easier to control.

Over the last years, the intent of reducing the operating time and the convalescence period, without however giving up on intraoperative comfort, have determined a diversification of the indications of local anesthesia with or without analgosedation. The reduced duration of action of sedoanalgesic agents allows their easy titration and quick postprocedural recovery ( ). Even the treatment of renal or ureteral lithiasis can be performed under this type of anesthesia, if the intervention is not very complex and requires a limited period of time ( ). A duration of 60–90 min is considered the limit over which regional or general anesthesia is required ( ). Also, overdistension of the upper urinary tract with irrigation fluid should be avoided because it may cause lumbar pains.

Starting the intervention under local anesthesia does not prevent the induction of general anesthesia at any moment, if the operating time is prolonged or if this is required by the patient’s condition. Local anesthesia of the urethra with 2% lidocaine gel may be sufficient for performing retrograde ureteroscopy in certain situations. However, in most cases, for ensuring the patient’s comfort, sedation by intravenous injection of diazepam, midazolam, or narcotics (fentanyl, morphine, demerol) is required ( ).

The introduction into medical practice of quickly acting substances for intravenous sedation or analgesia, together with the reduction of ureteroscope calibers, have led to an increased success of ureteroscopy performed under local anesthesia associated with sedoanalgesia.

The safety and tolerability of this intervention have been confirmed by numerous studies. Some authors state that approximately half of the ureteroscopic procedures performed in a urology department can be carried out under local anesthesia associated with sedation ( ). However, the studies that were performed included especially women with distal ureteral calculi. The dilation of the ureteral orifice does not represent a contraindication for local anesthesia with intravenous sedation. In men, the discomfort determined by rigid ureteroscopy is produced by the passing of the instruments through the membranous urethra and bladder neck.

6.3.1.5 Irrigation

Irrigation ensures the visibility necessary for the ureteroscopic procedures. The most frequently used irrigation fluid is saline solution heated to body temperature, especially due to the risk of absorption through pyelolymphatic or pyelovenous reflux, or after ureteral perforation ( ). If electroresection is necessary, saline solution can be replaced by glycine solution, sterile water, or sorbitol.

Ideally, the intrarenal pressure should be maintained under 30 cm H ₂ O. Overdistension of the collecting system may largely be responsible for the induction of postoperative pain ( ). The pressure may be ensured by suspending the saline solution bags 30–50 cm above the patient’s plane ( Fig. 6.5 ).

Due to the resistance of the tubing and of the irrigation channel, the pressure generated by gravity may not provide an adequate visibility. For this reason, different systems that determine optimization of visibility through an accurate control of pressure have been described, without the distension of the renal collecting system ( Fig. 6.6 ). The advantages of these techniques consist of the possibility of increasing pressure during the critical moments of the intervention. The disadvantages include the lack of control of constant visualization and the necessity for an operator to maneuver the equipment in complex cases.

The systems for pressure control are also useful for countering the negative effects on the irrigation flow of the accessory instruments introduced through the working channel that determines a reduction of the standard irrigation ( ).

In conclusion, the operator should use a level of pressure that ensures an adequate visibility, at the same time avoiding the risk of absorption and pyelovenous reflux.

6.3.2 Cystoscopy

Cystoscopy preceding the ureteroscopic approach represents the first step of the intervention, being necessary for assessing the morphology and dimensions of the ureteral orifice ( Fig. 6.7 ) and any associated bladder conditions.

If additional data regarding the upper urinary tract are necessary, an intraoperative retrograde pyelography may be performed ( Fig. 6.8 ).

6.3.3 Placing the Safety Guidewire

After the cystoscopic assessment, a 0.035–0.038 in. guidewire with a soft end is placed up to the renal pelvis ( Fig. 6.9 ).

This safety guidewire plays an essential role in maintaining the access toward the upper urinary tract, allowing repeated passages of the ureteroscope. The guidewire guides the ascension of the endoscope and contributes to the prevention of parietal lesions during ureteral dilation, ureteroscopy, or stent placing. After placing the safety guidewire, some authors recommend pharmacological stimulation of diuresis in order to reduce pyelorenal reflux and infectious complications. The accessibility of different types of guidewires is extremely important, especially in the case of patients in whom ureteroscopic approach may be difficult.

