In this hospital cohort, large differences were found in characteristics of and the prognosis for gynaecological fistulae caused by surgery as opposed to radiotherapy. Post-radiotherapy fistulae caused later symptoms, were larger in diameter, more often enterogenital and healed more seldom (26 %). Conversely, post-surgical fistulae had a very good healing rate (94 %).
At Haukeland University Hospital, where a national treatment centre was established in 2012, there has been a steady increase in both the total number of patients with gynaecological fistulae and the percentage of patients referred from other health regions. A review of the Norwegian Patient Register 2008–2014 revealed that a significantly larger proportion of fistula procedures, 31 %, had been performed under the Western Norway Regional Health Authority compared with the rest of Norway (4). In the last five-year period (2015–2019) a full 76 % of women with post-surgical fistula had been referred from other health regions (the Western Norway Regional Health Authority covers 21 % of Norway's population). This indicates that the centre's services have become more widely known and are now used for the whole of the patient group in question.
In our dataset, hysterectomy was the cause of 57 % of the post-surgical fistulae, and was the predominant cause of urogenital fistula. This is consistent with a British cohort from a urology department, where hysterectomy had caused 159/238 (67 %) of urogenital fistulae (6). Hospital registry data from the UK indicate the risk of urinary tract injury in connection with hysterectomy at 1/788 (0.13 %), and higher for radical cancer surgery (15). The fact that as many as 41/124 (33 %) of our post-surgical fistulae occurred in connection with cancer treatment supports these findings.
An increasing incidence of urinary tract injuries has been described in connection with the transition to use of laparoscopic technique for hysterectomies (10). In Norway laparoscopy is now the main method used for hysterectomies for patients with benign conditions (9) and its use in cancer treatment is increasing. Our dataset with 6 vaginal and 12 laparoscopic interventions in a total of 71 hysterectomies is too small for a conclusion to be drawn about the risk associated with the different surgical approaches.
Tension-free vaginal tape is the most common procedure for stress incontinence (11). A total of 9 % of post-surgical fistulae in our dataset were caused by tension-free vaginal tape. In Norway, 9 286 procedures involving tension-free vaginal tape were performed in the period 2004–08 (16). Extrapolated to the end of 2019, this number would be 31 443. This is equivalent to 3.5 per 10 000 women who underwent procedures involving tension-free vaginal tape being treated for fistula at our centre in this period.
The time from injury to onset of symptoms was significantly shorter for post-surgical fistula: a median of 1 week compared with 39 weeks in the group with post-radiotherapy fistula. This reflects the fact that a surgical procedure often results in an immediate fistula, while radiotherapy induces tissue changes over time. In both groups, however, a relatively long period elapsed between symptom and diagnosis: 17 and 14 weeks, respectively. This underlines the fact that health personnel should be more aware of the risk of fistula development as a possible cause of new-onset urine or faecal leakage following a surgical procedure or radiotherapy in the pelvic region. In our cohort, 9 % of the women healed purely as a result of temporary relief with a catheter or enterostomy. This is consistent with earlier studies (17), which show that it is beneficial to insert a catheter with good siphonage as soon as a fistula is suspected. The patient will then be able to avoid a fistula procedure.
The healing rate of 94 % (117/124) for post-surgical fistula is very good and equal to the healing rate for obstetric fistula in Norway (93 %) (5). Vaginoplasty has long been the centre's primary method, and a healing rate of 97 % is good, also when compared with data from the UK, where 86 % healing was found with transvesical fistuloplasty at a urological department (6).
Post-radiotherapy fistulae healed in only 26 % of our dataset, and 72 % of them remained with a permanent urostomy or enterostomy. A British study of urogenital post-radiotherapy fistulae found 53 % healing (6), and an American study of post-radiotherapy bowel complications found that 63 % of those with enterogenital fistulae needed a permanent stomy (18). Women with post-radiotherapy fistula often had problematic symptoms of radiation damage other than urinary/faecal leakage as a consequence of a fistula, such as bladder pain, dysuria and diarrhoea (13). Hyperbaric oxygenation is often used in attempts to treat these patients. Few patients in our cohort received this treatment, and we cannot assess the extent to which this contributes to fistula healing.
Participation in a study by 90 % of a patient cohort is high, and must be regarded as representative for our treatment cohort. Although patients were registered consecutively at the centre, information regarding specific clinical details and therapeutic outcomes was added retrospectively. The study therefore has the general limitations associated with a retrospective cohort study.
The primary goal of the study was to demonstrate the outcome of the treatment. As in several other studies (19), the lack of patient-reported data on quality of life can be regarded as a weakness. We are therefore currently reviewing possible relevant measures of quality to include in the service's register, to make provision for this aspect in future patient therapy.