What is the management for an extra renal pelvis with a proximal ureter kink?

Management of Extra Renal Pelvis with Proximal Ureter Kink

Initial observation is appropriate for stable patients with an extra renal pelvis and proximal ureter kink if there is no significant obstruction, infection, or progressive renal function deterioration, but intervention is warranted when complications develop. 1

Initial Assessment and Conservative Management

Observation without immediate intervention is the preferred initial approach for stable, asymptomatic patients. 1 The AUA Urotrauma Guidelines specifically state that parenchymal collecting system injuries often resolve spontaneously, and a period of observation is advocated in stable patients where renal pelvis or proximal ureteral injury is not suspected. 1

Key Diagnostic Considerations

• Distinguish true obstruction from anatomical variant: An extra renal pelvis is an anatomical variant that appears as a large hypoechoic mass outside the renal sinus and can mimic hydronephrosis. 2 Unlike true hydronephrosis, it is not associated with dilated calyces, parenchymal thinning, hydroureter, or kidney enlargement. 2

• Assess for functional obstruction: A redundant pelvis resulting in a kink at the ureteropelvic junction may contribute to urinary stasis and potential complications. 3 This anatomical configuration can lead to functional obstruction even without intrinsic stenosis. 3

• Evaluate renal function: Perform baseline assessment of differential renal function to establish whether the kink is causing functionally significant impairment. 4

Indications for Intervention

Prompt intervention is warranted when specific complications develop, even in initially stable patients. 1, 5

Absolute Indications for Drainage

• Obstructive pyelonephritis: Immediate urinary decompression via percutaneous nephrostomy (preferred, 92% survival rate) or retrograde ureteral stenting is mandatory, as antibiotics alone are insufficient and mortality reaches 40% without drainage. 5

• Enlarging urinoma: Urinary drainage should be performed via ureteral stent, potentially augmented by percutaneous nephrostomy or urinoma drain. 1

• Fever, increasing pain, ileus, fistula, or infection: These complications mandate drainage intervention. 1

Relative Indications for Surgical Repair

• Progressive renal function deterioration: Functionally significant impairment warrants consideration of definitive repair. 4

• Recurrent symptomatic episodes: Flank pain, recurrent infections, or stone formation despite conservative management. 4

• Suspected renal pelvis or proximal ureteral avulsion: Large medial urinoma or contrast extravasation on delayed imaging without distal ureteral contrast requires prompt intervention, either endoscopic or open. 1

Management Algorithm

Step 1: Initial Conservative Approach (Stable Patients)

• Observation with clinical monitoring for asymptomatic patients without evidence of obstruction. 1

• Follow-up imaging is not routinely required for uncomplicated cases but should be performed if complications are suspected (fever, worsening flank pain, ongoing symptoms). 1

Step 2: Endoscopic/Percutaneous Intervention (Complications Present)

• Retrograde ureteral stenting: First-line for incomplete injuries or functional obstruction when retrograde access is feasible. 1, 5

• Percutaneous nephrostomy: Preferred when retrograde stenting fails, is not possible, or in cases of obstructive pyelonephritis (95.2% clinical cure rate vs 86.4% with stenting). 1, 5

• Combined approach: Ureteral stent may be augmented by percutaneous nephrostomy or urinoma drain when single modality is insufficient. 1

Step 3: Definitive Surgical Repair (Failed Conservative/Endoscopic Management)

Dismembered pyeloplasty is the gold standard for definitive repair of ureteropelvic junction obstruction with redundant pelvis and kinking. 3, 4

• Surgical approach: Identify the ureter below the area of pathology and ensure tension-free anastomosis. 3 Dense scar tissue around the ureteropelvic junction is commonly encountered. 3

• Alternative technique: Ureterocalicostomy is indicated when inadequate ureteral length or intrarenal pelvis precludes direct anastomosis. 3, 6

• Intraoperative adjuncts: Place nephrostomy tube in all cases and consider transanastomotic stent for optimal outcomes. 3

• Minimally invasive options: Laparoscopic and robotic techniques are now considered gold standard for surgical intervention in patients requiring definitive repair. 4

Critical Pitfalls to Avoid

• Do not confuse extra renal pelvis with hydronephrosis on imaging: This anatomical variant does not automatically require intervention. 2

• Do not delay drainage in obstructive pyelonephritis: The obstructed collecting system must be drained emergently, as compromised antibiotic delivery mandates drainage for infection resolution. 5

• Do not perform blind catheterization: Always obtain imaging before instrumentation in suspected urinary tract injury or obstruction. 7

• Do not assume all redundant pelves require surgery: Many resolve spontaneously with observation alone. 1

• Ensure adequate preoperative imaging: Before surgical repair, anatomy should be precisely identified by antegrade and retrograde studies to plan the optimal approach. 3