Comparison Of Endorectal Advancement Flap And Two-stage Seton Fistulotomy For The Treatment Of Horseshoe Fistula:a Retrospective Analysis

BackgroundTwo-stage seton fistulotomy(TSSF)is one of the main operation methods for the treatment of horseshoe fistula and other complex anal fistulas,but its breaching sphincter and easily leads to the occurrence of fecal incontinence and other complications.Operations preserving sphincter function such as Endorectal Advancement Flap(ERAF),Ligation of intersphincteric fistula(LIFT),Video-assisted anal fistula treatment(VAAFT),is expected to improve the situation and reduce complication rates,but evidence is scant.Objectives1.To compare the healing rate and complication rate of the treatment of horseshoe fistula between ERAF and TSSF;2.To analyze the risk factors of postoperative recurrence in patients undergoing ERAF.MethodsThis is a retrospective,multicenter cohort study of all adult patients who underwent a ERAF or TSSF procedure for a cryptoglandular horseshoe1 fistula at the Sixth Affiliated Hospital of Sun Yat-sen University or Xian Daxing Hospital from January 2020 to November 2021.Patients were identified using administrative complex anal fistula codes.A total of 102 patients were included after screening.All patients were operated on by 1 of 2 colorectal surgeons with more than 10 years of experience in anal fistula surgery.Search the patient’s demographic information and clinical data in electronic and paper charts.Patients were followed up in outpatient clinic,telephone and wechat to obtain their healing or recurrence,and fill in the fecal incontinence scale(Wexner),visual analog scale(VAS),surgical satisfaction,etc.Main outcome was that the primary healing of the fistula tract,the secondary outcome included the overall success rate,operation time,intraoperative blood loss,complications,anus function,length of hospital stay,time to recurrence,hospitalization cost,operation cost,satisfaction with the surgery,and risk factor analysis for recurrence of ERAF.The measurement data conforming to normal distribution were expressed by Mean±SD,and the comparison between groups was performed by T test.Measurement data conforming to skewness distribution were represented by Median(IQR)or Median(range),and analyzed by nonparametric test and univariate/multivariate Logistic regression analysis.Classification data were expressed by rate(%),and analyzed by chi-square(X~2)test or Fisher’s exact test and univariate/multivariate Logistic regression analysis.In order to reduce the probability of error exclusion of influencing factors during univariate Logistic regression analysis,p<0.10 was taken as statistically significant difference.Kaplan-meier survival analysis was used to compare the recurrence time between the two groups,and Bonferroni method was used to compare the incidence of complications between subgroups.P<0.05 was considered statistically significant.Results102 patients were enrolled,including 25 in the ERAF group and 77 in the TSSF group.68.0%of ERAF procedure was performed by one surgeon.Another surgeon performed 32.0%of ERAF procedure and 100.0%of TSSF procedure.Primary healing rates were 80.0%versus 80.5%(p=1.000;ERAF vs.TSSF),and overall success rates were 92.0%versus 80.5%(p=0.230).The incidence of complications was 44.0%versus 70.1%(p=0.018),the incidence of postoperative pain was 28.0%versus 54.5%(p=0.021),the median VAS pain score on day 1 after surgery was 0(0-2.5)versus 2.0(0-5.0)(p=0.007),The median surgical duration(min)was 105.0(55.0-145.0)versus 46.0(32.5-63.5)(p<0.001),and the median postoperative hospital stay(days)was 24.0(6.5-29.0)versus 5.0(4.0-6.0)(p<0.001),the median total hospitalization cost(CNY)was 23125.5(17512.3-25018.5)versus 26710.1(21766.3-33464.3)(p=0.014),the median surgical cost(CNY)was 3266.0(2192.0-3826.0)versus 4930.0(2755.0-6028.5)(p<0.001),all of these indexes had statistically significant difference.The rates of postoperative temporary anal incontinence were 12.0%versus 16.9%(p=0.755).Multivariate Logistic regression analysis showed that the complication rate of ERAF was significantly lower(OR=0.31(95%CI,0.12-0.82),p=0.018).Univariate Logistic regression analysis showed that the risk factors for recurrence after ERAF included Parks classification(intersphincter/transsphincter vs.superior sphincter/external sphincter)(OR=0.17(95%CI,0.02-1.36),p=0.094),intraoperative blood loss(≤5ml vs.>5ml)(OR=12.0(95%CI,1.07-134.11),p=0.044).Further multivariate Logistic regression analysis showed that intraoperative blood loss>5ml was an independent risk factor,OR=15.457(95%CI,1.004-237.994),p=0.050.The median follow-up time was 55.7(13.0-95.6)weeks versus 47.9(15.7-108.7)weeks,p=0.351.Kaplan-meier survival analysis showed no difference in recurrence time(p=0.578).ConclusionsERAF procedure is an attractive,safe,effective and appropriate surgical technique of horseshoe fistula that preserving sphincter function,the primary healing rates and overall success rate is not inferior to TSSF procedure,and the incidence of complications,postoperative pain,cost and the total treatment time might be better than TSSF procedure.ERAF has good sociological and economic benefits.However,long-term results still need to be confirmed by randomized controlled trials with large sample sizes.