Discussion
BHIs remain difficult to diagnose after blunt force abdominal trauma due to vague clinical presentations and non-specific imaging findings on CT, making them challenging to rule in without a high index of suspicion.2 17 After a bowel resection and anastomosis, the AL rate and major factors affecting these ALs in patients with BHI are still not well defined. In this retrospective cohort study, we used data from multiple trauma centers to better predict specific determining factors that could influence the risk of an AL following resection and primary anastomosis for BHIs.
Our cohort found an overall 8.15% leak rate. Patients with BHIs limited to the small intestine (6.38%) occurred at nearly half the rate of those limited to the colon (13.41%). This leak rate is consistent with the literature, where colonic AL rates have been found to be higher than those of the small intestine. This difference is expected due to the colon’s higher level of bacterial flora, less vascularity, and increased intraluminal pressure.9 Our overall leak rate is within the published range for trauma patients, with ALs of 4.65% to 20.5% reported in the emergent setting.6 9 Broader studies representing all clinical indications for bowel resection with anastomosis report lower rates, around 3.6%,7 whereas those focusing on elective surgery report even lower rates at 2.8%.8
Of the potential predictors of AL we explored, we found that the classification of the index procedure as a DCS was most significantly associated with an increased risk of AL. These operations typically occur in cases of significant bleeding or contamination, and they must be followed by a second procedure for definitive management once the patient has been stabilized.18 19 Initially, DCS was only used to prevent prolonged operations in unstable trauma patients. This technique was developed to prevent death caused by the ‘lethal triad’ of hypothermia, acidosis, and coagulopathy.20 However, as the concept became widely accepted as a potentially lifesaving approach for the most critically injured, the pendulum swung to the other extreme, where DCS is used in nearly all trauma patients. Many trauma surgeons consider DCS currently overused; even patients who are relatively stable and could tolerate a slightly longer operation with definitive abdominal closure often receive abbreviated operations with temporary abdominal closure. A retrospective review is hypothesis-generating and not the correct study design to explore why DCS may be associated with higher leak rates. However, there are a few potential biomechanical theories that might explain this association: the potential complications of an open abdomen have been previously well described,21 and it is possible that increased AL may be another association.
Despite finding leak rates of between 6% and 14%, the authors do not have sufficient information to recommend a lower threshold for ostomy creation with these procedures—these data have shown primary anastomosis can be attempted in these patients. Patients with an AL experienced increased morbidity, including both organ space infections and SSIs, which further complicated their hospital stays.15 22 These patients were also more likely to be discharged with an ostomy, require reoperation, and be readmitted to the hospital for reasons other than ostomy reversal. However, these patients did not differ from those without an AL in terms of 30-day mortality, nor in terms of length of stay. In addition, those with an AL were not found to be any less likely to have their ostomy eventually reversed. Ostomy creation remains an important treatment option due to the possible reduction in patient morbidity through minimizing the risk of AL and its associated complications. However, an ostomy is a significant psychological burden for patients, with concerns about resuming sexual and social function.23 Therefore, the authors have shown in this study that primary anastomosis may safely remain the default option for BHI in both small and large intestines.
Other factors that we explored included diagnostic delay and anastomotic technique. Delay in diagnosis of traumatic bowel injury has been associated with additional complications due to possible septic shock and other injuries secondary to ischemic bowel perforation,24 but a recent study did not find an association between complications and diagnostic delay.25 Anastomotic technique, namely sutured versus handsewn methods, has also been studied extensively, with many studies finding the AL rate equivocal.26 However, we found no significant difference between the AL rate based on the technique of anastomosis nor the hospital day of surgery. Adjusted analysis using multiple patient characteristics, such as age, injury severity, and comorbidities, did not show significant variability in the calculated RR for these predictors. This suggests that the technique and timing of the anastomosis may be less influential in predicting an AL than other variables.
There have also been a multitude of patient characteristics proposed to be associated with the development of bowel ALs following both elective and emergent procedures: leukocytosis, ASA score of >2, and (but not limited to) comorbidities, such as congestive heart failure and peripheral vascular disease.9 27 These factors were partially consistent with those in the group with an AL (8.15%) compared with the no leak group, where patients with AL were more likely to have been diagnosed with at least one comorbidity and have a higher ASA score. However, we did not find any other patient presentation variables associated with an increased risk of ALs, such as the presence of shock, lactate, or base excess, in this population. White cell count was also not significantly different between the two groups; many patients developed leukocytosis. This suggests that the risk of AL in patients with BHI may be better predicted by the patient’s past medical history or other measurements obtained immediately prior to surgical intervention.
Other studies have also found that the need for blood transfusion, whether preoperatively or postoperatively, may be an independent predictor of increased risk of AL.13 27 Our data showed that the measured hemoglobin on presentation was not significantly different between those with AL and those without. In addition, significant blood loss, which we defined as transfusion of >6 units of packed red blood cells during the entire hospitalization, was not significantly different between those who developed AL and those who did not. This lack of significance may be secondary to the limited sample size. Further research is necessary to investigate the role of blood loss and vascular injury on the risk of AL, specifically for patients with BHI.
This study is limited due to its retrospective nature and focus on a specific subset of complications that occur after traumatic bowel injury. This creates multiple limitations that should be considered. Due to its retrospective review, results are hypothesis-generated rather than hypothesis-tested. In addition, information accuracy relies on proper and timely documentation within every electronic medical record. BHIs also remain a relatively rare diagnosis, with a smaller overall patient population; this study included many busy trauma centers but found less than 500. Because of the relatively small sample size of patients with BHI with an AL, many baseline characteristics and presenting characteristics were not found to be statistically significant. In addition, our study did not include all factors that have been found to be associated with AL in the literature, such as vasopressor requirement and volume overload. These factors have the potential to impact AL rate in many patients, specifically those admitted for significant trauma. We tried to mitigate this limitation by incorporating having shock during presentation and transfusing >6 units packed red blood cells as variables into the model. Furthermore, we intended to include hours of surgery as a variable to predict AL. However, due to limitations in data availability, we have to limit our analysis to hospital day of surgery.
In conclusion, this multicenter study focused on the factors impacting AL among patients with BHI who underwent resection and primary anastomosis. Interestingly, diagnostic delay and anastomotic method were not associated with AL, but DCS significantly increased the relative risk of AL among patients with BHI in this study. These findings provide a potential avenue for further exploration and research.