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Year : 2019  |  Volume : 32  |  Issue : 2  |  Page : 574-580

Risk factors for leak in emergent small bowel anastomosis

1 Department of General Surgery, Faculty of Medicine, Menoufia University, Shebin El-Kom, Egypt
2 Department of General Surgery, Ministry of Health, El-Bagour, Menoufia Governorate, Egypt

Date of Submission17-Mar-2018
Date of Acceptance21-Apr-2018
Date of Web Publication25-Jun-2019

Correspondence Address:
Ahmed SA Arafa
8 Mostafa Kamel Street, Kafr Fishaalkobra, Menouf 32511, Menoufia Governorate
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mmj.mmj_111_18

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The objective of this study was to identify risk factors associated with intestinal anastomotic leakage (AL) to generate hypothesis for further investigation to practically assist in surgical decision making and reduction of postoperative morbidity and mortality.
AL is a frequent complication of intestinal surgery and has been associated with postoperative morbidity and mortality.
Patients and methods
The study included 51 patients who presented to the Emergency Department at Menoufia University Hospital in the period between March and September 2017 requiring small bowel resection and reconstruction as an emergency procedure after illustrating the study to them and taking their consent to participate. Overall complication and leak rates were compared using Fisher's exact test. Individual case review by a group of peers was performed for patients with a leak who died to determine the relationship with mortality.
A total of 51 emergency patients meeting the inclusion criteria underwent resection with anastomosis during the study period. There were 13/51 (25.4%) patients with leaks, four of whom died. In bivariate analysis, factors that were associated with AL were advancing age, hypoalbuminemia 12/13 (92.3%), intraoperative hypovolemia 8/13 (61.5%), intraoperative hypotension, diffuse peritonitis, and low hemoglobin concentration. Mortality was significantly increased in patients with AL, as four (4/51, 7.843%) cases died; three (3/13, 23.07%) of them had AL.
Multiple factors should be taken into consideration before and during emergency small bowel resection anastomosis surgery to comprehensively assess the risk for AL and reduce postoperative morbidity and mortality.

Keywords: anastomotic leakage, risk factors, small bowel anastomosis

How to cite this article:
Farghaly AE, Ammar MS, Algammal AS, Arafa AS. Risk factors for leak in emergent small bowel anastomosis. Menoufia Med J 2019;32:574-80

How to cite this URL:
Farghaly AE, Ammar MS, Algammal AS, Arafa AS. Risk factors for leak in emergent small bowel anastomosis. Menoufia Med J [serial online] 2019 [cited 2020 May 27];32:574-80. Available from: http://www.mmj.eg.net/text.asp?2019/32/2/574/260885

  Introduction Top

Resection anastomosis of diseased small bowel segment is a common surgical procedure in surgical units. This operation has a wide range of indications such as inflammation, ischemia, traumatic injury, obstruction, or malignancy[1].

Failed healing of an intestinal anastomosis results in an anastomotic leak (AL), which is one of the most serious complications after gastrointestinal (GI) surgery, with a reported incidence in the range of 0.5–30%.

An AL increases mortality and morbidity as well as prolongs the length of hospital stay and increases the cost of care[2].

Furthermore, the management of an AL often necessitates additional invasive procedures such as reoperation or percutaneous drainage[1],[3].

A combination of various clinical signs and radiological findings are used to define an AL, which include peritonitis, wound discharge, wound infection, and intra-abdominal fluid and gas collection. Nevertheless, an intestinal anastomosis is essentially a surgically created wound, and the occurrence of an AL represents a failure of the healing of that wound. Thus, we can assume that the clinical process of intestinal healing will be affected by some of the factors that determine the process of wound healing. In general, the factors that influence the healing of an anastomosis can be divided into three categories:

  1. Patient-related factors such as age, sex, BMI, and comorbid conditions (i.e. diabetes, hypertension, heart disease, cancer, anemia, neutropenia, infection/sepsis, and malnutrition)
  2. Preoperative treatment-related factors such as prior abdominal surgery, chemotherapy, and radiotherapy, and the use of steroids and anticoagulation drugs
  3. Surgical procedure-related factors such as duration of surgery, volume of intraoperative blood loss, type of anastomosis, contamination, urgency of the procedure, blood supply of the remnant bowel, operating surgeon, and anastomotic tension[1],[3].

