What is the surgical management of Ureteropelvic Junction Obstruction (UPJO)?

Ureteropelvic Junction Obstruction (UPJO): Epidemiology, Pathology, and Surgical Management

Laparoscopic dismembered pyeloplasty (Anderson-Hynes technique) should be the first-line surgical treatment for UPJO due to its high success rate (>90%) and favorable morbidity profile compared to other approaches. 1

Epidemiology

• UPJO is characterized by impaired flow of urine from the renal pelvis to the ureter 2
• It can be congenital (most common) or acquired
• If left untreated, UPJO can lead to progressive renal impairment, making effective management crucial 2

Pathology

UPJO can be classified based on etiology:

1. Intrinsic causes:

   • Aperistaltic segment of ureter
   • Ureteral valves
   • Fibroepithelial polyps
   • High insertion of ureter into renal pelvis

2. Extrinsic causes:

   • Crossing vessels (seen in approximately 50% of cases) 3
   • Adhesions
   • Bands
   • Kinking of ureter

Diagnostic Evaluation

• Diuretic renogram (MAG3 preferred over DTPA): Evaluates split renal function, urinary tract drainage, and T1/2 of time activity curve (T1/2 >20 minutes indicates obstruction) 1
• CT scan with contrast and delayed images: Essential for accurate assessment of anatomy and degree of obstruction 1
• Color duplex sonography and spiral CT: Helpful in cases of ureteral kinking to identify crossing vessels 4

Indications for Surgical Intervention

• Worsening drainage on serial imaging
• Decreased renal function (<40% differential renal function)
• Deteriorating function (>5% change on consecutive renal scans)
• Symptomatic obstruction (pain, recurrent infections) 1

Surgical Management

First-Line Treatment

• Laparoscopic dismembered pyeloplasty (Anderson-Hynes technique) is the preferred approach for:

  • Cases with crossing vessels
  • Extremely distended renal pelvis
  • Long strictures
  • Failed previous repairs 1

  Success rates approach 94-100% with minimal complications (6.3%) 5, 4

Alternative Surgical Approaches

1. Endopyelotomy:

   • Best suited for intrinsic stenosis only
   • Success rates of 72.6-92.8% for intrinsic stenosis but only 51.4% for extrinsic causes 5, 4
   • Advantages: Shorter operative time (average 34 minutes vs. 124 minutes for laparoscopic pyeloplasty), less invasive 5
   • Disadvantages: Lower overall success rate compared to pyeloplasty

2. Open pyeloplasty:

   • Traditional gold standard with success rates >90%
   • Should not be first-line for most patients unless specific anatomical abnormalities require complex reconstruction 1
   • Higher morbidity due to muscle incision 3

3. Robot-assisted pyeloplasty:

   • Similar success rates to laparoscopic approach (>90%)
   • Advantages include improved suturing capability and shorter learning curve 2

4. Special anatomical considerations:

   • For pelvic kidneys or giant hydronephrosis: Pyelovesicostomy or calicovesicostomy 6
   • For intrarenal pelvis: Ureterocalicostomy 6
   • For crossed fused ectopia: Specialized approaches like ureteropyelostomy 6

Perioperative and Postoperative Care

Perioperative Care

• Safety guidewire should be used during endoscopic procedures
• Antimicrobial prophylaxis should be administered prior to intervention 1

Postoperative Care and Follow-up

• Diuretic renogram at 3-6 months post-procedure to assess renal function and degree of obstruction
• Ultrasound to assess for resolution of hydronephrosis
• Monitoring for symptom resolution 1

Complications

• Urine leakage (rare)
• Anastomotic re-stricture (uncommon)
• Bleeding (minimal with laparoscopic approach, average 96-150 mL) 3
• Infection

Conclusion

While multiple surgical options exist for UPJO, laparoscopic dismembered pyeloplasty offers the best combination of high success rate and minimal morbidity. The surgical approach should be selected based on the cause of obstruction (intrinsic vs. extrinsic), anatomical considerations, and surgeon expertise.