The Experimental Research Of Stent Anastomosis Of Small Intestine

Intestinal anastomosis is one of the most frequently used and basic procedure for general surgeons,the demands for an ideal intestinal anastomosis include:no leakage,no stricture,no residual foreign body and convenient,but no existing method is ideal.To solve the existing problem with anastomosis,we designed a new method:bigfragmentable stent anastomosis.We applied this method for small intestinal anastomosis,and made comparison with handsewn anastomosis.Materials and Method40 pigs were randomized into 8 groups,5 in each group.A,C group were stent group for end-to-end anastomosis,B,D group were their handsewn control groups.E,G group were stent group for end-to-side anastomosis, F,H group were their handsewn control groups.The special stent was made of 100%L-polylactic acid.All animals were operated under total anesthesia,stent anastomosis was performed for A,C,E,G groups and running single layer suturing was performed for B,D,F,H groups.The operative and anastomotic duration were recorded.The survival states and complications were noted postoperatively.A,B,E,F groups were sacrificed 2 weeks after the operation and burst pressure of anastomosis was checked.C,D,G,H groups were sacrificed 3 months after the operation and the perimeter of the anastomosis were measured.The pathologic changes of anastomosis tissue of each group were noted.Results1.There's no difference of body weight and sexual composition between groups.2.No animal died after operation.One animal in group A suffered from wound dehiscence on the operation day,and recovered after re-closure of the wound.3.Operative duration:Average operative duration of group A and B was 37.8±1.8 minutes and 42±0.7 minutes,there' s statistical significance(p=0.001).Average operative duration of group C and D was 40.6±5.4 minutes and 44.8±4.7 minutes,there' s no statistical significance(p=0.23).Average operative duration of stent end-to-end group(A+C)and control group(B+D) was 39.2±4.1 minutes and 43.4±3.5 minutes,there' s statistical significance(p=0.02).Average operative duration of group E and F was 41.4±1.3 minutes and 45.4±0.5minutes,there's statistical significance(p=0.00027). Average operative duration of group G and H was 42.8±3.4 minutes and 44.2±1.5 minutes,there' s no statistical significance(p=0.43).Average operation duration of stent end-to-side group(E+G)and control group(F+H) was 42.1±2.6 minutes and 44.8±1.2 minutes,there' s statistical significance(p=0.007).4.Anastomotic duration:Average anastomotic duration of group A and B was 150±12.2 seconds and 324±19.5 seconds,there' s statistical significance(p=1.52E-07). Average anastomotic duration of group C and D was 170±31.6 seconds and 328±27.7 seconds,there' s statistical significance(p=3.07E-05). Average anstomotic duration of stent end-to-end group(A+C)and control group(B+D)was 160±24.9 seconds and 326±22.7 seconds,there's statistical significance(p=6.95E-12).Average anastomotic duration of group E and F was 340±20 seconds and 542±25.9 seconds,there' s statistical significance(p=7.31E-07). Average anastomotic duration of group G and H was 364±32.1 seconds and 540±21.2 seconds,there' s statistical significance(p=7.16E-06). Average anastomotic duration of stent end-to-side group(B+G)and control group(F+H)was 352±28.2 seconds and 541±22.3 seconds,there's statistical significance(p=2.31E-12).5.Burst pressure:Average burst pressure of group A and B was 388±45.5cmH₂O and 184±61.9 cmH₂O,there's statistical significance(p=0.0003).The rapture site of group A was consistently anastomosis line,and rapture site of group B was consistently suture anchoring point.Average burst pressure of group E and F was 430±98.7cmH₂O and 178±49.7 cmH₂O,there's statistical significance(p=0.0009).The rapture site of group E was consistently anastomosis line,and rapture site of group F was consistently suture anchoring point.6.Perimeter of anastomosisThe normal intestinal perimeter of group C and D was 6.1±0.1 cm and 6.1±0.1cm,there' s no statistical significance.Anastomotic perimeter of group C and D was 4.6±0.1cm and 5.5±0.2cm,there' s statistical significance(p=1.58839E-06).The normal intestinal perimeter of group G and H was 6.2±0.1 cm and 6.1±0.1 cm,there's no statistical significance.Anastomotic perimeter of group G and H was 4.8±0.1 cm and 5.6±0.3 cm,there's statistical significance(p=0.0004).7.Pathology:(1).Gross appearance:Stents were all remained in the anastomosis in group A and E.Adhesion between anatomosis and surrounding intestine and omentum was observed in all animals.Edema and congestion of anastomosis was observed in all groups,but more severe in control groups.No abscess was observed.Stents have migrated out of the anastomosis in all animals in group C and G.Dense adhesion between anatomosis and surrounding intestine and omentum was observed in all animals.The anastomotic line was hardly to find on the mucosa surface in all animals,and there' no difference of gross appearance between stent and control groups on mucosa view.(2).Microscopic appearanceCollagen deposition and fibrous tissue hyperplasia was obvious in both stent and handsewn groups.There' s ulcer formation and granulation on anastomotic line,with abundant inflammatory cell infiltration,but more severe in handsewn group,and there' s more blood vessels in granulation of stent group.The collagen deposition displayed by Masson staining was similar in both groups.There's collagen deposition and scar formation in both stent and handsewn groups 3 months after the operation,and the pathologic changes were similar in both groups.Conclusions1.Both end-to-end and side-to end biofragmentable stent anastomosis is more convenient and time sparing than single layer handsewn anastomosis;2.Both end-to-end and side-to end biofragmentable stent anastomosis is stronger than single layer handsewn anastomosis;3.The perimeter of biofragmentable stent anastomosis is smaller than single layer handsewn anastomosis,but doesn't cause clinical stricture.