It is important to note that there are various and sometimes differing views as to what risk factors have been proven to predict AL with great accuracy[1].

The aim of this study was to detect the predisposing factors that may lead to anastomotic dehiscence following emergency small bowel resection anastomosis, the frequent clinical presentation, and related morbidities and mortalities.

  Patients and Methods Top

This is a prospective study that was conducted in Menoufia University Hospital Surgical Emergency Department. The study included 51 patients who presented to the Emergency Department at Menoufia University Hospital in the period between March 2017 and September 2017. A total of 51 patients requiring small bowel resection and reconstruction as an emergency procedure were included after illustrating the study to them and taking their consent to participate in the study and taking the approval of ethical committee.

Inclusion criteria

All the patients presenting to Menoufia University Emergency Department requiring urgent small intestinal resection and reconstruction whether for trauma or disease (intestinal obstruction, strangulated hernias, ischemia, tumors and specific infections) and who agreed to participate in the study were included.

Exclusion criteria

The following were the exclusion criteria:

  1. Patient recently explored in another institution
  2. History of previous intestinal surgery
  3. Primary stoma procedures
  4. Patients with anastomoses involving the duodenum, stomach or biliary tract, colon, and feeding jejunostomies
  5. Patients who died in the first 48 h postoperatively
  6. Patients with other GI tract injuries, for example, spleen injury or liver injury
  7. Patients with coagulation disorders and those with previous lower abdominal irradiation
  8. Those who were unwilling to participate in the study.


After taking consent of the patients to participate in the study after illustrating the study to them and letting them know how the study will be performed and its purpose and after taking approval of the ethical committee, we started as follows:

Preoperative preparation

  1. All patients were operated upon on an urgent basis. Patients arriving to the hospital as hemodynamically unstable owing to bleeding were immediately transferred to the operation room without any prior investigation, whereas other patients were prepared according to their etiology and operated upon according to their condition
  2. Routine laboratory examinations, ECG, abdominal radiography, abdominal ultrasound, and computed tomography were done
  3. A urinary catheter was routinely inserted before procedure
  4. All cases received general anesthesia
  5. Prophylactic antibiotic in the form of 1.5-g amoxicillin clavulanate injection was given at induction of anesthesia

Operative techniques

All cases underwent midline laparotomy skin incision [Figure 1] except for those with strangulated para umbilical hernia, who were explored through a transverse skin incision, and those with strangulated inguinal and femoral hernia, who were explored through an inguinal skin incision. Then all the anastomoses in our study were hand-sewn in two layers in an end-to-end fashion.
Figure 1: Exploration of one of our patients in the study through midline incision laparotomy, which shows gangrenous part of the small bowel due to intestinal obstruction due to intussusception, a cause for resection anastomosis of small bowel.

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Postoperative follow-up was done for 6 weeks for diagnosis of leakage.

Statistical analysis

Statistical presentation and analysis of the study were conducted using the mean, SD, and χ2-test for comparison between two groups regarding qualitative data and analysis of variance tests for comparison among different times in the same group regarding quantitative data.

Results were statistically analyzed by statistical package for the social sciences, version 16 (SPSS Inc., Chicago, Illinois, USA).

Difference was considered significant when probability of difference (P) was less than or equal to 0.05.

Overall complication and leak rates were compared using Fisher's exact test by Ronald Fisher which is a statistical significance test used in the analysis of contingency tables. Individual case review by a group of peers was performed for patients with a leak who died, to determine the relationship to mortality.

  Results Top

A total of 51 patients were categorized: 33 (64.7%) males and 18 (35.2%) females.

The demographic study showed 14 (27.4%) male and four (7.84%) female patients experienced traumatic injury, whereas 19 (37.25%) male and 14 (27.45%) female patients experienced diseased bowel. Patients with traumatic injury represented 35.294% of the total studied sample, whereas those with diseased bowel represented 64.71% of the total. Regarding the age of the studied cases, it ranged from 16 to 65 years, with a median of 40.5 years. In the traumatic group, 10 patients were between 16 and 25 years of age and seven patients were between 26 and 35 years of age, and in the diseased group, 14 patients were between 36 and 50 years of age and 12 patients were between 51 and 65 years of age [Table 1].
Table 1: Age and sex distribution among studied group (51 patients) according to primary etiology (trauma or disease)