In difficult cases, placing the guidewire may be facilitated by directing it through a ureteral catheter or under direct ureteroscopic control ( Fig. 6.10 ).

6.3.4 Ensuring Access to the Intramural Ureter

The ureterovesical junction and the intramural ureter constitute the ureteral segment with the smallest caliber, the mean diameter being 3 mm. If the ureterovesical junction is too narrow, it is necessary to use different techniques in order to help pass through the intramural trajectory of the ureter or to dilate the ureteral orifice by different methods.

The latter represents the most frequently used method for facilitating the approach to the intramural ureter, allowing the introduction and extraction of the ureteroscope and of the lithiasic fragments. Moreover, dilation may prevent fixation of the stone or of the ureteroscope in the intramural ureter, thus preventing the risk of terminal ureter avulsion.

Before the miniaturization of rigid and flexible ureteroscopes, ureteral dilation represented a routine maneuver within the intervention’s protocol. A study performed by demonstrated the absence of long-term sequelae after routine dilation of the ureteral orifice with the balloon catheter. Modern low-caliber instruments have reduced the necessity for dilation to approximately 14% of cases ( ). This is only required when the ureteral orifice cannot be easily passed or when multiple passages of the ureteroscope are required. Recently, ureteral access sheaths ensure a rapid dilation and allow repeated passages of the ureteroscope.

Dilation of the intramural ureter must be performed up to a diameter adapted according to the caliber of the ureteroscope used. This can be achieved by several active or passive methods.

Progressive, telescopic dilation can be performed using Teflon or polyethylene dilators, from 6 F to 18 F, advanced over a standard 0.038 in. guidewire, inserted cystoscopically. Repeated insertions of the dilators can traumatize the ureteral mucosa and musculature, causing bleeding with consecutive reduction of visibility in the endoscopic field.

An alternative is to use a Nottingham-type progressive cone dilator, with a diameter of up to 12 F ( Fig. 6.11 ). These two methods cannot be applied in cases of steinstrasse syndrome or if the stone is located in the distal ureter.

Dilation can also be performed using flexible metallic plugs with an olivary end, with dimensions ranging from 9 F to 13.5 F, passed through the sheath of the rigid cystoscope, over a guidewire ascended anteriorly into the ureter. This dilation method can also be used for juxtavesical pelvic ureteral lithiasis or even for steinstrasse syndrome. Another alternative is represented by dilation through coaxial systems of ureteral access, over which the working sheath is advanced.

Hydraulic dilation of the ureter using the Uromat represents an efficient procedure, which consists of achieving, through a hydraulic pump, an irrigation stream of up to 200 mm Hg. If the procedure does not have a long duration, the hyperpressure in the urinary tract does not determine adverse effects.

Passive dilation by placing a ureteral catheter or a stent for 48–72 h ( Fig. 6.12 ) was described by .

However, this technique presents several disadvantages. The most important is the fact that it transforms the ureteroscopy into a two-step procedure, determining an increase in duration and in hospitalization costs. It also increases the risk of urinary infections and may determine the stone’s mobilization.

The presence of ureteral stenoses, of an impacted ureteral stone, or of steinstrasse syndrome may prevent achieving passive dilation, requiring performing a percutaneous nephrostomy. The balloon catheter represents the most frequently used instrument for dilating the intramural ureter ( Fig. 6.13 ).

This has radiopaque marks at the two extremities of the balloon and is introduced into the ureter through a guidewire placed anteriorly up to the renal pelvis. The balloon is inflated using a normal 5 mL syringe or a LeVeen-type syringe that allows pressure control; 2–5 mL of 30–50% contrast media can be introduced, allowing the fluoroscopic control of the maneuver. The balloon is inflated slowly (1–2 atm/min) in order to prevent its rupture or the rupture of the ureter. The maximum inflation pressure should not exceed 15 atm. The inflation of the balloon continues until it takes a cylindrical shape, without strangulation rings.

