What are the indications for endopyelotomy (endoscopic procedure to treat ureteropelvic junction obstruction)?

Indications for Endopyelotomy

Endopyelotomy is indicated as first-line treatment for patients with intrinsic ureteropelvic junction obstruction (UPJO) without complicating factors such as crossing vessels, extremely distended renal pelvis, or long strictures. 1

Primary Indications

• Primary ureteropelvic junction obstruction (intrinsic stenosis)
• Failed previous pyeloplasty (secondary UPJO)
• Patients with preoperative pyelocaliceal volume less than 50 ml

Contraindications and Poor Prognostic Factors

• Presence of crossing vessels (identified on imaging)
• Extremely distended renal pelvis (>50 ml volume)
• Long strictures (>2.5 cm)
• Severe hydronephrosis (grade III/IV)
• Poor preoperative renal function
• Secondary UPJO (lower success rates compared to primary)

Patient Selection and Evaluation

• Complete imaging workup is essential before considering endopyelotomy:
  • CT urogram with 10-minute delayed images (gold standard, 97% sensitivity) 2
  • Magnetic resonance cholangiopancreatography (MRCP) 3
  • Color duplex sonography (to identify crossing vessels)
  • Diuretic renography (to assess renal function and degree of obstruction)
  • Retrograde ureteropyelography (to define anatomy)

Approaches to Endopyelotomy

Three main approaches can be used for endopyelotomy 3:

1. Antegrade percutaneous approach - requires percutaneous nephrostomy access
2. Retrograde ureteroscopic approach - using rigid or flexible ureteroscope
3. Acucise balloon catheter technique - fluoroscopically guided

Success Rates and Outcomes

• Overall success rates range from 80-90% for properly selected patients 4
• Success factors:
  • Preoperative pyelocaliceal volume <50 ml (87% success) vs >50 ml (76% success) 4
  • Primary UPJO has better outcomes than secondary UPJO
  • Absence of crossing vessels (crossing vessels identified in 60% of failed cases) 4

Advantages Over Open Surgery

• Less invasive with shorter recovery time (15.7 days vs 17.8 days for laparoscopic pyeloplasty) 1
• Shorter operative time (1.2 hours vs 3.5 hours for laparoscopic approach) 1
• Similar analgesic requirements and hospital stay compared to laparoscopic approach
• Does not compromise subsequent open surgery if endopyelotomy fails 4

When to Consider Alternative Approaches

• Laparoscopic dismembered pyeloplasty should be considered for:
  • Patients with crossing vessels
  • Extremely distended renal pelvis
  • Long strictures (>2.5 cm) 1
  • Failed endopyelotomy

Technique Considerations

• Endoluminal ultrasound guidance improves outcomes by:
  • Identifying crossing vessels (present in 31% of cases)
  • Guiding the site of incision
  • Identifying high insertion septa (15.5% of cases) 5
• Stent placement for 6-10 weeks post-procedure is standard practice 5

Complications

• Generally low morbidity with minimal blood loss (average 150-152 ml) 1
• No transfusions typically required
• Low risk of ureteral stricture formation
• Failure rates higher when vessels are present near the UPJ 5

Endopyelotomy offers a minimally invasive alternative to traditional open pyeloplasty with good success rates in properly selected patients. The key to successful outcomes lies in appropriate patient selection through comprehensive imaging to rule out extrinsic causes of obstruction, particularly crossing vessels.