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The primary pathology of cases in the studied sample was traumatic injury or diseased bowel [Table 2].
Table 2: The primary pathology of cases in the studied sample (51 patients)

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The indications for resection and anastomosis in the studied sample were gangrene of the small bowel, small bowel perforation, or intestinal obstruction. Gangrene of the small bowel represents the highest percentage (45.098%) of the total cases in the studied sample [Figure 1]. A total of 30 (58.824%) ileoileal, 14 (27.451%) jejunojejunal, and seven (13.725%) jejunoileal end-to-end anastomoses were constructed in the study period. Overall, 13 (25.49%) patients developed clinical AL: five (38.4%) patients had strangulated hernias, two (15.4%) patients had mesenteric vascular occlusion, four (30.8%) patients had traumatic injury, and two (15.4%) patients had intestinal obstruction.

In 10 patients, AL manifested with abdominal pain, nine had peritonitis, and six with fever. In four patients, AL manifested with a pelvic or intra-abdominal abscess [Table 3] and [Table 4].
Table 3: Anastomotic leakage (13 cases) presented in the studied sample (51 cases) postoperatively and its clinical presentation

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Table 4: Factors association with anastomotic leakage and its association with mortality in the studied sample (51 patients)

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Diagnosis of AL was made during laparotomy in seven patients, and six patients had fecal discharge from the wound or from the drain confirming the diagnosis [Figure 2].
Figure 2: One of our patients in the study shows anastomotic leakage after resection anastomosis of small bowel for multiple perforations owing to stab wound; intestinal content comes out from the wound confirming the diagnosis.

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  Discussion Top

AL remains an important complication in GI tract surgery. It is a significant cause of morbidity and mortality, necessitating redo operations and increasing length of hospital stay[4],[5].

Moreover, surgery in the emergency setting is associated with higher rate of AL and higher mortality rate after bowel anastomosis[6]

Small bowel anastomosis is primarily performed after resection of inflammatory disease, small bowel obstruction or abdominal trauma, or as a part of bariatric surgery with an AL incidence of 3.0%[7].

Errors in anastomotic construction have traditionally been incriminated in these leaks, but various other causative factors have been shown to be of importance as well. These include bowel obstruction and peritonitis[8], advancing patient age[9], male sex[10], preoperative radiation[10], intraoperative difficulties[3],[10], blood transfusions[3],[8], and level of anastomosis[3].

Emergency surgery is an independent risk factor for AL and associated mortality[6].

Our present work was prospectively conducted to clarify issues relating to factors causing leakage, with specific reference to emergency surgeries related only to small intestinal surgeries.

The rate of anastomotic breakdown in our study had a high figure of 13/51 (25%). In another study by Hyman et al.[11], leaks occurred in 33 (2.7%) patients, where 12 leaks were diagnosed clinically versus 21 radiologically.

Golub et al.[8] encountered a leak rate of 4.3% in the subset of their patients with small bowel anastomosis; however, this group consisted of both elective and emergency anastomoses.

The clinical manifestation of anastomotic dehiscence varies in magnitude from failure to thrive to profound sepsis. However, the physician must have a high index of suspicion to make an early diagnosis. Most patients with anastomotic dehiscence will have prolonged ileus, increased postoperative abdominal pain, fever, and leucocytosis. However, the spectrum can include sepsis, peritonitis, and/or hemodynamic instability[12].

In our study, investigations were requested whenever required for patients including complete blood picture, coagulation profile, liver function tests, kidney function tests, fasting blood sugar, ECG for those patients over 40 s or with positive cardiac history, and chest radiography to detect patients with comorbidities.

Surgeons are all too familiar with the potentially devastating consequences of an AL. Patients classically develop agonizing abdominal pain, tachycardia, high fever, and a rigid abdomen, often accompanied by hemodynamic instability. In these cases, urgent return to the operating room for peritoneal washout and fecal diversion is generally required; prolonged stays in the ICU and death are not uncommon[13].

However, a large number of patients ultimately found to have an AL develop a more insidious presentation, often with low-grade fever, prolonged ileus, or failure to thrive. In these patients, making the diagnosis may be much more difficult as the clinical course is often similar to other postoperative infectious complications. Radiologic imaging is usually required, even then, the diagnosis may be elusive or at least uncertain[14].

