9.1
History
The advances achieved in the ureteroscopic techniques, the design of the ureteroscopes, and working instruments have made the endoscopic management of ureteral strictures a reasonable alternative to open surgery.
The first endoscopic ureteral dilation was described by Pawlick in 1891, who used bougies inserted retrogradely for dilating ureteral strictures in a patient with urinary tuberculosis ( ). imagined a catheter with a balloon at the proximal end in order to achieve ureteral dilation. published the results obtained in a group of 100 patients with ureteral stricures treated by retrograde dilation using a ureteral catheter.
published the first results of ureteral balloon dilation as an alternative for the management of ureteral calculi. The author conceived this new device by adapting a rubber balloon at the terminal end of the ureteral catheter. Dilation of the ureteral segment situated distal to the stone was achieved by inflating the balloon, followed by its spontaneous elimination. The development of the balloon dilation technique for the treatment of ureteral strictures was based on this maneuver.
described a percutaneous transluminal coronary angioplasty by using a 3.0–3.8 mm balloon catheter. Subsequently, these were also used for dilating ureteral strictures, initially by antegrade approach ( ) and then in a retrograde manner ( ). The success rates obtained by the authors in the treatment of these strictures were approximately 83%. Moreover, balloon dilation still continues to represent a widely used therapeutic option.
described the intubated ureterotomy technique in the treatment of ureteropelvic junction stenoses, as well as in that of strictures located at the level of the proximal ureter. This procedure was first applied in an animal model, later being used successfully in current practice ( ).
Following the initial studies conducted by Davis, several authors have researched the histological modifications after 4–8 weeks of stenting of an incised ureteral stricture. They confirmed Davis’ observation that after ureterotomy, the ureteral musculature regenerates around a catheter ( ). The development of modern endourological alternatives was based on this approach in the management of ureteral stenoses.
The contribution of in improving small-caliber ureteroscopes relaunched the interest for the endourological treatment of ureteral strictures. The appearance of performant optical systems and the miniaturization of instruments have led to the broadening of the diagnostic and therapeutic indications in upper urinary tract conditions. With the introduction of minimally invasive surgical techniques, the treatment of ureteral strictures has registered significant changes. However, with the development of the endoscopic approach of the upper urinary tract, there has been an increase in the incidence of iatrogenic ureteral strictures.
The technique for retrograde endopyelotomy by ureteroscopic approach was described by . and published the results of endopyelotomy for the treatment of ureteropelvic junction (UPJ) stenosis obtained in large series of patients with significant follow-up periods. Initially, the technique was indicated only in patients with secondary UPJ stenoses. Due to the similarities between secondary UPJ stenosis and ureteral stenoses, it was considered that the technique could be applied with good results to both conditions, imposing itself as a minimally invasive treatment alternative. Endoureterotomy may presently be performed under direct visual control, minimizing the risk of the formation of strictures due to the trauma induced by the endoscope.
The introduction of flexible instruments for the diagnosis ( ) and subsequently for the treatment ( ) of upper urinary tract conditions marked a new step in the management of upper urinary tract stenoses.
The use of the Acucise TM device (Applied Medical Resources, Laguna Hills, CA) was reported by as a therapeutic alternative for UPJ stenosis, as well as for ureteral strictures. This catheter was imagined with the purpose of simplifying the endopyelotomy technique and of lowering the risk of formation of ureteral strictures secondary to retrograde approach, due to the use of large-diameter rigid ureteroscopes ( ). The Acucise device allows for the treatment of UPJ stenoses and of ureteral strictures by retrograde approach, under fluoroscopic control.
Endoluminal sonography performed intraoperatively (during endoureterotomy) was reported by . This procedure contributed to the reduction of the bleeding risk, allowing the surgeon to obtain real-time images of the periureteral vascularization before the incision.
9.2
Generalities
Ureteral strictures can be divided into intrinsic and extrinsic, benign or malignant, and iatrogenic or noniatrogenic. Extrinsic malignant strictures may be secondary to a primary malignant disease (cervix cancer, prostatic adenocarcinoma, bladder tumors, colon cancer) or to a metastatic disease. Extrinsic benign compressions (idiopathic retroperitoneal fibrosis) may determine unilateral or bilateral ureteral obstruction. Intrinsic malignant ureteral obstruction is most frequently secondary to transitional cell carcinoma.
Intrinsic benign strictures of the upper urinary tract may be congenital or secondary. The most frequent localization of congenital ureteral strictures is the ureteropelvic junction. Most ureteral strictures localized at a different level (excepting the UPJ) are secondary, the most frequent being iatrogenic strictures ( ) ( Fig. 9.1 ).
The procedures of open, endoscopic, or laparoscopic treatment represent the most frequent causes in the etiology of ureteral strictures. The development of ureteroscopy has led to a 1–11% increase in the incidence of ureteral strictures ( ). Gynecological procedures (especially radical hysterectomy), general, or vascular surgery are accompanied by a high risk of developing ureteral strictures ( Fig. 9.2 ).
Ureteroenteral strictures, after creating urinary reservoirs or after kidney transplantation, represent another pathological entity ( Fig. 9.3 ). Noniatrogenic ureteral strictures include those secondary after the spontaneous elimination of calculi or after chronic inflammatory disease at the ureteral level (such as those that occur in tuberculosis or schistosomiasis) ( ).
From the point of view of the etiopathogenic mechanism, benign ureteral strictures can be classified into ischemic or nonischemic ( ). Thus, ischemic strictures can be consecutive to open surgical procedures or to radiotherapy, while the nonischemic ones are congenital or secondary to the spontaneous elimination of calculi.
The formation of ureteral strictures is considered to be one of the postoperative complications of lithiasic disease, with an incidence of up to 5% ( Fig. 9.4 ). The development of the new endoscopic treatment methods, as well as the improvement of the existing ones, have led to the decrease in the incidence of this complication. Thus, a reduction in the incidence of ureteral strictures after ureteroscopy from 1.4% in 1982 to 0.5% in 1992 was observed. The treatment of impacted ureteral calculi can be difficult in the incidence of local modifications such as edema and epithelial hypertrophy. These modifications can be responsible for the formation of strictures and can increase the risk of ureteral lesions during endoscopic maneuvers (Herman, 1992).
The intimate mechanism of the formation of ureteral strictures has not been completely elucidated, but it is considered to be multifactorial. Thus, mechanical-type lesions (perforations, avulsions), relative ischemia occurring due to the use of large-caliber instruments, or thermal lesions are considered to be the main factors involved in the appearance of ureteral strictures. It has been demonstrated that strictures are the consequence of an inflammatory process secondary to the intraoperative injury of the urothelium. The ureteral mucosal lesions are followed by the appearance of a fibrinous exudate that precipitates in the traumatized areas, adheres to them, and in the end, favors the appearance of the stricture. Periureteral fibrosis is the consequence of urinary leakage, especially when a superimposed infection exists.
The improvement of instruments and of endoscopic surgical techniques has allowed for a reduction in the incidence of ureteral mucosal lesions and, implicitly, in the risk of triggering the physiopathological mechanisms involved in the development of iatrogenic stenoses ( ).
