What is the next step in management when intussuscepted mucosa is seen attached to the basket and semi-rigid ureteroscope (ureteroscope) during basket extraction of a midureteral stone, with no guidewire access and inability to cannulate the ureteral orifice?

Management of Intussuscepted Ureteral Mucosa During Basket Extraction of Midureteral Stone

Percutaneous nephrostomy tube (PCNT) placement is the most appropriate next step when intussuscepted mucosa is attached to the basket and semi-rigid ureteroscope during stone extraction, with no guidewire access and inability to cannulate the ureteral orifice. 1

Rationale for PCNT Placement

When faced with this urological emergency, the decision-making process should follow these considerations:

1. Urgent decompression required: With intussuscepted mucosa and inability to access the ureter from below, the collecting system remains obstructed and requires immediate drainage to prevent renal damage.

2. Antegrade access necessary: Since retrograde access is impossible (ureteral orifice cannot be cannulated), an antegrade approach via percutaneous nephrostomy is the only viable option for immediate decompression 1.

3. Technical feasibility: PCN placement has a high technical success rate (>95%) when accessing dilated collecting systems, making it a reliable intervention in this emergency scenario 1.

Management Algorithm

Immediate Steps:

1. Percutaneous nephrostomy tube placement under ultrasound and fluoroscopic guidance to decompress the collecting system 1, 2
2. Obtain appropriate imaging (CT urography) to assess the extent of ureteral injury
3. Administer antibiotics if signs of infection are present

Secondary Management (After Decompression):

• If partial ureteral injury: Consider antegrade stent placement via the nephrostomy tract
• If complete ureteral injury: Surgical repair will be required after initial stabilization

Technical Considerations for PCNT

• Use ultrasound for initial renal access followed by fluoroscopy for nephrostomy tube placement 1
• Select appropriate nephrostomy tube size (typically 8.5F-10F Cope loop for initial drainage) 3
• Ensure proper tube fixation to prevent dislodgement 4

Alternative Options and Why They're Not First-Line

1. Antegrade nephroureteral stent placement (Option B): While this may be considered as a secondary procedure, it requires initial PCN placement first, making PCNT the immediate priority 1.

2. Primary ureteroureterostomy (Option C): This surgical repair is not appropriate as an emergency first step before decompression and complete evaluation of the injury 1.

3. Ureteroneocystostomy with Boari flap (Option D): This complex reconstruction is reserved for definitive management of distal ureteral injuries after initial stabilization and complete assessment 1.

4. Ileal interposition (Option E): This is a last-resort option for extensive ureteral loss and not appropriate as an initial management step 1.

Pitfalls to Avoid

• Delaying decompression: Attempting complex reconstructive procedures before establishing drainage can lead to worsened renal function and increased morbidity 2.

• Inadequate imaging: Failure to properly assess the extent of ureteral injury after initial decompression can lead to inappropriate definitive management 1.

• Inappropriate nephrostomy placement: Emergently placed nephrostomy tubes are often not ideal for subsequent percutaneous endoscopic procedures, with only 22% being sufficient without need for additional access during definitive treatment 5.

In conclusion, when faced with intussuscepted ureteral mucosa during basket extraction with no retrograde access, percutaneous nephrostomy tube placement represents the safest and most effective initial management strategy to ensure renal preservation while allowing time for complete assessment and planning of definitive treatment.