Exploring The Related Factors Of Anal Fistula Recurrence And Anal Incontinence Based On Preoperative Evaluation By Magnetic Resonance Imaging

Objective:Anal fistula is a common disease in anorectal surgery,and common postoperative complications include recurrence and fecal incontinence.There are few studies on postoperative recurrence and fecal incontinence of anal fistula,and there are even fewer studies on postoperative recurrence and fecal incontinence related to MRI..This study is based on MRI to explore the risk factors for recurrence of anal fistula after surgery,and evaluate the related factors that affect postoperative anal function.It aims to provide a reference for reducing the risk of recurrence and incontinence,as well as the management of fistulas.Methods:This study mainly collected the clinical data and imaging data of patients with anal fistula who underwent surgical treatment in our hospital from January 2013 to June 2018,and performed preoperative MRI evaluation and postoperative follow-up on the patients included in the study,and recorded the patients’ anal function and fecal recurrence.In this study,recurrence is defined as a fistula that does not meet the healing standard(complete epithelialisation of the wound)after the operation or the fistula reappears after healing,or requires other surgery;patients with Wexner score≥5 were defined as "moderate to severe incontinence" and included in the fecal incontinence group.The researchers analyzed the factors related to recurrence and incontinence.Results:This study included 459 patients with anal fistula,all of whom received preoperative magnetic resonance examination and surgical treatment.The median age was 35 years,the median follow-up time was 30.9 months;the postoperative recurrence rate was 13.7%(63/459),and the incontinence rate(Wexner≥5 points)was 6%(27/459).Cryptoglandular anal fistula as recurrence(OR=0.443,CI95%(0.198-0.947),P=0.036)and incontinence(OR=0.095,CI95%(0.031-0.297),P<0.01),and the internal opening is located on the posterior midline(OR=0.365,CI95%(0.141-0.944),P=0.038)protective factors,the risk of fistula recurrence decreased.The lesion passes through the ischiorectal space(OR=2.333,CI95%(1.220-4.464),P=0.01),and the internal opening is located on the dentate line as a high risk factor for recurrence(OR=2.411,CI95%(1.243-4.677),P=0.009).In terms of surgery,loose-seton is a risk factor for recurrence(OR=3.736,CI 95%(1.481-9.420),P=0.005);and LIFT technique is also an obvious recurrence factor(OR=4.323,C195%(1.166-16.027),P=0.029).Anal fistula with abscess is a risk factor for anal incontinence,and Single abscess(OR=3.349,CI95%(1.104-10.164),P=0.033)and multiple abscesses(OR=5.153,CI95%(1.535-17.296),P=0.008)increased the risk of anal incontinence after anal fistula surgery.Subcutaneous fistula,intersphincter fistula(OR=0.117,CI95%(0.021-0.640),P=0.013)and low transsphincteric fistula(OR=0.075,CI95%(0.013-0.438),P=0.004),and passing through the perianal space(OR=0.300,CI95%(1.220-4.464),P=0.021)are all protective factors for incontinence.Conclusion:MRI is an accurate technique for evaluation of anal fistula,and postoperative clinical outcomes depend on multiple factors.The management of fistula is a very complicated process,including the preoperative evaluation of the fistula as much as possible,reasonable selection of surgical procedures,and postoperative follow-up.The results of the study are used as a reference index for early stage of fistula management.These indicators are used to identify patients with anal fistula who are at risk of potential recurrence and incontinence.