Retrograde Ureteroscopy in the Treatment of Ureteropelvic Junction Stenosis






Generalities


Ureteropelvic junction (UPJ) stenosis is defined as the deficiency in urine transportation from the pyelocaliceal system toward the proximal ureter. Its presence leads to the dilation of the pyelocaliceal system with potentially severe consequences for the kidney ( Fig. 10.1 ).




Figure 10.1


Right UPJ stenosis.

(a) Endoscopic and (b) pyelographic aspect.


The etiology of these stenoses is not completely known, being congenital ( Fig. 10.2 ) or secondary to a medical act ( Fig. 10.3 ). UPJ stenosis is the most common cause of neonatal hydronephrosis. According to the EAU guidelines, its overall incidence is 1:5000 neonates, the ratio between male and female gender being 2:1 ( ).




Figure 10.2


Endoscopic aspects of primary UPJ stenosis.



Figure 10.3


Endoscopic aspects of secondary UPJ stenosis.


The management of upper urinary tract obstruction, as a pathological entity, has been marked by technological progress both in terms of diagnosis and especially of treatment. The first attempt of a surgical treatment in UPJ stenosis belonged to Trendelenburg in 1886, while the first endoscopic intervention was carried out by Albarran in 1903, using an external endopyelotome. In 1983, Wickham and Kellet first described ureteroscopic pyelolysis, and in 1986, Inglis and Tolley reported their personal experience regarding this method. The presented data described a small number of cases in which the intervention was performed using rigid or flexible ureteroscopes and a 3–5 F cutting electrode, the incision being performed under direct visual control ( ). In 1985, Bagley imagined a combined percutaneous and ureteroscopic procedure for the management of UPJ obstruction.


In 1996, Thomas performed the first studies on preoperative ureteral endoprosthesis in order to facilitate the ureteroscopic passage during retrograde endoscopic treatment ( ; ). A new concept of retrograde endopyelotomy, carried out in a single step, was described by .


The retrograde incision of the stenosed junction using an Acucise™-type device (Applied Urology, Rancho Santa Margarita, CA) was initially reported in 1993 by Chandhoke. The various modalities of antegrade or retrograde endoscopic treatment follow the principle of “intubated ureterotomy” stated by Davis in 1943. The procedure consists of the endoscopic incision of the UPJ up to the proximal ureter, with a depth that allows the exposure of the peripyelic and periureteral fat or, in case of secondary stenosis, to pass the area of periureteral fibrosis. After performing the incision, a stent is placed for modeling. Endopyelotomy can be antegrade, by percutaneous approach, or retrograde, by ureteroscopic approach.


The retrograde technique, which is currently being used more and more frequently, has a well-documented efficiency, its success rate being equivalent with percutaneous procedures in selected cases. Modernly, due to the lower caliber instruments, the single-step approach of the UPJ stenosis is considered standard.





Indications


UPJ stenosis may become clinically manifest during midlife or even later. Sometimes the patient is asymptomatic and the obstruction can only be objectified by a series of studies. However, all diagnosed patients can benefit from reconstructive procedures ( ). They are indicated, regardless of age, when signs of global or ipsilateral renal function impairment appear ( ).


Currently, UPJ stenosis benefits from multiple treatment modalities. Most authors still consider open surgical pyeloplasty to be the “gold standard” of therapy for this pathological entity. The development of minimally invasive techniques in recent years has increasingly brought retrograde or antegrade endopyelotomy and laparoscopic pyeloplasty into the spotlight ( ).



Therapeutic Indications for UPJ Stenosis


The modern indications for treatment in UPJ stenosis are represented by the following:




  • presence of symptoms associated with obstruction



  • alteration of global renal function



  • progressive alteration of ipsilateral renal function



  • presence of associated lithiasis



  • presence of urinary infection



  • presence of hypertension (in rare cases)



Surgical intervention has the purpose of creating a normal, nonobstructive urinary flow, the ultimate goal being the improvement of the renal function ( Fig. 10.4 ).




