DOI: 10.1148/rg.245035219
RadioGraphics 2004;24:1331-1352
© RSNA, 2004
Fistulas of the Genitourinary Tract: A Radiologic Review1
Nam C. Yu, MD,
Steven S. Raman, MD,
Monica Patel, MD and
Zoran Barbaric, MD
1 From the Department of Radiological Sciences, David Geffen School of Medicine, University of California, 10833 LeConte Ave, Los Angeles, CA 90095-1721. Presented as an education exhibit at the 1999 RSNA scientific assembly. Received November 26, 2003; revision requested January 16, 2004, and received February 24; accepted March 9. All authors have no financial relationships to disclose. Address correspondence to S.S.R. (e-mail: sraman@mednet.ucla.edu).
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Abstract
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Fistulas of the genitourinary tract have diverse anatomic locations, causes, and clinical features. They can involve the upper urinary tract (kidney, ureter), the lower urinary tract (bladder, urethra), or the female reproductive tract (vagina, uterus). Causes include infection, inflammatory disease, neoplasms, congenital conditions, trauma, and iatrogenic injury. Diagnosis of genitourinary tract fistulas usually requires radiologic studies performed with fluoroscopic or cross-sectional modalities. Fistulography is the most direct means of visualizing a fistula and should be considered when feasible (eg, cutaneous fistulas). Intravenous urography and pyelography or ureterography are mainstays of investigation of the upper tract. Likewise, voiding cystourethrography and urethrography are central to study of the lower tract. Cross-sectional techniques, in particular computed tomography, are increasingly useful for diagnosis and are considered the primary test in some cases. Radiologists should be familiar with the radiologic features of genitourinary tract fistulas for accurate diagnosis and treatment planning. Management approaches depend on the type of fistula, the degree of morbidity, and the overall functional status of the patient and vary from conservative observation to aggressive surgical repair.
© RSNA, 2004
Index Terms: Fistula, genitourinary system, 80.245 • Genitourinary system, abnormalities, 80.245 • Genitourinary system, diseases, 80.245 • Genitourinary system, injuries, 80.245 • Urine, extravasation, 80.245
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LEARNING OBJECTIVES FOR TEST 4
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After reading this article and taking the test, the reader will be able to:
- Describe the anatomic locations, causes, and clinical features of genitourinary tract fistulas.
- List the appropriate diagnostic imaging studies for each type of genitourinary tract fistula.
- Identify the radiologic findings in the various types of genitourinary tract fistulas.
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Introduction
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Genitourinary tract fistulas are diverse in clinical presentation, etiology, and morbidity. Abnormal communications may form within the genitourinary system or may involve other organ structures including the gastrointestinal tract, vascular system, lymphatic system, and skin. Radiologists must be familiar with these entities because imaging is critical for diagnosis. Fistulas may also result from complications of interventional radiologic procedures. They may generally be classified into those that involve the upper urinary tract (kidney, ureter), the lower urinary tract (bladder, urethra), and the female reproductive tract (vagina, uterus).
Appropriate diagnostic studies vary depending on the anatomic sites of origin and termination of the fistula. In most cases, several imaging tests may be useful to establish the diagnosis (Table 1). The unique nature of each fistula type defies a convenient algorithmic approach. However, some general observations can be made: (a) Fistulography is the most direct means of visualizing a fistula and should be considered when feasible (eg, cutaneous types). (b) Intravenous urography (IVU) and pyelography or ureterography are mainstays of upper tract investigation. (c) Likewise, voiding cystourethrography (VCUG) and urethrography are central to the study of the lower tract. (d) Cross-sectional techniques, in particular CT, are providing increasingly more diagnostic power and are considered the primary test in some cases.
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Fistulas of the Upper Urinary Tract
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Renal Fistulas
Fistulas involving the kidney may communicate with the bowel, skin, blood vessels, lymphatic vessels, and thoracic cavity (pleura, bronchus) (1). Renal fistulas may be classified into those communicating with the renal collecting system via the parenchyma (reno- or nephro-) and those that communicate with the renal pelvis (pyelo-). In developed countries, fistulas involving the kidney are most commonly caused by iatrogenic trauma, including percutaneous nephrostomy or nephrolithotomy tract placement, extracorporeal shock wave lithotripsy (ESWL), and abdominal surgery. Other causes include radiation, penetrating trauma, and neoplastic invasion. Chronic infections usually associated with staghorn calculi (xanthogranulomatous pyelonephritis) and tuberculosis are now less common causes in the age of advanced antibiotics.
Reno- and Pyelo–Alimentary Tract Fistulas.—
Fistulas between the kidney and alimentary tract most commonly involve the colon, duodenum, and stomach. In a study of 92 fistulas between the kidney and bowel by Bissada et al (2), 59 were colonic, 22 were duodenal, seven were gastric, five were enteric, two were appendiceal, and one was rectal. Patients with chronic pyogenic renal infections (3), chronic renal tuberculosis (4), or necrotic renal neoplasms (5) are at increased risk, although penetrating and iatrogenic trauma are increasingly responsible (6). Adhesions between the duodenum and renal pelvis may predispose to fistula formation in the setting of a chronic infection. Rarely, inflammation or neoplasia within the duodenum or colon may lead to fistula formation with the kidney (2).
