Ureteral Injury

Ureteral injury is damage to the ureter by direct trauma, surgical injury or instrumentation. It presents with obstruction, urinary leakage (urinoma, fistula) or silent loss of renal function.

Causes:

• Iatrogenic injury accounts for 75 percent. Gynaecological surgery accounts for 50 percent (abdominal and laparoscopic hysterectomy, with 0.2 to 1 percent injury rates). Others are colorectal surgery, vascular surgery, and urological procedures, including ureteroscopy with 1 to 5 percent mucosal injury and 0.5 to 1 percent perforation or avulsion.
• External trauma accounts for about 25 percent. Penetrating trauma is more frequent than blunt, representing less than 3 percent of all urogenital trauma.
• The rest result from radiotherapy and endometriosis.

The ureter is vulnerable at the pelvic brim where it crosses the iliac vessels, in the broad ligament beneath the uterine artery ("water under the bridge"), and near the ureterovesical junction.

Risk factors: pelvic adhesions, endometriosis, large fibroids, malignancy, previous surgery and radiotherapy, congenital anomalies (duplex), bleeding and distorted anatomy.

Grades:

• I: haematoma.
• II: laceration under 50 percent of circumference.
• III: laceration 50 percent or greater.
• IV: complete transection with up to 2 cm devascularisation.
• V: avulsion with more than 2 cm devascularisation.

• Intraoperative recognition (the best scenario): observed injury, extravasation of urine or blue dye, a missing or clipped ureter, and absent efflux on cystoscopy.
• Postoperative (days to weeks): flank or abdominal pain, fever, ileus, abdominal distension, and high drain output with raised creatinine in the drain fluid.
• Also vaginal or wound urine leakage (ureterovaginal fistula, commonly from 1 to 4 weeks after hysterectomy), haematuria, urinoma, and sepsis.
• Anuria with bilateral injury, and rising creatinine.
• Delayed presentation: silent hydronephrosis, stricture, and loss of function; recurrent pyelonephritis.
• Trauma: haematuria in only 50 to 75 percent, and no specific signs. Keep a high index of suspicion in penetrating wounds to the abdomen or flank, and in deceleration injuries (children, ureteropelvic avulsion).

• Intraoperative: inspection and palpation.
• Intravenous indigo carmine (5 mL of 0.8 percent) or methylene blue 5 mL (or oral phenazopyridine preoperatively), or fluorescein 1 mL of 10 percent, with cystoscopy to observe the colour efflux; retrograde pyelography; ureteric catheterisation.
• Postoperative: raised creatinine in drain fluid compared with serum (a ratio above 1).
• CT urography with delayed (excretory) phase shows contrast extravasation, hydronephrosis, and a urinoma. Retrograde pyelography is the most accurate test to define site and degree of injury.
• Trauma: CT with delayed excretory phase (at 5 to 10 minutes).
• In an unstable patient, use on table intravenous pyelogram (a single shot after 2 mL/kg contrast bolus) or exploratory laparotomy with direct inspection.
• Renal ultrasound for hydronephrosis, renography for function, and blood tests.

• Priorities: resuscitation and control of haemorrhage in trauma, drainage of sepsis, and urinary diversion. Timing of repair depends on whether the injury is detected early.
• Contusion or partial laceration, stable: ureteral stenting (double-J stent for 4 to 6 weeks) with a drain and urethral catheter; percutaneous nephrostomy if a stent cannot be placed. Antibiotic cover.
• Immediate intraoperative repair (the best time) with a surgeon experienced in urology:
  • Débride devitalised edges, spatulate the ends, and perform a tension free, watertight anastomosis over a double-J stent with fine absorbable sutures (4-0 to 5-0 polyglactin), with a closed suction drain and omental wrap.
  • Injury in the lower third: ureteroneocystostomy with a psoas hitch (defects up to 5 to 6 cm) or Boari bladder flap (defects 10 to 15 cm) and a stent for 4 to 6 weeks.
  • Mid-ureter: end-to-end ureteroureterostomy for defects shorter than 2 to 3 cm, or transureteroureterostomy for longer defects.
  • Upper ureter with extensive loss: ileal interposition, renal autotransplantation, or a ureterocalicostomy.
  • Nephrectomy if the kidney is unsalvageable or the patient is unstable. In damage control, tie off the ureter with a catheter placement or nephrostomy and delay repair.
• Delayed diagnosis (above 5 to 7 days): initial urinary diversion with percutaneous nephrostomy and, if possible, antegrade stent placement. Treat infection, then delay repair to 6 to 12 weeks (3 months), when oedema and inflammation have settled.
• Ureteral stent trial first in ureterovaginal fistula (success about 50 percent); if unsuccessful, open or robotic ureteroneocystostomy.
• Postoperative: drain output and creatinine check, remove the catheter at 5 to 7 days, and remove the stent at 4 to 6 weeks. Image at 3 months (renal ultrasound, renography) to check for stricture.
• Prevention: identify the ureter at the start of surgery in the retroperitoneum, preoperative stent in complex pelvic surgery, careful haemostasis and dissection near the ureter, and caution with energy devices.
• Complications: stricture (5 to 10 percent), urinoma, sepsis, fistula, loss of renal function and hypertension.