Risk factors for recurrence and incontinence after anal fistula surgery

Fistula-in-ano continues to raise problems that require important therapeutic decisions. Our aim was to evaluate its recurrence and incontinence risk factors.

We analysed a series of 279 patients who had undergone anal fistula surgery with long-term follow-up.

42.7% of the fistulae were considered complex and 46% had been referred from other institutions. There was delayed healing or recurrence in 7.2% patients, which appeared at a median of 4 months. The factors associated with recurrence were the type of fistula (extrasphincteric/suprasphincteric), nonidentification of internal opening (IO), recurrent or complex fistulae (CF), and associated chronic abscess. Only CF and nonidentification of IO were statistically significant in the multivariate analysis. Preoperative incontinence was a risk factor for postoperative incontinence, as were suprasphincteric, recurrent and CF. The age and gender of the patient did not influence postoperative continence, nor did the surgeon or surgical technique appear as a risk factor, although after excluding preoperative incontinent patients, fistulotomy was the technique that showed a higher risk of incontinence. Multivariate analysis only confirmed previous incontinence as a RF.

The overall recurrence rate is acceptable, but high fistulae continue to be difficult to treat. IO identification is also essential for obtaining good results. It is important to identify the patients with preoperative incontinence as they are at a greater risk of deterioration after surgery.