Figure 10.4


Preoperative (a) and postoperative (b) radiologic aspect of the upper urinary tract in a patient with UPJ stenosis (IVU).


In general, early intervention is recommended for neonates and children in order to preserve the renal function ( ). However, the optimal moment for the intervention remains controversial in neonates due to the possibility of the presence of a functional-type obstruction ( ).


In a prospective study conducted on a group of 104 neonates with unilateral hydronephrosis, probably due to a congenital UPJ stenosis, it was found that only 7% of cases required pyeloplasty as a consequence of hydronephrosis progression or of a 10% decrease of the glomerular ultrafiltrate ( ). Renal function returned to normal values after the intervention in all these cases.



Therapeutic Options in UPJ Stenosis


The last century saw a continuous progress and diversification of the therapeutic options reserved for UPJ stenosis ( Table 10.1 ). Open surgical intervention (pyeloplasty) is a reconstructive type of surgery. While the first attempt dates back to 1886 (Trendelenburg), the first successful pyeloplasty was only performed in 1891 by Kuster. Changes to the technique, which included the use of a flap, were introduced in 1916 by Schwyzer, while Y–V pyeloplasty was modified by Foley in 1937.



Table 10.1

Therapeutic Alternatives in UPJ Stenosis















Retrograde endoscopic techniques

  • 1.

    Balloon dilation


  • 2.

    Endopyelotomy with the Acucise catheter


  • 3.

    Retrograde endopyelotomy using a rigid or flexible ureteroscope and




    • a.

      Cold knife


    • b.

      Ureteroresectoscope


    • c.

      Holmium:YAG laser


Antegrade endoscopic techniques Antegrade endopyelotomy using


  • 1.

    Cold knife – “classic”


  • 2.

    Electrocautery – Collins loop


  • 3.

    Holmium:YAG laser

Laparoscopic techniques Laparoscopic pyeloplasty
Open surgical techniques Open surgical pyeloplasty


In 1949, Hynes and Anderson described a modified technique that involved the anastomosis of the spatulated ureter at one end of the renal pelvis after the resection of the excess segment, a procedure that still has a wide applicability today.


Laparoscopic techniques allow for an accurate reproduction of an open surgical intervention. The major advantage of laparoscopy is the minimally invasive approach, with minimal operative trauma, rapid recovery, and short hospitalization.


Also, the laparoscopic approach allows for the transposition of the polar vessels at the level of the junction. However, in secondary UPJ stenosis, the laparoscopic procedure can be more difficult due to peripyelic and periureteral fibrosis.


One of the variants of this method is the robot-assisted procedure, which has the advantage of precise movements (with more degrees of freedom than traditional laparoscopy) and of a three-dimensional visualization of the workspace. Due to these characteristics, the duration of achieving the intracorporeal anastomoses and, in the end, the operating time, can be reduced. Currently, the operating time for a laparoscopic intervention is comparable to that of an open surgical intervention.


Regarding the endoscopic techniques, direct visual inspection of the stenotic area and interactively determining the site of incision are possible during the procedure. The results published in the literature prove that endopyelotomy can be a viable alternative in the treatment of UPJ stenosis. The desire to improve the surgical techniques in order to achieve higher success rates has led to combinations between endoscopic and laparoscopic techniques. These consist of the longitudinal endoscopic incision followed by the transverse suture of the incision by a minilaparoscopic approach ( ). The initial results of the technique are good, but the procedure requires the test of time in order to be adopted.


Although the success rates of the endoscopic procedures are percentually lower than those of traditional surgery, there are studies that claim these can be improved through a more judicious selection of patients.


Nephrectomy remains the only method of treatment if the kidney is urographically and scintigraphically nonfunctioning.



