Overview
Definition:
A rectourethral fistula is an abnormal communication between the rectum and the urethra, allowing passage of stool or flatus into the urethra, or urine into the rectum
Gracilis interposition is a surgical technique that utilizes the gracilis muscle flap to reconstruct the defect, providing a well-vascularized tissue barrier.
Epidemiology:
Rectourethral fistulas are relatively rare, with iatrogenic causes (e.g., post-prostatectomy, post-radiation, low anterior resection) being more common than congenital or inflammatory causes
Incidence varies significantly based on the inciting event.
Clinical Significance:
Rectourethral fistulas significantly impact quality of life, causing fecaluria, pneumaturia, recurrent urinary tract infections, perineal sepsis, and psychological distress
Successful repair is crucial for restoring continence, preventing infection, and improving patient well-being, making it a critical topic for surgical residents.
Clinical Presentation
Symptoms:
Passage of gas or stool per urethra (fecaluria/flatus in urine)
Passage of urine per rectum (incontinence of urine into rectum)
Recurrent urinary tract infections
Perineal pain and irritation
Difficulty voiding
Penile discharge.
Signs:
Digital rectal examination may reveal an abnormal communication or induration
Visual inspection may show perineal inflammation or discharge
Cystoscopy may visualize the fistula opening in the urethra
Proctoscopy may visualize the opening in the rectum
Rectal examination may reveal stool in the urethra or urine in the rectum during coughing.
Diagnostic Criteria:
Diagnosis is primarily clinical, confirmed by imaging and endoscopic evaluations
The presence of characteristic symptoms and signs, coupled with confirmatory investigations, establishes the diagnosis.
Diagnostic Approach
History Taking:
Detailed history of prior pelvic surgery (prostatectomy, anterior resection, radiation therapy)
History of inflammatory bowel disease
Trauma history
Onset and duration of symptoms
Character of discharge (stool, flatus, urine)
Associated voiding or defecation symptoms.
Physical Examination:
Focused perineal and genital examination
Digital rectal examination to assess for fistula tract, tenderness, and sphincter tone
Cystoscopy to visualize the urethral orifice
Proctoscopy to visualize the rectal orifice
Assessment for any associated abscesses or fistulas.
Investigations:
Cystography and/or retrograde urethrogram to delineate the fistula tract
MRI pelvis to precisely map the fistula, identify associated abscesses, and assess surrounding tissue planes
CT scan for assessing bony pelvis and any extent of sepsis
Endoscopic evaluation (cystoscopy and proctoscopy) is essential
Fistulogram may be used if the tract is clearly defined
Rectal contrast enema can help delineate the rectal side.
Differential Diagnosis:
Urethral stricture
Anal fissures
Proctitis
Diverticulitis with abscess
Enterovesical fistula (other etiologies)
Pelvic abscess without fistula
Cowperitis
Sphincter dysfunction.
Management
Initial Management:
Bowel preparation with laxatives and clear liquid diet
Broad-spectrum antibiotics to cover gram-negative and anaerobic organisms
Perineal hygiene
Urinary catheterization to divert urine and promote healing
Management of any concurrent abscesses.
Medical Management:
Antibiotic therapy targeting gut flora (e.g., fluoroquinolone or cephalosporin with metronidazole)
Antidiarrheals if significant bowel leakage is present
Sitz baths for perineal comfort.
Surgical Management:
Gracilis interposition is indicated for complex or recurrent rectourethral fistulas, particularly those post-radiation or with significant tissue loss
Indications include failure of conservative management, large fistulas, or those associated with compromised tissue
The procedure involves harvesting a vascularized gracilis muscle flap, tunneling it to the perineum, and using it to fill the fistula tract and create a barrier between the rectum and urethra
This is often combined with sphincteroplasty or other reconstructive techniques as needed
Surgical steps include exposure of the fistula, mobilization of rectal and urethral margins, harvest of the gracilis flap, placement of the flap, and secure closure of the surrounding tissues.
Supportive Care:
Nutritional support to promote healing
Pain management
Wound care
Psychological support due to the nature of the condition
Close monitoring for signs of infection or recurrence.
Complications
Early Complications:
Wound infection
Flap necrosis
Urinary retention
Anesthesia-related complications
Rectal or urethral injury during dissection
Bleeding.
Late Complications:
Fistula recurrence
Urethral stricture formation
Impotence
Perineal discomfort or pain
Chronic wound issues
Incontinence (fecal or urinary).
Prevention Strategies:
Meticulous surgical technique to avoid injury
Adequate vascular supply to the flap
Optimal wound closure and drainage
Prophylactic antibiotics
Close postoperative monitoring
Appropriate patient selection for surgical intervention.
Prognosis
Factors Affecting Prognosis:
Size and location of the fistula
Etiology of the fistula (e.g., radiation-induced fistulas have poorer prognosis)
Previous surgical attempts
Patient's overall health status and nutritional state
Presence of infection or sepsis
Surgical technique and surgeon's experience.
Outcomes:
Successful repair rates vary, but gracilis interposition generally offers good outcomes for complex cases, with reported success rates ranging from 70-90%
Recurrence can occur, necessitating further intervention
Functional outcomes regarding continence and sexual function are crucial considerations.
Follow Up:
Regular follow-up appointments are essential, typically starting within 2-4 weeks post-surgery and continuing for several months to a year
This involves clinical examination, imaging (e.g., cystography, MRI), and functional assessments to monitor for recurrence, complications, and functional recovery
Patients should be educated on signs of recurrence or infection.
Key Points
Exam Focus:
Understand the common etiologies of rectourethral fistulas, diagnostic modalities (especially MRI and cystography), and the principles of gracilis interposition surgery
Be prepared to discuss indications, contraindications, surgical steps, and potential complications.
Clinical Pearls:
A thorough preoperative assessment including imaging is paramount
Meticulous dissection and ensuring adequate flap vascularity are key to success in gracilis interposition
Postoperative care focused on preventing infection and monitoring for early signs of recurrence is critical for optimal outcomes.
Common Mistakes:
Underestimating the complexity of radiation-induced fistulas
Inadequate bowel preparation
Insufficient flap perfusion
Poor closure of the surrounding tissues leading to breakdown
Failure to manage associated sepsis or abscesses
Not providing adequate long-term follow-up.