This is a multi-center triple blinded randomized clinical trial in which we'll compare two techniques for the treatment of simple low transsphincteric perianal fistulas. 40 patients will undergo a fistulotomy with marsupialization and 40 patients will undergo a fistulotomy with open wound. There will be an inclussion visit in which personal information will be recorded and the consent will be signed. Randomization will be done after inclusion, following a balanced blocks model. Information of the surgery technic won't be available for the investigator. The patients will have a journal in which they'll write their postoperative symptoms. Follow up will be done at weeks 2, 4 and 6 by the main investigator of each center. Data will be based in clinical examination, patient's diary and medical records. Statistical analysis of the primary outcome will be based in a superiority analysis using the Mantel-Cox test, or in case needed, a multivariate Cox regression analysis. The secondary outcomes will be analyzed by comparing times, percentages, mean or median with parametric or non parametric tests as it corresponds.
This study will compare the results of marsupialization versus open wound after fistulotomy in low transsphincteric perianal fistulas.