The data regarding the etiopathogenic mechanisms of strictures do not distinguish between those due to calculi impacted for a long period of time and those secondary to acute obstruction. Some authors have defined an impacted stone as being the stone that does not allow ureteral catheterization with the help of a metallic guidewire. This definition is incomplete and imprecise because it refers to a transient situation (position) of the stone. In the opinion of many authors, impaction requires maintaining the stone in the same position for a period of over 2 months. Impacted ureteral calculi determine distinct histological modifications at the level of the ureteral wall ( Fig. 9.5 ). Histological studies have shown the presence of chronic inflammation, interstitial fibrosis, and mucosal hypertrophy at the level of impaction. Ureteral edema and fibrosis may appear through ischemia secondary to chronic hyperpressure or to an immunological reaction triggered by the stone. These modifications result in the adherence of the stone to the urothelium and increase the risk of ureteral lesions during the endoscopic maneuvers. The incidence of ureteral strictures after the ureteroscopic treatment of such calculi may reach 24% ( ).
In the case of ischemic strictures, frequently associated with fibrosis and vicious scars, the success rate of endoureterotomy is relatively low ( ). Strictures that occur consecutive to cystectomy and urinary derivations represent a special subgroup within ischemic strictures (the subgroup that is most difficult to treat). The fact that most strictures occur on the left side has led to the hypothesis that excessive ureteral mobilization, adventitial stripping, and a rectilinear trajectory (with a narrow tunnel beneath the mesosigmoid), constitute the main favoring factors ( ). The global incidence of anastomotic strictures after urinary derivations ranges from 3% to 9% ( ). Many authors consider that the type of anastomosis represents a significant risk factor, the antireflux anastomoses presenting a doubled risk compared to large ones, with reflux (7–14% vs. 3–7%) ( ).
The strictures of the uretero-vesical junction ( Fig. 9.6 ) most frequently occur after kidney transplantation, especially when the cases are complicated with ischemia of the ureter’s distal segment, as well as with the possible rejection of the allograft ( ). This problem can also occur after transurethral biopsy that involved the ureteral orifice.
Ureteral lesions secondary to pelvic or retroperitoneal interventions may represent etiological factors for the development of iatrogenic stenoses. The most frequently incriminated are interventions in the genital region, the iatrogenic ureteral lesions in such cases being described with an incidence ranging from 0.02% to 2.5% ( ). The risk factors are represented by malignant lesions, pelvic irradiation, endometriosis, surgical interventions for prolapse, etc.
9.2.1
Preoperative Assessment and Preparation
The clinical picture of patients with ureteral strictures may vary: some present flank pain; others may present hematuria, urinary tract infections, or a combination of these symptoms. Up to 25% of patients are asymptomatic, despite significant obstruction ( ). Many of these cases are discovered in patients followed postoperatively after ureteroscopy or urinary derivations. However, most patients with iatrogenic ureteral strictures after ureteroscopy are symptomatic ( ). Patients with a single kidney or with bilateral affection may present decompensated kidney insufficiency.
The first-line imagistic exploration is represented by abdominal ultrasonography. Although this can detect hydronephrosis, intravenous urography ( Fig. 9.7 ) or retrograde utereropyelography ( Fig. 9.8 ) is absolutely necessary for assessing the level and degree of obstruction.
Helical (spiral) computed tomography occupies an increasingly important place in the assessment of ureteral strictures, due to the fact that it provides additional anatomic details with regard to the neighboring vascularization compared to standard ureteropyelography ( ).
If the presence of an obstruction is equivocal, renal scintigraphy with diuretic nephrogram usually represents the elective diagnostic modality ( ). Difficult cases may require a pressure-flow study in order to establish the definitive diagnosis (Whitaker test).
Endoluminal ultrasonography ( Fig. 9.9 ), with or without tridimensional reconstruction, may be recommended for the preoperative assessment of ureteral strictures. Its advantages are represented by the possibility of detecting submucous or periureteral lesions (aberrant vascular structures, fibrosis, etc.) ( ). However, the method is invasive and cannot be used in complete ureteral stenoses.
The preoperative imagistic assessment of the stenosed ureteral segment is very important. The location and length of the stricture must be determined in order to establish the optimal modality for surgical approach ( Fig. 9.10 ). In some cases, intravenous urography may be sufficient. Antegrade ureteropyelography (via the nephrostomy tube, when it exists) usually provides very correct information regarding the stenosed segment. Antegrade and retrograde combined ureteropyelography may be performed preoperatively or at the moment of the intervention.
In patients with pyelonephritis or altered renal function, the management of the patient should start with an adequate drainage through percutaneous nephrostomy or by placing a ureteral stent. This therapeutic gesture will allow for the optimization of the renal function. Preoperative drainage is unnecessary in patients with normal renal function and minimal obstruction. Antibiotic therapy of urinary tract infections is required preoperatively. Some authors recommend preoperative stenting of the stenosed segment with the purpose of passively dilating the ureter, thus facilitating the endoscopic approach ( ). However, this maneuver is not possible in case of complete ureteral obstruction.
9.2.1
Preoperative Assessment and Preparation
The clinical picture of patients with ureteral strictures may vary: some present flank pain; others may present hematuria, urinary tract infections, or a combination of these symptoms. Up to 25% of patients are asymptomatic, despite significant obstruction ( ). Many of these cases are discovered in patients followed postoperatively after ureteroscopy or urinary derivations. However, most patients with iatrogenic ureteral strictures after ureteroscopy are symptomatic ( ). Patients with a single kidney or with bilateral affection may present decompensated kidney insufficiency.
The first-line imagistic exploration is represented by abdominal ultrasonography. Although this can detect hydronephrosis, intravenous urography ( Fig. 9.7 ) or retrograde utereropyelography ( Fig. 9.8 ) is absolutely necessary for assessing the level and degree of obstruction.
Helical (spiral) computed tomography occupies an increasingly important place in the assessment of ureteral strictures, due to the fact that it provides additional anatomic details with regard to the neighboring vascularization compared to standard ureteropyelography ( ).
If the presence of an obstruction is equivocal, renal scintigraphy with diuretic nephrogram usually represents the elective diagnostic modality ( ). Difficult cases may require a pressure-flow study in order to establish the definitive diagnosis (Whitaker test).
Endoluminal ultrasonography ( Fig. 9.9 ), with or without tridimensional reconstruction, may be recommended for the preoperative assessment of ureteral strictures. Its advantages are represented by the possibility of detecting submucous or periureteral lesions (aberrant vascular structures, fibrosis, etc.) ( ). However, the method is invasive and cannot be used in complete ureteral stenoses.
The preoperative imagistic assessment of the stenosed ureteral segment is very important. The location and length of the stricture must be determined in order to establish the optimal modality for surgical approach ( Fig. 9.10 ). In some cases, intravenous urography may be sufficient. Antegrade ureteropyelography (via the nephrostomy tube, when it exists) usually provides very correct information regarding the stenosed segment. Antegrade and retrograde combined ureteropyelography may be performed preoperatively or at the moment of the intervention.
