The Experimental Research Of Laparoscopic Biofragmentable Stent Anastomosis Of Colon In Porcine

Purpose This experiment verifies whether there are differences between laparoscopic biofragmentable stent anastomosis and laparoscopic hand-sewn anastomosis of colon, and whether there are advantages of laparoscopic stent anastomosis, furthermore, this experiment investigates the feasibility and security of laparoscopic biofragmentable stent anastomosis of colon.Methods20pigs were randomized into4groups,5in each group. A, C group were stent group for end-to-end anastomosis, B, D group were handsewn control groups. The special stent was made of polyglycolic acid and12.75%barium sulphate. All animals were operated under total anesthesia with tracheal intubation, laparoscopic stent anastomosis was performed for A, C groups and laparoscopic single layer suturing was performed for B, D groups. We completed group C, D firstly and group A, B secondly to observe the influence of skill enhancement on operation. The operative and anastomotic duration were recorded. The survival states and complications were noted postoperatively. A、B groups were sacrificed2weeks after the operation and burst pressure of anastomosis was checked. C, D groups were sacrificed3months after the operation and the perimeter of the anastomosis were measured. Anastomotic tissues were histologically analyzed under the hematoxylin-eosin (HE) staining, Masson staining, the immunohistochemical staining of anti-TGF-β1, anti-b-FGF and anti-a-SMA.Results There’s no difference of body weight and sexual composition between groups.1animal died11weeks after operation in group C, autopsy showed it died of bowel obstruction caused by congenital intestinal valvular disease. All of the other pigs had no complications during the experiments.Average operative duration of group A and B was56.6±16.6minutes and100.8±34.1minutes, there’s statistical difference (p=0.031). Average operative duration of group C and D was86.6±10.9minutes and115.8±20.8minutes, there’s statistical difference (p=0.024). Average operative duration of stent end-to-end group (A+C) and control group (B+D) was71.6±20.6minutes and108.3±27.8minutes, there’s significant statistical significance (p=0.004). Average operative duration of the early5cases (group C) and late5cases (group A) of laparoscopic stent anastomosis was86.6±10.9minutes and56.6±16.6minutes, there’s statistical difference (p=0.010). Average operative duration of the early5cases (group D) and late5cases (group B) of laparoscopic hand-sewn anastomosis was115.8±20.8minutes and100.8±34.1minutes, there’s no statistical difference (p=0.426).Average anastomotic duration of group A and B was23.6±14.8minutes and57.2±24.3minutes, there’s statistical difference (p=0.030). Average anastomotic duration of group C and D was42.6±18.0minutes and73.8±11.5minutes, there’s statistical difference (p=0.011). Average anstomotic duration of stent group (A+C) and control group (B+D) was33.1±18.5minutes and65.5±19.9minutes, there’s significant statistical significance (p=0.001). Average anstomotic duration of the early5cases (group C) and late5cases (group A) of laparoscopic stent anastomosis was42.6±18.0minutes and23.6±14.8minutes, there’s no statistical difference (p=0.106). Average anstomotic duration of the early5cases (group D) and late5cases (group B) of laparoscopic hand-sewn anastomosis was73.8±11.5minutes and57.2±24.3minutes, there’s no statistical difference (p=0.204).Average burst pressure of group A and B was108.0±34.9cmH2O and97.5±60.2cmH2O, there’s no statistical difference (p=0.751), but group B had1case of intestinal fistula. The rupture site of2cases in group A was anastomosis line, and rapture site of of2cases in group B was consistently suture anchoring point. Rupture site of other cases in both groups was not on anastomosis line.The normal intestinal perimeter and anastomotic perimeter of group C was7.7±0.2cm and7.7±0.4cm, there’s no statistical difference. The normal intestinal perimeter and anastomotic perimeter of group D was8.3±1.1cm and7.1±1.1cm, there’s statistical difference (p=0.047). There is no statistical difference between group C and D in normal intestinal perimeter and anastomotic perimeter.Stents were remained in the anastomosis of4cases and1case stent migration was observed in group A. Adhesion between anastomosis and surrounding intestine and omentum was observed in all animals. Edema and congestion of anastomosis was observed in all groups.1case intestinal fistula with abdominal abscesses was observed in group B.Stents had migrated out of the anastomosis in all animals in group C. Adhesion between anastomosis and surrounding intestine and omentum was observed in all animals. The anastomotic line was hardly to find on the mucosa surface in both groups.2cases of intestinal cavity getting smaller were observed in group D, but no intestinal obstruction was observed in group C and D.2weeks after operation, anastomotic tissue histological study showed mucosal deletion, proliferation of granulation tissue. Collagen deposition and fibrous tissue hyperplasia was found in both groups. There was abundant inflammatory cells infiltration in both group but more severe in hand-sewn group. The immunohistochemical staining of anti-a-SMA was negative in both groups showed no smooth muscle growth in anastomotic tissue. There was no difference of the immunohistochemical staining of anti-b-FGF and anti-TGF-β1between two groups.3months after operation, anastomotic tissue histological study showed that mucosa was completely covering the anastomotic tissue. Fibrous tissue proliferation, collagen deposition and scar formation with smooth muscle growth was observed in both groups. There was more smooth muscle found in stent group. The immunohistochemical staining of anti-a-SMA was positive in both groups showed smooth muscle growth in anastomotic tissue. There was no difference of the immunohistochemical staining of anti-b-FGF and anti-TGF-β1between two groups.Conclusion:Laparoscopic biofragmentable stent anastomosis is a safe and feasible method of intestine anastomosis which makes the anstomosis easier and faster. Laparoscopic stent anastomosis and laparoscopic single layer hand-sewn anastomosis of colon makes an equal healing result.