The Systematic Evaluation Of Bowel Necrosis In Incarcerated Hernias And The Establishment And Application Of Experimental And Clinical Research

PART1THE ESTABLISHMENT OF INCARCERATED HERNIA IN ANIMAL MODEL AND SYSTEMATIC EVALUATION OF THE DEGREE OF BOWEL NECROSISBackground and ObjectiveBowel necrosis (BN), or intestinal necrosis, displays early non-specific and delayed bowel-specific symptoms. There are many schemic bowel diseases (SBD) which can cause BN in clinical practice. While incarcerated hernia is a common cause of SBD which can lead to bowel strangulation and necrosis. The ultimate clinical outcomes will very serious if not timely release the incarceration.It is simple to evaluate the extent of bowel wall necrosis, which can transform from mucosal to transmural infarction of full-thickness of necrosis. But as a human system, besides the morphological changes of intestinal tissues, it can present with local and systemic manifestations of inflammations, cellulitis, intestinal obstruction, and systemic shock. So with the extension of BN time, the result of clinical outcomes is different, and the treatments and prognosis are different correspondingly.There is no reliable and prompt test that can predict intestinal ischemia and determine the necrosis time. On the reason of particular clinical manifestations of BN in incarcerated hernia, there is currently no a systematic clinical system to evaluate the extent of BN. The purpose of this study was to establish a rat model of incarcerated ventral hernia and simulate the process of BN from strangulation to the ultimate outcomes. We also drawed up a systematic score system based on the quantitative score of the local and systemic manifestations of BN, and ultimately, to provide experimental basis for the clinical classification of BN.MethodsWe selected104healthy adult male Wistar rats and made animal models of incarcerated ventral hernia. These rates were divided into13groups (including one control group) according to incarceration time, with increasing time of1h (control group),2h,4h,6h,8h,12h,16h,20h,24h,28h,32h,36h,>36h, respectively, and were sacrificed at corresponding time. We observed the morphological and histological changes of bowel wall, the inflammation extent of local areas, systemic manifestations, and developed a systematic score system of BN and counted the scores of each point. We compared the difference of BN score with the control group and within the experimental groups.Results1. The bowel wall damage achieved full-thickness of necrosis at4-6h’s incarceration, and the abdomen showed mechanical bowel obstruction at corresponding time. The bowel wall cracked, the local side presented with inflammation and there was evidence of bacterial growth at16-20h’s incarceration, meanwhile, the abdomen presented with obvious peritonitis. Incarcerated for longer than32h, the bowel morphology disappeared, the local side presented with cellulitis, and all the rats died at near72h.2. The systematic BN score of the experimental groups increased with increasing time and reached maximum with death at longer than72h’s incarceration compared with the control group. There was significant difference of BN score between4-6h,16-20h,32-36h groups and longer than8h’s incarceration (all P<0.05).Conclusions1. This model of strangulated ventral hernia in rats can better simulate the process of bowel wall from strangulation to necrosis, while showing the clinical manifestations of the process and final outcomes.2. With the extension of incarceration time, the systematic intestinal necrosis score showed an obvious correlation with incarceration time. The systematic intestinal necrosis score system can objectively reflect the consequences of BN in incarcerated hernia. PART2THE ESTABLISHMENT OF BOWEL NECROSIS GRADING SYSTEM AND EXAMINATION OF THE RELATIONSHIP WITH CLINICAL CHARACTERISTICS IN INCARCERATED GROIN HERNIA PATIENTSBackground and ObjectiveIncarcerated hernia cases may necessitate emergency interventions in clinical practice, but under such circumstances morbidity and mortality rates may increase. Groin hernias that occur with incarceration are a serious surgical emergency associated with increased risk of obstruction and strangulation. Approximately15%of patients with incarcerated groin hernia developed bowel necrosis (BN) and underwent bowel resection, with a mortality of5%.Although the final outcome of the incarcerated bowel is strangulation and necrosis, the performance of local and systemic symptoms and signs are different with the extension of necrosis time. At early stage of BN, the bowel wall manifest full-thickness necrosis but with no perforation, the surgical field is not clearly or obviously polluted. But at late stage of BN, the bowel wall loss its normal form and collapsed or cracked. The surgical field can present with cellulitis, and the wound will be clearly contaminated. So the BN degree is different as an extension of necrosis time. But there is currently no grading system for the degree of BN in clinical practice.We have established the incarcerated hernia animal model and preliminary evaluated the degree of BN with systematic evaluations in the previous study. In this study, we screened for inclusion