What is Ureteral Injury?
In simple terms, damage to the ureter, which is the tube that carries urine from the kidneys to the bladder, doesn’t happen often. The most common reason this injury occurs is due to unintentional damage during a surgical operation, whether it be an open surgery, laparoscopic, or an endoscopic procedure. Injuries to the ureter that are not caused by surgery are mostly due to penetrating injuries.
These injuries are often not very obvious, so doctors need to be extra cautious and alert. If such damage isn’t identified or is mishandled, it can create serious problems. These concerns can include an accumulation of urine in an abnormal location (urinoma), the formation of pus-filled pockets (abscess), narrowing of the ureter tube (ureteral stricture), loss of function or complete removal of the kidney on the injured side (ipsilateral kidney), or even death.
What Causes Ureteral Injury?
The most common source of ureter damage, which is a tube that carries urine from your kidneys to your bladder, is accidental injury during surgeries such as open surgery, laparoscopy, or endoscopic procedures. This could happen due to a variety of reasons, for instance stitches accidently being too tight around the ureter, a cut or tear, a violent pull, lack of blood supply, or too much heat energy.
Injuries to the ureter are quite rare, making up less than 1% of all injuries to the urinary and reproductive organs that can occur as a result of blunt force or sharp objects. Gunshot wounds are a common source of such injuries and they typically affect the upper part of the ureter, closer to the kidneys.
These injuries can be grouped based on where they occur:
– At the point where the ureter joins to the kidney, known as the Ureteropelvic junction (UPJ).
– The part of the ureter in the abdomen which extends from the UPJ to the large blood vessels in the lower abdomen, known as the iliac vessels.
– The portion of the ureter below the iliac vessels in the pelvis.
They can also be classified by when they are diagnosed, either immediately following injury or after some delay following surgery.
The American Association for the Surgery of Trauma (AAST) grades the severity of ureter injuries in the following way:
– Grade I: A bruise or blood clot forms without loss of blood supply.
– Grade II: Less than half of the ureter is cut or torn.
– Grade III: Half or more of the ureter is cut or torn.
– Grade IV: The entire ureter is cut or torn, with less than 2 cm missing or lacking blood supply.
– Grade V: The entire ureter is cut or torn, with more than 2 cm missing or lacking blood supply.
Risk Factors and Frequency for Ureteral Injury
Ureter damage, which is damage to the tube that carries urine from the kidneys to the bladder, is relatively rare after an external physical injury. It is seen in less than 4% of cases involving penetrating trauma, such as gunshot wounds and in less than 1% of all cases of blunt trauma. Patients who do sustain ureter damage from gunshot wounds often have other significant injuries and have a high risk of death.
Damages to the ureter can also happen during surgery. The rate of such injuries can be anywhere from 0.5% to 10%. From 13 studies, the following procedures were found to contribute to damage:
- Hysterectomy (surgical removal of the uterus) – 54%
- Colorectal surgery (surgery on the colon or rectum) – 14%
- Pelvic procedures such as ovarian tumor removal – 8%
- Surgery to secure the ureter in place (transabdominal urethropexy) – 8%
- Abdominal vascular surgery (surgery on the blood vessels in the abdomen) – 6%
A review of cases over a 16 year period found that most of the ureter damages during surgery happened during gynecological surgeries (55%). The rest occurred during urological procedures (25%), colorectal procedures (15%), and vascular procedures (5%).
The chance of damaging the ureter is usually lower when the surgical procedure is done laparoscopically. This means that surgery is performed through small incisions using a special camera and instruments. In one study, for over 90,000 large intestine removal surgeries (colectomies), the rate of ureter damage was 0.54% for laparoscopic surgery compared to 0.66% for traditional open surgery.
Signs and Symptoms of Ureteral Injury
Identifying a ureteral injury (damage to the tubes in your body that carry urine from your kidneys to your bladder) quickly can be challenging. So, if you’re going through a procedure that has a higher chance of causing this injury, or if you’ve had a traumatic event like a penetrating injury near the ureter or a sudden stop injury, you should be aware of the possibility. Children can also suffer from a certain type of injury called a UPJ avulsion because their spines are more flexible, which allows for extreme bending that can cause this injury.
