10.2.1

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 ).

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.

10.2.2

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.

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.

10.2.3

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 ) ( ).

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 ( ).

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.

10.3.1

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 ) ( ).

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

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 ).

10.3.2

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 ).

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.

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 ).

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

10.3.3

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 ).

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.

10.3.4

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 ).

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.

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

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.

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

10.3.4.1

Cold-Knife Endopyelotomy

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

Cold-knife endopyelotomy of a UPJ stenosis.

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.

10.3.4.2

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.

Nd:YAG laser endopyelotomy.

10.3.5

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 ).

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