The Imaging Evaluation Of Anorectal Function After Prophylactic Ileostomy Combined With Anus Preserving Operation Of Low Rectal Cancer

Objective By dynamic MRI and 3D HR-ARM multimodal examination,anorectal function in patients with low rectal cancer ofanus-preserving operation was quantitatively evaluated by analyzing the morphology and dynamics of anorectal region.To explore the best time window for ileostomy after ostomy,provide visual,quantitative,and reproducible imaging evidence for clinically appropriate treatment plans.Materials and methods A total of 72 patients with low rectal cancer diagnosed by anorectal department of Tianjin Union Medical Center were enrolled in the study.All the patients were examined by rectal touch,colonoscopy and conventional pelvic MRI.Fifty patients who met the inclusion criteria and intended to perform anus-preserving operation were subjected to dynamic MRI and 3D HR-ARM examination.Anorectal surgery for low rectal cancer was performed within one week after the examination.Among the 50 patients,39 patients who underwent anus-preserving operation combined with prophylactic ileostomy were included in the experimental group,and only 11 patients who underwent simple anus-preserving operation were included in the control group.The patients in the experimental group were required to receive follow-up examinations before closure surgery and were divided into three groups according to the time for preventive prophylaxis: group A was performed within three months and three months after the anus-preserving operation;group B were operated on three months or more than six months and six months after the anus preservation operation;group C were patients undergoing surgery for more than 6 months after the anus preservation operation.Patients in the control group were followed up within one month after the operation.50 patients reviewed the examination including routine and dynamic pelvic MRI,3D HR-ARM examination.SPSS 25.0 statistical software was used to perform T test s,one-way analysis of variance,Spearman and Pearson correlation analysis.The anorectal function after anus-preserving operation was compared between the two groups of patients,that is,whether the dynamic MRI and 3D HR-ARM examination had any differences between the relevant measures.Comparison of the incidence of anastomotic leakage and anus recovery time in the two groups was compared.To compare the gender difference in the anorectal function after anus-preserving operation in the experimental group.It was examined correlation analysis between dynamic pelvic MRI and 3D HR-ARM parameters before and after anus-preserving operation.Comparing the experimental group,patients in the three groups undergoing anus-preserving operation were examined for their anorectal function(including routine and dynamic pelvic MRI,3D HR-ARM examination after surgery,and whether there were statistically significant differences.The correlation between the index of statistical difference and the time window of repayment.Results(1)There was no statistically significant difference in anorectal function data between the experimental group and the control group in the dynamic MRI examination before the anus preserving operation(P>0.05).(2)Before preventive ileostomy surgery in anus-preserving operation of low rectal cancer,the experimental group and control group differences in patients with dynamic MRI examination respectively puborectalis thickness(PR-T)at rest phase and lifting phase and external anal sphincter thickness(EAS-T)at lifting phase were statistically significant statistically significant difference(P<0.05);the average thickness of the PR-T and EAS-T in the experimental group were all larger than those in the control group.In the 3D HR-ARM examination,there were statistically significant differences between the two groups in the five indexes of anal maximal systolic pressure(MSP),anal relaxation rate(ARR)and fisrt sensory threshold(FST),initial defecation threshold(IDT)and maximum tolerance threshold(MTT)(P<0.05).Among the two indexes of the MSP and the ARP,the average of the experimental group was greater than the control group;but in the IST,the IDT,and the MTT,the average of the experimental group was smaller than the control group.(3)After sphincter preserving,only 2.5%(1/36)of patients in the experimental group had anastomotic leakage,and 9.1%(1/11)of patients in the control group.The incidence of anastomotic leakage in the control group was higher than the experimental group.Twenty-nine patients(74.4%)in the experimental group returned to exhaust within 3 days,and only 4 patients(36.3%)in the control group.In the experimental group,the recovery rate was significantly higher in the control group within 3 days.(4)After anus-preserving operation,the gender in the dynamic MRI examination were statistically significant difference of the M line at lifting phase and defecation phase,the internal anal sphincter thickness(IAS-T)at defecation phase,and the mean of male patients is less than that of women in those indexes.But there was no significant difference in all indexes of the 3D HRARM examination.