URETERIC INJURIES

Ureteric injuries: mechanisms and diagnosis
Types, causes, and mechanisms
- External (rare blunt (e.g. high speed road traffic accidents, fall from a height); penetrating (knife or gunshot wounds)).
- Internal trauma (= iatrogenic) (during pelvic or abdominal surgery e.g. hysterectomy, colectomy, AAA repair; ureteroscopy). The ureter may be divided, ligated, or angulated by a suture; a segment excised or damaged by diathermy.

External injury: diagnosis
Based on a high index of suspicion for the possibility of ureteric injury in the above types of scenarios. Imaging studies: IVU or CT can be used to determine the presence of a ureteric injury. If doubt remains regarding the integrity of the ureters, retrograde ureterography should be done.

Internal (iatrogenic) injury: diagnosis
The injury may be suspected at the time of surgery, but injury may not become apparent until some days or weeks post-operatively.

Intra-operative diagnosis
For ureteric contusions and perforations seen at the time of ureteroscopy, insert a JJ stent. During abdominal or pelvic surgery firstly optimize exposure of the suspected injury site by packing bowel out of the way, controlling bleeding, and ensuring the theatre lights are appropriately positioned. Examine both ureters (bilateral injuries can occur).

Direct inspection of the ureter
A good way of inspecting the ureter for injury, but requires exposure of a considerable length of ureter to establish that it has not been injured. Lower ureteric exposure is more difficult than upper ureteric.

Extravasation after injection of methylene blue into the ureter
Look for leakage of dye from a more distant section of ureter.

On-table IVU
Technically difficult; does not always demonstrate the presence or site of injury.

On-table retrograde ureterography
Via an incision made in the bladder or via a cystoscope. A very accurate method of establishing the presence or absence of a ureteric injury. Both ureters can easily be examined.

Post-operative diagnosis
The diagnosis is usually apparent in the first few days following surgery , but it may be delayed by weeks, months, or years (presentation: flank pain; post-hysterectomy incontinence a continuous leak of urine suggests a ureterovaginal fistula).

Symptoms and signs of ureteric injury
May include:
- an ileus (due to urine within the peritoneal cavity)
- prolonged post-operative fever or overt urinary sepsis
- persistent drainage of fluid from drains, the abdominal wound, or the vagina. Send this for creatinine estimation. Creatinine level higher than that of serum = urine (creatinine level will be at least 300µmol/l)
- flank pain if the ureter has been ligated
- abdominal mass, representing a urinoma (a collection of urine)
- vague abdominal pain
- the pathology report on the organ that has been removed may note the presence of a segment of ureter!

Investigation: IVU or retrograde ureterogram. Ultrasonography may demonstrate hydronephrosis, but hydronephrosis may be absent when urine is leaking from a transected ureter into the retroperitoneum or peritoneal cavity. The IVU usually shows an obstructed ureter or occasionally a contrast leak from the site of injury.