in a prospective study of incarcerated groin hernia patients and aimed to establish a novel classification system for BN based on the observation of bowel morphology, local and systemic sighs changes. We also analyzed the correlations between clinical characteristics with BN stages, especially for the relationship with patient outcomes.MethodsIncarcerated groin hernia patients treated with emergency hernia repair and bowel resection from January2003to January2013were screened for inclusion in a prospective study. A novel three-grade classification system was proposed for BN (grade Ⅰ-Ⅲ) based on incarceration time (4-12,>12-36, or>36h), bowel function, qualitative assessment of bowel morphology and hernia sac, and presence/absence of bacterial growth, peritonitis, mechanical obstruction, and systemic shock. Correlations between clinical characteristics, morbidity and mortality with BN grade were determined.Results1.68patients were included, with49,14, and5grade I, II, and III according to the grading system, respectively. The overall morbidity and mortality was32.4%and7.4%, respectively.2. Age>65years, presence of comorbidities, and high American Society of Anesthesiologists (ASA) score significantly correlated to higher BN grade (all P<0.05).3. Morbidity which included wound and abdominal complications and other systemic complications increased with higher.BN grade (P<0.05). Mortality increased with BN grade, with2.0%,14.3%, and40.0%mortality at grade I, II, and III, respectively (P<0.05).Conclusions1. The proposed BN classification system can objectively reflect the degree of bowel damage and its corresponding adverse outcomes, especially for older patients with comorbidities and poor ASA scores.2. It is a good clinical guidance for selection of appropriate management and a useful tool for improving poor prognosis linked to BN. Urgent surgical treatment should be performed to avoid BN exacerbation. PART3THE ESTABLISHMENT OF BOWEL NECROSIS INDEX AND FACTORS AFFECTING BOWEL NECROSIS AND PATIENT OUTCOMES IN INCARCERATED GROIN HERNIABackground and ObjectiveCurrently, there were few reports of factors affecting BN and patient outcomes in incarcerated hernias. It was undoubted that incarceration time was the main factor that cause and exacerbate BN. While other factors, such as age, sex, comorbidities, and hernia type, was whether or not affecting factors were quite different. Most studies indicated that BN followed by bowel resection was the main factor affecting the outcomes. But other factors, such as age, comorbidities, the tolerance to surgery also played important roles in prognosis, and the results were quite different. Furthermore, there were more controversials of the use of mesh in incarcerated hernias, especially for BN patients.In this study, we retrospectively studied the clinical data of the incarcerated groin hernia patients. The aim of this study was to investigate risk factors for BN and factors that affecting morbidity and mortality, especially for the relationship between BN degree and repair method with patient outcomes. We also established bowel necrosis index (BNI) based on the factors that cause and aggravate BN to judge the extent of BN and ultimately estimate the prognosis.MethodsWe retrospectively studied1168incarcerated groin hernia patients who underwent urgent surgical interventions between January2003and December2013. Factors that increasing the risk of BN, affecting morbidity and mortality, were analyzed using univariate and multivariate statistic analysis. Based on the factors that increasing BN risk and causing BN degree, quantitative score was made to establish BNI.Results1. All the patients were performed urgent surgical interventions with hernia repair. The final sample was1147, included195(17%) cases of BN patients underwent bowel resection and952cases of no BN patients. Morbidity and mortality occurred in194(16.9%) and58(5.1%) patients, respectively.2. Pearson’s chi-squared tests analysis showed there were significant differences in age, gender, accompanying disease, the incarceration time, hernia type, with or without bowel obstruction and peritonitis between two groups (P<0.05). While the incarceration time longer than6h (P<0.001, odds ratio=8.32), hernia type of femoral (P=0.018, odds ratio=10.47), and obvious peritonitis (p=0.005, odds ratio=4.79) was the independent factor for BN.3. There was no BN with BNI score5-10, Grade I BN with BNI score11～18, Grade II BN with BNI score19～26, and Grade III BN with BNI score>26.4. Presence of accompanying disease, high ASA score, general anesthesia, mesh repair, and BN was found to affect morbidity by univariate analysis (P<0.05), Advanced age, presence of accompanying disease, high ASA score, and BN were found to affect mortality by univariate analysis (P<0.05). But multivariate analysis of Logistic regression showed BN was the sole factor affecting morbidity and mortality (P<0.05).5. The wound infection rate of mesh repair patients with Grade II&III necrosis was significantly higher than primary suture patients, and leading to the increase of overall morbidity (P<0.05). But for Grade I necrosis patients with mesh repair, the wound infection rate had no difference comparing with