Indications for Retrograde Endoscopic Treatment in UPJ Stenosis


The individualization of treatment takes into account especially the ratio between risks and benefits, and the choice for one of the therapeutic alternatives must be discussed with the patient.


Although, theoretically, the retrograde ureteroscopic approach can be used in most cases of UPJ stenosis, the experience gained has allowed the adoption of some criteria that can optimize the results of these interventions. Impaired preoperative renal function, the length of stenosis, or severe hydronephrosis are considered to be negative prognostic factors.


Thus, in patients with differential ipsilateral renal function less than 20%, the drainage of the renal unit by placing a JJ ureteral stent or a percutaneous nephrostomy can initially be recommended. Reassessment of the renal function represents the decisive element in choosing between a reconstructive treatment and excision ( ).


A length of the stenotic area greater than 2 cm is a relative contraindication for retrograde endoscopic treatment, and these cases can benefit from open or laparoscopic pyeloplasty ( ).


Preoperative hydronephrosis is an important factor in choosing the approach because the size of the renal pelvis will remain unchanged in case of an endoscopic intervention. This is the reason why open or laparoscopic pyeloplasty (conventional or robot-assisted) is recommended in patients with important dilation of the pyelocaliceal system ( Fig. 10.5 ) ( ).




Figure 10.5


Right UPJ stenosis, with grade IV hydronephrosis (retrograde pyelography).


Although retrograde endopyelotomy under direct visual control can also be carried out in the presence of polar vessels, the success rate in such cases is relatively low, ranging between 32–53%, thus supporting the idea of selecting patients in order to improve the success rate ( ).


Imagistic evaluation has demonstrated the presence of polar vessels in 46–60% of cases ( ).


Choosing the open or the laparoscopic approach offers the possibility of direct visualization of the polar vessels, thereby allowing UPJ translocation and performing a Hynes–Anderson-type pyeloplasty. In case of endoscopic approach, imagistic evaluation can preoperatively predict the intervention’s outcome ( ).


Patients with UPJ stenosis and polar vessels represent the best indication for an open or laparoscopic surgical reconstructive therapy ( ).


The impact of the ureter’s insertion site ( Fig. 10.6 ) at the pyelic level on the results of endopyelotomy is still a controversial subject. Thus, while some authors believe that high insertion is associated with a reduction in the rate of success, thereby becoming a contraindication for the endoscopic approach, other studies did not identify this difference ( ).




Figure 10.6


Retrograde ureteroscopic approach of a UPJ stenosis with high insertion of the ureter (a, b), laser incision (c–e), pre- and postoperative comparative aspect (f), correctly positioned pyelostent (g), wide UPJ at 3 months after intervention (h).




Association of renal lithiasis represents an indication for the antegrade approach in the detriment of the retrograde one, this attitude allowing both conditions to be solved in a single procedure. However, the development of modern flexible ureteroscopes with an increased reliability and the introduction of the Ho:YAG laser have transformed retrograde endopyelotomy associated with intracorporeal lithotripsy into a viable alternative in selected cases with low lithiasic mass.


The average success rates after primary retrograde endopyelotomy or after open interventions are relatively similar, and a failed retrograde intervention does not seem to adversely affect the results of consecutive pyeloplasty ( ). On the other hand, the results of iterative endopyelotomy are modest ( ).


This is why some authors propose pyeloplasty if the endoscopic procedures fail, respectively endopyelotomy in case of the recurrence of the stenosis operated by open surgery. In this type of “secondary” UPJ stenosis, endopyelotomy is a viable alternative with a success rate that may reach 87.5% ( ; , ; ).


Another factor that may determine modest postoperative results is represented by the reduced production of growth factors ( ).


Balloon dilation of UPJ stenosis was first performed in the 1980s. However, due to the low success rates, this method has lost popularity.


Although the incidence of complications was very low and the success rate was initially encouraging, these were quickly overshadowed by the very high percentage of restenoses. The method was abandoned after a short period due to the fact that the mere dilation of the affected segment does not allow the regeneration of healthy tissue.