In patients with pyelonephritis or altered renal function, the management of the patient should start with an adequate drainage through percutaneous nephrostomy or by placing a ureteral stent. This therapeutic gesture will allow for the optimization of the renal function. Preoperative drainage is unnecessary in patients with normal renal function and minimal obstruction. Antibiotic therapy of urinary tract infections is required preoperatively. Some authors recommend preoperative stenting of the stenosed segment with the purpose of passively dilating the ureter, thus facilitating the endoscopic approach ( ). However, this maneuver is not possible in case of complete ureteral obstruction.
9.3
Indications
All asymptomatic patients or those with obstruction consecutive to a benign ureteral stenosis have surgical indications with the purpose of preserving renal function.
The open surgical techniques used for the treatment of ureteral strictures (ureteroneocystostomy, kidney mobilization, Boari flap, transureteroureterostomy, intestinal interposition, kidney autotransplantation, nephrectomy) require abdominal interventions (some major) that are associated with high morbidity and with prolonged hospitalization and social reintegration.
The endoscopic alternatives are cold-knife incision, electrocautery incision (incision with a Collins loop), Acucise balloon, dilation balloon, and, relatively recently, the laser. Regarding the indications for using metallic ureteral stents, they are not yet fully systematized, most authors recommending placing this type of stent both in malignant and in benign ureteral stenoses.
The indications for the ureteroscopic approach of ureteral stenoses are represented by the following:
- •
benign inflammatory ureteral stenoses
- •
iatrogenic ureteral stenoses
- •
ureteral stenoses under 2 cm
9.4
Instruments
A wide variety of instruments can be used for the endoscopic management of ureteral strictures, depending on the therapeutic alternative chosen.
Balloon catheters (with high pressure) are available in a wide range of dimensions ( Fig. 9.11 ): diameters between 4 mm and 8 mm (after inflation) and lengths of 5–10 cm. Many of these are designed to support pressures from 12 atm to 20 atm, which is more than enough for most ureteral strictures.
The Acucise RP 35 device represents a balloon catheter (with low pressure: 1 atm) with a diameter of 10 F, which may reach 24 F after inflation. The catheter has a diameter of 6 F, which ensures an easy intraoperative access, without requiring preoperative stenting. An electrocautery fiber with a diameter of 150 μm and a length of 3 cm is fixed along the balloon’s surface. This allows for simultaneously achieving balloon dilation and incision.
Cold-knife incision of the stricture requires using a rigid ureteroresectoscope of 11–13 F ( Fig. 9.12 ). The incision knives are available in different configurations: straight, half-moon, or hook. Knives that slide on a metallic guidewire can be used, allowing for a better control of the incision, especially above the stenosis area.
Incision with the electrocautery is achieved with Hubert-type electrodes (Cook Urological, Spencer, IN, USA) or with the Rite cutting device (ACMI Corporation, Southborough, MA, USA). The Rite type instrument has a low caliber (3 F), allowing its insertion through the flexible ureteroscope. The possibility of rotating the tip during the intervention allows for very good control of the incision.
The Nd:YAG and Ho:YAG lasers ( Fig. 9.13 ) can also be used efficiently for the incision of ureteral strictures ( ).
Energy can be transmitted through 200 and 365 μm fibers, inserted both through rigid and through flexible ureteroscopes.
Most authors consider that using a low power of the laser (25 W) is sufficient for the successful incision of strictures and for preventing complications secondary to injury of the neighboring structures ( ).
9.5
Notions of operative technique
The development of endourological alternatives in the management of ureteral strictures was based on studies conducted by Davis on animals in 1943. He demonstrated that epithelialization of a ureteral stenosis stented with a JJ catheter occurs in 7 days. Muscular regeneration is complete at 6 weeks after the procedure ( ).
Most authors agree with the fact that the success rate of endourological techniques is lower compared to open surgery. However, endourological approach is preferred due to its low morbidity, its reduced operative time and hospitalization period, and its costs. Moreover, the failure of minimally invasive techniques does not influence the prognosis if subsequent open surgery is required.
The main endourological alternatives for the management of ureteral strictures are as follows:
- •
balloon dilation
- •
endoureterotomy
- •
metallic stents
9.5.1
Balloon Dilation
Since the introduction of transluminal balloon dilation as a therapeutic alternative in arterial coronary disease ( ), this method has been used by many authors for the ureteral dilation of benign strictures. It represents the least traumatic modality of endoscopic approach and, at the same time, it constitutes a reasonable initial option.
The technique consists of four operative steps:
- 1.
access to the upper urinary tract
- 2.
placement of the dilation balloon at the level of the stricture
- 3.
inflation of the balloon
- 4.
insertion of the ureteral stent
Fluoroscopic control is essential for the correct positioning and for the adequate inflation of the balloon ( Fig. 9.14 ).
There are many studies in the literature regarding the efficiency of this method according to the slow or rapid dilation of ureteral strictures. Thus, Clayman experimentally studied the two techniques in pigs, dilating the distal ureter to 24 F and demonstrating that both procedures present the same safety profile ( ). The slow dilation, over a period of over 10 min, determines a lower residual inflammatory process at 6 weeks compared to rapid dilation. However, epithelialization of the denuded area, immediate inflammation, and submucous bleeding are similar in both groups immediately after the procedure ( ).
The effects of balloon dilation on the dynamics of the upper urinary tract and on the ureteral wall’s morphology were studied by , who noted the presence of circumferential edema in the lamina propria, which extends into the muscularis, a fact that is responsible for the obstructive modifications detected by urodynamics. Progressive resorption of the pathological inflammatory modifications, reduction of the obstruction, and the normalization of the ureter’s radiological aspect occur after a period of 6 weeks. The recommendations for maintaining an internal ureteral drainage with the JJ catheter for a period of 6 weeks were based on these observations.
Several authors have reported favorable results regarding the balloon dilation of ureteral strictures. The success rates are variable, between 48% and 88%, with an average of 55% ( Table 9.1 ).
| Author | Number of cases | Success rate (%) | Follow-up (months) |
|---|---|---|---|
| 44 | 48 | – | |
| 11 | 82 | 10 | |
| 24 | 63 | 21 | |
| 127 | 50 | – | |
| 17 | 60 | 17 | |
| 14 | 64 | 22 | |
| 19 | 58 | 24 | |
| 17 | 76 | 15 |
However, there is no consensus regarding the optimal dimension of the dilation balloon and the most efficient technique (rapid or slow dilatation). Balloons between 4 mm and 10 mm are generally used, the number of inflation cycles varying from 1 to 10, while the duration of inflation is between 30 s and 10 min. There are also controversies regarding both the optimal dimension of the stent (between 6 F and 16 F) and the duration of maintaining it after the procedure (2 days to 12 weeks). In general, the success rate of balloon dilation for benign strictures is lower compared to that after endoureterotomy, and sometimes several procedures are necessary for obtaining the desired result ( Fig. 9.15 ). Most authors agree that the main indication for balloon dilation is represented by nonischemic, very short strictures.
Few complications are described in the literature for this technique, the most frequent being the dilation balloon’s rupture. However, unlike the balloons used in the past, which were made of polyvinyl (with a high risk of tearing), the modern ones are made of reinforced polyethylene, significantly reducing the rate of intraoperative complications.
9.5.2.
