Perianal fistulas passing through the upper or middle third of the external anal sphincter present a challenge to many surgeons. Despite new treatment modalities such as closure of the fistulous tract with fibrin glue or a bioprosthetic plug, transanal advancement flap repair still provides a useful tool in the treatment of these fistulas. It enables healing of the fistula without damage of the external sphincter and consequent fecal incontinence. Initially, the reported healing rates varied between 84% and 100% [12–15]. However, during the last decade, it has become clear that TAFR fails in one out of three patients [1–7]. Until now, no definite risk factor for failure has been identified. Recently, we examined the outcome of repeat flap repair in 26 patients, who encountered a failure after the initial procedure . In all these patients, we noticed complete healing of the advancement flap, except at the site of the original internal opening. This remarkable clinical finding and the lack of predictive factors for failure suggest that persistence of the fistula might be due to ongoing disease within the remaining fistulous tract. Obliteration of this tract with a surgical adhesives such as fibrin glue and Bio Glue® as an adjunct to flap repair [7, 16–18] has not only failed to improve the healing rate, but even had a detrimental effect on the outcome. Some authors advocate preoperative seton drainage, since it allows drainage of the fistulous tract, thereby reducing the inflammatory activity within the tract and resolving secondary tracts [5, 9, 10]. In a retrospective study, Sonoda and co-workers were the first to observe a beneficial effect . In a relatively large series of 105 patients, 56 patients underwent preoperative seton drainage. Comparing patients with and without preoperative seton drainage, they found a healing rate of 73.2% and 51.2%, respectively. This difference was statistically significant. However, their study included a large number of patients suffering from a rectovaginal fistula and patients with a fistula due to Crohn's disease. Only 44 patients presented with a fistula of cryptoglandular origin. Unfortunately, the authors omitted to provide data regarding preoperative seton drainage in this group of patients. Van der Hagen and co-workers described the outcome of TAFR after preoperative seton drainage in 23 patients with a fistula of cryptoglandular origin . Five of these patients also had a diverting stoma. Although the healing rate was quite high (78%), no comparison was made with patients undergoing TAFR alone. Two other studies, conducted by Zimmerman et al. and by Van Koperen and co-workers indicate that preoperative seton drainage does not affect the outcome of TAFR [6, 11].
The present series comprised 278 patients. Sixty-eight of our patients underwent seton drainage prior to TAFR. Since we were not able to show any beneficial effect of preoperative seton drainage in this relatively large series, it seems unlikely that this type of preoperative treatment provides a useful tool to enhance the outcome of TAFR. However, a drawback of the present study is its retrospective design. We have considered the possibility that the complexity of the fistula might have been a reason to allow preoperative seton drainage. Reviewing the clinical charts, we found no specific reasons for seton placement. Both centers are tertiary referral centers, and the major part of the patients was referred from smaller hospitals. A part of these patients were admitted to one of both centers with a seton in situ. Many surgeons are not confident with treating high transsphincteric fistulas, and the policy of some of these referring surgeons is to place a seton to bide the time until definite treatment. Moreover, we analyzed the fistula characteristics. We found no differences in the baseline fistula and patients characteristics between patients with and without preoperative seton drainage. Patients admitted, to any of the centers, with a seton did not have a more complex fistulae. Moreover, clinical chart review revealed no specific reasons for seton placement. The main reason was the fact that most surgeons are uncomfortable in treating patients with a high transsphincteric fistula. To bide the time until definite surgery, some referring surgeons have the policy to place a seton in order to minimize complaints and prevent acute anal sepsis. Taking into account the facts stated above, in our opinion, the risk on selection bias is negligible. In our opinion, preoperative seton drainage does not positively affect the outcome of TAFR by diminishing the inflammatory activity in the fistulous tract.
All our patients who underwent TAFR at the Erasmus Medical Center, in Rotterdam, were immobilized for 5 days and received a clear liquid diet for 5 days. During this time period, metronidazole and cefuroxime were administered intravenously three times daily. The patients who underwent TAFR at the Leiden University Medical Center were immobilized for a minimum of 24 h and did not receive additional antibiotics. Until now, there is no evidence for the use of antibiotics, liquid diets, mechanical bowel preparation, or for keeping patients immobilized. The lack of differences in healing rates found between the two clinics might indicate that these precautions have no beneficial effect. Further research is warranted to elucidate this subject. So far, no factors have been identified that affect the outcome of TAFR. Persistence of the fistula seems to be caused by ongoing disease in the remaining fistulous tract. Further research is warranted to assess the impact of this ongoing disease on the outcome of flap repair.