Clinical Application And Animal Study Of Intracolonic Bypass To Protect The Low Rectal Anastomosis

PART I Use of ValtracTM-secured intracolonic bypass to protect the low rectal anastomosis in open anterior resectionObjective:To assess the efficacy and safety of the ValtracTM-secured intracolonic bypass (VIB) in protecting low rectal anastomosis and to compare the efficacy and complications of VIB with those of loop ileostomy (LI).Method:From January 2002 to April 2006,83 patients with rectal cancer who underwent elective low anterior resection received VIB or LI. Demographics, clinical features, and operative data were recorded.Result:Forty-four patients (53.0%) received a VIB and 39 patients (47.0%) a LI. The demographics and clinical features of the groups were similar. None of the patients developed clinical anastomotic leakage. Longer overall postoperative hospital stay (21.3±5.8 days) and higher costs incurred (3.5±0.9 ten-thousand Yuan) were observed in the LI group than in the VIB group (12.5±6.3 days,2.5±0.7 ten-thousand Yuan; P<0.05). Stoma-related complications in the LI group included dermatitis (12.8%), bleeding (2.6%), and intestinal obstruction after stoma closure (5.1%). No complications were observed in the VIB group except for the ValtracTM ring discharging en bloc, which compromised fecal evacuation in two cases (4.5%). The mean time to ValtracTM ring loosening was 14 ± 3 (12-16) days.Conclusion:The VIB procedure is a safe, effective, but time-limited, diverting technique to protect an elective low colorectal anastomosisPART II Use and mini-invasive value of ValtracTM-secured intracolonic bypass in laparoscopic-assisted rectal cancer resectionObjective:To assess the efficacy and safety of the ValtracTM-secured intracolonic bypass (VIB) in protecting laparoscopic-assisted low rectal anastomosis and to compare the efficacy and complications of VIB with those of loop ileostomy (LI).Methods:Medical records of the 43 patients with rectal cancer who underwent elective laparoscopic-assisted low anterior resection and received VIB procedure or LI between May 2010 and May 2013 were retrospectively analyzed, including the patients’ demographics, clinical features, and operative data.Result:Twenty-four patients (55.8%) received a VIB and 19 patients (44.2%) a LI procedure. Most of the demographics and clinical features of the groups, including Dukes stages, were similar. However, the median distance of the tumor edge from the anus verge in the VIB group was significantly longer (7.5cm; inter-quartile range [IQR] 7.0-9.5cm) than that of the LI group (6.0cm; IQR 6.0-7.0cm). None of the patients developed clinical anastomotic leakage. The comparisons between the LI and the VIB groups were adjusted for the significant differences in the tumor level of the groups. After adjustment, the LI group experienced longer overall postoperative hospital stay (14.0 days, IQR:12.0-16.0 days; P<0.001) and incurred higher costs (6.3 ten-thousand Yuan, IQR:3.7-4.2 ten-thousand Yuan) than the VIB group (7.0 days,4.8 ten-thousand Yuan; P<0.05). Stoma-related complications in the ileostomy group included dermatitis (2,10.5%), stoma bleeding (1,5.3%), and wound infection after closure (2,10.5%). No BAR-related complications occurred. The mean time to ValtracTM ring loosening was 14.1±3.2 days.Conclusion:The VIB procedure, as a good partner with the laparoscopic-assisted rectal cancer resection, appears to be a safe and effective, but time-limited, diverting technique to protect an elective low colorectal anastomosis.PART Ⅲ Synthesis of Poly (lactic-co-glycolic acid) elastomers and manufacture of new intracolonic bypass deviceObjective:To develop and manufacture a new type of intracolonic bypass device (NIBD) by polylactic-co-glycolic acid (PLGA), and to detect the air-tightness and loosing time of the NIBD.Method:PLGA was synthesized via bulk ring-opening polymerization with GA and L-LA (80:20) as raw materials. The mould was modified on the basis of original design model, and the NIBD was manufactured by injection molding with PLGA. The air-tightness and self-degradability of the NIBD was tested in vitro and in vivo experiment. The loosening time of the NIBD was detected in vivo experiment.Result:The target product PLGA was successfully synthesized and the NIBD was manufactured with PLGA. The air tight test pressure of new intracolonic bypass system was more than 20kPa and its self-degrading time was longer than that of ValtracTM ring in vitro experiment. Its loosening time is about 4 weeks in vivo experiment.Conclusion:The NIBD was successfully manufactured with PLGA. The air-tightness, self-degradability, and loosing time of the new intracolonic bypass system was competent for fecal diverting.PART IV Animal study of new intracolonic bypass device to protect the rectal anastomosisObjective:To compare the safety and efficacy of the new intracolonic bypass device (NIBD) with those of ValtracTM introcolonic bypass (VIB).Method:A total of 20 Bama minipigs were randomized to two groups with the NIBD and VIB to protect the lower rectal anastomosis. The general condition, anastomosis, and time of bypass loosing were recorded and compared between two groups.Result:10 minipigs (50.0%) received a NIBD and 10 minipigs (50.0%) a VIB. Only 1 minipig in VIB was dead at 3 days postoperatively, and none in NIBD. One in each group showed anastomotic dehiscence, but none of the minipigs developed clinical anastomotic leakage. The pre-operative and post-operative weight, bowel preparation, intra-operative adverse events postoperative eating, post-operative defecation time, mortality, wound infection, and uncommon activity of two groups were similar. Longer operative time (108.8±35.5min) was observed in NIBD group than in VIB group (83.5±20.0min, P<0.05). The Methylene leak test showed that the lower leak rate at 3-week post-operatively (1/10,10.0%) and at 4-week post-operatively (5/10,50.0%) were observed in NIBD group than in VIB group [8/9(88.8%),9/9(100.0%); P<0.05]. Also, the lower bypass dropping rate at 3-week post-operatively (1/10,10.0%) and at 4-week post-operatively (4/10,40.0%) were observed in NIBD group (10%,40%) than in VIB group [7/9(77.7%),9/9(100.0%); P<0.05]. The dropping time of NIBD (30.8±5.5d) was longer than that of VIB (18.1±6.0d) (P<0.05).By the pathologic test 5-week postoperatively, the serious inflammation reaction and the raptured muscle layer at the site of VIB anastomosis were observed; otherwise, the mild inflammation reaction and complete muscle layer at the site of NIBD anastomosis.Conclusion:The animal experience showed that the NIBD appeared to be a safe and effective diverting technique to protect a low rectal anastomosis, with longer protective time, but longer operative time than those of VIB.