Therapeutic Indications for UPJ Stenosis


The modern indications for treatment in UPJ stenosis are represented by the following:




  • presence of symptoms associated with obstruction



  • alteration of global renal function



  • progressive alteration of ipsilateral renal function



  • presence of associated lithiasis



  • presence of urinary infection



  • presence of hypertension (in rare cases)



Surgical intervention has the purpose of creating a normal, nonobstructive urinary flow, the ultimate goal being the improvement of the renal function ( Fig. 10.4 ).




Figure 10.4


Preoperative (a) and postoperative (b) radiologic aspect of the upper urinary tract in a patient with UPJ stenosis (IVU).


In general, early intervention is recommended for neonates and children in order to preserve the renal function ( ). However, the optimal moment for the intervention remains controversial in neonates due to the possibility of the presence of a functional-type obstruction ( ).


In a prospective study conducted on a group of 104 neonates with unilateral hydronephrosis, probably due to a congenital UPJ stenosis, it was found that only 7% of cases required pyeloplasty as a consequence of hydronephrosis progression or of a 10% decrease of the glomerular ultrafiltrate ( ). Renal function returned to normal values after the intervention in all these cases.





Therapeutic Options in UPJ Stenosis


The last century saw a continuous progress and diversification of the therapeutic options reserved for UPJ stenosis ( Table 10.1 ). Open surgical intervention (pyeloplasty) is a reconstructive type of surgery. While the first attempt dates back to 1886 (Trendelenburg), the first successful pyeloplasty was only performed in 1891 by Kuster. Changes to the technique, which included the use of a flap, were introduced in 1916 by Schwyzer, while Y–V pyeloplasty was modified by Foley in 1937.



Table 10.1

Therapeutic Alternatives in UPJ Stenosis















Retrograde endoscopic techniques

  • 1.

    Balloon dilation


  • 2.

    Endopyelotomy with the Acucise catheter


  • 3.

    Retrograde endopyelotomy using a rigid or flexible ureteroscope and




    • a.

      Cold knife


    • b.

      Ureteroresectoscope


    • c.

      Holmium:YAG laser


Antegrade endoscopic techniques Antegrade endopyelotomy using


  • 1.

    Cold knife – “classic”


  • 2.

    Electrocautery – Collins loop


  • 3.

    Holmium:YAG laser

Laparoscopic techniques Laparoscopic pyeloplasty
Open surgical techniques Open surgical pyeloplasty


In 1949, Hynes and Anderson described a modified technique that involved the anastomosis of the spatulated ureter at one end of the renal pelvis after the resection of the excess segment, a procedure that still has a wide applicability today.


Laparoscopic techniques allow for an accurate reproduction of an open surgical intervention. The major advantage of laparoscopy is the minimally invasive approach, with minimal operative trauma, rapid recovery, and short hospitalization.


Also, the laparoscopic approach allows for the transposition of the polar vessels at the level of the junction. However, in secondary UPJ stenosis, the laparoscopic procedure can be more difficult due to peripyelic and periureteral fibrosis.


One of the variants of this method is the robot-assisted procedure, which has the advantage of precise movements (with more degrees of freedom than traditional laparoscopy) and of a three-dimensional visualization of the workspace. Due to these characteristics, the duration of achieving the intracorporeal anastomoses and, in the end, the operating time, can be reduced. Currently, the operating time for a laparoscopic intervention is comparable to that of an open surgical intervention.


Regarding the endoscopic techniques, direct visual inspection of the stenotic area and interactively determining the site of incision are possible during the procedure. The results published in the literature prove that endopyelotomy can be a viable alternative in the treatment of UPJ stenosis. The desire to improve the surgical techniques in order to achieve higher success rates has led to combinations between endoscopic and laparoscopic techniques. These consist of the longitudinal endoscopic incision followed by the transverse suture of the incision by a minilaparoscopic approach ( ). The initial results of the technique are good, but the procedure requires the test of time in order to be adopted.