Presenting symptoms are usually nonspecific. Patients with renoduodenal fistula may present with malaise, weight loss, and nonspecific upper gastrointestinal symptoms. Flank pain, pyuria, and fever are frequently present. Physical findings include flank tenderness or a flank mass. Renocolic fistulas may manifest in a similar manner, although fecaluria and pneumaturia may occasionally be present. Electrolyte abnormalities such as hyperchloremic acidosis may be present with significant renocolic fistulas secondary to reabsorption of urine within the gut.
Imaging is critical for establishing the diagnosis of reno–alimentary tract fistulas. Parvey et al (7) found that CT was the single most useful diagnostic modality for renocolic fistulas. In three cases, CT demonstrated significant extrarenal inflammation or an abscess extending from the left kidney to the descending colon. Complex material and gas may be present within the renal collecting system. Gas in the kidney or ureter mayalso be visible at plain radiography. Excretory urography may not be useful since the affected kidney is usually nonfunctional. Direct antegrade or retrograde pyelography is more effective due to better opacification and higher pressures capable of demonstrating small or partially occluded tracts (1). Retrograde pyelography may sometimes be ineffective due to obstruction at the ureteropelvic junction. Traditional contrast material gastrointestinal examinations such as upper gastrointestinal series or barium enema study usually fail to demonstrate the tract.
Management of renoalimentary fistula involves treating the underlying cause and may require urinary diversion with percutaneous nephrostomy. For chronic fistulas, however, surgical removal of the nonfunctioning kidney and fistulectomy may be needed, as patients with chronic fistulas are at risk of recurrent abscess or development of squamous cell carcinoma.
Renocutaneous Fistula.—
Renocutaneous fistulas can occur from xanthogranulomatous pyelonephritis or other chronic infections in the native kidney (8,9) and from ischemia to the transplant kidney (10). Penetrating and iatrogenic trauma may be responsible. Patients may present with tenderness and swelling at the involved skin near the flank or lumbar regions. In rare cases, the fistula may track along the psoas muscle, causing a groin or thigh abscess (11). Purulent discharge may be present, and an occasional stone may be delivered at the cutaneous site through the tract. Coexistent communications between the kidney and other structures (alimentary tract, pleura, bronchus) may be present, especially in the setting of actinomycosis.
CT enhanced with intravenous contrast material is probably the best initial examination to demonstrate a soft-tissue tract along the fistula and the extent of inflammation. Single and multi–detector row helical scanners allow volumetric imaging with multiplanar capabilities to aid visualization. Intravenous contrast material may be excreted into the affected calix and cutaneous tract if the surrounding parenchyma is functional (Fig 1). However, a direct sinogram is often necessary as the affected kidney is nonfunctional. The tract may be injected with iodinated contrast material for CT or fluoroscopy (12). MR sinography may be helpful with its multiplanar capability and ability to suppress fat signal.
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Figure 1a. Calicocutaneous fistula as a complication of partial nephrectomy for renal cell carcinoma. (a) CT urogram shows air in the collecting system (arrow) and contrast material extravasating to the incision site (arrowhead). (b) CT urogram obtained at another level shows the fistula (arrowheads) extending outside the kidney through the soft-tissue layers. (c) Nephrostogram also shows the leaking contrast material (arrowhead). Percutaneous nephrostomy was performed to divert the urine to aid healing of the fistula.
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Figure 1b. Calicocutaneous fistula as a complication of partial nephrectomy for renal cell carcinoma. (a) CT urogram shows air in the collecting system (arrow) and contrast material extravasating to the incision site (arrowhead). (b) CT urogram obtained at another level shows the fistula (arrowheads) extending outside the kidney through the soft-tissue layers. (c) Nephrostogram also shows the leaking contrast material (arrowhead). Percutaneous nephrostomy was performed to divert the urine to aid healing of the fistula.
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Figure 1c. Calicocutaneous fistula as a complication of partial nephrectomy for renal cell carcinoma. (a) CT urogram shows air in the collecting system (arrow) and contrast material extravasating to the incision site (arrowhead). (b) CT urogram obtained at another level shows the fistula (arrowheads) extending outside the kidney through the soft-tissue layers. (c) Nephrostogram also shows the leaking contrast material (arrowhead). Percutaneous nephrostomy was performed to divert the urine to aid healing of the fistula.
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Forniceal-Lymphatic Fistula.—
Fistulas between the renal collecting system at the fornix and the lymphatic system have been described (13). The relatively abundant lymphatic drainage surrounding the fornices communicates eventually with the retroperitoneal lymphatic system via the peripelvic system. Parasitic renal or lymphatic infections and renal tuberculosis are leading causes worldwide. Primary parasitic causes include filariasis (Wuchereria bancrofti), echinococcosis, cysticercosis, ascariasis (roundworm), and malaria. In developed countries, retroperitoneal neoplasms, trauma, pregnancy, and developmental anomalies of lymphatic systems must also be considered. Lymphangiography, with or without CT to rule out an associated retroperitoneal mass or lymphadenopathy, is the diagnostic study of choice (14,15) (Fig 2).
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Figure 2a. Lymphaticocalicoforniceal fistulas in two patients with filariasis. (a) Lymphangiogram shows leakage of contrast material, which highlights the calices (arrow). (b) Lymphangiogram shows opacification of the calices and ureter (arrow).
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Figure 2b. Lymphaticocalicoforniceal fistulas in two patients with filariasis. (a) Lymphangiogram shows leakage of contrast material, which highlights the calices (arrow). (b) Lymphangiogram shows opacification of the calices and ureter (arrow).
