Ureteropelvic Junction Obstruction Treatment & Management

In children with ureteropelvic junction (UPJ) obstruction, medical therapy is focused on maintaining sterile urine and assessing renal function and the degree of hydronephrosis. Typically, when imaging studies reveal an incomplete obstruction, the patient is monitored with routine renal ultrasonography and nuclear medicine renography.

Currently, medical therapy is unavailable for the treatment of both adult and pediatric cases of UPJ obstruction.

Initially, most children are treated conservatively and monitored closely. Intervention is indicated in the event of significantly impaired renal drainage or poor renal growth. The accepted criteria for intervention in infants and children include T 1/2 greater than 20 minutes, differential function less than 40%, and ongoing parenchymal thinning with or without contralateral compensatory hypertrophy. Intervention is also indicated in those with pain, hypertension, hematuria, secondary renal calculi, and recurrent UTIs.

Surgical intervention to treat an obstructed UPJ is warranted, especially upon deterioration of renal function.

• The principles of surgical repair, as initially described by Foley, include the following:

  • Formation of a funnel
  • Dependent drainage
  • Watertight anastomosis
  • Tension-free anastomosis

In children, the procedure of choice is an Anderson-Hynes dismembered pyeloplasty. The approach may be performed through a flank, dorsal lumbotomy, or anterior extraperitoneal technique. Laparoscopy has gained increasing acceptance in pediatric surgery and is often used to perform pyeloplasties in children. In many cases, laparoscopic pyeloplasty is technically unfeasible in very small children and infants because of space constraints. Using this method, the obstructed segment is completely resected, with reanastomosis of the renal pelvis and ureter in a dependent funneled fashion. The decision of whether to use a ureteral stent transiently during the initial healing process is based on the personal preference of the surgeon. The success rate of dismembered pyeloplasty for treating an obstructed UPJ exceeds 95%.

Laparoscopic pyeloplasty offers a minimally invasive treatment option that may be used in patients with either primary or secondary UPJ obstruction and is emerging as a new criterion standard in the treatment of UPJ obstruction.^[1] Success rates are comparable with those of open pyeloplasty procedures, and some studies have shown that laparoscopy offers the advantages of decreased morbidity, shorter hospital stay, and quicker recovery. Laparoscopic pyeloplasty is a technically demanding procedure that generally requires significant laparoscopic experience. Robotic-assisted laparoscopic pyeloplasty has become increasingly popular as the robots have become more prevalent. A small intrarenal pelvis is a relative contraindication to laparoscopic pyeloplasty.

Endoscopic treatment alternatives include an antegrade or retrograde endopyelotomy, which is an endoscopic incision performed through the obstructing segment.

Prior to incising a UPJ obstruction, intraluminal ultrasonography or another imaging study is recommended to evaluate adjacent ureteral vasculature. Endoluminal ultrasonography is particularly useful in evaluating an obstructed UPJ because it allows for complete real-time evaluation with specific attention to the presence or proximity of blood vessels prior to an endoscopic incision. It is also useful in defining the ureteral anatomy and in directing the incision technique in order to maximize the surgical outcome.

An endopyelotomy incision is performed through the area of obstruction with a laser, electrocautery, or endoscopic scalpel. Most surgeons dilate the newly incised area with a balloon catheter to help ensure a complete incision. This is followed by prolonged ureteral stenting, for a period of 4-8 weeks. The stent acts as internal scaffolding during healing and maintains renal drainage. Success rates with the percutaneous and ureteroscopic endopyelotomy are 80-90%.

When open pyeloplasty fails, endopyelotomy is particularly useful, even in the pediatric population.

In patients who have a suboptimal result from endopyelotomy, repeat incision can be performed with success. Traditional open or laparoscopic pyeloplasty is also indicated after failed endopyelotomy.

Of the open surgical repairs used to treat UPJ obstruction, the Anderson-Hynes dismembered pyeloplasty is particularly useful for the high-insertion variant. The benefit of this procedure is complete excision of the diseased segment of ureter and reconstruction with healthy viable tissue.

The Foley Y-V plasty is also useful for the high-insertion variant but cannot be used if transposition of a lower-pole vessel is needed.

Endopyelotomy for high-insertion UPJ obstruction is patterned after this open surgical procedure but is contraindicated in the presence of a crossing posterior or lateral vessel.

Spiral and vertical flaps (eg, Culp and DeWeerd, Scardino and Prince) are useful when a long-strictured segment of diseased ureter is encountered. With these procedures, the proximal ureter is re-created with redundant renal pelvis that is tubularized.

Ureterocalicostomy, ie, anastomosis of the ureter to a lower-pole renal calyx, is usually reserved for failed open pyeloplasty when no extrarenal pelvis and significant hilar scarring are present. With this procedure, the ureter is sutured directly to a lower pole calyx after a modest partial nephrectomy is performed to remove parenchyma in the area of anastomosis.

Endopyelotomy

Endopyelotomy is a reasonable option in patients with mild-to-moderate hydronephrosis and reasonably good renal function. The stricture should be short (< 1.5 cm), and no crossing vessels should be defined on preoperative or intraoperative imaging (ie, intraluminal ultrasonography). Endopyelotomy may be the preferred option in patients in whom prior pyeloplasty has failed. Antegrade and retrograde approaches are equally efficacious.