Correctly performed, the balloon dilation of the ureter is a relatively nontraumatic maneuver, ensuring safe access to the upper urinary tract ( ). Ureters dilated to diameters of 15–18 F can heal completely. After ureteral dilation, a transient degree of vesicoureteral reflux can occur, without long-term clinical significance ( ). Lesions of the mucosa and subsequent leakage of the contrast media were observed in 52%, respectively 19% of patients in whom balloon dilation up to 24 F was performed ( ). Placing a ureteral stent after the procedure contributes to preventing the occurrence of secondary ureteral stenoses ( ).

In exceptional situations, when dilation of the intramural ureter is impossible using the aforementioned procedures, an endoscopic incision of the ureteral orifice can be performed ( Fig. 6.14 ). The balloon dilators currently used have variable sizes, with a balloon diameter ranging from 3 F to 30 F, and with a length between 4 cm and 20 cm.

The approach to the intramural ureter can be facilitated by using two guidewires ascended through the ureter, and the endoscope can be easily oriented between them ( Fig. 6.15 ). The method removes the necessity for dilating the ureteral orifice, the maneuver being much less traumatic (without requiring postoperative ureteral stenting) and less expensive ( ).

Another alternative for facilitating the access to the upper urinary tract is represented by using the ureteral access sheath. Its most important indication is represented by the ureteroscopic treatment of large renal or proximal ureteral calculi. The sheath is chosen according to the patient’s constitution, the localization of the stone, and the caliber of the ureteroscope used.

The procedure has two important advantages: minimalization of ureteral trauma (by repeated insertions of the ureteroscope) and the hypopressure in the overlying urinary tract (which reduces the infectious risk and that of the patient’s hyperhidration) ( ). The use of the access sheath allows for maintaining a reduced pressure (below 30 cm H ₂ O) in the pyelocaliceal system, even while using an increased irrigation flow ( ).

On the other hand, some authors consider that the potential disadvantages can contraindicate the use of the ureteral access sheath. As opposed to balloon dilation, the placing of the sheath determines the exertion of scissoring forces in the distal ureter, which may increase the risk of stenoses at this level. Although long-term evaluations indicate a reduced rate of these ureteral strictures ( ), controlled studies are still necessary in order to assess the long-term effects ( ).

The access sheath occupies a part of the internal diameter of the ureter, its interior caliber being approximately 2 F smaller than the external one. For this reason, a dilation up to a larger diameter compared to classic ureteroscopy is required. This may determine the reduction of the blood flow at the level of the ureteral wall by approximately 65% when 14–16 F sheaths are used ( ). For this reason, it is recommended to avoid using sheaths in patients with a history of radiotherapy or retroperitoneal interventions. The potential risk of ureteral ischemia increases in cases that require prolonged interventions. If the sheath is placed only under fluoroscopic control, stone fragments or tumors located in the distal ureter may not be observed.

Certain associated pathological modifications (e.g., large prostatic adenomas) may make placing the access sheath impossible or may deform it, preventing the facile insertion of the ureteroscope ( ).

Moreover, due to the large-scale introduction of laser lithotripsy, which allows for fragmentation of stones into very fine particles, fewer and fewer retrograde ureteroscopic procedures require repeated excursions into the upper urinary tract ( ).

The use of the ureteral access sheath determines additional costs. However, a recent analysis of their use has shown a reduction of the operative time and, implicitly, of the procedure’s costs ( ).

6.3.5 Ascending the Ureteroscope

Rigid or semirigid ureteroscopy begins by advancing the ureteroscope under direct visual control, along the guidewire, up to the urinary bladder. The ureteral orifice is then approached, the ureteroscope being advanced under visual and fluoroscopic guidance.

