Chapter 85 Fistulae: Gastrointestinal and Urinary Tract
INTRODUCTION
Description: A fistula is an abnormal communication between two cavities or organs. In gynecology, this usually refers to a communication between the gastrointestinal or urinary tract and genital tract. (Connections directly to the skin are not discussed here.)
Prevalence: Gastrointestinal fistulae are uncommon; urinary tract fistulae are estimated to occur after 1 of 200 abdominal hysterectomies.
ETIOLOGY AND PATHOGENESIS
Causes: Urinary tract fistulae may result from surgical or obstetric trauma, irradiation, or malignancy, although the most common cause by far is unrecognized surgical trauma. Roughly 75% of urinary tract fistulae occur after abdominal hysterectomy. Signs of a urinary fistula (watery discharge) usually occur from 5 to 30 days after surgery (average 8 to 12), although they may be present in the immediate postoperative period. Fistulae between the gastrointestinal tract and vagina may be precipitated by the same injuries that cause genitourinary fistulae; most common are obstetric injuries and complications of episiotomies (lower one third of vagina). Fistulae may also follow hysterectomy or enterocele repair (upper one third of vagina). Inflammatory bowel disease or pelvic radiation therapy may hasten or precipitate fistula formation.
Risk Factors: Gastrointestinal—obstetric tears, puncture wounds, inflammatory bowel disease, intra-abdominal surgery, carcinoma, radiation therapy, perirectal abscess. Although Crohn’s disease, lymphogranuloma venereum, or tuberculosis are recognized risk factors, these are uncommon. Urinary tract—surgery or radiation treatment. Urinary tract fistulae are most common after uncomplicated hysterectomy, although pelvic adhesive disease, endometriosis, or pelvic tumors increase the individual risk.
