To establish the predictive model of tunnel thread-drawing therapy of complex anal fistula surgery through a retrospective study by comparing the difference of the cases with and without recurrence,so as to improve the accuracy of the preoperative evaluation,and to reduce both the recurrence rate and postoperative irreversible injury.Methods:During January 2011 and December 2013 at the Shanghai University of Traditional Chinese Medicine,Longhua Hospital,217 patients received the tunnel thread-drawing therapy of complex anal fistulas.Comparisons were performed between the recurrence group and non-recurrence group on demographic,clinical signs and manifestations,MRI diagnostic data,differences in postoperative care.COX regression analysis of factors affecting patients’ recurrence was used for the prediction model to forecast the outcome.The validation group was used to validate the prediction model.Univariate analysis and multivariate analysis methods were combined on the clinical data.The Mann-Whitney test was used on non-normally distributed data.Results:Key findings from the analysis suggested that the recurrence was related with BMI,affected anal muscles,anal secreta and the internal opening quadrant.Conclusion:Through single factor analysis,it was found that when the intersphincteric,sphincter and extrasphincteric fistula occurred in the 6-9 quadrant,the range covered more than two quadrants,or the inflammation covered more than three types of muscle (the inner sphincter,the puborectalis and the levator ani muscle) or the gap (the ischiorectal space and the retrorectal space),it had the possibility to affect prognosis.