The ureteroscope is introduced into the intramural ureter by raising the superior margin of the orifice with its distal end by using one of the following procedures:

•

fixing the ureterescope perpendicular to the ureteral orifice, followed by lowering it by 90°, associated with its advance in the direction of the intramural trajectory
•

simultaneously exerting a lowering (90°) and twisting (180°) motion
•

twisting the ureterescope fixed at the level of the ureteral orifice (180°)

Once advanced into the intramural ureter, the ureteroscope is brought back to its initial position.

The following rules must be respected when negotiating the ureteral orifice and ascending the endoscope:

•

the introduction of the endoscope into the ureter must be performed under direct visual control, always maintaining the ureteral lumen in the center of the endoscopic field ( Fig. 6.16 )

Figure 6.16

Ascending the ureteroscope into the intramural ureter.
•

the endoscope is advanced proximally only if the ureteral lumen is clearly seen, and if the instrument slides easily along the lumen

The proximal advancing of the ureteroscope will be done without exerting excessive pressure, permanently keeping the guidewire in the center of the endoscopic field ( Fig. 6.17 ). Thus, the occurrence of ureteral perforations can be prevented.

Some authors do not recommend the routine use of the safety guidewire ( Fig. 6.18 ).

Knowing the ureter’s anatomy and anticipating its curves facilitate the ascent of the ureteroscope. Thus, the progression of the rigid endoscope is more difficult at the level of the iliac vessels. In women, it is easier to advance the rigid endoscope along the entire length of the ureter.

As long as a minimal effort is exerted in order to achieve the proximal advancement of the ureteroscope, the endoscopic field remains round. Its deformation into a half-moon reflects the exertion of an excessive force on the instrument.

Sometimes, the advancement of the ureteroscope may be more difficult due to the following reasons:

•

reduced visibility due to bleeding
•

reduced ureteral caliber
•

ureteral sinuosities

Regaining a clear endoscopic field may be achieved by increasing the irrigation flow, by facilitating the evacuation of the irrigation fluid, or sometimes even by removing the optics until the fluid evacuated through the endoscope’s sheath becomes clear. Another method is injecting saline solution through a ureteral catheter introduced up to the distal end of the endoscope.

The narrower areas of the ureter ( Fig. 6.19 ) can be dilated using balloon catheters. The dilator can be advanced on the guidewire up to the narrow area that has been observed by fluoroscopy. Dilation is achieved using a technique similar to that used in the dilation of the ureteral orifice. If elimination of the obstruction fails, either ureteral stenting for several weeks or endoureterotomy is recommended. Ureteral sinuosities or narrowed areas of the ureter can prevent performing rigid and semirigid retrograde ureteroscopy in approximately 10% of cases.

The tortuous parts of the ureter ( Fig. 6.20 ) can raise technical difficulties.

Ureteral sinuosities can be passed by using one or more of the following maneuvers:

•

Negotiating the area by orienting the tip of the endoscope according to the sinuosity, so that the ureteral lumen is kept in the center of the endoscopic field ( Fig. 6.21 ).

Figure 6.21

Negotiating the ureteral sinuosities with the semirigid ureteroscope.
•

Positioning the patient in Trendelenburg with ascension of the kidney and alignment of the proximal ureter. This maneuver is inefficient in the presence of pyelonephritis, which determines fixation of the kidney.
•

Ascending a ureteral catheter or a rigid guidewire up to the renal pelvis, thus obtaining an alignment of the ureter.
•

Advancing a second guidewire through the ureteroscope’s working channel. The endoscope is rotated so that it is placed between the two guidewires, which therefore contributes to the opening and alignment of the ureter, facilitating the passage ( Fig. 6.22 ).

Figure 6.22

Passing a ureteral sinuosity by using two guidewires.

6.3.6 Extraction of Ureteral Calculi

The modality of removing ureteral stones depends both on their dimensions and location, as well as on the status of the underlying and overlying urinary tract.

The extraction of unimpacted ureteral calculi is achieved according to their dimensions. Those with a size under 6 mm can be extracted with a forceps or a balloon catheter, without requiring their fragmentation ( Figs 6.23 and 6.24 ).