Although the success rates of the endoscopic procedures are percentually lower than those of traditional surgery, there are studies that claim these can be improved through a more judicious selection of patients.


Nephrectomy remains the only method of treatment if the kidney is urographically and scintigraphically nonfunctioning.





Indications for Retrograde Endoscopic Treatment in UPJ Stenosis


The individualization of treatment takes into account especially the ratio between risks and benefits, and the choice for one of the therapeutic alternatives must be discussed with the patient.


Although, theoretically, the retrograde ureteroscopic approach can be used in most cases of UPJ stenosis, the experience gained has allowed the adoption of some criteria that can optimize the results of these interventions. Impaired preoperative renal function, the length of stenosis, or severe hydronephrosis are considered to be negative prognostic factors.


Thus, in patients with differential ipsilateral renal function less than 20%, the drainage of the renal unit by placing a JJ ureteral stent or a percutaneous nephrostomy can initially be recommended. Reassessment of the renal function represents the decisive element in choosing between a reconstructive treatment and excision ( ).


A length of the stenotic area greater than 2 cm is a relative contraindication for retrograde endoscopic treatment, and these cases can benefit from open or laparoscopic pyeloplasty ( ).


Preoperative hydronephrosis is an important factor in choosing the approach because the size of the renal pelvis will remain unchanged in case of an endoscopic intervention. This is the reason why open or laparoscopic pyeloplasty (conventional or robot-assisted) is recommended in patients with important dilation of the pyelocaliceal system ( Fig. 10.5 ) ( ).




Figure 10.5


Right UPJ stenosis, with grade IV hydronephrosis (retrograde pyelography).


Although retrograde endopyelotomy under direct visual control can also be carried out in the presence of polar vessels, the success rate in such cases is relatively low, ranging between 32–53%, thus supporting the idea of selecting patients in order to improve the success rate ( ).


Imagistic evaluation has demonstrated the presence of polar vessels in 46–60% of cases ( ).


Choosing the open or the laparoscopic approach offers the possibility of direct visualization of the polar vessels, thereby allowing UPJ translocation and performing a Hynes–Anderson-type pyeloplasty. In case of endoscopic approach, imagistic evaluation can preoperatively predict the intervention’s outcome ( ).


Patients with UPJ stenosis and polar vessels represent the best indication for an open or laparoscopic surgical reconstructive therapy ( ).


The impact of the ureter’s insertion site ( Fig. 10.6 ) at the pyelic level on the results of endopyelotomy is still a controversial subject. Thus, while some authors believe that high insertion is associated with a reduction in the rate of success, thereby becoming a contraindication for the endoscopic approach, other studies did not identify this difference ( ).




Figure 10.6


Retrograde ureteroscopic approach of a UPJ stenosis with high insertion of the ureter (a, b), laser incision (c–e), pre- and postoperative comparative aspect (f), correctly positioned pyelostent (g), wide UPJ at 3 months after intervention (h).




Association of renal lithiasis represents an indication for the antegrade approach in the detriment of the retrograde one, this attitude allowing both conditions to be solved in a single procedure. However, the development of modern flexible ureteroscopes with an increased reliability and the introduction of the Ho:YAG laser have transformed retrograde endopyelotomy associated with intracorporeal lithotripsy into a viable alternative in selected cases with low lithiasic mass.


The average success rates after primary retrograde endopyelotomy or after open interventions are relatively similar, and a failed retrograde intervention does not seem to adversely affect the results of consecutive pyeloplasty ( ). On the other hand, the results of iterative endopyelotomy are modest ( ).


This is why some authors propose pyeloplasty if the endoscopic procedures fail, respectively endopyelotomy in case of the recurrence of the stenosis operated by open surgery. In this type of “secondary” UPJ stenosis, endopyelotomy is a viable alternative with a success rate that may reach 87.5% ( ; , ; ).