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Renopleural and Renobronchial Fistulas.—
Renopleural fistula usually results from a large percutaneous nephrostomy tract placed by using the upper pole approach, where the pleural cavity may be traversed (16). Pneumothorax or a fistulous tract may develop on removal of the catheter, especially if obstruction of the ureter persists. Renobronchial fistulas most commonly result from chronic renal infections, perinephric abscess, and, in appropriate epidemiologic settings, tuberculosis and ecchinococcal disease. The affected patient may present with productive cough, a urine-like taste in the mouth, dysuria, fever, and flank pain. Ipsilateral diaphragmatic elevation, pleural effusion, pneumonia, and atelectasis may be seen at plain radiography or CT of the chest. CT of the abdomen may reveal associated renal abnormalities such as staghorn calculus, nonfunctioning kidney, or abscess.
Renovascular Fistula.—
Communication between the collecting system and an artery or vein most often occurs from iatrogenic trauma associated with percutaneous nephrostomy and nephrolithotomy procedures (17). Vessels may be inadvertently punctured during needle insertion or the catheter may erode into adjacent vascular structures, leading to fistula formation. Arteriocaliceal fistula in a transplant kidney following biopsy has been described (18). The presentation may vary from severe hemorrhage to intermittent hematuria. Angiography can be both diagnostic and therapeutic (selective transcatheter embolization) (18,19). In some cases, partial nephrectomy may be necessary.
Ureteral Fistulas
The ureter may form abnormal communications with the intestines, vascular system, skin, and female reproductive tract. The site of termination is often suggestive of the etiology.
Uretero–Alimentary Tract Fistula.—
Fistulas between the ureter and the alimentary tract may involve the duodenum, jejunum, ileum, and colon. Ureterocolic fistulas are most common and can be caused by urinary calculi, iatrogenic trauma, diverticulitis, radiation therapy, transitional cell carcinoma, and tuberculosis (20,21). Ureteroileal fistulas may complicate Crohn disease but may also be caused by iatrogenic or accidental trauma (22,23). Ureteroduodenal fistulas are extremely rare, with only about a dozen cases reported in the literature in the past century, to our knowledge. Etiologies include chronic or recurrent infections, trauma, and duodenal ulcer disease (24,25). Patients with uretero–alimentary tract fistulas may present with flank pain, hematuria, recurrent urinary tract infections, pneumaturia, fecaluria, and diarrhea.
Excretory urography (Fig 3), retrograde pyelography, and delayed contrast-enhanced CT are reasonable options for diagnosis. Barium studies of the intestinal tract may show abnormalities such as small bowel mucosal disease or diverticula but often will not reveal the fistula. Management may involve percutaneous nephrostomy and stent placement for urinary drainage with possible surgical resection.
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Figure 3. Ureteroileal fistula in a patient with retroperitoneal fibrosis and high ureteral obstruction. Intravenous urogram shows left-sided hydronephrosis and extravasation of contrast material into the retroperitoneum (R) and eventually into the ileum (I). The exact site of the fistula in the small intestine is not seen.
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Ureteroarterial Fistula.—
Ureterovascular fistulas are rare but potentially life-threatening iatrogenic complications of endourologic procedures and pelvic and vascular surgeries (26,27). A spontaneous fistula between an iliac artery aneurysm and the distal ureter has also been described (26). Patients with a history of pelvic irradiation and stiff indwelling ureteral stents seem to be at higher risk. Ureteral ischemia is believed to contribute to fistula formation. Hematuria of varying severity is the predominant symptom. Angiography is considered the primary study of choice and may serve a therapeutic role. Diagnosis may also be achieved with excretory urography, retrograde pyelography or ureterography (Fig 4), and contrast-enhanced CT with varying success (28,29).
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Figure 4. Ureteroarterial fistula. Retrograde ureterogram shows transient filling of an arterial vessel (arrow). Ureteroscopy showed pulsating hemorrhage, which confirmed the diagnosis.
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Ureterocutaneous Fistula.—
Ureterocutaneous fistulas may occur as a consequence of iatrogenic trauma (30) (Fig 5), xanthogranulomatous pyelonephritis (31), and urinary calculous disease (32). One case occurring as an unusual complication of failed prosthetic hip surgery has been reported (33). Spontaneous fistula formation is rare. Diagnostic imaging typically involves preliminary excretory urography to visualize upper tracts as well as cystography and fistulography as needed for further localization.
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Figure 5a. Ureterocutaneous fistula as a complication of ureterolithotomy. (a) Nephrostogram shows gross disruption of the proximal ureter (arrow) with extravasation of contrast material. (b) Nephrostogram of another patient shows a more subtle proximal ureterocutaneous fistula (arrows).
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Figure 5b. Ureterocutaneous fistula as a complication of ureterolithotomy. (a) Nephrostogram shows gross disruption of the proximal ureter (arrow) with extravasation of contrast material. (b) Nephrostogram of another patient shows a more subtle proximal ureterocutaneous fistula (arrows).
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Ureteral Fistulas to the Female Reproductive Tract.—
Ureterosalpingeal fistulas connect the ureter to the fallopian tube. These abnormalities have been described in the setting of urinary calculous disease (34), infection (35), and laparoscopic laser treatment of endometriosis (36). Fistulous tracts between the uterus and ureter are rare, occurring primarily as complications of obstetric and gynecologic procedures such as low transverse cesarean section or uterine curettage for elective abortion (37). Cases have also been reported secondary to ureteral calculus or uterine neoplasm (38). Affected women will present with urinary outflow from the vagina, and pelvic examination can demonstrate urine leakage at the cervical os. Diagnostic work-up includes retrograde VCUG, cystourethroscopy, and excretory urography. Ureterouterine fistula can be differentiated from vesicouterine fistula by methylene blue dye administration into the bladder with a Foley catheter and obtaining yellow urine from the vagina (39). Pelvic US or CT may be useful for preoperative evaluation and surgical planning.
