Urethral fistulas are fistulas between the urethra and the body surface, either directly or through other systemic organs that are abnormally connected, and commonly include vesicovaginal fistulas, urethrovaginal fistulas, urethrorectal fistulas, ureterovaginal fistulas and urethral cutaneous fistulas (collectively called urethral fistulas).
So how exactly is a urethral fistula classified?
1, according to the occurrence of urethral fistula in the urethra, divided into anterior urethral fistula and posterior urethral fistula.
2, by the cause and time of occurrence, and divided into congenital urethral fistula and acquired urethral fistula, the latter can be divided into two categories: traumatic and pathological.
3. According to the urine flow, urethral fistula is divided into external and internal fistula. An external fistula is a fistula in which urine is partially or completely discharged through an abnormal channel in the urethra during urination, such as in the penis, scrotum, and perineum. Internal fistula is a fistula in which urine is first discharged into other organs and then out of the body, such as urethro-vaginal fistula and urethro-rectal fistula.
4, according to the anatomical parts can be divided into:
(1) Urethrovaginal fistula: Urethra with a fistula hole leading to the vagina, also includes complete urethral defect, urethral longitudinal laceration, urethral transection.
(2) Vesicovaginal fistula: A fistula in the bladder that connects to the vagina.
(3) Vesicourethrovaginal fistula: A fistula at the junction of the bladder neck and urethra that is connected to the vagina, involving the bladder and urethra, with the urethra shorter than 3 cm.
(4) Vesicovaginal fistula: The fistula involves the cervix and vagina, and the anterior lip of the cervix is severely torn or defective.
(5) Ureterovaginal fistula: The fistula communicates between the ureter and the vagina.
Etiology
Congenital urethral fistula occurs because:
(1) After the 5th week during fetal development, the urogenital folds fail to separate the rectum from the urogenital diaphragm, allowing the urethra to communicate with the rectum (male) or the vagina (female), resulting in urethrorectal fistula (male) or urethrovaginal fistula (female). The former is often associated with congenital atresia of the distal rectum.
(ii) Hypospadias.
(iii) Duplicate urethra.
Acquired urethral fistulas occur as a result of
①Urethral injury, such as urethral injury during war injury, car accident, workplace accident, especially posterior urethral injury associated with pelvic fracture, and riding injury to the urethral bulb.
②Injuries in the urethra caused by surgery, instrumentation of the pelvis, anterior vaginal wall or urethra, and stones and foreign bodies in the urethra.
(iii) Defects of the urethra or anterior vaginal wall due to childbirth or obstructed labor.
④Malignant tumors of the urethra or anterior vaginal wall, cervix, and radiotherapy.
⑤ direct ulceration of urethral tuberculosis, gonorrhea, periurethral abscess, perineal abscess, urethral diverticulum, infection of urethral glands, or causing urethral stricture, occurrence of urinary flow obstruction and breakthrough to the outside of the urethra after secondary infection
(6) local tissue necrosis caused by wire ties or metal rings in the penis.
(7) Necrosis and secondary infection caused by improper position of long-term indwelling catheter or traction of the catheter to the lower extremity end, which compresses the urethra at the penile-scrotal junction.
Diagnostic criteria
(I) Medical history: History of trauma, surgery or obstructed labor, urethral tuberculosis, urethral cancer, cervical cancer and local long-term radiotherapy.
(ii) Clinical manifestations.
Urethral skin fistula can be seen as urine flowing out of the body from the skin fistula hole, so the diagnosis is not difficult.
In the case of urethro-rectal fistula, there is anal urination and the urine from the urethra is often mixed with feces and gas.
In urethrovaginal fistula, if the fistula is large and located at the proximal end of the urethra, there may be continuous leakage without automatic urination in the obstruction, and if the fistula is small and located at the distal end of the urethra, urine is discharged from both the urethra and the vagina only during urination.
(iii) Physical examination: necessary rectal examination and gynecological examination can help in diagnosis.
1, urethrorectal fistula: Diagnosis can be confirmed by rectal palpation, urethrography, proctoscopy or urethrocystoscopy.
2. urethrovaginal fistula: vaginal examination, urethral probe examination, melanoma test and colposcopy or urethroscopy can help in diagnosis.
(d) Voiding cystourethrography, X-ray plain radiographs of the pelvic area, and intravenous urography can also help in the diagnosis.
(E) Differential diagnosis
1. Ureteral orifice ectopic: it is a congenital developmental anomaly, mostly with double renal pelvis and double ureteral malformation. In addition to the normal urethral orifice, it can be found in the urethra, perineum, uterus, vagina and other parts of the body with persistent drip-like fistula. In intravenous pyelogram, duplicate renal pelvis and duplicate ureter can be seen and are often accompanied by hydronephrosis.
2. Vesicovaginal fistula: persistent dripping urine from the vagina. After injection of US blue solution in the bladder, the gauze in the vagina is blue stained and it is not necessary to wait until after urination for observation. Cystoscopy reveals the intravesical fistula opening.
3. Ureterovaginal fistula: caused by surgical injury in the pelvis or vagina. There is a persistent punctate leak in the vagina. After gauze is inserted in the vagina, the bladder is filled with US blue solution and urination or no urination, there is no blue staining of the gauze. With excretory urography or retrograde urography, ureteral contrast spillage is seen with dilated ureteral fluid accumulation above its level. In retrograde ureteral intubation, there is obstruction in the middle and lower ureter.
Treatment
The treatment of urethral fistula is to remove the fistula and restore the normal passage of the urinary tract.
(i) Surgical approach
The treatment of urethral fistula should be decided according to the cause of occurrence, the location and size of the fistula.
1. Urethral fistula due to trauma should be treated with early diversion of urinary flow. In those with significant inflammation, surgery must be performed only after the inflammation has subsided.
2. If there is a stricture in the urethra distal to the fistula hole, the stricture must be released first.
3, more thorough excision of the scar around the fistula, layered sutures, suture incisions do not overlap, cystostomy drainage of urine.
4. For pathological urethral fistula, the primary disease must be treated first and then the urethral fistula must be repaired, and if necessary, the urinary flow must be rerouted.
(ii) Surgical complications
1, failure of repair and re-formation of urethral fistula.
2, urethral stricture.
3.If urethral diversion is performed, the corresponding complications can occur.