primary suture patients (P>0.05). The use of mesh did not influence the morbidity and mortality with multivariate analysis (P>0.05).Conclusions1. Incarceration time longer than6h, femoral hernia, and obvious peritonitis was the independent risk factors for BN in incarcerated groin hernia patients. Intestinal necrosis, which was followed by bowel resection, was the sole factor affecting morbidity and mortality.2. The BNI of incarcerated hernia can guide clinicians objectively judge the presence or absence of BN and estimate the degree of BN. It is a useful clinical tool for predicting and improving poor prognosis linked to BN combined BN staging system.3. The use of mesh can significantly increase the overall morbidity, especially for postoperative wound complications, but is not the sole factor affecting the outcome. PART4THE PRIMARY TENSION-FREE HERNIOPLASTY IN INCARCERATED GROIN HERNIA WITH BOWEL NECROSISBackground and ObjectiveThere is no consensus yet with regard to the use of prosthesis in incarcerated hernia with a bowel resection. The traditional view of hernia surgery for incarcerated hernia with BN was negative of Tension-free hernioplasty. The reason was that the operation field has been contaminated and it was not safe to use a mesh for correction because of wound infection could increase the risk for recurrence-in many cases, leading to repair failure and had to reoperation. But some others deemed that the use of mesh for hernia repair was feasible. Their reasons were that the bowel wall has not yet perforation and the surgical field was not clearly or obviously polluted. Other studies have found that wound infections were unrelated with the use of mesh.It was no doubt that prosthetic mesh repair should be performed only under clean conditions of elective ones. Although there were many successful reports of simultaneous bowel resection and tension-free hernioplasty for incarcerated hernia with BN, not all patients with different degree of BN could be feasibly performed mesh repair. With the extension of necrosis time, the wound will transform from pollution to infection. At early stage of BN, the surgical field belongs to contaminated or potentially contaminated wound. But at late stage, the surgical field can present cellulites and the wound belong to clearly contaminated or infectious wound. Barely mesh repair under such conditions can only lead to repair failure.It is the first consideration of whether using mesh repair according to the conditions of surgical field, but the patients’general conditions are also very critical in determining the success of the surgery. Furthermore, how to avoid and reduce pollution also play important roles in the success of operation as well as the comprehensive postoperative treatments.We have firstly defined BN degree classification system in incarcerated groin hernia patients in previous studies and have proven that the degree of BN was related with age, presence of comorbidities and high ASA score, and BN was the sole factor affecting morbidity and mortality. On the other hand, the use of mesh in Grade I necrosis patients did not increase the wound infection rate. The purpose of this study is to explore the feasibility of simultaneous bowel resection and tension-free hemioplasty under different BN grades and sum up the successful experience.Methods40cases of incarcerated groin hernia patients with BN were performed emergency hernia repair at our department between January2005and June2013. We used our grading system to grad the degree of BN. According to the patients’general conditions combined with individualized treatment principles,21cases of Grade I necrosis patients and4cases of Grade Ⅱ necrosis patients were selectively performed simultaneous bowel resection and tension-free hernioplasty. The rest of the7patients of Grade I necrosis,5patients of Grade II necrosis, and3patients of Grade III necrosis were repaired by primary sutures. Correlations between ASA score, postoperative complications with BN grade were determined.ResultsThere was no death case in the selectively25cases of tension-free hernioplasty patients. Postoperative complications developed in8patients with wound infection,5patients with hematoma, and4patients with recurrence of hernia. There was1case of Grade I necrosis patient with mesh repair developed superficial wound infection and healed by dressing without removing the mesh.4cases of Grade Ⅱ necrosis patient developed wound infection, including2patients with mesh repair, in which1patient had to remove the mesh because of severe deep wound infection. After6months of follow up, there were4cases of recurrence, including1Grade II necrosis patient with removing the mesh.Pearson’s chi-squared tests revealed that BN grading correlated with ASA score (r=0.388,P=0.018), and complications increased with higher BN grade and poor ASA score (P<0.05).Conclusions1. It can be success for patients with Grade I necrosis and ASA score I, II in incarcerated groin hernia with simultaneous bowel resection and tension-free hernioplasty.2. It should be a rational choice of selective mesh repair both according to the BN degree and according to patient’s general conditions for incarcerated hernia with bowel necrosis.