An Exploratory Analysis Of The Formation Of Damp-heat Betting Anal Leak And Its Recurrence Risk Factors Based On Perianal MRI

Objective:Understanding the characteristics of different types of anal fistula and anatomical differences,analysis of risk factors of recurrent patients with anal fistula,and exploring different from clinical observation in the treatment of choice for patients with anal fistula.To provide a certain direction about diagnosis and treatment scheme for clinical doctors.Methods:Retrospective analysis magnetic resonance imaging and clinical data of patients with hot and humid betting type of anal fistula to discuss characteristics about anal fistula and differences of anatomy.and analysis of influence of anal fistula recurrence risk factors.Results:Four hundred and twenty-one patients were included in this study with 378 cases of male,15.2%of whom recurred,with 300(71.2%)intersphincteric fistula,105(24.9%)transphincteric fistula and 16(3.8%)supersphincteric fistula.The mean BMI(body mass index)of 24.75kg/m~2.The mean hospitalization is 8.17 days.The number of fistula whose internal opening located in the back anal is 282.There are significant difference in the height of internal opening,the thickness of the external sphincter and internal sphincter lateral clearance between the different types of anal fistula patients with anal fistula.And there are 81(19.2%)horseshoe anal fistula,compared with other pure anal fistula,its height of internal opening(3.25+/-1.18 cm vs 1.18+/-0.99 cm)and thickness of internal sphincter lateral clearance(2.37+/-0.04 mm vs 1.99+/-0.18 mm)are greater than the latter(P<0.05).Also,types of anal fistula,position of internal opening and selection of operation are independent risk factors for recurrence of anal fistula.And the risk of recurrence in horseshoe anal fistula is higher than other pure anal fistula((RR=52.4,95%CI 4.40-624.08),in elderly patients are higher than the young and middle-aged patients(RR=37.15,95%CI 1.87-738.84).preoperative abscess incision can also help reduce the risk of recurrence of the fistula(RR=0.004,95%CI 0.00-0.06).Meanwhile,the risk of recurrence will be increased as the increasing of height of internal opening or the thickness of intersphincter and the decreasing of thickness of internal sphincter lateral and anterior clearance.Conclusion:The anal fistula form may be affected by thickness of extersphincter and internal sphincter lateral clearance,and different types of anal fistula have significant differences about the height and location of internal opening,including horseshoe anal fistula,type of anal fistula,location and height of internal opening,operation method,the thickness of the internal sphincter,lateral and anterior of the internal sphincter gap,age difference and preoperative abscess incision are independent risk factors for recurrence of anal fistula.