If there’s a delay in diagnosing a ureteral injury, you might experience continuous pain in your side or abdomen, a lump in your side, persistent constipation, a urinary tract infection, kidney swelling, or increased levels of creatinine and BUN (measures of kidney function) in your blood. Another warning sign might be if you have high fluid output from an abdominal drain after surgery. Although blood in your urine might suggest a ureteral injury, not having blood in your urine doesn’t mean you don’t have one. Plus, blood in the urine isn’t always an accurate indicator of this kind of injury.
Testing for Ureteral Injury
In cases where you have a surgical drain, your doctor may take some fluid from it to test for ‘spot creatinine’. If the fluid is urine, this chemical will typically appear within a range of 25-450 mg/dL. If the fluid is not urine, the spot creatinine will be similar to what’s in your blood. In order to check how well your kidneys are functioning, your doctor may order a basic metabolic panel. An elevated BUN/creatinine reading can indicate an issue with your kidney’s urination system, meaning it’s not removing toxins correctly.
Imaging studies are vital tools for doctors to check for damage to the ureter, the tube that carries urine from the kidneys to the bladder. A retrograde pyelogram (RPG), a type of X-ray examination, is the most accurate to determine where and how severe the ureteral damage may be. Antegrade pyelogram is another helpful imaging test if the patient already has antegrade access. A CT scan (‘CT urogram’) of the abdomen and pelvis with Intravenous contrast and delayed images can be utilized to identify any injury to the ureter accurately.
Other signs of damage to the ureter or renal pelvis that a CT scan might highlight include ‘perinephric stranding’ (swelling around the kidneys), fluid buildup around the kidney and ureters, blood clotting around the kidneys (perinephric hematoma), abnormal swelling or movement of the ureter, and difficulty visualizing the entire ureter. If a CT scan isn’t conclusive and the doctor suspects ureteral injury, they will likely order an RPG.
The most foolproof way to identify damage to the ureter is through direct visualization during surgical exploration, the doctor checks the ureter by moving it and examining the entire wall for bruising, bleeding, or breaks. If the doctor notices urine leakage outside the ureter or the ureter appears cloudy, discolored, or lacking blood supply, they may conclude it’s injured. To aid in this inspection, a dye study using chemicals like indigo carmine or methylene blue can be employed. The dye is either injected directly into the renal pelvis or backward during a procedure known as ‘cystoscopic ureteral catheterization’.
Treatment Options for Ureteral Injury
To help prevent injuries to the ureters (tubes that carry urine from the kidneys to the bladder), during surgeries that occur close to these tubes, doctors sometimes place stents or catheters in the ureters. This is often done in surgeries related to the female reproductive system, the lower part of the large intestine (rectosigmoid), and the large blood vessels in the abdomen (aortoiliac surgeries). This is particularly important if the area to be operated on has been scarred from prior surgeries. However, some controversy exists as to whether these stents actually prevent ureteral injury.
In the event of a ureteral injury, several principles are vital for successful repair. Firstly, all damaged tissue must be cleaned out. The ureter needs to be mobilized enough to allow a stress-free reconnection (anastomosis). It’s also key to maintain the outer layer and blood supply of the ureter to ensure adequate blood flow. The ends of the ureter should be opened up in a manner like a fishtail (spatulated). A watertight, tension-free, lining-to-lining (mucosa-to-mucosa) join should be created over a ureteral stent using a suture that gets absorbed by the body over time.
The type of repair depends on where the injury is on the ureter and when it was identified. If the injury is mild to moderate, doctors might place a ureteral stent and allow the ureter to heal over the stent. If the injury is to the upper or middle ureter, direct ureteroureterostomy (UU) or transureteroureterostomy (TUU) could be considered. If the injury is to the lower ureter, ureteral reimplantation (ureteroneocystostomy), a psoas hitch, or a boari flap might be considered.
UU involves directly reconnecting the injured ureter and is most suitable for short ureteral injuries. It’s often the preferred repair for the abdominal ureter if a tension-free anastomosis can be created. TUU involves joining the injured ureter to the ureter on the opposite side in an end-to-end fashion. This method can be used when a psoas hitch or a Boari flap can’t be carried out. Ureteral reimplantation involves reconnecting the ureter directly to the bladder and is useful for injuries to the pelvic part of the ureter. A psoas hitch is a technique in which the dome of the bladder is pulled upwards and stitched to the psoas tendon. A Boari flap is a technique in which a flap of bladder is rotated upwards and joined into a tubular shape. Both techniques are useful if there is an injury to the distal ureter, creating too great of a distance between the healthy ureter and the bladder.