Endoureterotomy
The development of small-caliber semirigid ureteroscopes (7.5 F) and of flexible ones, as well as of accessory instruments, has allowed the safe access of the upper urinary tract. The incision modalities for ureteral stenoses include cold knife, electrocautery, laser (Nd:YAG and Ho:YAG), and the Acucise balloon.
The approach of ureteral stenoses can be antegrade, retrograde, or combined.
9.5.2.1
Antegrade Approach
Antegrade percutaneous approach is generally reserved for the treatment of proximal ureteral stenoses, in patients who also present an associated renal condition (calculi) ( ). In order to gain access to the stenosed area with the semirigid instrument, it is recommended that the percutaneous pathway be done through the upper or middle calyx. Most authors recommend posterior or posterolateral incision of the strictured area, until the retroperitoneal fat is visualized ( Fig. 9.16 ) ( ). In order to achieve optimal results, the incision must start at the renal pelvis and extend approximately 1 cm caudal to the stenosed area.
Stenoses located in the middle ureteral segment can be approached antegradely or retrogradely. The antegrade approach is identical to that previously described, the only difference being that at the cephalic extremity of the stenosis, the incision will be extended 1 cm proximally into healthy ureteral tissue (up to the vicinity of the ureteropelvic junction). For strictures located in the vicinity of the iliac vessels, it is recommended that a flexible ureteroscope be used ( Fig. 9.17 ), which requires using electrocautery probes (2–3 F) or laser probes (200 or 400 μm).
The use of direct visual approach under fluoroscopic control in two planes provides a better intraoperative orientation. The incisions are made laterally for proximal ureteral strictures (located above the iliac vessels), anteriorly for those located at the level of the iliac vessels (10 o’clock on the right, respectively 2 o’clock on the left), and anteromedially for those located below this level. Pelvic ureteral stenoses located in the vicinity of the uterine artery in women or of the vas deferens in men will be incised posteriorly at 6 o’clock. In all cases, the incision must be extended 1 cm proximal and distal to the stricture, with exposure of the periureteral fat. In patients with very tight strictures, initial balloon dilation may be necessary in order to allow for a correct incision ( ).
9.5.2.2
Retrograde Approach
The choice of a retrograde or antegrade approach is made according to the particularities of the case and to the surgeon’s preference. However, the low morbidity rate, the reduced hospitalization period, and the ease of retrograde access to the upper urinary tract represent elements that recommend retrograde approach as the first-line alternative for most patients with ureteral strictures ( ).
Most frequently, retrograde approach is used for the treatment of distal ureteral strictures. Sometimes, these may be located at the level of the ureteral orifice, of the intramural ureter, or in the proximity of the uretero-vesical junction. In these cases, the incision should be extended up to the ureteral orifice ( ). A ureteroresectoscope can be used, the incision being made at 12 o’clock, extended over a distance of approximately 1 cm beyond the stricture area, with Collins- or Orandi-type probes, the electrocautery being set at 50 W. Flexible or rigid instruments can be used for stenoses located at the level of the proximal ureter, the incision being made in the manner previously described.
The Acucise-type balloon can be used as a therapeutic alternative for proximal or distal ureteral stenoses ( ). The balloon is positioned under fluoroscopic control. There are a series of particularities regarding the modality of performing each type of incision according to the affected ureteral segment ( Table 9.2 , Figs 9.18–9.21 ).
| Ureteral segment | Type of incision | Observations |
|---|---|---|
| Proximal and middle | Posterior ( Fig. 9.19 ) or posterolateral |
|
| Above the iliac vessels | Lateral or posterolateral ( Fig. 9.20 ) |
|
| At the level of the iliac vessels | Anterior (10 o’clock on the right, 2 o’clock on the left) ( Fig. 9.21 ) |
|
| Below the iliac vessels | Anteromedial |
|
| At the level of the uterine artery or vas deferens | Posterior (6 o’clock) |
|
| Ureteral orifice | 12 o’clock |
|
At the level of the proximal ureter, above the iliac vessels, the electrocautery wire (which makes the incision) will be oriented posterolaterally, while below the iliac vessels it will be directed anteromedially in order to avoid the iliac artery and vein (which pass lateral to the ureter). For strictures located at the level of the iliac vessels, most authors recommend avoiding the use of the Acucise and to use ureteroscopic approach under visual control. In cases with uretero-vesical reimplantation, the incision of potential stenoses will be performed anterolaterally.
9.5.2.3
Combined Antegrade and Retrograde Approach
Complex ureteral strictures, especially those located at the level of a uretero-enteral anastomosis, frequently require a combined antegrade and retrograde approach ( Fig. 9.22 ).
The procedure allows for a rapid identification of the stenosed area, which is usually “hidden” between the urinary derivation’s folds (which makes the approach only in a retrograde manner very difficult).
A particular situation is represented by complete ureteral strictures. In these cases, the extent of the stenosis area can be assessed by simultaneously performing a retrograde and an antegrade ureteropyelography (through the nephrostomy tube). For short strictures (1 cm), endoureterotomy using the “cut to the light” technique may be indicated (by inserting the ureteroscope antegradely, the incision being made retrogradely). Although some authors have reported good results even for strictures of up to 5 cm in length ( ), most of them recommend that complete ureteral stenoses longer than 2 cm be approached by open surgical procedures.
9.5.2.4
Operative Technique
The patient is placed in the lithotomy position for the standard retrograde intervention. If simultaneous antegrade and retrograde approach is necessary, it is recommended to position the patient in decubitus with the legs apart (split-leg prone position) ( ) or, as an alternative, the patient can be placed in a dorsolithotomy position, lifting the flank with the affected ureter (by placing a role of textile material), thus allowing easier access to the nephrostomy area.
The first intraoperative step consists of radiologically detecting the stenosed ureteral segment. A retrograde ureteropyelography is performed for this purpose, followed by placement of a guidewire that must be ascended beyond the stricture; this can sometimes represent the most difficult moment of the intervention. Most authors recommend using hydrophilic guidewires. After placing the safety guidewire, the ureteroscope is ascended up to the level of the involved ureteral segment, with direct visual control in order to exclude other causes of ureteral obstruction (tumors or calculi) that could pass unobserved during the previous radiological explorations. If there are doubts regarding the etiology of the stricture, material can be collected for biopsy or for cytological examination before making the incision ( Fig. 9.23 ).
Knowing the ureteral anatomy and the safest areas for making the incision (depending on the location of the obstruction) are very important elements for performing the intervention safely and with a low rate of complications. The use of intraoperative endoluminal ultrasonography offers the advantage of obtaining correct information regarding the periureteral structures, being extremely useful for choosing the safest incision area ( ).
If the electrocautery is used, the safety guidewire must be isolated with the help of a ureteral catheter or replaced with a special guidewire, such as a nitinol one coated with polyurethane. This can prevent transmission of the energy from the electrocautery to the other ureteral structures, which could cause undesired secondary lesions.
The incision can be made safely with a cold knife, with the electrocautery’s probe, or with the holmium:YAG laser ( ). Cold-knife incision can prevent the development of tissular fibrosis consecutive to the intervention, with minimal secondary lesions ( Fig. 9.24 ). The use of a flexible ureteroscope requires using the Rite electrode or a Ho:YAG laser.
