What Are the Main Causes of Ureteral Injuries?

The ureter is a slender tubular organ made of muscle and mucous membranes. It is located in the retroperitoneal space. The surrounding ureter is well protected and has a considerable range of motion. Therefore, ureteral injuries caused by external violence (except for penetrating injuries) are rare; however, ureteral injury is often caused by inspection operations and extensive pelvic surgery in the ureter. When the ureter is injured by external violence, its symptoms are almost completely concealed by the other visceral injuries that accompany it, so it is mostly found during surgical exploration.

Basic Information

English name: injury of ureter
Visiting department: Urology

Common causes: Open surgical injury, intraluminal device injury, radiation injury, trauma, external violence caused by ureteral injury
Common symptoms: Hematuria, extravasation of urine, leakage of urine, pain in lumbar region, throbbing pain, etc.

Causes of ureteral injury

Open surgical injury

It often occurs in pelvic and posterior peritoneal anatomy such as colon, rectum, hysterectomy and large vessel surgery. Due to the complex anatomy, hurried hemostasis, large clamps and ligation caused accidental injury to the ureter; tumors move or adhere to the ureter Posterior peritoneal fibrosis, etc. will make the operation difficult, and it is easier to accidentally hurt. Injuries may not be found during the operation, and may be detected only after urine leakage or anuria occurs.

2. Intraluminal instrument damage

Ureteral ureteral injury can occur through cystoscopic retrograde ureteral intubation, dilatation, holstering, biopsy, ureteral nephroscopy, and stone removal (crushed). When the ureter is narrow, twisted, stuck, or inflamed, the ureter may be torn or even broken, so it must be handled with care.

3. Radioactive damage

Found in cervical cancer, prostate cancer and other radiotherapy, edema, bleeding, necrosis, urinary leakage or fibrous scar tissue formation, causing ureteral obstruction.

4. Traumatic injury caused by external violence

It is more common due to gunshot wounds, occasional sharp stab wounds, and traffic accidents, ureter tears caused by falling from high places, often accompanied by damage to large blood vessels or abdominal organs.

Clinical manifestations of ureteral injury

According to the nature and type of injury, the clinical manifestations are different. If other important organs are injured at the same time, the symptoms of ureteral injury can often be masked.

Hematuria

It is common for the ureteral mucosa to be damaged by instruments. Generally, hematuria will relieve itself and disappear. If the ureter is completely disconnected, urine overflow may not occur. Therefore, the presence or severity of urine after injury is not consistent with the degree of ureteral injury.

2. Urinary extravasation

It can occur at the beginning of the injury, or delayed urinary extravasation due to necrosis of the ureteral wall due to blood supply failure (clamping, suture, or ischemia after adventitial peeling) 4 to 5 days later. Urine leaked from the ureteral injury to the posterior peritoneal space, causing local swelling and pain, abdominal distension, muscle spasm on the affected side, and marked tenderness. If the peritoneum is ruptured, urine can leak into the abdominal cavity and cause peritoneal irritation. Once secondary infections occur, sepsis such as chills and high fever can occur.

3.Urine leak

Such as urine and abdominal wall wounds or vaginal and intestinal wounds connected, the formation of urine leakage, endure.

4. Obstruction symptoms

After the ureter is sutured and ligated, it can cause complete obstruction. Due to the increased pressure of the renal pelvis, there may be pain on the affected side, lumbar muscle tension, pain in the kidney area, and fever. Anemia can occur if the solitary kidney or bilateral ureters are ligated. Those with ureteral stenosis can cause incomplete obstruction, and also produce symptoms such as waist pain and fever.

5. Other

Ligation of the ureter can cause swelling and throbbing pain in the lumbar region of the affected side, and can enlarge the kidney during physical examination. If there is no secondary infection, ligating one side of the ureter may not be neglected with severe symptoms, but patients often lose a kidney due to it. Anuria can occur after solitary kidney or bilateral ureteral ligation. Therefore, those who still have no urine 12 hours after pelvic or abdominal surgery should be alert to the possibility of ureteral injury.

Ureteral injury examination

90% of ureteral damage caused by external violence is microscopic hematuria. Urinary examination and other tests for ureteral damage caused by other causes are of little help in diagnosis. Unless bilateral ureteral obstruction is present, serum creatinine levels are normal.

Intravenous urography

More than 95% of ureteral injuries can be diagnosed by intravenous urography, 50% can locate the level of the ureteral injury site, which can be manifested as complete ureteral obstruction; ureteral distortion or angle; ureteral rupture, perforation, and contrast agent extravasation , The pelvic ureter is dilated above the lesion.