If ureteral injury is detected immediately, it can usually be managed with the placement of a ureteral stent for 4 to 6 weeks. Major pelvic ureteral injuries can be managed with distal ureter ligation and reimplantation into the bladder. This may require a psoas hitch and/or Boari flap. Major abdominal ureteral injuries can be repaired using various techniques. If the patient is unstable, temporary measures like placing a percutaneous nephrostomy tube can be done.
When a ureteral injury is detected after a delay, scarring (stricture) often develops. Medical experts suggest that if a ureteral injury is detected within 72 hours after a surgery, it should be immediately repaired. If discovered after three days, a ureteral stent or a percutaneous nephrostomy tube should be placed, with definitive repair delayed until six weeks after the injury. If there is a collection of urine that has leaked outside the ureter or bladder (urinoma), a drain should be inserted. A complete imaging of the ureteral defect should be obtained. Repairs can be performed using an open surgical approach, keyhole surgery (laparoscopically), or with the help of a robot.
What else can Ureteral Injury be?
If a bladder injury is unnoticed, urine might leak into the space behind the abdomen, causing symptoms similar to those of a ureter (the tube that carries urine from the kidneys to the bladder) injury. The common treatment is to use a Foley catheter, which is a tube inserted into the bladder to drain urine, for a week to ten days. After this, a cystogram (an X-ray of the bladder) should be done to ensure the bladder has healed.
A lymphocele, a collection of lymph fluid, could also cause pain in the side of the body. Normally, this doesn’t need any treatment, but if it becomes extremely painful or gets infected, a drain might need to be placed by a specialist in interventional radiology – a field of medicine that uses imaging and minimally invasive procedures for diagnoses and treatments.
A hematoma, a collection of blood outside of blood vessels, can also cause pain in the side of the body. This condition is generally managed with non-invasive treatment such as rest and pain relievers.
Ureteral fistulae, abnormal connections between the ureter and another part of the body, can also appear in females. If it connects with the vagina, it can result in persistent urinary incontinence, or the inability to control urination. Its treatment is the same as that for a ureteral injury.
What to expect with Ureteral Injury
If detected quickly, patients have a great chance of recovering smoothly as a urologic surgeon can fix the ureter promptly. Early diagnosis is seen as the most important element that affects the chances of recovery. If the diagnosis of the ureteral injury is delayed, there’s a much higher chance of complications. A study found that when the diagnosis was delayed, complications occurred in up to 40% of cases, compared to only 10% of cases where the diagnosis was immediate.
Possible Complications When Diagnosed with Ureteral Injury
Output: If the urine leaks from a damaged ureter, it could result in a urinoma, or a pool of urine within body tissues. Over time, this can lead to an infection or abscess. Spilled urine can also irritate the intestines and the thin tissue that lines the abdomen, which may cause pain and a condition called ileus, where the intestines don’t move food through properly. If the ureter, which is a tube that carries urine from the kidney to the bladder, becomes narrowed and urine can’t be drained, kidney function could be lost and even result in the loss of a kidney. When not detected on time, a hole called a ureterovaginal fistula may form between the ureter and the vagina.
- Urinoma – a pool of urine inside the body
- Infection or abscess
- Intestinal irritation
- Ileus – a condition causing disruption in the movement of food through intestines
- Loss of kidney function
- Loss of a kidney
- Ureterovaginal fistula – a hole between the ureter and the vagina
Recovery from Ureteral Injury
The type of aftercare you’ll need will depend on the specific type of repair operation you’ve had – it will also be influenced by your personal preference. For example, if you’ve had surgery to repair a damaged part of your ureter (the tube that carries urine from your kidney to your bladder) and it has been reattached to your bladder, and if a small surgical cut (cystotomy) has been made on your bladder during the process, you might need to have a catheter (Foley catheter) to help with urination. This is typically left in place for about 7 to 10 days after the surgery.
There’s some difference of opinion on how long a stent (a tube used to keep your ureter open) should be left in. Some experts suggest leaving it for up to 6 weeks, while others recommend removal after just 2 weeks. This decision, however, will be left up to your doctor.
Once the stent is ready to be removed, a Retrograde Pyelogram (RPG – a type of X-ray used to view your urinary tract) can be performed to make sure that your ureter has healed correctly and there is no leakage or narrowing (stenosis). After this, it’s generally recommended that you continue to have ultrasound scans of your kidney to ensure that there’s no narrowing down of your ureter over time (restenosis).