Pelvic surgeries, most predominantly hysterectomy, may also result in ureterovaginal fistulas. In a 15-year review of genitourinary fistulas at the Mayo Clinic, ureterovaginal fistulas accounted for 31 of 303 cases, with the vast majority resulting from hysterectomy (40). Coexistent vesicovaginal fistula is common. Patients present with urinary incontinence per the vagina sometimes accompanied by fever and chills usually within 2–4 weeks following surgery, as urine has collected in the pelvis and dissected into the vaginal suture line. The diagnosis may be established radiographically with vaginography, excretory urography, and retrograde pyelography, as well as with CT and MR imaging (41). Excretory urography is sensitive and may reveal extravasation of contrast material in a collection outside the ureter, eventually draining into the vaginal cavity (Fig 6). The presence of an obstructed ureter in patients with vaginal drainage may also suggest the diagnosis (42) (Fig 7). To our knowledge, no large series studies have examined the efficacy of other imaging modalities. With aggressive early percutaneous nephrostomy and ureteral stent placement, Dowling et al (42) reported successfully treating ureterovaginal fistulas in 11 of 23 patients (48%).
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Figure 6. Ureterovaginal fistula after total abdominal hysterectomy and bilateral oophorectomy in a woman with cervical cancer. Intravenous urogram shows an abnormal communication (arrow) and contrast material filling the vagina (arrowheads).
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Figure 7a. Ureterovaginal fistula in a woman with a watery vaginal discharge. (a) VCUG image shows a normal appearance. Thus, a vesicovaginal or urethrovaginal fistula is ruled out. (b) Intravenous urogram shows obstruction of the left ureter, which is likely due to a surgical clip (arrow). (c) CT urogram shows the fistula, which is faintly outlined by contrast material (arrowheads). (d) CT urogram shows resultant opacification of the vagina (V).
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Figure 7b. Ureterovaginal fistula in a woman with a watery vaginal discharge. (a) VCUG image shows a normal appearance. Thus, a vesicovaginal or urethrovaginal fistula is ruled out. (b) Intravenous urogram shows obstruction of the left ureter, which is likely due to a surgical clip (arrow). (c) CT urogram shows the fistula, which is faintly outlined by contrast material (arrowheads). (d) CT urogram shows resultant opacification of the vagina (V).
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Figure 7c. Ureterovaginal fistula in a woman with a watery vaginal discharge. (a) VCUG image shows a normal appearance. Thus, a vesicovaginal or urethrovaginal fistula is ruled out. (b) Intravenous urogram shows obstruction of the left ureter, which is likely due to a surgical clip (arrow). (c) CT urogram shows the fistula, which is faintly outlined by contrast material (arrowheads). (d) CT urogram shows resultant opacification of the vagina (V).
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Figure 7d. Ureterovaginal fistula in a woman with a watery vaginal discharge. (a) VCUG image shows a normal appearance. Thus, a vesicovaginal or urethrovaginal fistula is ruled out. (b) Intravenous urogram shows obstruction of the left ureter, which is likely due to a surgical clip (arrow). (c) CT urogram shows the fistula, which is faintly outlined by contrast material (arrowheads). (d) CT urogram shows resultant opacification of the vagina (V).
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Fistulas of the Lower Urinary Tract
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Bladder Fistulas
Bladder fistulas may involve the gastrointestinal tract, skin, urethra, or female reproductive tract. The latter will be discussed later in the section on female reproductive tract fistulas.
Enterovesical Fistula.—
Fistulous connections between the bladder and small or large bowel most often occur in the setting of diverticulitis, gastrointestinal or genitourinary neoplasms, and inflammatory bowel disease (43). Radiation therapy, pelvic surgery, and foreign bodies have also been implicated. There is a male predominance, although women are at significantly increased risk after hysterectomy. This is believed to be due to the uterus serving as an intervening barrier between the bladder and the bowel. The site of bowel involvement is predictive of the etiology. Colovesical fistulas most often arise from diverticular disease (Fig 8) and represented 65% of all diverticular fistulas in one series (44). Colon adenocarcinoma may also be responsible (Fig 9).Crohn disease accounts for the majority of ileovesical fistulas (Fig 10), and the prevalence may be as high as 10% in this group. The association with Crohn disease explains the much younger age of patients presenting with ileovesical fistulas. Rectovesical fistulas are almost always due to neoplasm or trauma (45) (Fig 11). Foreign bodies implicated in enterovesical fistulas include Foley catheters in the bladder and fish and chicken bones in the bowel. However, these cases are extremely unusual. Infections including tuberculosis and syphilis, while dominant in the past, are now rare causes. The clinical presentation of enterovesical fistula may include recurrent cystitis, pneumaturia, fecaluria, fever, and abdominal pain.
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Figure 8. Sigmoidovesical fistula secondary to diverticulitis. CT cystogram shows an air-fluid level in the bladder and contrast material in the colon, findings that suggest the diagnosis. Associated active diverticulitis is noted with bowel wall thickening (arrow). The affected section of the sigmoid colon is contiguous to the left posterior bladder wall, which appears focally thickened with obliteration of the fascial plane between the colon and the bladder. Air bubbles are noted along this connecting tract (arrowheads), thus highlighting the fistula.