After catching the stone between the spirals of the Dormia catheter, it is withdrawn concomitantly with the ureteroscope ( Fig. 6.25 ). If stone impaction is observed during the extraction, the maneuver must be stopped in order to avoid lesions or avulsion of the ureter.

In this case, the lithotripsy probe is introduced through the working channel in order to process the stone between the probe’s spirals, and only after that can the fragments be extracted safely.

Stones larger than 6 mm will be extracted only after intracorporeal lithotripsy. Due to the risk of proximal migration, fragmentation will be achieved after immobilization of the stone with a special balloon catheter or with a basket catheter introduced through the endoscope’s secondary working channel ( Fig. 6.26 ).

Fixation of the stone can also be achieved with the 5 F ureteral catheter ascended through the central working channel or by using the Detler cone, advanced above the stone.

Impacted stones, which have a reduced risk of proximal migration, can be extracted after fragmentation in situ (ultrasonic, electrohydraulic, pneumatic, or laser).

In order to allow the complete and complication-free elimination of the fragments, lithotripsy must be performed up to dimensions smaller than the guidewire’s diameter (0.035 in.).

As an alternative method, lithotripsy of the stone can be done into fragments that can be completely removed with extraction instruments ( Fig. 6.27 ). The presence of small, but removable, lithiasic pieces at the end of the procedure requires ureteral stenting.

A series of technical difficulties are raised by the treatment of soft ureteral calculi, especially due to the particularities of the extracting instruments with a design conceived for manipulating rough lithiasic fragments ( ). Extraction of this type of calculi is done especially using basket catheters ( Figs 6.28 and 6.29 ).

In certain situations, the approach of pyelocaliceal calculi can be achieved with rigid and semirigid endoscopes ( Figs 6.30 and 6.31 ). When the anatomy of the pyelocaliceal system does not allow for this type of approach, flexible endoscopes will be used.

6.3.7 Methods of Calculi Lithotripsy

The methods of intracorporeal lithotripsy include ultrasonic, electrohydraulic, ballistic, or laser lithotripsy ( Table 6.1 ).

Table 6.1

Types of Contact Lithotripsy

Principle	Mechanism	Probe	Advantages	Disadvantages
Ultrasonic	Ultrasound generator that produces sinusoidal vibrations (20–27 kHz)	Rigid	Cheap, efficient (especially for softer calculi); allows concomitant suction of fragments; reduces the duration of the surgical intervention in case of large calculi	Reduced efficiency for ureteral calculi; the probe can frequently block; cannot be used with flexible instruments
Electrohydraulic	Generates an electric arch at the probe’s tip, producing shock waves close to the stone	Flexible	Cheap, efficient; allows fragmentation of stones with a medium roughness; flexible probe	May produce lesions of the soft tissues; ascendent migration of the fragments; inefficient for rough calculi
Pneumatic	Compressed air that triggers the probe	Rigid	Cheap and efficient; allows the destruction of any type of stone	Rigid probes; may determine the stone’s propulsion
Ho:YAG laser	Photothermal effect	Flexible	Very efficient, can fragment any type of stone; may be used with flexible instruments; allows retrograde lithotripsy of renal calculi	Very expensive; fragmentation of the calculi may take more time

6.3.7.1 Ballistic Lithotripsy

The success rates of ballistic lithotripsy vary in different studies between 73% and 96%, an efficacy similar to that of electrohydraulic lithotripsy ( ). The arching of the probe during lithotripsy determines a significant reduction of the impact force ( ).

The relatively nontraumatic nature of ballistic lithotripsy ( ) allows the avoidance of placing a ureteral stent at the end of the procedure. reported the use of a ureteral stent in only nine patients in a group of 68 who underwent ballistic lithotripsy.

As in the case of other fragmentation methods, the ballistic lithotripter must be activated only in case of a correct visualization of the stone and of the probe’s position ( Fig. 6.32 ). The stone’s fixation, which is relatively easy in case of a renal or vesical localization, may be difficult in case of ureteral stones. Sometimes, the stone’s fixation between the spirals of a basket catheter or occlusion of the proximal ureter by one of the previously mentioned methods may be necessary.

