Iatrogenic ureteral injury with urinoma following laparoscopic hysterectomy: CT diagnosis and follow-up

Clinical History

A perimenopausal woman suffering from menometrorrhagia underwent total abdominal laparoscopic hysterectomy and adnexectomy after preoperative diagnosis of large (12 cm) uterine leiomyoma, and was discharged on third postoperative day after an uneventful course.
Three days later, she presented to the emergency department with fever (39°C) unresponsive to broad-spectrum antibiotics and pelvic tenderness.

Imaging Findings

Vaginal examination palpated a soft mass, corresponding to a sizeable hypoanechoic collection on ultrasound (Fig. 1), which was interpreted as vaginal stump haematoma by gynaecologists but doubled in volume 72 hours later. Laboratory assays revealed markedly abnormal urinalysis with raised C-reactive protein (329 mg/l). Then, urgent multidetector CT (Fig. 2) depicted a large fluid-attenuation collection cranial to the urinary bladder and vagina, partially opacified in the excretory phase, consistent with urinoma from incomplete right ureteral laceration.
Conservative treatment included ureteral stenting and prolonged catheterization. Two days later, unenhanced CT (Fig. 3) showed minimal size decrease of the urinoma. Meanwhile, pathology revealed an intra-myometrial proliferation consistent with endometrial stromal sarcoma.
One month later, follow-up CT (Fig. 4a, b) showed near-complete resolution of the urinoma, ipsilateral development of abnormal nephrographic appearance and of enhancing urothelial thickening suggesting pyeloureteritis and pyelonephritis. With the ureteral stent still in place, further CT follow-up at 2 months (Fig. 4c, d) showed progression of infectious reno-ureteral changes.

Discussion

Iatrogenic urinary tract injuries represent well-known, potentially dangerous complications after gynaecologic operations. Despite technical advancements and surgeons’ experience, postoperative complications are reported after 0.2-1.6% of all gynaecologic surgeries and may lead to medico-legal suits. Acute urologic complications may occur during open or laparoscopic surgery for either benign or malignant disease, with the highest incidence after open (2.78%) and laparoscopic (3-6.2%) radical hysterectomy (RH). Other risk factors include advanced malignancy, diabetes, obesity, and abnormal pelvic configuration by tumour, adhesions, previous surgery or irradiation [1-6].
The urinary bladder is the most commonly injured organ (60-70% of cases), followed by the ureter (24-30% of cases). Whereas bladder injuries are most commonly detected and repaired intraoperatively, iatrogenic ureteral injuries (IUI) are increasing (0.2-0.4% of patients) after the widespread use of laparoscopy, and are diagnosed late (1 week to 1 month) in almost two-thirds of cases. Most IUI during hysterectomy occur either at the pelvic brim near the infundibulopelvic ligament or along the pelvic side wall where the ureter crosses the uterine artery. Prophylactic ureteral stenting may be beneficial in patients with adhesions or previous pelvic surgery [1-8].
Presentation of IUI typically includes pelvic or flank pain and tenderness, ileus, fever, worsening renal function and abnormal urinalysis days to weeks after surgery [3, 6].
As this case demonstrates, CT imaging plays a key role in elucidating postoperative complications, and delayed imaging (5-20 minutes after intravenous contrast) should be done in every patient after gynaecologic surgery. IUI involve the left and right ureter with similar frequency, at the lower third in the majority (80-90%) of patients. CT findings in IUI may include lumen discontinuity, urine extravasation or both, sometimes ureteral obstruction from ligation. Urinomas are fluid-attenuation (0-20 Hounsfield Units, HU) collections with enhancement on excretory phase acquisitions corresponding to urine leak. Opacification is inhomogeneous in larger lesions, denser close to the leaking source, and progressive on repeated delayed imaging. Visualization of level, entity and length of IUI is crucial for correct therapeutic planning. Ureteral opacification distal to the injury site is preserved in partial lacerations, absent with complete transection. In patients with bladder catheter, suspected urinoma from small bladder fistulas may be confirmed using CT-cystography [6, 9-12].
Unrecognized urinomas are associated with increased morbidity from superinfection or renal function deterioration. Postoperatively detected IUI may be treated conservatively with nephrostomy, ureteral stenting or percutaneous drainage, or otherwise require surgical repair with end-to-end anastomosis or uretero-neocystostomy [3, 7, 9-11].

Differential Diagnosis List

Final Diagnosis

Urinoma from iatrogenic ureteral injury during laparoscopic hysterectomy

URL:	https://eurorad.org/case/12226
DOI:	10.1594/EURORAD/CASE.12226
ISSN:	1563-4086