Another factor that may determine modest postoperative results is represented by the reduced production of growth factors ( ).


Balloon dilation of UPJ stenosis was first performed in the 1980s. However, due to the low success rates, this method has lost popularity.


Although the incidence of complications was very low and the success rate was initially encouraging, these were quickly overshadowed by the very high percentage of restenoses. The method was abandoned after a short period due to the fact that the mere dilation of the affected segment does not allow the regeneration of healthy tissue.





Retrograde endopyelotomy technique



Preliminary Measures


The preoperative evaluation should include paraclinical investigations, which can document the presence of the UPJ organic stenosis, as well as its morphofunctional consequences, with direct implications on the therapeutic option.


The investigational protocol may include renal ultrasonography, IVU, renal scintigraphy ( Fig. 10.7 ), the Whitaker test, and, in order to identify possible polar vessels, spiral CT or endoluminal ultrasonography ( Fig. 10.8 ) ( ).




Figure 10.7


Renal scintigraphy with isotopic nephrogram in a patient with left UPJ stenosis.



Figure 10.8


UPJ evaluation by 3D endoluminal ultrasonography.

Source: With permission from .


An important step in the preoperative preparation of patients is the antibiotic prophylaxis of common uropathogens.


Retrograde endopyelotomy under direct visual control is performed under spinal or general anesthesia. The latter has the advantages of controlling breathing and of avoiding sudden movements that can lead to severe traumatic complications.


Sometimes, under spinal anesthesia, due to the dilation caused by the irrigation fluid, the patients may experience lumbar pains, especially if the anesthesia was carried out at a lower metameric level.


The intervention is performed in the classic lithotomy position.


The instruments needed include appropriate endoscopes, energy sources, and accessories, with some differences according to the type of incision ( Table 10.2 ).



Table 10.2

Instruments Necessary for the Retrograde Approach of UPJ Stenosis


















Cystoscope Bladder inspection, retrograde ureteropyelography
Fluoroscope Intraoperatory monitoring, placing the pyelostent
Ureteroscope Semirigid, flexible, rigid ureteroresectoscope
Energy sources Electrosurgery source, Ho:YAG, Nd:YAG
Accessory instruments Guidewires, fulguration electrodes, Acucise catheter, ureteral catheters for electric insulation, endopyelotomy knife



Cystoscopy and Placement of Guidewires


After the cystoscopic evaluation of the bladder, which is a compulsory stage during each retrograde endoscopic intervention, RUP is performed ( Fig. 10.9 ).




Figure 10.9


Radiological aspects of UPJ stenosis (retrograde ureteropyelography).


This will document the presence of the organic UPJ stenosis, its length, the ureter’s insertion site at the pyelic level, and the possible associated ureteral or pyelocaliceal lesions.


Evaluation of the upper urinary tract by pyelography is also recommended in patients who underwent preoperative ureteral endoprosthesis, after removing the JJ catheter.


Subsequently, the safety guidewire will be placed, if possible, surpassing the area of stenosis at the UPJ level ( Fig. 10.10 ). This safety guidewire will be maintained throughout the entire endoscopic intervention.




Figure 10.10


Guidewire ascended up to the pyelocaliceal level (a), after surpassing the UPJ stenosis (b).


In certain situations (tight stenoses, etc.), surpassing the UPJ with the guidewire is only possible ureteroscopically, under direct visual control ( Fig. 10.11 ).




Figure 10.11


Insertion of the guidewire at the level of the punctiform UPJ under direct visual control.



Ureteral Access


The endoscopic approach of the UPJ stenosis can be achieved with rigid, semirigid, or flexible ureteroscopes, all with specific advantages and disadvantages, described in the previous chapters.


