Animal Experimental Study On Artificial Annus Occluder Shape Design

Background and objectiveColostomy is one of the effective treatment measures for the treatment of colorectal diseases, but stoma complications are still the main reasons for stoma quality of life and long-term survival,traditional ostomy care through the use of the ostomy bag to collect the excreta, althouh can solve the stoma excreta management problem effectively, the stoma complications and the ostomy bag to wear on the stoma has a huge impact on peoples life,not only themselves but also their family. Many patients therefore lost confidence in life, and long-term use of the ostomy bag will be increased in patients with skin infections, making the necrosis of stoma and other complications incidence, and higher cost.With the rising incidence of colorectal cancer and other diseases,for example rectal trauma, inflammation, and congenital malformations led to permanent colostomy needs line up as many as thousands of people, one of the most common is the ileum colostomy, called colostomy. United States has stoma population about100,000each year,has been rising up to100million, more than10million stoma people increased each year in britain annual and about7000-8000cases of colostomy in Hong Kong. According to a estimates of the China Institute of stoma President Yu Dehong professor that China’s new permanent colostomy have about100,000people annual,the cumulative enterostomy about$100million,there are increasing trend in the future. This is a special group, stoma have a profound impact on their psychological, physical and social. Intestinal stoma affect peoples’quality of life because of:1. Enterostomy unable to control bowel movements, often excreta exclude, dirty body, clothing, and smelling; intestinal stoma skin around the long stool, intestinal fluid stimulation easily complicated by various types of dermatitis.3.for the long-term wear ostomy need to paste on the skin, prolonged use will easy to produce skin allergies, dermatitis, and also is expensive for long time using.Thus, the key solution of permanent colostomy and postoperative stoma care waste managements to develop a artificial anal occluder(AAO) can control defecation simulated anus.So that it can block the stoma and can automatically control the defecation,Once it come true the ten million stomas will no longer need to wear embarrassing ostomy bag. so can solve many problems of stoma complications fundamentally,stoma quality of life and living confidence has greatly improved. However, the current problems in the medical profession is how to design an automatic control bowel movemment occluder (Artifical anuas occluder, AAO) to replace the long-term wear heavy ostomy bag. Accordingly peoples do a series of related studies at home and abroad. from Coloplast Coloplast developed the world’s first self-adhesive ostomy bags start in1957, ostomy bag officially entered the life of stoma patients, However, due to need to long wear, and the ostomy heavy odor, serious impact on social activities and private life of stoma patients. In order to solve this problem, Denmark Burcharth, who devised an expansion of the material made of disposable ostomy bolt in1986, for the abdominal wall with permanent colostomy.Emboli can be inserted into the stoma intestinal swelling, to block the stoma,this br ought a major improvement in the handling of the colostomy, although the trial effect is encouraging, but the emboli shedding and leakage is still common complications, and these products are disposable supplies, and a heavier burden on long-term use in patients with medical expenses. Since then, reusable stoma closure device to become one of the hotspots of stoma care products for some time, artificial anus occluder is devided into two kinds of the abdominal wall colostomy occluder and in situ colostomy occluder depending on the different parts of using.Purpose:This topics is the Guangdong Province and research research funded projects and main do rearch in abdominal wall colostomy occluder shape design with animal experiments, because the occluder is very large, we choose the miniature pig as an experimental object, after the establishment of the colostomy animal model, we do animal experiments on the occluder bolt body size and shape to explore the complications of the use of occluder when the optimal size range and shape by observation the leakage of the stoma, the stoma general concept, inflammatory infiltration, perfusion and testing serum enzyme indicatorsContents and methods1making of artificial anus occluder model1.1Making the default programMaking several programs and reviewing literature in preliminary experiments. to understand its colorectal lumen diameter size about35kg Tibet mini pigs as basis of the AAO design. making three preset programs, and drawing projects map and three-dimensional color pictures.1.2Material selectionSelect silicone rubber materials for prototyping which has been widely used clinically and confirmed with good biological tissue compatibility1.3Sample productionSelect sample production units, according to our three-dimensional color pictures of the three design engineering production line graph, for rapid injection molding to produce a different size and shape of the occluder model1.4Determine the final sampleColostomy occluder (AAO) model is divided into two parts:composed by the adhesion to the skin around the stoma base and fixed at the base of the seal plug, the base apron and a fixed ring part take from the Two-piece ostomy bag produced by Coloplast company, the occluder bolt body is cylindrical, insert colostomy intestine and fixed on the abdominal wall together with the base part to prevent feces, the length of occluder bolt body part is fixed at5.0cm, and produce different size and shape model used in animal experiments2Making animal modelAll mini-pigs adapt to the environment before the experiment,three days of preoperative fasting for24h, ban drinking8h, the preoperative preparation in accordance with the extraperitoneal colon colostomy establish