6.3.7.2 Ultrasonic Lithotripsy

Ultrasonic lithotripsy is based on the stone’s fragmentation by the energy provided by the high-frequency vibration of a rigid metallic transducer. This type of lithotripsy requires performing a ureteral dilation in order to allow the use of rigid ureteroscopes. For fragmentation, the tip of the metallic transducer must be in direct contact with the stone. Its dissolution should be started from the periphery, avoiding its perforation. The resultants small fragments must be suctioned or extracted with adequate clamps.

For an efficient dissolution, the stone must be positioned between a probe’s spirals and maintained in a fixed position in order to avoid the recoil.

The possibility for the ultrasonic destruction of calculi differs according to their chemical composition, dimensions, density, and roughness. Smaller calculi are fragmented more quickly. Also, the destruction of calculi with a smooth surface is more difficult than for rough stones ( ).

reported a rate of complete fragmentation of 96.6% in a group of 118 patients using 2.5 F probes, which can be advanced through small-caliber ureteroscopes. Similar results were reported by .

In another study, compared the results obtained by ultrasonic lithotripsy with 3 F probes in a group of 25 patients with those provided by ballistic lithotripsy in a group of 122 patients. The success rate was significantly higher in the case of ballistic lithotripsy (97.3% vs. 84%).

6.3.7.3 Electrohydraulic Lithotripsy

Electrohydraulic lithotripsy of ureteral calculi requires the use of a probe with dimensions varying between 1.6 F and 1.9 F ( Fig. 6.33 ). This is introduced through the working channel of the rigid or flexible ureteroscope, its end being placed 2–5 mm from the end of the ureteroscope in order to protect the optical system during the electric discharges. The probe is advanced until it is close to the stone, but not in direct contact with it, the maximum efficiency of the waves being obtained when the distance between its end and the stone is of approximately 1 mm ( ). In order to reduce the risk of ureteral lesions, single impulses with low intensity (50–60 V) are initially generated. The intensity can subsequently be increased, according to the stone’s resistance.

However, it is recommended to limit the maximum energy level used in order to minimize the risk of perforation ( ). The insulation of the distal end loosens after 50–60 s from the generation, requiring the probe to be replaced ( ).

The resulting fragments can be extracted with a clamp or with a basket catheter ( Figs 6.34 and 6.35 ). It is not recommended to attempt fragmenting the stone into particles smaller than 2 mm due to the increased risk of ureteral wall injury.

The success rate of stone fragmentation is of approximately 90%. The success rate also depends on the composition, dimensions, and surface of the lithiasic fragments ( ). The stone-free rate decreases with the increase of the stone’s dimensions, being significantly lower than that obtained through Ho:YAG lithotripsy ( ).

6.3.7.4 Laser Lithotripsy

The advances regarding laser lithotripsy are due to the introduction of the Ho:YAG laser, with a wavelength of 2150 nm, released in a pulsed manner through quartz fibers. The safety and efficacy of Ho:YAG have been underlined by many studies. Sofer detected a complication rate of under 1% with an efficacy of 97–100% after a single procedure, without dilating the ureteral orifice or placing a ureteral stent after the ureteroscopy ( ).

Another study, conducted by Grasso and Bagley ( ), assessed the efficacy of treatment by retrograde ureteroscopy with Ho:YAG lithotripsy for proximal ureteral calculi with a diameter larger than 2 cm. The success rate after one procedure was 95%, only one patient requiring a second intervention. No significant intra- or postoperative complications were recorded.

The laser lithotripsy technique is relatively simple and implies placing the fiber in contact with the stone’s surface before activation. Good visibility is essential for preventing ureteral perforation. After initiating laser lithotripsy, a short break is frequently necessary due to the “snowstorm” determined by the lithiasic fragments ( Fig. 6.36 ) ( ).

Due to the potential of this type of laser for sectioning metal, it is necessary to avoid the discharge of the fiber in the immediate vicinity of the accessory instruments ( Fig. 6.37 ), especially of the fine ones made of nitinol ( ).