Endopyeloplasty

Reported by Gill et al from the Cleveland clinic in 2002, endopyeloplasty essentially consists of horizontal suturing of a standard vertical endopyelotomy incision performed through a percutaneous tract via a 26F nephroscope.^[6] Indications for endopyeloplasty include short-segment UPJ obstruction, an absence of crossing vessels, and an absence of prior surgery in the UPJ. Endopyeloplasty yields results comparable to those of endopyelotomy, but additional studies are needed for validation.

Laparoscopic pyeloplasty

This procedure is replacing open pyeloplasty as the criterion standard.^[1] Most large series report 95% success rates. Unlike endopyelotomy, laparoscopic pyeloplasty can be offered to patients with severe hydronephrosis, crossing vessels, and long-segment strictures. However, the significant learning curve associated with laparoscopic suturing has limited its widespread use. In skilled hands, the indications for laparoscopic pyeloplasty may be extended to secondary UPJ obstruction, concomitant renal calculi, and anomalous and solitary kidneys. Salvage laparoscopic pyeloplasty is an excellent option with durable long-term outcomes in patients in whom open pyeloplasty has previously failed.^[7]

Robotic-assisted laparoscopic pyeloplasty

This procedure is particularly helpful in the surgeon who is learning the laparoscopic technique. The da Vinci robotic surgical system has been used successfully for laparoscopic reconstruction. It offers several advantages to surgeons unskilled in laparoscopy, including increased degrees of suturing freedom, stereoscopic vision, tremor filtration, and scaling. The results are similar to those of conventional laparoscopic pyeloplasty. Incorporation of robotic skills enables urologists with limited laparoscopic skills to offer minimally invasive options to their patients. In the pediatric population, although only a few published series have addressed long-term outcomes, the short-term data suggest that outcomes are similar to those of open pyeloplasty.^[8]

Single-site pyeloplasty

Recently, reports have described early experiences with laparoscopic single-site pyeloplasty, during which pyeloplasty is performed via a single port placed at the umbilicus. Long-term follow-up with this technically demanding procedure is lacking, with improved cosmesis being the only theoretical advantage.^{[9, 10]}

• History and physical examination
• Evaluation of CBC count, electrolytes, renal function, and coagulation profile
• Radiographic and functional studies of the kidney in question
• Evaluation of the normal contralateral kidney
• Evaluation of peri-UPJ vascular anatomy
• Anesthesia evaluation

Techniques of surgical repair of an obstructed ureteropelvic junction

One of the goals of laparoscopy is to mirror open techniques, so most of the principles of surgical repair apply to both. In addition to creating a funnel with dependent drainage, care must be taken to minimize tissue handling and tension on the reconstructed UPJ. Whether to use ureteral stents or nephrostomy tubes after open or laparoscopic repair is based on personal preference.

Principles of endopyelotomy

Endopyelotomy may be performed either antegrade or retrograde, ureteroscopically. A safety guidewire must be placed within the ureter prior to endoscopic incision. Intraluminal ultrasonography or preoperative imaging is essential to define peri-UPJ vascular anatomy.

The endoscopic incision should be performed full-thickness through the UPJ and into perirenal fat with laser energy, electrocautery, or an endoscopic scalpel. To ensure a proper incision, extravasation of contrast should be seen on pyelography during the procedure. The incision is most commonly performed posterolaterally.

Balloon dilation is often performed after the incision is made to ensure completeness. Ureteral stenting for 4-8 weeks after the endoscopic procedure is common, although no consensus exists regarding size and duration of stents.

• Risk factors for failure after endopyelotomy include the following:

  • Length of UPJ obstruction
  • Diminished renal function (< 25%)
  • Massive hydronephrosis with a redundant renal pelvis
  • Crossing vessels
  • Crossing vessels with massive hydronephrosis (worst outcome)

Prophylactic antibiotic therapy should be given postoperatively. Remove the endopyelotomy stent after 4-8 weeks.

Follow up with renal ultrasonography 1-3 months after surgery. In addition, follow up with IVP or nuclear medicine renal scan 3-6 months after surgery.

Serial renal imaging is recommended for the first year after surgery and should be continued less frequently thereafter if results have normalized.

For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center. Also, see eMedicine's patient education articles Intravenous Pyelogram and Adhesions, General and After Surgery.

Potential complications from open surgical pyeloplasty include UTI and pyelonephritis, urinary extravasation and leakage, recurrent ureteropelvic junction (UPJ) obstruction, or stricture formation. Treatment of urinary leakage is centered around catheter drainage, such as nephrostomy, ureteral stent, or perianastomotic drain, to direct urine away from the perianastomotic tissues and to decrease the risk of postoperative stricture disease.

Specific complications from endopyelotomy include significant intraoperative bleeding if the endoscopic incision is made inadvertently into a major polar vessel, postoperative infection, and recurrence of obstruction. If significant intraoperative bleeding is encountered with hypotension, emergency arteriography and embolization are indicated.

Open and laparoscopic pyeloplasty yield long-term success rates that exceed 95%. The success rate for endopyelotomy approaches 80-90%.

The future of treatment of ureteropelvic junction (UPJ) obstruction will certainly include a broadening of the application of laparoscopic techniques. As laparoscopic pyeloplasty has gained acceptance and the surgical experience increased, the procedure has become shorter. The use of robotic assistance may broaden the application of laparoscopy.