Iatrogenic Ureteral Injury: Pathophysiology, Imaging, and Management — A Comprehensive Review for Urology and Radiology

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Introduction

Iatrogenic ureteral injury is a critical complication that may arise during endourologic or pelvic procedures. While relatively uncommon, its consequences can be severe, including persistent urinary leak, infection, stricture formation, and renal impairment. This article provides a comprehensive, evidence-based review of the condition, integrating the latest insights from international literature, case analysis, and imaging findings.

We will review pathophysiology, epidemiology, clinical presentation, imaging features, treatment strategies, and prognosis. 

Case Presentation

A 19-year-old male presented with left flank pain seven days after ureteroscopic stone removal.

Initial Imaging:

[Figure 1] Axial non-contrast CT: Demonstrated perinephric and retroperitoneal fluid collection of low attenuation (~8 HU).


[Figure 2] Coronal non-contrast CT: Showed subtle hydronephrosis and fluid tracking along the left ureter.

Follow-up Imaging:

[Figure 3] 30-min delayed KUB radiograph after CT: Showed contrast extravasation in the retroperitoneum.


[Figure 4] Retrograde pyelogram: Confirmed contrast leak at the distal ureter with ureteral laceration. A guidewire traversed the defect.

Diagnosis: Iatrogenic ureteral laceration with urinoma formation.

Pathophysiology

Iatrogenic ureteral injuries typically result from:

  • Direct mechanical trauma (perforation, avulsion, or laceration during ureteroscopy).

  • Ischemic injury from devascularization due to extensive dissection or cauterization.

  • Urinary extravasation leading to urinoma formation, which may extend into the retroperitoneum, psoas compartment, or even intraperitoneal cavity.

  • Persistent leak may cause secondary infection, abscess, or fibrosis leading to stricture formation

Epidemiology

  • Occurs in 0.5–1% of urologic, retroperitoneal, or gynecologic surgeries.

  • Most frequently associated with ureteroscopic lithotripsy and pelvic surgeries.

  • Distal ureter is most vulnerable (80% of cases) due to its proximity to the uterine artery, cervix, and pelvic brim.

  • Delayed recognition is common: approximately two-thirds of patients present after 7–10 days with flank pain, fever, or sepsis rather than intraoperatively.

Clinical Presentation

  • Immediate intraoperative recognition is ideal but rare.

  • Delayed presentation includes:

    • Flank pain

    • Fever, leukocytosis

    • Nausea, vomiting

    • Persistent hematuria

    • Rising creatinine if bilateral or solitary kidney involved.

  • Complications: urinoma, abscess, fistula, peritonitis.

Imaging Features

1. CT Urography

  • Non-contrast CT: reveals perinephric/retroperitoneal fluid (~0–20 HU).

  • Delayed excretory phase: extravasated contrast with HU values rising to 80–200.

  • Hydronephrosis may be seen.

2. Retrograde Pyelography

  • Gold standard for defining laceration site and extent.

  • Demonstrates contrast leak, irregularity, and can guide stent placement.

3. MRI Urography

  • Alternative in contrast allergy or pregnancy.

  • Urinoma appears hypointense on T1 and hyperintense on T2 sequences.

Case Imaging Recap:

  • [Figure 1] Axial non-contrast CT: Perinephric fluid, 8 HU (suggestive of urinoma).

  • [Figure 2] Coronal non-contrast CT: Dilated ureter, perinephric collection.

  • [Figure 3] Delayed KUB: Contrast extravasation into retroperitoneum.

  • [Figure 4] Retrograde pyelogram: Distal ureteral laceration with contrast leak.

Treatment

  • Urinary diversion is the cornerstone.

    • Ureteral stenting (4–8 weeks) allows mucosal healing.

    • Percutaneous nephrostomy may be used if retrograde stenting fails.

  • Adjunctive management: Percutaneous urinoma drainage if large or infected.

  • Definitive repair (reimplantation, ureteroureterostomy, or psoas hitch/Boari flap) if stent fails or stricture develops.

  • Antibiotics are essential if infection is present.

Prognosis

  • With early stent placement, healing rate >80%.

  • Delayed diagnosis increases risk of sepsis, strictures, or nephrectomy.

  • Long-term prognosis depends on timely recognition, adequate diversion, and absence of infection.

Quiz

Q1. What is the most common mechanism of iatrogenic ureteral injury during ureteroscopy?

  • (A) Ischemic necrosis

  • (B) Direct perforation or laceration

  • (C) Radiation-induced fibrosis

  • (D) Congenital weakness
    Answer: (B) Direct perforation or laceration.
    Explanation: Mechanical trauma during instrumentation is the leading cause.

Q2. Which imaging modality is most sensitive for detecting ureteral contrast leak?

  • (A) Ultrasound

  • (B) CT Urography

  • (C) MRI

  • (D) Retrograde Pyelography
    Answer: (D) Retrograde Pyelography.
    Explanation: Direct visualization of contrast leak at the injury site.

Q3. Typical delayed presentation time for iatrogenic ureteral injury is:

  • (A) Immediately post-op

  • (B) 7–10 days post-op

  • (C) 1 month post-op

  • (D) 6 months post-op
    Answer: (B) 7–10 days post-op.
    Explanation: Majority present after a latent period with flank pain/fever.

Q4. What is the mainstay of conservative management?

  • (A) Antibiotics alone

  • (B) Observation only

  • (C) Ureteral stenting ± percutaneous nephrostomy

  • (D) Immediate nephrectomy
    Answer: (C) Ureteral stenting ± nephrostomy.
    Explanation: Provides urinary diversion and promotes healing.

Q5. Which segment of ureter is most commonly injured in pelvic surgery?

  • (A) Upper third

  • (B) Middle third

  • (C) Lower third

  • (D) Entire length equally
    Answer: (C) Lower third.
    Explanation: Due to anatomical proximity to pelvic surgical field.

References

[1] F. N. Burks and R. A. Santucci, “Management of iatrogenic ureteral injury,” Ther Adv Urol., vol. 6, no. 3, pp. 115–124, 2014.
[2] R. L. Titton, D. A. Gervais, P. F. Hahn, M. G. Harisinghani, R. S. Arellano, and P. R. Mueller, “Urine leaks and urinomas: Diagnosis and imaging-guided intervention,” Radiographics, vol. 23, no. 5, pp. 1133–1147, 2003.
[3] V. Romero, H. Akpinar, J. J. Smith, and D. G. Assimos, “Changing patterns in iatrogenic ureteral injuries,” Rev Urol., vol. 13, no. 4, pp. e179–e183, 2011.
[4] S. Selzman and A. Spirnak, “Iatrogenic ureteral injuries: A 20-year experience in treating 165 injuries,” J Urol., vol. 155, no. 3, pp. 878–881, 1996.
[5] M. Brandes, “Management of ureteral injuries: A review of world literature,” Urology, vol. 70, no. 5, pp. 846–853, 2007.
[6] M. Arora, S. Kumar, and A. K. Bansal, “Endourological management of ureteral injuries,” Indian J Urol., vol. 36, no. 1, pp. 12–18, 2020.
[7] M. K. Dyer and T. R. Mellon, “Imaging of ureteral trauma: Techniques and interpretation,” Radiol Clin North Am., vol. 61, no. 1, pp. 151–167, 2023.


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