Construction Of A Risk Score System For Adult Acute Small Bowel Obstruction

Acute small bowel obstruction(SBO)accounts for about 3% of the emergency inpatients.SBO is easy to progress to strangulated small bowel obstruction(SSBO)without timely treatment.As a fatal acute abdomen accompanying blood supply disorder of small bowel,SSBO is usually caused by mesenteric vascular compression,thrombosis or embolism.In the patients with SBO,the incidence of SSBO was 5-42%,and the total mortality was 20-40%.Effective treatment of SSBO relies on timely and accurate preoperative diagnosis.Misdiagnosis of SSBO probably leads to unnecessary surgical trauma,while missed diagnosis may delay the operation time and increase mortality and medical costs.The etiology of SBO is difficult to be determined before operation due to its complexity.Investigation of etiology is helpful to provide scientific basis for treatment of SSBO.Moreover,many studies attempt to establish prediction model by clinical manifestations,laboratory and radiological variables,however,no consistent conclusion has been reached up to now.Previous studies have shown that neither classical clinical manifestations nor laboratory indicators could predict SSBO independently.Among the diagnostic methods on SBO,the detection rate is only 50 ~ 60% in X-ray examination and and the etiological determination is inaccurate too.With the rapid progress of hardware and software technology,MSCT has obvious advantages in identification of the pathogeny and ischemia of SBO.Nowadays,most of the studies on predictive scoring models focus on adhesive small bowel obstruction(ASBO)since it is the main types of SBO.Nevertheless,the conclusions from ASBO are not applicable for the patients with SBO caused by non adhesion factors(incarcerated hernia,intra-abdominal abscess,peritonitis,appendicitis etc.).Although there are also a few studies on the prediction model of all etiological SBO,but some variables(oral or intravenous contrast agents)of these models are difficult to be collected in the emergency department.For physician and general surgeon in the emergency department,it is necessary to construct a simple,practical and comprehensive scoring model for SSBO identification.In this research,a case control study was carried out to analyze the etiological characteristics,the clinical,laboratory and CT variables of SBO to develop a small bowel obstruction score(SBO-score)system.PART I: The diagnostic value of CT plain scan for adult strangulated small bowel obstructionObjective: This study aimed to explore the predictive variables of CT for adult strangulated small bowel obstruction(SSBO)and investigate the diagnostic value of CT scan for SSBO.Methods: The clinical data of 487 cases with small bowl obstruction(SBO)who were admitted to the hospital of Drum Tower Clinical College of Nanjing Medical University from June 2010 to September 2016 were analyzed retrospectively.15 kinds of CT scan signs,clinical operation and pathological information were collected in each patient.The differences between SSBO group and simple group were compared by multivariate regression equation.Results: There were 259 patients in the strangulation group and 228 patients in the simple group.Univariate analysis of the data indicated that there were 7 significant factors related to SSBO,including segmental mesenteric fluid,thick-walled small bowel,intraabdominal free fluid,mesenteric fat density syndrome,intestinal wall of hyperattenuation,cable sign,beak sign.The multivariate logistic regression analysis showed that there were statistically significant in 5 risk factors,according to the intensity of the effects was as follows: segmental mes-enteric fluid(OR=15.165),intraabdominal free fluid(OR=6.359),mesenteric fat density syndrome(OR=5.891),intestinal wall of hyperattenuation(OR=4.026),thick-walled small bowel(OR=2.026).Conclusions: Regression analysis of multiple preoperative criteria demonstrates that segmental mesenteric fluid,intraabdominal free fluid,mesenteric fat density syndrome,intestinal wall of hyperattenuation,thick-walled small bowel are the variables predictive of SSBO.PART II: Construction of a risk score system for adult acute small bowel obstructionObjective: Accurate identification and early surgery are the main treatment strategies for acute intestinal obstruction combined with strangulation in adults.Therefore,it is very important to find accurate preoperative prediction tools.The aim of this study was to screen for valuable risk factors of adult strangulated small bowel obstruction and create a simple and practical predictive scoring system.Methods: The clinical data of 487 adult patients with acute small bowel obstruction who were hospitalized in Drum Tower Clinical Medical College of Nanjing Medical University from June 2010 to September 2016 were analyzed retrospectively.47 preoperative risk factors were analyzed.A multi-factor regression equation and the area under the curve of the ROC working curve were used to create a scoring system for acute small bowel obstruction.Results: There were 259 cases of strangulated small bowel obstruction(53.18%)in 487 patients with acute small bowel obstruction.Variables with predictive value for strangulated small bowel obstruction included mesenteric fluid sign [odds ratio(OR),(OR = 12.943)],muscle tension(OR = 7.275),signs of ascites(OR = 6.424),increased bowel wall density(OR = 4.3),bowel wall thickening sign(OR = 1.848),WBC count(OR = 1.144)and male(OR = 0.479).On this basis,a 7-point SBO-Score(Small Bowel Obstruction-Score)scoring system was established in which the risk of strangulated small bowel obstruction increased nine-fold from low-risk stratification to high-risk stratification with moderate predictive efficacy(AUC,0.901;standard error,0.014;95% CI,0.873-0.929).Conclusions: Based on a retrospective study of 487 adult patients with acute small bowel obstruction,we screened the related risk factors and established a novel risk stratification model to predict strangulated small bowel obstruction in adults.PART ?: Etiological analysis of acute small bowel obstruction in adultsObjective: This study aimed to explore the characteristics of etiological spectrum of small bowl obstruction(SBO)and its relation with strangulated small bowel obstruction(SSBO).Methods: from June 2010 to September 2016,320 adult patients with SBO were admitted to the hospital of Drum Tower Clinical College of Nanjing Medical University.According to the degree of intestinal ischemia and the pathogeny,the patients were divided into seven etiological groups,simple group(non-strangulated group)and strangulation group.Furthermore,the strangulation group were divided into necrosis and non-necrosis subgroup.The pathogeny distribution and its relationship to the intestinal strangulation were analyzed retrospectively.Results: Of 320 cases,107(33.4%)had adhesions,73(22.8%)had external hernias,46(14.4%)had volvulus,32(10.0%)had internal hernias,28(8.8%)had intussusceptions,7(2.2%)had tumors,and 27(8.4%)had other causes.The patients caused by volvulus and intussusceptions in the strangulated group were significantly more than that in the simple group(p<0.05).The patients caused by tumor in the strangulated group were less than that in the non-strangulated group(p<0.05).The patients caused by external hernias and internal hernias in the necrosis subgroup were significantly more than that in the non-necrosis subgroup(p<0.05).Of the adhesion,volvulus and internal hernia cases,the numbers of patients with the history of abdominal surgery were 105(98.1%),33(71.7%)and 30(93.8%)respectively.Conclusions: Adhesions is the principal cause of SBO in adults,following by external hernias.Volvulus and intussusceptions tend to cause SSBO in adults.External hernias and internal hernias easily lead to the small intestine necrosis.