Laboratory Studies
If the ureteral injury is noted intraoperatively, additional laboratory tests are rarely, if ever, needed. If ureteral injury is suspected postoperatively, laboratory tests, including a complete blood cell count (CBC) with manual differential and an electrolyte panel with blood urea nitrogen (BUN) and serum creatinine level, are needed to assess for possible infection and kidney dysfunction.
Creatinine measurement of fluid from a surgically placed pelvic drain, fluid collected from a draining abdominal incision, or fluid from computed tomography– or ultrasound-guided aspiration of an abdominal or pelvic fluid collection may be helpful in distinguishing whether the fluid is urine (elevated creatinine level) or not (creatinine level similar to that of serum).
Imaging Studies
If the ureteral injury is noted intraoperatively and an imaging study is necessary to localize the lesion, the best choice is retrograde ureteropyelography. After placement of a cystoscope in the bladder and cannulation of the affected ureteral orifice with a ureteral catheter, dilute diatrizoate (Cystografin) is injected into the ureter under fluoroscopy or while taking a kidneys, ureters, bladder (KUB) image. If the dye is seen in the renal pelvis without any ureteral extravasation or significant narrowing along the ureter, the ureter is in continuity and the case may be managed conservatively, with either observation or stent placement. If narrowing or extravasation is seen, then appropriate management should be performed as clinically indicated and discussed below.
If ureteral injury is suspected postoperatively, imaging studies evaluating for hydronephrosis, ipsilateral kidney function, and continuity of the ureter are necessary. These imaging studies may include one or more of the following:
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Intravenous urography (IVU)
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Abdominal and pelvic computed tomography (CT) scan with intravenous contrast and delayed images
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Renal ultrasonography
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Retrograde ureteropyelography.
While IVU largely has fallen out of favor, it remains the best imaging study to evaluate for continuity of the ureter in cases of ureteral injury. Unlike renal ultrasonography and a retrograde ureteropyelography, IVU can assess for function of the ipsilateral kidney and the drainage of the ureter in a series of sagittal images. Hydronephrosis, ureteral integrity, and any extravasation can usually be seen readily with IVU. A CT scan can also be used to assess for both function of the ipsilateral kidney and drainage of the ureter. Because CT images are a series of cross sections, visualizing ureteral integrity and continuity is often more difficult with CT scanning than with IVU. However, CT scanning has the advantage of imaging for concomitant conditions at the same time (ie, pelvic fluid collection). Both CT and IVU require administration of IV contrast material and utility may therefore be limited due to elevated serum creatinine.
Renal ultrasonography is a noninvasive method to visualize the kidney and demonstrates hydronephrosis with great sensitivity without the use of radiation or IV contrast. However, renal ultrasonography cannot be used to assess kidney function or the continuity of the ureter and results may be normal despite injury being present. Therefore, if renal ultrasonography is performed, retrograde ureteropyelography is often necessary to evaluate the course and continuity of the ureter.
Other Tests
If one is unsure whether a ureteral injury has occurred intraoperatively, intravenous administration of 10 mL of indigo carmine, methylene blue, or 0.25-1.0 mL of 10% sodium fluorescein with 20 mg of furosemide may help to localize a ureteral injury. Extravasation of blue dye indicates complete or partial ureteral discontinuity.
Postoperatively, if any drainage is noted from the vagina, an attempt should be made to diagnose a ureterovaginal or vesicovaginal fistula. This may be accomplished with a bedside test. For this test, a tablet of oral phenazopyridine (Pyridium) is administered. The bladder is instilled via a catheter with saline that is colored with methylene blue. A vaginal tampon is inserted. Since phenazopyridine turns the urine orange, if an orange liquid is observed on the end of the tampon, a presumptive diagnosis of a ureterovaginal fistula can be made. Alternatively, if the tampon absorbs a blue liquid, the diagnosis of vesicovaginal fistula can be made. However, since both types of fistulas may be present simultaneously, further diagnostic testing is required, such as a retrograde ureteropyelogram or CT urogram.
Diagnostic Procedures
If surgical repair is contraindicated due to sepsis or hemodynamic instability, urinary diversion via percutaneous nephrostomy tube placement should be performed. This allows decompression of an enclosed and potentially infected space and helps to treat a urinary source of sepsis.
Histologic Findings
In very rare cases, ureteral injuries are first diagnosed based on identification of the ureter histologically in the pathologic specimen.
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An illustration of the blood supply to the ureter running within the adventitial layer.
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Relevant anatomy of the ureter, illustrating its course from the renal pelvis to the bladder. Note the ureter's proximity at the pelvic brim to the infundibulopelvic ligament.
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Relevant anatomy of the ureter. Notice the proximity of the ureter to the uterine vessels at the level of the cervix. Most ureteral injuries following gynecologic surgery occur in this area.
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An illustration of the shape and configuration of a Boari flap.
