NEGLIGENT FISTULAE

ABSTRACT

The cause of vesicovaginal fistulas after hysterectomy is not clearly understood. In an attempt to determine its cause, the records of 12 patients who had vesicovaginal fistula develop (after total abdominal hysterectomy) were compared with 12 consecutive patients who underwent total abdominal hysterectomy without fistula formation. Most of the patients who had vesicovaginal fistulas develop had excessive postoperative abdominal pain, distension or paralytic ileus, or both. Hematuria and symptoms of irritability of the bladder were also noted in the fistula group and prolonged postoperative fever and increased white blood cell count occurred more often. In contrast, the postoperative course was uncomplicated in the nonfistula group. The clinical course observed in many of the patients with vesicovaginal fistulas suggests that the patients had an unrecognized injury to the bladder resulting in urinary extravasation. It is postulated that the fistula develops when the urinoma (collection of urine, arising from damage, in this case to the bladder) drains into the vaginal cuff which is dependent and usually not closed. It may be possible to abort the development of many vesicovaginal fistulas by early recognition and treatment of an unsuspected bladder injury. It is suggested that patients with severe abdominal pain, distension, paralytic ileus, hematuria or symptoms of severe irritability of the bladder after abdominal hysterectomy be investigated early for a possible bladder injury. Author.

1. (Page 409) The exact cause of a vesicovaginal fistula after hysterectomy is not clearly understood...The most commonly stated explanations are that it results from avascular [loss of bloodsupply] necrosis [death of tissue] of the base of the bladder or erosion [damage by rubbing] from sutures placed between the bladder and the vaginal cuff [residual vagina after the uterus has been removed]...Experience...suggested to us that many fistulas develop from an unsuspected bladder injury.

2. (Page 411) DISCUSSION...It is noteworthy that most of the patients who had a vesicovaginal fistula develop had excessive postoperative abdominal pain, distension or a paralytic ileus. Postoperatively, four of the eight patients with these symptoms are presented and the clinical course was similar in the remaining four patients.

3. ...The results suggest that the development of excessive abdominal pain, distension or a paralytic ileus [temporary failure of bowel functioning for nonmechanical reasons, often localised infection or other irritation] after a total abdominal hysterectomy signal the possibility of an unsuspected bladder perforation. The undrained urinoma or contamination of the peritoneal cavity with urine, or both, are responsible for these symptoms. The vesicovaginal fistula forms when the urinoma drains from the vaginal cuff which is dependent and usually left open...The fact that the vesicovaginal fistulas invariably involve the vaginal cuff supports this theory.

4. (Page 412) Other symptoms that signal the possibility of an unsuspected bladder injury include gross hematuria from the indwelling urethral catheter...symptoms of significant bladder irribility...The development of these symptoms and especially the presence of excessive abdominal pain, distension or paralytic ilues should alert the surgeon to perform appropriate diagnostic studies promptly to exclude the possibility of an unrecognized bladder perforation. Additionally, the frequent practice of ignoring varying amounts of vaginal leakage in the hope that it represents vaginal discharge or seroma must be avoided if a bladder injury or diagnosis of impending vesicovaginal fistula is to be established early. The diagnostic evaluation may include cystography, dye studies, such as bladder instillation of methylene blue, and cystoscopy.

5. ...If a relatvely small leak is noted that drains either directly into the vagina or extraperitoneally behind the bladder, a large Foley catheter should be placed in the urethra for an extended period (minimum of three ot four weeks) to provide maximal drainage. Prior to removing the catheter, contrast studies and possibly cystoscopy are repated to determine if the leak is still present and to assess it size. If the perforation is still present but smaller, additional bladder drainage is used. On the other hand, if the fistula remains unchanged, further dainage with the hope of spontaneous fistula closure is futile. Large bladder perforations with extravasation of large arounds of urine intraperitoneally should be closed immediately after they are discovered. Once a large fistula is formed, it is unlikely that it will close despite adequate drainage. After surgical correction is deemed necessary, the optimal time to repair an established vesicovaginal fistula remains controversial.

6. The exact cause of a vesicovaginal fistula has been ambiguous. The results of this study suggest that many vesicovaginal fistulas develop from an unsuspected bladder injury which has generally not been considered to play a causative role. After a difficult hysterectomy or any complex surgical dissection in the pelvis close to the bladder, it is reasonable to consider distending the bladder with fluid or dye solution ot exclude an unfortunate bladder perforation. Early diagnostic and therapeutic measures should be used if the postoperative course suggests a possible bladder injury. Based upon an understanding of the pathologic and cautive finding of vesicovaginal fistulas, it may be possible to prevent the development of many such fistulas.

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