In many cases in our database, we were able to show that a postoperative abscess was due to a small AL. Bruce et al.[2] performed a systematic review of studies measuring the incidence of ALs after GI surgery; in the 97 studies reviewed, there were a total of 56 separate definitions and presentations of AL.

A leak may be defined by the need for reoperation, clinical findings, or radiologic criteria, making comparisons between studies difficult or impossible. Furthermore, there is typically a 'cutoff' at 30 days postoperatively and/or hospital discharge for diagnosis, which will fail to capture many leaks[11].

Regarding the clinical presentations of patients with AL in our study, the commonest presentation were abdominal pain in 10 (76.9%) cases, sepsis in nine (69.2%), and fever in six (46.2%).

In our study, two (3.09%) patients had diabetes, one (1.96%) patient had renal failure, one (1.96%) patient had chronic pulmonary disease, one (1.96%) patient had cardiopathy (various), and six (11.76%) patients had liver diseases. Mortality rate was higher in those with AL than in those without[6] and this was in agreement with result of the current study as four (7.8%) cases of mortality (three males and one female), and three of them had AL (3/13 – 23.1%) who died in the postoperative period due to sepsis-related multiorgan failure following anastomotic dehiscence.

Mortality rates following AL are high and mainly determined by patient factors such as age and comorbidity[6].

Studies report additional patient morbidity rates ranging from 20 to 30% and mortality rates varying between 7 and 10%[11].

Various risk factors for AL have been analyzed by several investigators. Age, sex, obesity, level of anastomosis, smoking, blood transfusion, tumor diameter, preoperative chemotherapy or radiotherapy, physical status, obstruction, and coronary heart disease have been shown to be significant risk factors for leakage[15].

In contrast, Behrman et al.[9] found that advanced age is a risk factor for suture line leak in their study of patients with trauma.

Hypoalbuminemia (serum albumin <3 g/dl) was noted to be associated with anastomotic disruption (12/13; 92.3%) in our series. Notably, our patients were more likely to be hypoalbuminemic as a result of the acute disease process rather than chronic malnourishment. However, the consequences remain the same. Other workers have also noted the deleterious effects on low serum albumin levels on wound healing and anastomotic integrity[8].

Intraoperative hypovolemia (8/13; 61.5%) was shown in our study to have a great association with AL.

Intraoperative complications were defined by Lipska et al.[16] as unexpected adverse events (surgical or anesthetic) occurring in the operating room during the surgical time and documented in the operative and anesthetic reports at the time of surgery by the study nurse in collaboration with the surgeon and anesthesiologist. Surgical complications included injury of bowel, other organs, or blood vessels; bleeding; stapling device malfunction; and others. Anesthetic complications are defined as hypotension less than 20% of the baseline measurement, or any systolic mean pressure of less than 85 mmHg or mean arterial pressure of less than 60 mmHg and a patient treated pharmacologically or with fluids, myocardial infarction, oxygen saturation less than 90% for more than 5 min, and metabolic acidosis (in patients with arterial line and any pH <7.30). Intraoperative bleeding was considered a complication if intraoperative blood transfusion was needed. Patients with intraoperative adverse events were 4.1 times more likely to leak than those not having complications[17].

Intraoperative hypotension [systolic blood pressure <80 mmHg; 8/13 (61.5%)] was found to be an independent risk factor for anastomotic dehiscence by multivariate analysis in our study.

In our study, diffuse peritonitis was associated with AL in 10 (76.9%) of the total patients included in the study.

Low hemoglobin concentration (<9 g/dl%) was noted in eight (61.5%) of the patients with anastomotic dehiscence. Fall in hemoglobin leads to decreased oxygen carrying capacity of blood which causes relative ischemia at the site of newly established anastomosis.

Other studies have also reported intraoperative adverse events as independent risk factors for AL. Intraoperative complications in some instances may directly affect the anastomotic creation or in other instances may cause abdominal contamination, for example, bowel injury and soiling of the abdominal cavity and wound, with intestinal content increasing the chances of AL[8].

When comorbidities were evaluated together as a total comorbidity burden, a significant difference between groups became obvious. This phenomenon may be explained within the nature of the index, which considers both the number and the severity level of comorbidities[17].