The ideal incision should penetrate the entire thickness of the ureteral wall, until the periureteral fat is visualized ( ) ( Fig. 9.25 ). However, when there is significant periureteral fibrosis, this goal becomes difficult or even impossible to achieve. In these situations, the incision is made deep enough to provide an adequate luminal diameter. Balloon dilation can be performed after the ureteroscopic incision, thus obtaining an additional enlargement of the stenosed area. The efficiency of the incision is checked by injecting contrast media (antegradely or retrogradely). Its leakage indicates the incision’s efficiency.
Strictures that determine complete ureteral obstruction raise more difficult problems. Placing a safety guidewire along the stenosed ureteral segment represents the key element of the procedure with regard to its importance and degree of difficulty. If the segment is very short and the proximal and distal ends of the ureter are well aligned, the rigid tip of the guidewire can be used for “puncturing” the stricture under sonographic and fluoroscopic control. Stabilizing the guidewire with the help of a ureteral catheter can facilitate surpassing the stenosed area.
Longer strictures require an incision made under direct visual (ureteroscopic) control from one end of the obstructed segment to the other. This implies simultaneous retrograde and antegrade ureteroscopic approach ( Fig. 9.26 ), using the “cut to the light” technique. With both tips of the ureteroscopes at the proximal and distal end of the stenosis respectively, these are aligned in the first step under fluoroscopic control in two planes. The light source of the working ureteroscope is subsequently turned off, in order to locate the opposite end of the stricture by visualizing the light of the secondary ureteroscope. The incision can be made with the electrocautery or the Ho:YAG laser, aiming to establish ureteral continuity ( ). In order to safely perform the operative procedure, the guidewire must be maintained in place during the entire intervention.
Strictures of uretero-enteral anastomoses can be difficult to treat due to the extensive postoperative periureteral fibrosis, as well as the difficult or even impossible to achieve retrograde access (from the enteral segment). Also, due to the oncological history of the patients, the high risk of local recurrence must be taken into account. In these cases, the success rate is lower compared to other ureteral strictures.
Complete uretero-vesical obstruction, secondary to renal transplantation or ureteral orifice resection, represents a similar problem, and identification of the ureteral orifice may be difficult. In these cases, perforation of the stenosed proximal segment by antegrade approach can be achieved, followed by retrograde incision ( ).
All authors recommend postoperative internal drainage. As in the case of patients with endopyelotomy, there are controversies regarding the proper dimension of the stent, as well as the period for which it is kept in place ( ). Usually it is preferred to use 6/10 F endoureterotomy stents, positioning the 10 F part at the level of the incised segment. Although there are no comparative studies conducted in significant groups of patients, it is considered that using a common 7 or 8 F JJ stent can be just as efficient.
According to Davis’ studies, the muscular tissue of the ureteral wall regenerates in 6 weeks. It is therefore considered that the stent should be kept in place for at least 6 weeks.
Postoperative follow-up consists of imagistic examinations performed to detect any recurrent obstructions: renal ultrasonography, excretory urography, retrograde ureteropyelography, or renal scintigraphy. Renal ultrasonography may show the presence of normal renal parenchyma, as well as the absence of hydronephrosis. The method is advantageous with regard to the cost-efficiency ratio and is easier to tolerate than contrast enhanced imagistic tests. It is usually recommended to repeat it at 3 and 6 months after the procedure, and then once a year if the patient’s status remains stable. Any modification detected by ultrasonography requires contrast-enhanced investigations or renal scintigraphy.
9.5.2.5
Results
There are few series of patients that can be analyzed in order to assess the results of incisional endoscopic treatment for ureteral strictures ( Table 9.3 ).
| Author | Number of cases | Success rate (%) | Follow-up (months) |
|---|---|---|---|
| 12 | 83 | 15 | |
| 8 | 75 | 4 | |
| 20 | 88 | – | |
| 8 | 75 | 29 | |
| 38 | 82 | 28 | |
| 12 | 67 | 11 | |
| 40 | 71 | 9 | |
| 7 | 86 | 22 | |
| Total | 145 | 78 | 4–29 |
Most data regarding such incisions are combined with the results of other therapeutic modalities, thus making them difficult to interpret. The comparison of studies that use different techniques can be misleading because the studied groups usually are not homogeneous, with notable differences regarding the type of incision, follow-up period, etiology, and the length and location of strictures.
Endoureterotomy generally associates a success rate of 55–85% in case of benign ureteral strictures ( , 2006).
Endoureterotomy for strictures located in the distal and middle ureter has recorded success rates between 66% and 88%. The mean success rate for the 145 patients (from these combined series) was of 78%, being higher than that obtained by balloon dilation (67%).
In a long-term analysis of the results of endoureterotomy for benign ureteral stenoses by using different incision modalities, described a global success rate of 80%. The different modalities that were used did not significantly affect the results. All recurrences occurred within the first year after the intervention, and repeating endoureterotomy was followed by success in 25% of these cases. The authors underlined the fact that all patients in whom the function of the affected kidney represented less than 25% of the global renal function recorded failures of the endoscopic management of benign ureteral strictures. These results support the hypothesis regarding the importance of the urinary flow at the level of the sectioned area with implications in maintaining its permeability. Moreover, injection of steroids at the level of the stenosed area in order to reduce formation of scar tissue did not prove to be efficient in these cases.
Eshghi and Lifson described the results obtained by cold-knife endoureterotomy in 89 patients. The global success rate was 95% for the first procedure and 98% for cases that required repeated procedures. No significant complications secondary to using this technique were recorded ( ).
There are authors who have described success rates for cold-knife endoureterotomy of up to 100%, although the short follow-up period (3–8 months) makes these results questionable ( ).
conducted a multicenter study assessing the Acucise device. The technique was applied in 49 cases, obtaining a success rate of 55% after a mean follow-up period of 8.7 months (between 1.2 months and 17 months).
reviewed 36 cases of ureteral strictures treated by endoureterotomy performed with the electrocautery. The intervention was successful in 64% of cases, the results being higher in cases with strictures under 1.5 cm (80%) compared to longer strictures (27%). Also, low success rates were recorded in patients with a history of radiotherapy (33%).
, using Ho:YAG laser endoureterotomy, reported a success rate of 76%.
A lower success rate was obtained for the incision of uretero-enteral strictures, most probably due to their ischemic nature. Thus, reported success rates of 73, 51, and 32% at 1, 2, and 3 years after the intervention, respectively. All endoscopic reinterventions failed. Using the Ho:YAG laser, obtained favorable results in 56% of cases over a mean follow-up period of 3 years, while , using cold-knife endoureterotomy, reported a success rate of 60.5%. The incision of uretero-enteral strictures with the Acucise device recorded relatively modest results, with an efficiency of only 30% after a mean follow-up period of 48 months ( ).
9.5.2.6
Prognosis
Most studies reveal several predictive factors regarding the long-term results of endoureterotomy.
9.5.2.6.1
Location of the Stricture
Endoureterotomy of distal and proximal ureteral strictures records a higher success rate compared to those located in the middle ureter ( ). describe a success rate of only 25% for strictures located in the middle third of the ureter that benefited from endoscopic incision, compared to 80% positive results in the case of distal and proximal ureteral strictures treated in the same manner.