chitterlings stoma model.3Animal experimental study3.1Experimental study of colostomy closure with a diameter of change on the impact of stoma complications3.1.1Leakage rateRecord stoma leakage within2h of eating after occluder placed at each group1,4,8weeks,3.1.2The general concept and microscopic viewGross observation of local intestinal stoma with or without ischemia, necrosis and the surrounding tissue of the stoma with or without infection, etc,(b)In the block before and after the block.1,4,8weekend clip a small amount of intestinal mucosa in each group of animals stoma, soaked in10%formalin fixed, stained, and then frozen sections, Counting absolute value of neutrophils and lymphocyte in40high magnification.3.1.3Determination of intestinal perfusion Fixed after animal were anesthetized, Doppler flowmetry probe is gently placed vertically in the colon bowel in the distal2cm away from the stoma, perfusion to the block before each group as a baseline, record the5s,50s,5min,50min perfusion after block, to calculate the mean by graphics software after conversion, as measured values and draw the perfusion curve.3.2Study of stoma blood flow on different shape of the artificial anus occluder3.2.1Determination of local perfusion for the Stoma bowelAfter laser doppler flowmetry and16-channel physiological instrument connected put the needle probe of LDF at the maximum diameter of the occluder determined the10min,30min,60min perfusion after the system is stable and the occluder is stuffed the needle probes were placed at four time points of the intestinal wall position after each group measured (3,6,9,12o’clock),determination average perfusion of different sites within a certain time in same group3.2.2Determination of iFABPSelect the intestinal wall vein revealed the apparent position then extract5ml venous blood, determine the content of iFABP employing the intestinal fatty acid binding protein (iFABP) Elisa, Kit,data displayed with (x±s).4Statistical analysisStatistical analysis with software package SPSS13.0, measurement data displayed with mean±standard deviation (x±s), comparison among groups with repeated measures analysis of variance (LSD method), P<0.05as significant difference. Results1Impact on stoma complications of Occluder change in diameter1.1Comparison of the leakageLeakage rate of each group was no significant difference before and after occluder leakage rate between3.5cm、4.0cm group and3.0cm group were significantly different (P<0.05) after block after the first week and4.0cm and3.0cm group at4weeks and8weeks were significantly different (P<0.05), overall leak rate increase with the diameter as a trend, but there were no significant difference among the three groups at4weeks and8weeks1.2Inflammatory cell infiltrationThe lth week and8th weeks of each diameter group neutrophil count was no significant difference before and after block,at the4th weeks,3.5cm and4.0cm compared with3.0cm group were significant difference (P<0.01),lymphocyte count was significantly different (P<0.01) among different diameter groups and different time points, at the1th week after block,3.5cm and4.0cm group compared with3.0cm group was no significant difference at the4th week,3.5cm and4.0cm group compared with the3.0cm group are significant differences (P<0.01). and at the8th week,3.5cm compared with3.0cm group were no significant differences, but4.0cm compared with3.0cm group were significantly different (P<0.05).1.3Comparison of intestinal perfusionThe blood flow of3.0cm group compared with baseline levels decreased little Began to recover in the first5min,restored to the block level before to the first50min the blood flow has a rapid decline at3.5cm and4.0cm group after5s block, down to the lowest point at the50th second,the blood flow at3.5cm group began to recover after5min block and4.0cm group recovery trend is not obvious, but still more than in200PU 2Impact of intestinal blood flow on different shape2.1Determination of groups bowel perfusionStoma intestinal perfusion of group A compared with the control group there was a significant difference at all time points (p<0.05). and group B compared with the control group were significantly different (p<0.05) at the first10min block, showed no significant difference at the remaining time points compared with control group. It can be seen from Figure2,the intestinal perfusion of group A is changing over time, has a rapid decline, followed by a downward trend slowed Group B in the block10min perfusion decreased to the lowest point But then began to rise slowly, and the perfusion of the control group did not change significantly2.2Intestine perfusion of different bit-pointBlood flow perfusion volume was no significant difference between the different sites of A, B, C, shown in Figure2:no significant difference in groups among different sites before the perfusion volume but the three perfusion gradually increased generally.2.3Determination of intestinal fatty acid binding protein (iFABP)The iFABP contents of A, B, two groups were4.35±0.29and4.43±0.07, between the two groups showed no significant difference (p=0.672>0.05), also still were no significant difference between the two groups1h block after (p=0.864>0.05), and were significantly different at the2h and3h (p<0.05).Shown in Figure3: the iFABP content within the block1h Rise gradully in group A, then rising rapidly, and get to maximum after2h block, then decreased gradually Group B increased at first, but the upward trend is not obvious,2h later return to the block level before gradually. Conclusion1. To make an animal experimental study on artificial annus occluder which is designed and and made by myself for the first time, and to explore the best size and shape of it.2. It can be considered that at the basis of leakage is not serious situation, when the diameter of artificial anal occluder is0.5～1.0cm larger than stoma diameter will has a good sealing effect, and least blocking complications.3Colostomy occluder bolt body is cylindrical has lower impact on stoma and higher security compared with spherical body.