When should imaging be obtained in a patient with suspected post-surgical complications following a right ureteronephrectomy?

Imaging for Suspected Post-Surgical Complications Following Right Ureteronephrectomy

CT scan with IV contrast and delayed imaging (urogram) should be performed for patients with suspected post-surgical complications following a right ureteronephrectomy. 1

Clinical Indications for Imaging

Imaging should be obtained when patients present with signs and symptoms suggestive of post-surgical complications, including:

• Fever
• Worsening flank pain
• Increasing abdominal pain
• Ileus
• Signs of infection
• Abdominal distention
• Ongoing blood loss
• Development of fistula 1

Imaging Modality Selection Algorithm

First-line Imaging:

• CT scan with IV contrast and delayed (urographic) phase - This is the gold standard for evaluating suspected complications after ureteronephrectomy 1
  • The delayed phase (5-10 minutes) is essential to evaluate for urinary extravasation and urinoma formation
  • Allows visualization of contrast extravasation, fluid collections, and vascular complications

Alternative Imaging Options:

• Intravenous urography (IVU) - May be used when CT is not available or in low-resource settings 1

  • Note that IVU has a high false-negative rate (37-75%) 1

• Ultrasound - Generally not recommended as the primary diagnostic tool for post-surgical complications 1

  • May be used for follow-up of previously identified fluid collections
  • Limited in detecting ureteral injuries or small collections

Specific Complications and Imaging Findings

Urinoma Formation

• CT findings: Fluid collection with density similar to urine, may enhance at periphery with contrast
• May increase in size on follow-up imaging if untreated 1

Vascular Complications

• CT with arterial and venous phases can identify active bleeding, pseudoaneurysms, or arteriovenous fistulas
• Look for contrast extravasation or large perirenal hematoma 1

Ureteral Injury

• CT findings: Contrast extravasation, delayed pyelogram, hydronephrosis, lack of contrast in the distal ureter 1
• Particularly important after right ureteronephrectomy to evaluate the contralateral ureter

Management Based on Imaging Findings

If imaging demonstrates complications such as enlarging urinoma, drainage should be achieved via:

• Ureteral stent (primary approach)
• May be augmented by percutaneous urinoma drain or percutaneous nephrostomy 1

Follow-up Imaging

• Routine follow-up imaging is not recommended for uncomplicated cases 1
• Follow-up imaging should be performed if:
  • Initial imaging shows a significant complication requiring intervention
  • Patient develops new or worsening symptoms
  • To evaluate response to intervention 1, 2

Common Pitfalls

• Relying solely on the presence of pain to determine need for imaging - silent obstruction can occur in up to 2.9% of patients after urological procedures 2
• Failing to include delayed imaging phase - may miss urinary extravasation
• Not considering the possibility of injury to the contralateral collecting system
• Delaying imaging in a patient with concerning symptoms - can lead to progressive renal damage 2

Recent evidence suggests that post-procedural imaging changes management in approximately 35.4% of urological cases, with 9.5% requiring additional surgical intervention 3, highlighting the importance of appropriate imaging for suspected complications.