9.5.2.6.2
Type of Stricture
The stricture’s etiology represents an important prognostic factor. A frequent cause of ureteral strictures is represented by fibrosis secondary to open or endoscopic surgical interventions. These lesions, which are relatively nonischemic, have a higher success rate for endoureterotomy compared to poorly vascularized, ischemic strictures ( ). Ureteral strictures secondary to radiotherapy or to extraluminal metastatic neoplasias, which are based on a mechanism of extrinsic compression, register poor results after endoureterotomy. On the other hand, in patients with lithiasis and associated ureteral stricture, remission of the stricture is observed once the stone is removed and the inflammatory process disappears.
9.5.2.6.3
Length of the Stricture
Most authors state that the treatment of long ureteral strictures ( Fig. 9.27 ) has a very low success rate, regardless of the method of endourological treatment used (endoincision or balloon dilation). Thus, , in a series of 25 patients with ureteral strictures shorter than 2 cm, describe a success rate of 84% after their balloon dilation. In comparison, in patients with strictures longer than 2 cm, dilation was successful in only 50% of cases. Similar results are also reported regarding endoureterotomy. Based on these data, it can be stated that the indication of endoureterotomy is addressed to ureteral strictures shorter than 2 cm.
9.5.2.6.4
Duration of the Stricture
As opposed to other factors such as location, length, or type of stricture, its duration does not influence prognosis. Ureteral strictures with a duration ranging from 8 months to 18 months have been treated successfully ( ).
9.5.2.6.5
Renal Function
The degree of damage to the ipsilateral renal unit represents an important predictive factor regarding the success of the endoscopic treatment for ureteral strictures. Patients whose renal unit on the affected side contributes less than 25% to the global function have a low success rate after endoureterotomy. The explanation lies in the fact that the affected kidney releases a lower amount of growth factors (epidermal, etc.). The renal production of growth factors directly correlates with the glomerular filtration rate. Thus, the postoperative unfavorable evolution would be due to an insufficient mitogenic stimulation ( ).
9.5.2.7
Complications
The complications of endoureterotomy are generally common to those of retrograde ureteroscopy or of percutaneous nephrolithotomy (in the case of antegrade approach), the most frequent being represented by infections, ureteral avulsions and perforations, damage to neighboring structures (intestine, vascular structures), and urinomas ( ). Major complications are rare (0.5–1%) and include massive bleeding due to damage to the adjacent vascular structures that require blood transfusions, sepsis, and uretero-enteral fistulas ( ). Thus, reported one case (out of 20 patients treated by cold-knife endoureterotomy) with important vascular damage that required immediate laparotomy. The risk of these complications can be reduced by adequate preparation and selection of patients, by assessment of the vascular structures by endoluminal ultrasonography, and by making a correct incision (depending on the affected ureteral segment).
The most frequent late complication after endoureterotomy is represented by restenosis, which may require either repeating the procedure or choosing another therapeutic alternative (placing a metallic stent, ureteral resection with termino-terminal anastomosis, interposition of an intestinal segment – enteroureteroplasty).
9.5.2.8
Controversies
Several controversies exist regarding the endoscopic treatment of ureteral strictures, the most important ones being related to the modality of incision, the choice of the type of stent, and the duration for which it is kept in place. Injection of corticosteroids at the level of the stricture or the use of urothelial stents represents new methods that are under assessment.
9.5.2.8.1
Choosing the Optimal Modality of Incision
There are no significant differences regarding the efficiency of endoureterotomy according to the modality of incision that was chosen: cold knife, electrocautery, Nd:YAG ( Fig. 9.28 ), or Ho:YAG laser. However, Ho:YAG laser incision seems to be preferred by most authors because it offers not only a high success rate, but also an optimal control of the incision and a better hemostasis ( ).
9.5.2.8.2
Adjuvant Steroid Therapy
The use of corticosteroids as adjuvant therapy after endoureterotomy is based on the premise that formation of collagen can be blocked, thus reducing the restenosis rate. This method is addressed to certain selected cases: patients with ischemic-type strictures or long strictures, in whom endoureterotomy as a single therapeutic method has a low chance of success (the associated conditions contraindicating an open surgical intervention). The most frequently used agent was triamcinolone in doses of 120 and 200 mg (3–5 mL, 40 mg/mL), injected through a 3 F Greenwald needle into the bed of the incised ureteral stricture. There are not enough data regarding this method’s long-term efficacy. The literature describes success rates of up to 50% after 5 years of postoperative follow-up ( ).
9.5.2.8.3
Caliber of the Stent
There is no consensus regarding the optimal caliber of the ureteral stent used after endoureterotomy. Although ureteral stents with calibers between 5 F and 16 F have been used ( Fig. 9.29 ), no direct correlation could be established between the dimension of the stent used and the efficiency of therapy. Some authors prefer large-caliber stents, while others state that these stents can compromise the vascularization of the affected ureteral segment by mechanical compression ( ). However, recent studies have shown similar results between 6 F and 8 F stents and large-caliber (7–14 F) stents (pyelostent) ( ).
9.5.2.8.4
Duration of Maintaining the Ureteral Stent
Most authors agree that ureteral stenting after endoureterotomy quickens the healing process, preventing urinary leakage and restenosis. However, maintained for too long, the stents can generate inflammation, muscle fiber hyperplasia, or scars, processes that may compromise healing. There is currently no consensus regarding the optimal period for maintaining a ureteral stent after endoureterotomy. report similar results regarding the success rate of ureteral strictures regardless whether the period for maintaining the postoperative stent was 1, 3, or 6 weeks.
9.5.3
Metallic Stents
The successful use of metallic stents in the treatment of diseases of the vascular system and of the biliary tract led to their introduction as a therapeutic alternative in the management of urinary tract diseases.
The first applications of metallic stents in the treatment of ureteral stenoses were described by Gort in 1990. Pauer and Lugmayr were the first authors to use metallic stents in the management of patients with malignant ureteral stenoses ( ). The continuous improvement of the quality and design of metallic stents gradually led to their large-scale use. Regarding the indications for using metallic ureteral stents, they have not yet been completely systematized, most authors recommending their placement especially in malignant ureteral stenoses. It is generally accepted that patients with benign stenoses longer than 2 cm, with multiple recurrences, with associated conditions that contraindicate an open surgical intervention, may benefit from placing a metallic stent ( Fig. 9.30 ).
Thus, Herrero described good results by inserting metallic stents in patients with ureteral stenoses after kidney transplantation ( ). describe the use of thermoexpandable metallic stents in the management of uretero-ileal stenoses. published the results obtained in a group of 10 patients with ureteral obstruction secondary to a benign recurrent condition (endometriosis, fibrosis after radiotherapy, etc.), followed over a period of 10.6 months; remission of obstruction after inserting a metallic stent was described in all cases. followed for 18 months a group of 13 patients with benign ureteral strictures in whom metallic stents were placed, describing only three cases that presented stent encrustation (which required its removal at 4, 11, and 33 months, respectively). Similar results were also described by .