In particular situations (e.g., fixed basket catheters with stones inside), this problem becomes a potential advantage: one of the basket’s spirals will be sectioned by laser, allowing the disengagement and extraction of the catheter.

The tip of the probe should be placed at least 2 mm from the endoscope’s end, in order to prevent the destruction of the optical system or of the working channel; 200 and 365 μm fibers can be used for flexible intracorporeal lithotripsy. Ho:YAG laser lithotripsy depends on the pulsed energy generated and on the fiber’s diameter. Thus, its efficacy is correlated with the energy’s density, which increases with the decrease of the fibers’ diameter ( ). The energy necessary for the fragmentation of the stones is lower than that used for other therapeutic laser applications. A power of 0.6–1.2 J is generally used, with a frequency of 5–15 Hz ( ). Due to the risk of the stone’s propulsion and of the fiber’s destruction, it is recommended to begin the procedure with a reduced energy of 0.6 J and with a frequency of 6 Hz, which will subsequently be increased as needed ( ). Lithotripsy is performed by moving the laser beam over the stone’s surface in order to avoid the generation of large fragments. The laser beam must be kept at least 1 mm from the ureteral wall ( Fig. 6.38 ).

6.3.8 Ureteral Stenting

Classically, ureteral stenting ( Fig. 6.39 ) has been routinely recommended at the end of the procedure in all patients who undergo ureteroscopy for ureteral calculi.

Nevertheless, numerous recent studies have re-evaluated the utility and indications of this maneuver ( ).

There are many theoretical advantages of placing a JJ stent. This allows the elimination of the obstruction that may occur as a result of ureteral edema, protecting the renal function and improving its symptomatology. Also, stenting facilitates the elimination of remaining lithiasic fragments, contributes to the healing of ureteral lesions, and prevents the occurrence of secondary stenoses.

On the other hand, placing of the ureteral stent determines the occurrence of a specific morbidity ( ; , ; ). The potential complications include fracture ( Fig. 6.40 ) or migration of the stent ( Figs 6.41 and 6.42 ), ureteral erosion, and encrustation.

The incidence of stent encrustation is approximately 15% after 3–4 weeks, reaches 76% after more than 12 weeks ( ; ), and can raise a series of therapeutic issues, in some cases requiring combined endoscopic approach ( Fig. 6.43 ) ( ).

Ureteral stenting is also associated with irritative symptoms of the lower urinary tract, lumbar pains, and urinary infections. Over 90% of patients present micturition disturbances determined by the presence of the stent ( ). Hematuria is a frequent manifestation determined by the presence of the stent ( ).

Regarding the patients’ comfort, did not observe any significant differences regarding postoperative pain between those in whom ureteral stenting was performed and those in whom a JJ stent was not placed. However, the incidence of irritative vesical symptoms is significantly higher (83.3% vs. 13.3%) in patients in whom a ureteral stent was placed after the intervention.

The studies conducted by Denstedt and by Borboroglu, respectively, also demonstrated an increased incidence of lumbar and abdominal pains, of dysuria and pollakiuria in patients in whom an autostatic ureteral catheter was placed after the intervention ( ).

Byrne observed that bladder irritative symptoms and lumbar pains are more intense in the first days after the intervention in patients without a ureteral stent, the ratio reversing after the sixth day from the ureteroscopic approach ( ).

Regarding the necessity for postprocedural antialgic treatment, the studies performed have shown that it is not influenced by placing a ureteral stent ( ). Also, routine ureteral stenting determines an increased incidence of transient vesicoureteral reflux.

One of the important arguments in favor of ureteral stenting at the end of the ureteroscopy is represented by the increase in the stone-free rate. However, Denstedt observed a stone-free rate of 100% in patients who underwent laser lithotripsy of the stones into fragments smaller than 3 mm, without placing a ureteral stent. Other studies have also demonstrated that after the lithotripsy of stones into small enough fragments, which do not require extraction with a forceps or a basket catheter, there are no significant differences between the stone-free rates with or without ureteral stenting ( ).