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Figure 9a. Sigmoidovesical fistulas as a complication of colonic adenocarcinoma in two patients. (a) Cystogram obtained by using a suprapubic catheter shows opacification of the sigmoid colon (S) and rectum (R) in addition to the bladder (B). The fistula is not clearly seen. (b) Cystogram shows contrast material throughout the large intestine. The contrast material originates at the sigmoid colon, which is contiguous to the bladder at the site of the carcinoma (arrow).
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Figure 9b. Sigmoidovesical fistulas as a complication of colonic adenocarcinoma in two patients. (a) Cystogram obtained by using a suprapubic catheter shows opacification of the sigmoid colon (S) and rectum (R) in addition to the bladder (B). The fistula is not clearly seen. (b) Cystogram shows contrast material throughout the large intestine. The contrast material originates at the sigmoid colon, which is contiguous to the bladder at the site of the carcinoma (arrow).
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Figure 10a. Ileovesical fistulas. (a) Cystogram of a patient with a history of abdominal surgery shows leakage of contrast material from the bladder (B) into the ileum (I) and proximal colon, thus indicating the diagnosis. (b) Image from a small-bowel follow-through study, obtained in a patient with a fistula due to Crohn disease, shows contrast material in the bladder (B), which is the key diagnostic finding.
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Figure 10b. Ileovesical fistulas. (a) Cystogram of a patient with a history of abdominal surgery shows leakage of contrast material from the bladder (B) into the ileum (I) and proximal colon, thus indicating the diagnosis. (b) Image from a small-bowel follow-through study, obtained in a patient with a fistula due to Crohn disease, shows contrast material in the bladder (B), which is the key diagnostic finding.
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Figure 11a. Rectovesical fistulas. (a) VCUG image of a patient with a history of prostatectomy for prostate carcinoma shows a fistula (arrow) with resultant rectal opacification (R). (b) CT cystogram enhanced with intravenous contrast material, obtained in a woman who had undergone suspension of the bladder neck with Dexon mesh (United States Surgical, Norwalk, Conn), shows leakage of contrast material out of the bladder, around the mesh (arrowheads), and into the rectum (R). Transvaginal removal of the mesh was necessary to close the fistula. (c) CT cystogram of another patient shows a fistula with contiguity of the posterior bladder and colonic walls, loss of fascial planes (arrowheads), and leakage of contrast material into the distal sigmoid colon (S) and rectum (R).
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Figure 11b. Rectovesical fistulas. (a) VCUG image of a patient with a history of prostatectomy for prostate carcinoma shows a fistula (arrow) with resultant rectal opacification (R). (b) CT cystogram enhanced with intravenous contrast material, obtained in a woman who had undergone suspension of the bladder neck with Dexon mesh (United States Surgical, Norwalk, Conn), shows leakage of contrast material out of the bladder, around the mesh (arrowheads), and into the rectum (R). Transvaginal removal of the mesh was necessary to close the fistula. (c) CT cystogram of another patient shows a fistula with contiguity of the posterior bladder and colonic walls, loss of fascial planes (arrowheads), and leakage of contrast material into the distal sigmoid colon (S) and rectum (R).
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Figure 11c. Rectovesical fistulas. (a) VCUG image of a patient with a history of prostatectomy for prostate carcinoma shows a fistula (arrow) with resultant rectal opacification (R). (b) CT cystogram enhanced with intravenous contrast material, obtained in a woman who had undergone suspension of the bladder neck with Dexon mesh (United States Surgical, Norwalk, Conn), shows leakage of contrast material out of the bladder, around the mesh (arrowheads), and into the rectum (R). Transvaginal removal of the mesh was necessary to close the fistula. (c) CT cystogram of another patient shows a fistula with contiguity of the posterior bladder and colonic walls, loss of fascial planes (arrowheads), and leakage of contrast material into the distal sigmoid colon (S) and rectum (R).
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CT is the primary imaging modality for suspected cases of enterovesical fistulas. Although it often fails to demonstrate the fistulous tract, other suggestive findings can typically be seen, such as intravesical air, focal bladder wall thickening, and extraluminal masses. Advantages of CT are its noninvasive nature and ability to demonstrate any associated intraabdominal processes. Intravesical air, in particular, is a key finding; hence, if possible, CT should be performed prior to instrumentation of the bladder. Initial scanning should also be performed after oral administration of contrast material but before intravenous administration of contrast material to demonstrate enhancement of the bladder. Cystoscopy is suggestive in almost all cases, but it fails to actually demonstrate the fistula in more than half of cases (44). However, it is accepted as a routine component of the work-up. Cystography is less sensitive. Barium enema study demonstrates only 35% of fistulas, and upper gastrointestinal series do not offer significant diagnostic value apart from demonstration of possible associated bowel mucosal abnormalities. After a contrast-enhanced bowel study, however, small amounts of barium may be detected in the urine, which can be detected by radiography of a centrifuged sample (46). MR imaging and US have been used to delineate enterovesical fistulas, although experience is limited (47,48).
Vesicocutaneous Fistula.—
Vesicocutaneous fistulas usually occur secondary to surgical procedures or trauma. They occur at suprapubic cystostomy sites after catheter removal, but almost all close spontaneously. Factors such as impaired wound healing and bladder outlet obstruction may play a role in maintaining the fistulous connection. Spontaneous fistulas are extremely rare but have been reported in the setting of radiation therapy (49). The tract can easily be visualized by means of fistulography through the visible cutaneous site. Diagnosis and localization can also be accomplished with cystoscopy and cystography; cystoscopy-assisted repair is effective in selected patients (50).