Another study by Makela et al.[18] identified the presence of two or more underlying comorbidities to be an independent risk factor for AL and supports the concept of a cumulative effect of preoperative comorbidities.

The effect of comorbidities, such as diabetes, renal failure or liver diseases and atherosclerosis on local blood flow and AL, has been described in the literature, where in our study renal failure in one (7.7%) and liver diseases in one (7.7%) were found not to affect the occurrence of AL.

Premorbid medical conditions, male sex, leukocytosis, systemic hypertension, tobacco and alcohol use, age, previous abdominal surgery, malnutrition, metabolic disorders, weight loss, obesity, cardiovascular disease, diabetes mellitus, and multiple blood transfusions have been associated with anastomotic dehiscence[19].

In our study, the effect of sex as a risk for AL was not significant (P = 0.8), but in a study by Trencheva et al.[16], the relative risk for AL in males was 2.3 times higher. Other studies have reported that the male sex is a predisposing factor for AL.

One possible explanation for this difference is a narrower pelvis in male patients, which makes the surgical dissection and creation of an anastomosis technically more challenging than in female patients[17].

The mortality rate for an AL in the literature typically is in the 10–15% range[13].

Regarding the mortality rate, it is clear from our results that there was a significant association between AL and death.

Our study corroborated this finding and demonstrated a perioperative patient mortality rate of 30.7% that was significantly increased in patients with AL, as we had four cases of mortality (three males and one female), and three (23.076%) of them had AL and died in the postoperative period owing to sepsis-related multiorgan failure following anastomotic dehiscence.

This study is one of the very few prospective observational trials designed to evaluate predisposing factors for AL as the main outcome. The data from this study also provide information for the development of mathematical predictive models that weight the importance of each variable.

From the limitations of this study, the diagnosis of AL was made retrospectively in some patients, on clinical grounds, as well as the need for radiological or surgical intervention. The optimal method for diagnosis of a leak is the demonstration of a leak with contrast at either a water-soluble contrast medium study or a computed tomography, or else demonstration of a leak at repeated operation.

A power calculation in our study was not undertaken, so it is possible that some features that were not significant with our sample size would be significant in a very large sample size, whereas the strengths of this study include the variety of factors used to assess the occurrence of ALs.

The ultimate goal in intestinal anastomosis surgery is to produce a healthy, stable, and mechanically sound anastomosis, which can restore full anatomic integrity and biological function of the GI tract[1].

  Conclusion Top

Our observations show that emergency small bowel anastomoses have a high risk of anastomotic dehiscence despite attention to technical detail during their construction. Multiple factors should be taken into consideration before and during emergency resection anastomosis surgery to comprehensively assess the risk for AL. In addition, AL has a significant association with mortality. ALs place a heavy burden on the patient and surgeon. A steady hand is required to optimize outcomes. Major disruptions typically present early and necessitate prompt and aggressive intervention to prevent the development of sepsis and multiorgan failure. Minor leaks often present rather late in the postoperative period and typically require deliberate, thoughtful, and individualized management decisions.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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Murrell ZA, Stamos MJ. Reoperation for anastomotic failure. Clin Colon Rectal Surg 2006; 19:213–216.  Back to cited text no. 4
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Bakker IS, Grossmann I, Henneman D, Havenga K, Wiggers T. Risk factors for anastomotic leakage and leak-related mortality after colonic cancer surgery in a nationwide audit. Br J Surg 2014; 101:424–432.  Back to cited text no. 6
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Behrman SW, Bertken KA, Stefanacci HA. Breakdown of intestinal repair after laparotomy for trauma: incidence, risk factors and strategies for prevention. J Trauma 1998; 45:227–233.  Back to cited text no. 9
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Lipska MA, Bissett IP, Parry BR. Anastomotic leakage after gastrointestinal anastomosis men are at a higher risk. ANZ J Surg 2006; 76:579–585.  Back to cited text no. 16
Trencheva K, Morrissey KP, Wells M, Mancuso CA. Identifying important predictors for anastomotic leak after bowel resection. Prospective study on 616 patients. Ann Surg2013; 257:108–113.  Back to cited text no. 17
Makela JT, Kiviniemi H, Laitinen S. Risk factors for anastomotic leakage after bowel resection with anastomosis. Dis Colon Rectum 2003; 46:653–660.  Back to cited text no. 18
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  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3], [Table 4]


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