Study On The Internal Correlation Of The Anus Function And The Change Of Colo-anarectal Dynamics After Low Anterior Resection In Patients With Rectal Cancer

Objective:To approach the internal correlation of the anus function and the change of Colo-anarectal dynamics in lower rectal cancer at different period after low anterior resection (LAR).Methods:Forty patients with lower rectal cancer who underwent low anterior resection (LAR)and forty normal control were enrolled in study.The anal resting pressure(ARP),maximal squeezing pressure(MSP),high pressure zone(HPZ),rectal resting pressure(RRP),first perception(FP),urge volume(UV),maximal tolerable rectal volume(MTV),rectal compliance(RC)and rectoanal inhibitory reflex(RAIR)were assessed with anorectal manometry before and at the 1st,3rd,6ed,month after operation.The t test wax used to compare preoperative and postoperative data.The multinomial logistic regression was used to evaluate the relativity between the anus functions and postoperative manometry.A P value of less than 0.05.0.01 was considered statistically significant(SPSS13.0 for windows).Results:①There were no significant change of the ARP,MSP,HPZ,RRP,FP,UV,MTV,RC and RAIR of health adult compared rectal cancer patients before operation(P＞0.05).②The ARP decreased significantly(P＜0.05)at the 1st month(30.47±13.78 mm Hg)after LAR,But it reconered gradually,and there were no significant difference at the 3nd(43.78±11.43 mm Hg)adecreased 6ed month(46.42±10.67 mm Hg)compared with the ARP before operation(45.46±12.56 mm Hg)(P＞0.05).③There were no significant change on the dates of Msp(preoperative:132.53±30.12 mm Hg vs postoperative:1st month:121.45±31.57 mm Hg,3rd month:128.35±30.47 mm Hg,6ed month: 135.12±29.57 mm Hg)(P＞0.05)measured before and after operation.④The anus HPZ shifted downward significantly at the 1st month(2.71±0.36CM)after LAR(P＜0.05),and it accepled gratually,There were no significant change at thvsn.3rd(3.57±0.46CM)and 6ed month(3.61±0.40CM)after LAR compared with anus HPZ before operation(3.60±0.42CM)(P＞0.05).⑤The RRP increased significantly at the 1st(9.10±4.18 mm Hg)and 3rd month(7.84±3.05 mm Hg)after LAR(P＜0.05),then it decreased and there were no significant difference at the 6ed month(6.01±4.05 mm Hg)after LAR compared with the date before operation(5.92±3.35 mm Hg) (P＞0.05).⑥There were significant reducing on the FP and UV at the 1st and 3rd month after LAR (P＜0.05),and no significant cange at the 6ed month after operation than the dates before LAR (P＞0.05).⑦The MTV decreased mostly significant at the 1st month(120.95±28.47ml)after LAR (P＜0.01),and at the 3rd(150.23±32.67)and 6ed month(160.93±30.58ml)the change existed significantly still compared with the date before operation(205.87±36.58ml)(P＜0.05).⑧The RC significantly deduced at the 1st(2.84±0.43ml/mm Hg)and 3rd month(3.95±0.45 ml/mm Hg)after LAR(P＜0.05),and the deducing was not significant at the 6ed month(4.81±0.53 ml/mm Hg)compared with the date before operation(5.65±0.57)(P＞0.05).⑨The positive rates of RAIR were 40%,52.8%and 60%at the 1st,3rd and 6ed month after LAR,it increased gratually,but there were still significant decrease compared with the RAIR(90%)before operation(P＜0.05).⑩The anus function recovered by dgrees,the excellent rates were 70%,82.5%and 90% separately at the 1st,3rd and 6ed month after LAR(α=0.0125 x~2=13.801 P=0.001).(11)There were significant positive correlation between the ARP,MTV,RC and the anus function(P:0.002,0.007,＜0.001 r_s:0.478,0.419,0.529).(12)1st was a significant positive correlation between the anastomotic level and the anus function(P＜0.001 r_s=0.556).Conclusions:①The changes of the anus function and the colo-anarectal dynamics after LAR with rectal cancer are temporarity.it will recover gradually with time passing by(6 month later).②The anastomotic level affected the anus function after rectal cancer operation.③The distance between the anastomotic level and the edge of alls≥4 cm is a essential condition of preserve a complete anus function.④The long-time influnce of rectal cancer with LAR to anus function after operation is not serious.LAR is the first choice operation pattern to preserve the anus function of rectal cancer patients.