Vesicourethral Fistula.—
Vesicourethral fistulas may result from urethral injury associated with trauma or pelvic surgery (51,52). Specific procedures predisposing to this condition include urethral stent placement and vesicourethral suspension procedures involving anterior fixation of the urethra (Marshall-Marchetti operation). Sometimes, such fistulas are intentionally created (Fig 12). Persistent urinary incontinence is the primary symptom. VCUG and retrograde urethrography can demonstrate the anomalous communication and guide surgical management.
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Figure 12a. Vesicourethral fistulas. (a) VCUG image shows a false urethral passage (arrow), which extends from the prostatic urethra to the base of the bladder and was created intentionally. (b) VCUG image obtained later shows that the fistula has become the dominant channel, whereas the prostatic urethra has closed. (c) VCUG image of another patient shows a spontaneously formed fistula, which was secondary to a urethral diverticulum (arrow).
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Figure 12b. Vesicourethral fistulas. (a) VCUG image shows a false urethral passage (arrow), which extends from the prostatic urethra to the base of the bladder and was created intentionally. (b) VCUG image obtained later shows that the fistula has become the dominant channel, whereas the prostatic urethra has closed. (c) VCUG image of another patient shows a spontaneously formed fistula, which was secondary to a urethral diverticulum (arrow).
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Figure 12c. Vesicourethral fistulas. (a) VCUG image shows a false urethral passage (arrow), which extends from the prostatic urethra to the base of the bladder and was created intentionally. (b) VCUG image obtained later shows that the fistula has become the dominant channel, whereas the prostatic urethra has closed. (c) VCUG image of another patient shows a spontaneously formed fistula, which was secondary to a urethral diverticulum (arrow).
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Other Bladder Fistulas.—
Vesicoarticular fistulas are rare complications of surgery or pelvic trauma; the hip joint is often involved with septic arthritis. VCUG can delineate the fistula, whereas CT may reveal associated abnormalities (Fig 13). The bladder may also form fistulas with the vagina (vesicovaginal) or uterus (vesicouterine). These entities are discussed later along with other fistulas of the female reproductive tract.
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Figure 13a. Vesicoarticular fistula secondary to pelvic trauma and complicated by an abscess and a septic joint. (a) VCUG image shows a fistula (arrow) from the bladder to the right hip. (b) CT image enhanced with intravenous contrast material shows an extensive abscess (A) of the right hip joint.
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Figure 13b. Vesicoarticular fistula secondary to pelvic trauma and complicated by an abscess and a septic joint. (a) VCUG image shows a fistula (arrow) from the bladder to the right hip. (b) CT image enhanced with intravenous contrast material shows an extensive abscess (A) of the right hip joint.
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Urethral Fistulas
The urethra may form anomalous communications with the rectum, perineum, bladder, and male or female genital structures. They may be congenital or acquired. Cystourethroscopy and VCUG or urethrography are the main diagnostic modalities.
Urethrorectal Fistula.—
Urethrorectal fistulas may be congenital in children and acquired in adults (Fig 14). Congenital cases usually occur in association with imperforate anus (53). The mechanism involves urethral "blowout" associated with a distal obstruction or failure of the mesoderm layer to completely encircle the urethral groove in the developing embryo. In adults, they arise as complications of prostate surgery, infections including tuberculosis, neoplasm, radiation therapy, and urethral instrumentation (54,55). In neonates, urine may be meconium stained. Concurrent imperforate anus requires postnatal surgery. Adults may present with recurrent urinary tract infections, urine per the rectum, fecaluria, hematuria, and infection of the seminal vesicles. Surgical repair is required in most cases, although conservative therapy may be attempted in selected patients. The diagnosis can be confirmed at examination of the rectum and cystourethroscopy. VCUG or retrograde urethrography can delineate the fistulous tract for surgical planning. Lateral images may be needed to demonstrate thin tracts, which may otherwise be obscured by contrast material in the rectum or urethra (1).
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Figure 14a. Causes and radiologic features of acquired urethrorectal fistulas in four patients. (a) Contrast-enhanced CT image shows a fistula (arrow), which was due to cryoablation of a prostatic carcinoma. Air pockets that extend to the urethra (arrowhead) are seen in the prostate. (b) Retrograde urethrogram shows leakage of contrast material into the rectum (R). The fistula was the result of radiation seed therapy in the prostate (arrowhead). (c) VCUG image of a patient with a prostatic abscess shows leakage of contrast material at the prostatic urethra (arrowheads) with opacification of the rectum (R). (d) VCUG image shows a fistula (arrow), which was a complication of transperineal prostatectomy.
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Figure 14b. Causes and radiologic features of acquired urethrorectal fistulas in four patients. (a) Contrast-enhanced CT image shows a fistula (arrow), which was due to cryoablation of a prostatic carcinoma. Air pockets that extend to the urethra (arrowhead) are seen in the prostate. (b) Retrograde urethrogram shows leakage of contrast material into the rectum (R). The fistula was the result of radiation seed therapy in the prostate (arrowhead). (c) VCUG image of a patient with a prostatic abscess shows leakage of contrast material at the prostatic urethra (arrowheads) with opacification of the rectum (R). (d) VCUG image shows a fistula (arrow), which was a complication of transperineal prostatectomy.