In case of a reduced diameter of the intramural ureter that does not allow for an easy passage of the ureteroscope, its dilation with the balloon catheter or with progressive ureteral dilation sets is indicated. In some cases, the ureteral orifice can be negotiated using two guidewires or pressurized irrigation systems (Uromat).


If the ureteral caliber is too small to allow the passage of the ureteroscope, a JJ catheter is placed and the intervention will be resumed after 5–10 days, during which passive dilation takes place.


The ureteroscope can be ascended on a second working guidewire or can be passed beside the safety guidewire, which was placed priorly ( Fig. 10.12 ).




Figure 10.12


Advancing the ureteroscope beside the safety guidewire.


In men, the optimal approach of the UPJ is sometimes difficult, particularly due to the reduced mobility of the ureteroscope determined by its passage through the urethra.


In case of the impossibility of passing the ureteroscope through the junction, its dilation with a balloon catheter can be attempted.



Junction Incision


The incision of the stenotic junction will be preceded by a careful inspection of the segment in order to identify any pulsations at this level indicating the presence of polar vessels. It will be performed in the posterolateral segment, during the withdrawal movement of the ureteroscope ( Fig. 10.13 ).




Figure 10.13


Laser incision in the posterior region of the UPJ.


The procedure is repeated until the peripyelic and periureteral fat from the retroperitoneal space is clearly exposed ( Fig. 10.14 ), respectively until the area of fibrosis is completely passed in case of secondary stenosis ( Fig. 10.15 ). The incision should be made until an adequate diameter of the junction is obtained, allowing for the easy ascent of the ureteroscope.




Figure 10.14


Laser incision of a primary UPJ stenosis, until the periureteral fat is clearly exposed.



Figure 10.15


The laser incision of a recurrent UPJ stenosis, until the area of fibrosis is passed.


The incision is done distally until normal ureteral mucosa is reached. The classic technique recommends sectioning the junction area up to 1 cm distal to the stenosis itself, which creates the conditions for optimal healing, with minimal risk of restenosis.


The radiological control of a correct technique involves objectifying the leakage of the contrast agent that was injected through the ureteroscope ( Fig. 10.16 ). Although performing a pyelography at the end of the intervention is not absolutely necessary, the maneuver is useful for confirming the complete incision of the stenotic area.




Figure 10.16


Leakage of the contrast agent in retrograde pyelography, confirming a correctly done incision.


The incision of the stenotic UPJ can be done using the following:




  • the “cold-blade” knife



  • laser fiber



  • incision electrodes




Cold-Knife Endopyelotomy


The procedure is similar to an optical urethrotomy, but uses “scissors”-type knives ( Fig. 10.17 ).




Figure 10.17


Positioning the cold-blade knife during retrograde endopyelotomy.


This is sharp on both edges, which makes possible not only the incision by opening the instrument and using the cutting edge from the external part of the upper distal arm ( Fig. 10.18 ), but also cutting through shearing maneuvers ( Fig. 10.19 ).




Figure 10.18


Cold-knife endopyelotomy of a UPJ stenosis.



Figure 10.19


Cold-knife endopyelotomy of a valvular type UPJ stenosis (a, b): cutting the tissue through shearing motions (c, d) followed by widening the junction through progressive incisions in a classic manner (e, f).




Cold incision can be difficult to perform in case of secondary UPJ stenosis, especially because of the area of fibrosis present at this level. The use of the endopyelotomy knife allows for an accurate incision of the junction ( ). However, the use of the cold knife implies an increased risk of bleeding compared to laser fiber incision.



Laser Endopyelotomy


Ho:YAG or Nd:YAG lasers can be used for the incision of stenosed UPJ. It is recommended to use 365 μm fibers on the semirigid ureteroscope, respectively 200 μm fibers on the flexible ureteroscope. Ho:YAG laser incision is preferred because of its increased safety profile, which is due to a reduced tissue penetrability (0.5–1 mm compared to 5–6 mm for the Nd:YAG laser). The use of the Ho:YAG laser also has the advantage of fragmenting existing secondary kidney stones. When using the flexible ureteroscope and the laser, pyelocaliceal stones can be processed during the same procedure.