Some authors have suggested that placing an autostatic ureteral catheter after ureteroscopy determines a decrease in the incidence of postoperative stenoses ( ). Nevertheless, the studies that have been conducted have not demonstrated a statistically significant difference between the rates of this complication according to whether or not a JJ stent was placed after the uncomplicated ureterosopic approach ( ).

Another argument in favor of ureteral stenting is the reduction of the readmission rate due to postoperative complications, first of all due to pain that cannot be controlled by oral medication ( ). The results of different studies have demonstrated that the readmission rates in patients without ureteral stenting is approximately three times higher, however, without presenting significant values (4.3%) ( ).

The assessment of the impact of ureteral stenting on the duration of the surgical intervention has led to contradictory results. did not observe significant differences for this parameter, the mean operating time being 36 versus 34 min. On the other hand, the studies conducted by Netto and after that by Byrne showed an increase by approximately 12 min of the intervention’s duration as a result of placing the ureteral stent ( ).

Stenting determines a significant increase in the costs incurred by the ureteroscopic treatment of ureteral lithiasis, requiring additional maneuvers for extracting the stent.

In conclusion, recent data suggest that ureteral stenting is not necessary after uncomplicated ureteroscopic approach. However, there are specific situations that require placing an autostatic catheter. Absolute indications include the presence of renal insufficiency, patients with a single kidney, kidney transplantation, and ureteral wall injuries during the ureteroscopic procedure. Relative indications are represented by the presence of important ureteral edema ( Figs 6.44 and 6.45 ), pregnancy, calculi larger than 2 cm, impacted ureteral calculi, and the presence in the immediate history of urinary infection or sepsis.

6.3.1 Preliminary Measures

The preliminary measures have in mind patient selection, preoperative preparation, anesthesia, the steps preceding the actual intervention, and patient positioning on the operating table.

6.3.1.1 Patient Selection

Prior anamnestic assessment may provide important data regarding associated diseases, as well as any previous interventions that may make the ureteroscopic approach more difficult.

The preoperative clinical and paraclinical examinations are essential for preparing and planning the endoscopic intervention. Retrograde ureteroscopy is difficult in patients in whom the standard lithotomy position cannot be ensured due to skeletal deformations. The presence of a prostatic median lobe or a large cystocel may also determine difficulties in achieving a rigid or semirigid retrograde ureteroscopic approach.

Preoperative imaging explorations include ultrasonography of the urinary tract, simple renovesical radiography, and intravenous urography.

Preoperative intravenous urography or retrograde ureteropyelography allow for the specification of the position and size of the stone, the degree of obstructive suffering of the affected renal unit, and the anatomy of the urinary tract below and above the stone, as well as some congenital (ureteral bifidities or duplicities) or acquired conditions (ureteral stenoses or retroperitoneal fibrosis) that may make the retrograde endoscopic approach more difficult. This information is useful in estimating the intervention’s degree of difficulty, guiding the planning of the procedural tactics and its associated risks.

The urine must be sterile. Preoperative urinary infection requires adequate treatment. In case of a positive uroculture, targeted antibiotic therapy should precede the intervention by 48–72 h. Acute pyelonephritis contraindicates retrograde ureteroscopy. In this situation, ureteroscopy will be preceded by the clinical resolution of the septic status by ensuring the drainage of the renal unit by percutaneous nephrostomy or ureteral stenting and antibiotic treatment according to the antibiogram.

Even in the absence of a urinary infection, parenteral antibiotic prophylaxis is indicated immediately preoperatively or 12 h before the intervention.

Assessment of coagulation plays an essential role, not only in choosing the therapeutic modality and the instruments, but also in anticipating an increased risk of intraoperative bleeding, with a consecutive reduction of visibility. Oral anticoagulation treatment must be replaced before the intervention with administration of low molecular weight heparin, with predictable and easier to correct effects.

6.3.1.2 Patient Positioning

The patient should be placed on the endoscopy table in the standard lithotomy position, with the lower limb contralateral to the approached ureter in hyperabduction and in a lower position ( Fig. 6.4 ).