9.5.1
Balloon Dilation
Since the introduction of transluminal balloon dilation as a therapeutic alternative in arterial coronary disease ( ), this method has been used by many authors for the ureteral dilation of benign strictures. It represents the least traumatic modality of endoscopic approach and, at the same time, it constitutes a reasonable initial option.
The technique consists of four operative steps:
- 1.
access to the upper urinary tract
- 2.
placement of the dilation balloon at the level of the stricture
- 3.
inflation of the balloon
- 4.
insertion of the ureteral stent
Fluoroscopic control is essential for the correct positioning and for the adequate inflation of the balloon ( Fig. 9.14 ).
There are many studies in the literature regarding the efficiency of this method according to the slow or rapid dilation of ureteral strictures. Thus, Clayman experimentally studied the two techniques in pigs, dilating the distal ureter to 24 F and demonstrating that both procedures present the same safety profile ( ). The slow dilation, over a period of over 10 min, determines a lower residual inflammatory process at 6 weeks compared to rapid dilation. However, epithelialization of the denuded area, immediate inflammation, and submucous bleeding are similar in both groups immediately after the procedure ( ).
The effects of balloon dilation on the dynamics of the upper urinary tract and on the ureteral wall’s morphology were studied by , who noted the presence of circumferential edema in the lamina propria, which extends into the muscularis, a fact that is responsible for the obstructive modifications detected by urodynamics. Progressive resorption of the pathological inflammatory modifications, reduction of the obstruction, and the normalization of the ureter’s radiological aspect occur after a period of 6 weeks. The recommendations for maintaining an internal ureteral drainage with the JJ catheter for a period of 6 weeks were based on these observations.
Several authors have reported favorable results regarding the balloon dilation of ureteral strictures. The success rates are variable, between 48% and 88%, with an average of 55% ( Table 9.1 ).
| Author | Number of cases | Success rate (%) | Follow-up (months) |
|---|---|---|---|
| 44 | 48 | – | |
| 11 | 82 | 10 | |
| 24 | 63 | 21 | |
| 127 | 50 | – | |
| 17 | 60 | 17 | |
| 14 | 64 | 22 | |
| 19 | 58 | 24 | |
| 17 | 76 | 15 |
However, there is no consensus regarding the optimal dimension of the dilation balloon and the most efficient technique (rapid or slow dilatation). Balloons between 4 mm and 10 mm are generally used, the number of inflation cycles varying from 1 to 10, while the duration of inflation is between 30 s and 10 min. There are also controversies regarding both the optimal dimension of the stent (between 6 F and 16 F) and the duration of maintaining it after the procedure (2 days to 12 weeks). In general, the success rate of balloon dilation for benign strictures is lower compared to that after endoureterotomy, and sometimes several procedures are necessary for obtaining the desired result ( Fig. 9.15 ). Most authors agree that the main indication for balloon dilation is represented by nonischemic, very short strictures.
Few complications are described in the literature for this technique, the most frequent being the dilation balloon’s rupture. However, unlike the balloons used in the past, which were made of polyvinyl (with a high risk of tearing), the modern ones are made of reinforced polyethylene, significantly reducing the rate of intraoperative complications.
9.5.2.
Endoureterotomy
The development of small-caliber semirigid ureteroscopes (7.5 F) and of flexible ones, as well as of accessory instruments, has allowed the safe access of the upper urinary tract. The incision modalities for ureteral stenoses include cold knife, electrocautery, laser (Nd:YAG and Ho:YAG), and the Acucise balloon.
The approach of ureteral stenoses can be antegrade, retrograde, or combined.
9.5.2.1
Antegrade Approach
Antegrade percutaneous approach is generally reserved for the treatment of proximal ureteral stenoses, in patients who also present an associated renal condition (calculi) ( ). In order to gain access to the stenosed area with the semirigid instrument, it is recommended that the percutaneous pathway be done through the upper or middle calyx. Most authors recommend posterior or posterolateral incision of the strictured area, until the retroperitoneal fat is visualized ( Fig. 9.16 ) ( ). In order to achieve optimal results, the incision must start at the renal pelvis and extend approximately 1 cm caudal to the stenosed area.
Stenoses located in the middle ureteral segment can be approached antegradely or retrogradely. The antegrade approach is identical to that previously described, the only difference being that at the cephalic extremity of the stenosis, the incision will be extended 1 cm proximally into healthy ureteral tissue (up to the vicinity of the ureteropelvic junction). For strictures located in the vicinity of the iliac vessels, it is recommended that a flexible ureteroscope be used ( Fig. 9.17 ), which requires using electrocautery probes (2–3 F) or laser probes (200 or 400 μm).
The use of direct visual approach under fluoroscopic control in two planes provides a better intraoperative orientation. The incisions are made laterally for proximal ureteral strictures (located above the iliac vessels), anteriorly for those located at the level of the iliac vessels (10 o’clock on the right, respectively 2 o’clock on the left), and anteromedially for those located below this level. Pelvic ureteral stenoses located in the vicinity of the uterine artery in women or of the vas deferens in men will be incised posteriorly at 6 o’clock. In all cases, the incision must be extended 1 cm proximal and distal to the stricture, with exposure of the periureteral fat. In patients with very tight strictures, initial balloon dilation may be necessary in order to allow for a correct incision ( ).
9.5.2.2
Retrograde Approach
The choice of a retrograde or antegrade approach is made according to the particularities of the case and to the surgeon’s preference. However, the low morbidity rate, the reduced hospitalization period, and the ease of retrograde access to the upper urinary tract represent elements that recommend retrograde approach as the first-line alternative for most patients with ureteral strictures ( ).
Most frequently, retrograde approach is used for the treatment of distal ureteral strictures. Sometimes, these may be located at the level of the ureteral orifice, of the intramural ureter, or in the proximity of the uretero-vesical junction. In these cases, the incision should be extended up to the ureteral orifice ( ). A ureteroresectoscope can be used, the incision being made at 12 o’clock, extended over a distance of approximately 1 cm beyond the stricture area, with Collins- or Orandi-type probes, the electrocautery being set at 50 W. Flexible or rigid instruments can be used for stenoses located at the level of the proximal ureter, the incision being made in the manner previously described.
The Acucise-type balloon can be used as a therapeutic alternative for proximal or distal ureteral stenoses ( ). The balloon is positioned under fluoroscopic control. There are a series of particularities regarding the modality of performing each type of incision according to the affected ureteral segment ( Table 9.2 , Figs 9.18–9.21 ).
| Ureteral segment | Type of incision | Observations |
|---|---|---|
| Proximal and middle | Posterior ( Fig. 9.19 ) or posterolateral |
|
| Above the iliac vessels | Lateral or posterolateral ( Fig. 9.20 ) |
|
| At the level of the iliac vessels | Anterior (10 o’clock on the right, 2 o’clock on the left) ( Fig. 9.21 ) |
|
| Below the iliac vessels | Anteromedial |
|
| At the level of the uterine artery or vas deferens | Posterior (6 o’clock) |
|
| Ureteral orifice | 12 o’clock |
|
At the level of the proximal ureter, above the iliac vessels, the electrocautery wire (which makes the incision) will be oriented posterolaterally, while below the iliac vessels it will be directed anteromedially in order to avoid the iliac artery and vein (which pass lateral to the ureter). For strictures located at the level of the iliac vessels, most authors recommend avoiding the use of the Acucise and to use ureteroscopic approach under visual control. In cases with uretero-vesical reimplantation, the incision of potential stenoses will be performed anterolaterally.