The laser fiber will be positioned at the proximal end of the area of stenosis or even inside the renal pelvis. The settings of the Ho:YAG laser for incision will be 1.2 J and 10–15 Hz ( ). Improper handling of the fiber, triggering it inside the ureteroscope, may cause the destruction of the working instrument, thus compromising the intervention. Small vessels can be coagulated with the laser fiber in a noncontact manner.


Despite the disadvantages of an increased tissue penetrability, the Nd:YAG laser ( Fig. 10.20 ) has the advantage of excellent hemostasis properties.




Figure 10.20


Nd:YAG laser endopyelotomy.





Endopyelotomy With Electrocautery


The incision of the UPJ with electrocautery is achieved by using small electrodes or a Collins loop for the ureteroresectoscope. The use of electrodes makes the incision similar to the one performed with the laser fiber, but with a much more pronounced thermal effect.


In order to prevent possible complications caused by the use of electrical current, it is recommended to isolate the safety metallic guidewire from the ureter and junction. This is done by sliding a ureteral catheter with a permeable end on the guidewire, which also allows for the decompression of the pyelocaliceal system when necessary.


Due to the increased diameter of the ureteroresectoscope, retrograde incision with the Collins loop is more difficult to perform and less frequently used. In addition, the dimensions of the endoscope increase the risk of ureteral wall ischemia.


Due to the partial obstruction of the endoscopic field by the loop, some authors recommend placing it after the ureteroresectoscope has been ascended up to the level of the junction.



Acucise Endopyelotomy


The Acucise device consists of a 6–10 F ureteral catheter that presents in its distal part a balloon on which a 150 μm/3 cm filiform electrode is applied.


After passing the stenosis with a metallic guidewire, the Acucise catheter is advanced on it. When the guidewire cannot be ascended to the pyelocaliceal level, it should be placed with the help of the ureteroscope under direct visual control. When the endopyelotomy catheter cannot pass through the stenosis, it is recommended to place a JJ catheter for a period of 2 weeks, resuming the procedure after the passive dilation of the ureter and the junctional zone.


The balloon is positioned under fluoroscopic control, using the two radiopaque markers at its ends as landmarks. In order to visualize the positioning of the endopyelotomy device, injection of contrast agent into the renal pelvis is recommended, and the area of stenosis should be found between the two indicators.


In order to minimize the risk of bleeding, it is absolutely necessary to correctly objectify the incision wire positioned laterally. The fluoroscopic appearance in which the working guidewire crosses the incision wire means a flawed positioning due to the coiling of the latter. In these circumstances, the application of the cutting current will almost inevitably lead to vascular lesions.


Two guidewires are never used in the case of endopyelotomy with the Acucise catheter. After correctly positioning and inflating the balloon with contrast agent diluted with standard saline, incision of the junction is done by applying a cutting current of 75–100 W for 3–5 s. Some authors recommend keeping the balloon inflated for 5–10 min in order to achieve hemostasis by compression ( ).


Pielography performed after the incision and balloon deflation allows the result to be evaluated immediately through the leakage of the contrast agent at the level of the junction.


If this phenomenon is not visible, it is recommended to repeat the incision during the same procedure ( ).



Postoperative Stenting


After withdrawing the ureteroscope, a 7/14 F pyelostent will be ascended on the safety guidewire maintained in position ( Fig. 10.21 ), under cystoscopic and fluoroscopic control. The segment with the increased diameter will be positioned in the area where the incision was made ( Fig. 10.22 ).


Oct 10, 2019 | Posted by in UROLOGY | Comments Off on Retrograde Ureteroscopy in the Treatment of Ureteropelvic Junction Stenosis
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