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Figure 14c. Causes and radiologic features of acquired urethrorectal fistulas in four patients. (a) Contrast-enhanced CT image shows a fistula (arrow), which was due to cryoablation of a prostatic carcinoma. Air pockets that extend to the urethra (arrowhead) are seen in the prostate. (b) Retrograde urethrogram shows leakage of contrast material into the rectum (R). The fistula was the result of radiation seed therapy in the prostate (arrowhead). (c) VCUG image of a patient with a prostatic abscess shows leakage of contrast material at the prostatic urethra (arrowheads) with opacification of the rectum (R). (d) VCUG image shows a fistula (arrow), which was a complication of transperineal prostatectomy.
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Figure 14d. Causes and radiologic features of acquired urethrorectal fistulas in four patients. (a) Contrast-enhanced CT image shows a fistula (arrow), which was due to cryoablation of a prostatic carcinoma. Air pockets that extend to the urethra (arrowhead) are seen in the prostate. (b) Retrograde urethrogram shows leakage of contrast material into the rectum (R). The fistula was the result of radiation seed therapy in the prostate (arrowhead). (c) VCUG image of a patient with a prostatic abscess shows leakage of contrast material at the prostatic urethra (arrowheads) with opacification of the rectum (R). (d) VCUG image shows a fistula (arrow), which was a complication of transperineal prostatectomy.
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Urethroperineal and Urethrocutaneous Fistulas.—
Urethroperineal fistulas and urethrocutaneous fistulas may result from surgical treatment of urethral strictures, repair of hypospadias, prostate surgery, chronic untreated periurethral abscesses, and trauma (1) (Fig 15). In endemic areas, parasitic infections involving Schistosoma hematobium or Dracunculus medinensis must be considered (56). Objects used on the penis to enhance sexual performance have been linked to a case of urethrocutaneous fistula (57). Congenital cases of urethroperineal fistulas must be distinguished from urethral duplication of the hypospadiac form for proper surgical planning. Patients may present with a variety of symptoms including perineal infection and urinary dribbling. Cystourethroscopy may allow direct visualization of the fistula. Radiographic diagnosis relies on VCUG or retrograde urethrography for determination of the location, size, number, and route of communication. Fistulography may also be performed through the cutaneous site. Cross-sectional techniques may be useful to demonstrate associated abnormalities such as abscesses.
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Figure 15a. Urethroperineal fistulas in three patients. (a) Retrograde urethrogram shows a fistula (arrow), which was due to perineal trauma from a forklift accident. (b) Retrograde urethrogram of a patient with a prostatic abscess shows a large urethroperineal fistula. (c) VCUG image shows a fistula (arrowheads), which was created as a means of temporary urinary diversion as part of two-stage urethroplasty for anterior strictures.
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Figure 15b. Urethroperineal fistulas in three patients. (a) Retrograde urethrogram shows a fistula (arrow), which was due to perineal trauma from a forklift accident. (b) Retrograde urethrogram of a patient with a prostatic abscess shows a large urethroperineal fistula. (c) VCUG image shows a fistula (arrowheads), which was created as a means of temporary urinary diversion as part of two-stage urethroplasty for anterior strictures.
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Figure 15c. Urethroperineal fistulas in three patients. (a) Retrograde urethrogram shows a fistula (arrow), which was due to perineal trauma from a forklift accident. (b) Retrograde urethrogram of a patient with a prostatic abscess shows a large urethroperineal fistula. (c) VCUG image shows a fistula (arrowheads), which was created as a means of temporary urinary diversion as part of two-stage urethroplasty for anterior strictures.
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Other Urethral Fistulas.—
In males, the urethra may also develop communications with the corpus cavernosum (58), the corpus spongiosum (59), or the scrotum (60). These entities are almost always secondary to iatrogenic causes including penile implants (urethrocavernosal), traumatic catheterization (urethrospongiosal), bladder neck incision, hypospadias repair, and renal transplantation (urethrovasoscrotal). Urethrocavernosus fistula in the setting of a corpus cavernosum abscess has been reported (61). Blunt penile trauma and straddle injury may be etiologic. Urethrography can demonstrate the fistulous tracts. Urethrovaginal fistula is discussed later.
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Fistulas of the Female Reproductive Tract
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Gynecologic and obstetric procedures and surgeries cause the majority of female genitourinary tract fistulas. The vagina is, by far, most commonly involved. Table 2 summarizes the major etiologies and relative frequencies, based on a 15-year review of cases at the Mayo Clinic (40).
Colovaginal Fistula
Communication between the colon and vagina is most often caused by diverticular disease, accounting for 40% of all diverticulum-related fistulas (62). In this setting, the sigmoid colon is most commonly involved. Most women with sigmoidovaginal fistulas have a history of hysterectomy. Other causes include gynecologic neoplasms, inflammatory bowel disease, radiation, infection, and trauma. Rectovaginal fistulas are rare and represent a small portion of all anorectal fistulas. This condition is most commonly caused by obstetric complications, perineal infections, neoplasms, radiation, trauma, and inflammatory bowel disease. Diverticular disease, usually absent in the rectum, does not play a role. Women with colovaginal fistulas may present with feces, flatus, or mucus per the vagina. Anal incontinence may be present in cases of rectovaginal fistulas due to associated anal sphincter compromise.