2. Retrograde ureteral intubation and pelvic ureterography

When intravenous pyelography cannot be clearly diagnosed or in doubt, retrograde ureteral intubation and pelvic ureterography should be used to confirm the diagnosis.

3. Ultrasound

Hydrostasis and extravasation can be found, which is a better inspection method to exclude ureteral injury early after surgery.

4.CT inspection

Due to the difference in the location and nature of the injury, CT manifestations are different. Contrast leakage is often caused by ureteral rupture caused by pelvic surgery. CT scans have high density of ascites.

5. Indigo rouge intravenous injection test

When ureteral damage is suspected during surgery, indigo rouge is injected intravenously, and blue urine will flow out of the ureteral fissure. During the operation or postoperative cystoscopy and indigo rouge intravenous injection, if there is no blue urine ejected from the ureteral orifice on the injured side, ureteral intubation to the injured site is blocked, which mostly indicates ureteral obstruction.

6. Beautiful blue test

Injecting melanin solution through the catheter can identify ureteral fistula and bladder fistula. If the fluid flowing from the bladder or vaginal wound is still clear, bladder fistula can be ruled out.

7. Excretory urography and computed tomography

Both can show urinary extravasation, urinary leakage or obstruction at the ureteral lesion, and retrograde pyelography can show obstruction or contrast agent extravasation.

8. Radionuclide renal imaging

Can show the upper urinary tract obstruction on the ligation side.

Diagnosis of ureteral injury

When performing abdominal surgery, especially retroperitoneal and pelvic surgery, be aware of the possibility of ureteral injury. The possibility of ureter should be considered when suture and cut the tubular tissue during surgery. During the operation, it was found that blood and water samples accumulated continuously in the wound. When indigo rouge was injected intravenously, the presence of blue fluid accumulation in the wound was observed, so that ureteral damage could be detected early. This diagnosis is only considered when trauma or postoperative is often due to extravasation of urine or anuria. But it needs to be distinguished from kidney and bladder damage. Nephrograms often show upper urinary tract obstruction on the ligated side. Excretory urography or retrograde ureterography can often make a clear diagnosis.

Ureteral injury treatment

When the ureter is damaged, it should be repaired as soon as possible to ensure patency and protect kidney function. Urinary extravasation should be completely drained to avoid secondary infection. For mild ureteral mucosal injury, hemostatic drugs and antibacterial drugs can be used for treatment, and the changes of symptoms can be closely observed. Small perforations are expected to heal themselves if they can be inserted and retained in a suitable ureteral stent tube.
The upper ureteral injury can be explored through a lumbar incision, and the middle and lower ureteral injuries can be explored through a curved lower incision on the injured side or a rectus abdominis incision. When exploring, it should be noted that the middle and lower ureters are often pushed forward with the peritoneum, making searching difficult.

Ureteral trauma

If there is serious injury to other organs and the patient is in critical condition, the patient's life should be rescued first. The extravasated urine can be completely drained, and the injured side nephrostomy can be performed for the second-stage repair of ureteral injury.

2. Ureteral injury caused by retrograde intubation

It is generally not severe and can be treated conservatively. However, if extravasation of urine, infection, or large gaps occur, surgery should be performed as soon as possible. Violence should not be used during the application of the stone. For example, if the stone basket is used to trap the stone, the stone can be pulled out immediately. Violent traction can cause ureter rupture and exfoliation, making repair difficult.

3. Ureteral injury during surgery

It should be repaired in time. If there are clamps or ligatures, the sutures should be removed, and the ureteral stent tube should be left to drain urine. However, if it is estimated that the ureteral blood supply has been damaged, the ureter should be removed and re-anastomized if there is a possibility of stenosis in the future. In order to ensure the success of the operation, the ureteral injury should be completely removed. But the anastomosis must be tension-free. The anastomosis must be aligned and sutured intermittently with absorbable sutures. The lower ureter near the bladder can be anastomosed with the bladder by anti-reflux methods such as the submucosal tunnel method or the nipple method.

If ureteral injury or ligation is found only after surgery, in principle, early surgery should be sought. Postoperative patients often do not have the conditions for reoperation and urine leakage often occurs about 10 days after surgery. At this time, the wound is edema, congestion is fragile, and the chance of failure to repair is greater. Therefore, those who have no surgical repair conditions can make nephrostomy first, and then repair it in two stages. In order to prevent accidental ureteral injury during the operation, the ureteral catheter can be placed in the bladder before the operation as a sign of the operation. The intestinal replacement of the ureter has more complications and should be used with caution.