9.5.2.3
Combined Antegrade and Retrograde Approach
Complex ureteral strictures, especially those located at the level of a uretero-enteral anastomosis, frequently require a combined antegrade and retrograde approach ( Fig. 9.22 ).
The procedure allows for a rapid identification of the stenosed area, which is usually “hidden” between the urinary derivation’s folds (which makes the approach only in a retrograde manner very difficult).
A particular situation is represented by complete ureteral strictures. In these cases, the extent of the stenosis area can be assessed by simultaneously performing a retrograde and an antegrade ureteropyelography (through the nephrostomy tube). For short strictures (1 cm), endoureterotomy using the “cut to the light” technique may be indicated (by inserting the ureteroscope antegradely, the incision being made retrogradely). Although some authors have reported good results even for strictures of up to 5 cm in length ( ), most of them recommend that complete ureteral stenoses longer than 2 cm be approached by open surgical procedures.
9.5.2.4
Operative Technique
The patient is placed in the lithotomy position for the standard retrograde intervention. If simultaneous antegrade and retrograde approach is necessary, it is recommended to position the patient in decubitus with the legs apart (split-leg prone position) ( ) or, as an alternative, the patient can be placed in a dorsolithotomy position, lifting the flank with the affected ureter (by placing a role of textile material), thus allowing easier access to the nephrostomy area.
The first intraoperative step consists of radiologically detecting the stenosed ureteral segment. A retrograde ureteropyelography is performed for this purpose, followed by placement of a guidewire that must be ascended beyond the stricture; this can sometimes represent the most difficult moment of the intervention. Most authors recommend using hydrophilic guidewires. After placing the safety guidewire, the ureteroscope is ascended up to the level of the involved ureteral segment, with direct visual control in order to exclude other causes of ureteral obstruction (tumors or calculi) that could pass unobserved during the previous radiological explorations. If there are doubts regarding the etiology of the stricture, material can be collected for biopsy or for cytological examination before making the incision ( Fig. 9.23 ).
Knowing the ureteral anatomy and the safest areas for making the incision (depending on the location of the obstruction) are very important elements for performing the intervention safely and with a low rate of complications. The use of intraoperative endoluminal ultrasonography offers the advantage of obtaining correct information regarding the periureteral structures, being extremely useful for choosing the safest incision area ( ).
If the electrocautery is used, the safety guidewire must be isolated with the help of a ureteral catheter or replaced with a special guidewire, such as a nitinol one coated with polyurethane. This can prevent transmission of the energy from the electrocautery to the other ureteral structures, which could cause undesired secondary lesions.
The incision can be made safely with a cold knife, with the electrocautery’s probe, or with the holmium:YAG laser ( ). Cold-knife incision can prevent the development of tissular fibrosis consecutive to the intervention, with minimal secondary lesions ( Fig. 9.24 ). The use of a flexible ureteroscope requires using the Rite electrode or a Ho:YAG laser.
The ideal incision should penetrate the entire thickness of the ureteral wall, until the periureteral fat is visualized ( ) ( Fig. 9.25 ). However, when there is significant periureteral fibrosis, this goal becomes difficult or even impossible to achieve. In these situations, the incision is made deep enough to provide an adequate luminal diameter. Balloon dilation can be performed after the ureteroscopic incision, thus obtaining an additional enlargement of the stenosed area. The efficiency of the incision is checked by injecting contrast media (antegradely or retrogradely). Its leakage indicates the incision’s efficiency.
Strictures that determine complete ureteral obstruction raise more difficult problems. Placing a safety guidewire along the stenosed ureteral segment represents the key element of the procedure with regard to its importance and degree of difficulty. If the segment is very short and the proximal and distal ends of the ureter are well aligned, the rigid tip of the guidewire can be used for “puncturing” the stricture under sonographic and fluoroscopic control. Stabilizing the guidewire with the help of a ureteral catheter can facilitate surpassing the stenosed area.
Longer strictures require an incision made under direct visual (ureteroscopic) control from one end of the obstructed segment to the other. This implies simultaneous retrograde and antegrade ureteroscopic approach ( Fig. 9.26 ), using the “cut to the light” technique. With both tips of the ureteroscopes at the proximal and distal end of the stenosis respectively, these are aligned in the first step under fluoroscopic control in two planes. The light source of the working ureteroscope is subsequently turned off, in order to locate the opposite end of the stricture by visualizing the light of the secondary ureteroscope. The incision can be made with the electrocautery or the Ho:YAG laser, aiming to establish ureteral continuity ( ). In order to safely perform the operative procedure, the guidewire must be maintained in place during the entire intervention.
Strictures of uretero-enteral anastomoses can be difficult to treat due to the extensive postoperative periureteral fibrosis, as well as the difficult or even impossible to achieve retrograde access (from the enteral segment). Also, due to the oncological history of the patients, the high risk of local recurrence must be taken into account. In these cases, the success rate is lower compared to other ureteral strictures.
Complete uretero-vesical obstruction, secondary to renal transplantation or ureteral orifice resection, represents a similar problem, and identification of the ureteral orifice may be difficult. In these cases, perforation of the stenosed proximal segment by antegrade approach can be achieved, followed by retrograde incision ( ).
All authors recommend postoperative internal drainage. As in the case of patients with endopyelotomy, there are controversies regarding the proper dimension of the stent, as well as the period for which it is kept in place ( ). Usually it is preferred to use 6/10 F endoureterotomy stents, positioning the 10 F part at the level of the incised segment. Although there are no comparative studies conducted in significant groups of patients, it is considered that using a common 7 or 8 F JJ stent can be just as efficient.
According to Davis’ studies, the muscular tissue of the ureteral wall regenerates in 6 weeks. It is therefore considered that the stent should be kept in place for at least 6 weeks.
Postoperative follow-up consists of imagistic examinations performed to detect any recurrent obstructions: renal ultrasonography, excretory urography, retrograde ureteropyelography, or renal scintigraphy. Renal ultrasonography may show the presence of normal renal parenchyma, as well as the absence of hydronephrosis. The method is advantageous with regard to the cost-efficiency ratio and is easier to tolerate than contrast enhanced imagistic tests. It is usually recommended to repeat it at 3 and 6 months after the procedure, and then once a year if the patient’s status remains stable. Any modification detected by ultrasonography requires contrast-enhanced investigations or renal scintigraphy.
9.5.2.5
Results
There are few series of patients that can be analyzed in order to assess the results of incisional endoscopic treatment for ureteral strictures ( Table 9.3 ).
| Author | Number of cases | Success rate (%) | Follow-up (months) |
|---|---|---|---|
| 12 | 83 | 15 | |
| 8 | 75 | 4 | |
| 20 | 88 | – | |
| 8 | 75 | 29 | |
| 38 | 82 | 28 | |
| 12 | 67 | 11 | |
| 40 | 71 | 9 | |
| 7 | 86 | 22 | |
| Total | 145 | 78 | 4–29 |
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