Conventional fluoroscopic methods such as vaginography (Fig 16) and barium enema study in conjunction with physical examination have traditionally been used for diagnosis (63). Vaginography has reported sensitivities of 40%–100%. In many cases, endoscopic techniques may be contributory (64). CT and MR imaging can also be useful. Endorectal US may reveal associated anal sphincter injury for anorectovaginal fistulas. In one series, it was 100% sensitive and specific for detection of a sphincter defect but only 28% sensitive in demonstrating the fistula itself (65).
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Figure 16. Sigmoidovaginal fistula in a woman with a history of hysterectomy. Vaginogram shows a fistula involving the vaginal cuff (arrow). The vagina (V), sigmoid colon (S), and rectum (R) are highlighted by the contrast material.
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The preferred management is surgery for fistula takedown with colon resection and primary anastomosis. Conservative management may be attempted for poor surgical candidates (62).
Urethrovaginal Fistula
Fistulas between the urethra and vagina most commonly result from postoperative and obstetric complications, pelvic trauma, or irradiation of pelvic neoplasms. In the series of Lee et al (40), 32 of 53 cases of urethrovaginal fistulas followed surgery for urethral diverticulum, stress incontinence, or cystocele repair. Eight cases were related to radiation therapy for gynecologic neoplasms. Coexistent vesicovaginal fistulas were noted in 10 patients. Traumatic childbirth may be causative, and coexistent vesicovaginal fistulas are especially common in this setting. A fistula between the urethra and neovagina is a known complication of transgender surgery. As with other genitourinary fistulas in women, sustained leakage of watery fluid per the vagina is the dominant symptom and is often debilitating.
The diagnosis can be made by direct visualization with vaginoscopy and cystourethroscopy. VCUG should also be diagnostic (Fig 17). An associated vesicovaginal fistula may also be seen. Vaginography is unlikely to demonstrate thin tracts. To our knowledge, no large studies have evaluated the role of cross-sectional techniques specifically for urethrovaginal fistulas. Larger tracts should be demonstrated with sonography or delayed contrast-enhanced CT. T2-weighted MR imaging with single-shot fast spin-echo sequences, the half-Fourier rapid acquisition with relaxation enhancement (RARE) technique, or delayed contrast-enhanced T1-weighted gradient-recalled-echo (GRE) sequences with fat saturation may be useful for diagnosis. Surgical repair is highly successful in the majority of cases.
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Figure 17a. Urethrovaginal fistulas in four patients. (a) VCUG image shows a small fistula (arrow), which may be difficult to differentiate from a urethral diverticulum. (b) VCUG image shows a larger fistula, which is clearly demonstrated by contrast material in the vagina (arrow). The fistula is complicated by a urethral diverticulum (arrowhead). (c) VCUG image shows a very large fistula that has caused gross disruption of the urethrovaginal wall. (d) Intraoperative photograph shows a Foley catheter in the urethra that is visible from the vagina through the fistulous defect (arrow).
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Figure 17b. Urethrovaginal fistulas in four patients. (a) VCUG image shows a small fistula (arrow), which may be difficult to differentiate from a urethral diverticulum. (b) VCUG image shows a larger fistula, which is clearly demonstrated by contrast material in the vagina (arrow). The fistula is complicated by a urethral diverticulum (arrowhead). (c) VCUG image shows a very large fistula that has caused gross disruption of the urethrovaginal wall. (d) Intraoperative photograph shows a Foley catheter in the urethra that is visible from the vagina through the fistulous defect (arrow).
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Figure 17c. Urethrovaginal fistulas in four patients. (a) VCUG image shows a small fistula (arrow), which may be difficult to differentiate from a urethral diverticulum. (b) VCUG image shows a larger fistula, which is clearly demonstrated by contrast material in the vagina (arrow). The fistula is complicated by a urethral diverticulum (arrowhead). (c) VCUG image shows a very large fistula that has caused gross disruption of the urethrovaginal wall. (d) Intraoperative photograph shows a Foley catheter in the urethra that is visible from the vagina through the fistulous defect (arrow).
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Figure 17d. Urethrovaginal fistulas in four patients. (a) VCUG image shows a small fistula (arrow), which may be difficult to differentiate from a urethral diverticulum. (b) VCUG image shows a larger fistula, which is clearly demonstrated by contrast material in the vagina (arrow). The fistula is complicated by a urethral diverticulum (arrowhead). (c) VCUG image shows a very large fistula that has caused gross disruption of the urethrovaginal wall. (d) Intraoperative photograph shows a Foley catheter in the urethra that is visible from the vagina through the fistulous defect (arrow).
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Vesicovaginal Fistula
Described since antiquity, vesicovaginal fistulas usually occur as a complication of childbirth in developing countries and as complications of gynecologic procedures in developed countries. Hysterectomy is a common culprit for bladder injury and subsequent fistula formation (66). The remainder of the cases are attributed to irradia-tion, trauma, and fulguration. Patients with a history of other medical conditions such as diabetes, atherosclerosis, and pelvic inflammatory disease seem to be more susceptible in the postoperative setting. Neoplasms of the bladder and cervix, especially with ischemic endarteritis obliterans from irradiation, may lead to a vesicovaginal fistula (67). Women from developing countries with underlying infections such as tuberculosis and schistosomiasis are also at risk. A constructed ileal neobladder in postcystectomy patients may form a fistula with the vaginal pouch as well as other structures including the skin, alimentary tract, and perineum (Fig 18); prior irradiation appears to be a risk factor (68). Vesicovaginal fistula most often manifests as constant watery leakage per the vagina. There may be significant delay (months to years) in presentation for postirradiation cases (67).
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Abstract
LEARNING OBJECTIVES FOR TEST...