(5)The correlation analysis between preoperative dynamic pelvic MRI and 3D HR-ARM measurements in the experimental group is as follows: the resting phase H line was positively correlated with the ARR(r=0.353,P=0.030),and the EAS-T was positively correlated with the MSP(r=0.323,P=0.048);in lifting phase there was a positive correlation between ARA and the IDT(r=0.382,P=0.018),the H line length was positively correlated with the residual anal pressure(RAP)(r=0.367,P=0.024);in defecating phase,there was a positivecorrelation between the EAS-T and the residual anus pressure(RAP)(r=0.347,P=0.033),the IAS-T was also negatively correlated with the RAP(r=0.332,P=0.042).In the experimental group after anus-preserving operation,there was a positive correlation between the resting phase M line and the ARR(r=0.342,P=0.044);the lifting phase ARA was negatively correlated with the MSP(r=-0.349,P=0.037),there was a positive correlation between PR-T and MSP(r=0.401,P=0.011);in defecating phase,there was a positive correlation between PR-T and RAP(r=0.330,P=0.040),positive correlation between IAS-T and RAP(r=0.342,P=0.033),ARA and IDT was a positive correlation(r=0.411,P=0.009).(6)In the dynamic MRI evaluation of anorectal function in lifting phase of ARA,lifting phase of H lineand the three-phase of PR-T were statistically significant differences in A,B,C three groups(P<0.05).The maximum resting pressure(MRP)of the anus,MSP and MTT in the 3D HR-ARM examination were statistically significant differences in three groups(P<0.05).The other indexes were not statistically significant difference in three group.(7)In A,B,and C groups,the statistical analysis of the differences can be obtained in the three groups of A,B and C.The ARA of lifting phase was statistically significant difference respectively between group A and group B,and group A and group C(P<0.001;P=0.001);group A of patients with ARA greater than the group B and group C.The H line of lifting phase was statistically significant difference respectively between group A and group B,and group B and group C(P=0.027;P < 0.001);group B of patients with H line smaller than the group A and group C.The PR-T gradually increased with time in three phases.There was statistically significant difference respectively between group A and group B,and group A and group C.And the PR-T of group A is less than that of B and C.It is thinnest in defecating phase and the thickness of resting phase between in the other two phases.The MRP was statistically significant difference respectively between group A and group B,and group A and group C(P=0.038;P=0.017);group A of patients with MRP greater than the group B and group C.The MSP was statistically significant difference respectively between group A and group B,and group A and group C(P=0.038;P=0.017);group A of patients with MRP lower than the group B and group C(P=0.007;P=0.003);the value of MSP in the group B was morethangroup A and group C.The MTT was statistically significant difference in three groups.(8)The results of the correlation analysis between the statistically-different indicators of the three experimental groups and the close time window as follows: the lifting phase ARA was negatively correlated with time(r=-0.425,P=0.007);resting phase PR-T(r=0.382,P=0.016),lifting phase PR-T(r=0.343,P=0.033),defecting phase PR-T(r =0.364,P=0.023),MSP(r=0.431,P=0.006)and MTT(r=0.871,P<0.001)were positively correlated with stoma remission time.Conclusion(1)Patients with low rectal cancer anus-preservation and prophylactic ileostomy were significantly superior to those with simple anus-preservation in the recovery of anorectal dynamic function after anus-preserving operation;however,patients with simple anus-preserving anorectal surgery had superior anorectal sensory functionto ostomy patients.(2)There was a gender difference in the anorectal dynamic function between patients who had received anus-preserving operation.The mean of the M-line and IAS-T was lower in males than in females.The anorectal dynamic function of males was better than that of females,and there was no gender difference in sensory function.(3)Dynamic pelvic MRI can qualitatively and quantitatively observe anorectal function before and after anal anus-preserving operation.There was a significant correlation between the maximal systolic pressure,the rate of relaxation of the anal canal,the initial defecation threshold,and the residual pressure of the anal canal in dynamic pelvic MRI and 3D HR-ARM examinations.(4)Patients with anus-preserving operation combine with prophylactic ileostomy can reduce the incidence of postoperative anastomotic fistula complications.It is helpful to recover the function of intestinal tract and anorectal function after the operation,and improve patients’ quality of life.(5)Patients had better recovery of anorectal function within 3-6 months after anus-preserving operation than those within 3 months,and there was no significant difference between patients more than 6 months.Therefore,our study believes that 3 to 6 months after anus-preserving operation is the optimal time window for colse stoma.(6)Dynamic pelvic MRI can objectively reflect the preoperative and postoperative anorectal function of rectal cancer,and has correlation with multiple indicators in 3D HR-ARM examination.And it can better evaluate the anorectal function from rectal motility and rectal sensation,providing an objective basis for the detection of anorectal function and the individualization of the patient’s treatment plan.The MTT for anus-preserving operation combined with prophylactic ileostomy patients was highly correlated with colse stoma time,and there was a correlation between ARA,PR-T,MSP and colse stoma time time.Therefore,the longer the waiting time,the stronger the patient’s ability to control the fecal.