The approach to patients who have sustained colon trauma has changed dramatically over the last several decades. This has been associated with a significant improvement in colon-related mortality from approximately 60% during World War I to 40% during World War II, 10% during the Vietnam War and even lower in the current era. Colon-related morbidity, however, still remains high and in most prospective studies the abdominal sepsis rate is approximately 20% (Table 33-1).1,2,3,4,5,6,7 In patients with destructive colon injuries, high Penetrating Abdominal Trauma Index (PATI), or multiple blood transfusions the incidence of intra-abdominal sepsis has been reported to be as high as 27%.8,9
TABLE 33-1Incidence of Abdominal Septic Complications in Colon Injuries (Prospective Studies) ||Download (.pdf) TABLE 33-1 Incidence of Abdominal Septic Complications in Colon Injuries (Prospective Studies)
|Author ||Number of patients ||Abdominal sepsis (%) |
|George et al1 ||102 ||33 |
|Chappuis et al2 || 56 ||20 |
|Demetriades et al3 ||100 ||16 |
|Ivatury et al4 ||252 ||17 |
|Gonzalez et al5 ||114 ||24 |
|Demetriades et al6 ||297 ||24 |
|Overall ||921 ||22 |
In the United States, the overall incidence of blunt and penetrating trauma remains similar7; however, this will vary depending on the center's incoming demographic. In general, blunt trauma patients can be expected to be older, have a higher total burden of injury and endure longer hospital stays with a higher mortality and complication rate.7 In abdominal gunshot wounds the colon is the second most commonly injured organ after the small bowel and is involved in approximately 27% of cases undergoing laparotomy.10,11 In anterior abdominal stab wounds the colon is the third most commonly injured organ after the liver and small bowel and is found in approximately 18% of patients undergoing laparotomy. In posterior stab wounds the colon is the most commonly injured organ and is seen in about 20% of patients undergoing laparotomy.12 The right colon is most frequently injured after blunt force trauma7 whereas the transverse colon is the most commonly injured segment after gunshot wounds and the left colon the most commonly injured segment after stab wounds.
Stab wounds or low-velocity civilian gunshot wounds usually cause limited damage and most are amenable to debridement and primary repair (Fig. 33-1). High-velocity penetrating injuries, such as in war-related trauma, cause major tissue damage and almost always require colon resection (Fig. 33-2).
Low-velocity gunshot wounds cause local damage to the colon.
High-velocity destructive injury to the colon.
Blunt trauma to the colon occurs in approximately 10.6% of patients undergoing laparotomy.13 Most of these injuries are superficial and only about a third will have full-thickness colon perforations.13 Motor vehicle associated trauma is the most common cause of blunt colon injury. This can result in rapid deceleration with mesenteric tearing and ischemic necrosis of the colon (Fig. 33-3). Transient formation of a closed loop and blowout perforation may also occur. Seatbelt use increases the risk of hollow viscus perforations. The presence of a seatbelt mark sign should increase the index of suspicion for hollow viscus injury. In rare cases a colonic wall hematoma or contusion may result in delayed perforation several days after the injury.
High-speed motor vehicle injury with mesocolon avulsion and necrosis of the colon.
In blast injuries such as in war or terror-related explosions, hollow viscera are more susceptible to injury than solid organs (Fig. 33-4). The blast wave is more likely to cause colon rupture than any other intra-abdominal organ.14 Penetrating shrapnel secondary to the blast is often the direct cause of the hollow viscus injury.14
Blast injury to the colon. (Image used with permission of Captain P. Rhee.)
In patients with penetrating abdominal trauma undergoing immediate laparotomy, the diagnosis of colon injury is made intraoperatively. For those selected to undergo a trial of nonoperative management, the diagnosis is based on CT scan evaluation with IV contrast, which is particularly useful for gunshot wounds, and serial clinical examination.15 Other investigations, such as ultrasound, diagnostic peritoneal lavage, or laparoscopy, have little or no role in the contemporary evaluation of suspected colon injuries.
The preoperative diagnosis of colon injury following blunt trauma can be difficult, especially in unevaluable patients. The diagnosis can be suspected on CT, which remains the diagnostic modality of choice, by the presence of free gas, unexplained free peritoneal fluid, or a thickened colonic wall (Fig. 33-5). Because of the imperfect sensitivity of CT, the diagnosis may be delayed by many days with catastrophic consequences. Finally, a rectal examination may show blood in the stool, especially in cases with distal colon or rectal injuries however the rectal examination lacks sensitivity16 and therefore cannot be relied upon to rule out an injury.
CT scan of a victim involved in a high-speed traffic injury. Note the thicken ascending colon wall (circle). The patient had rupture of the cecum.
Intraoperatively, especially for penetrating trauma due to stab wounds and shotgun wounds where the injuries can be very small, every paracolic hematoma should be explored and the underlying colon should be evaluated carefully. Failure to adhere to this important surgical principle is a serious error with medical and legal implications. For most gunshot wounds, the injuries tend to be large and are relatively easily diagnosed in the operating room. With blunt trauma, however, the findings may be subtle and all hematomas should be evaluated completely. Careful examination of the mesentery is also warranted. Any defects should be closed to prevent herniation after ensuring the viability of the colon segment associated with the defect.
The American Association for the Surgery of Trauma (AAST) developed a grading system for colon injuries that is useful in predicting complications and comparing therapeutic interventions. The AAST Colon Injury Scale is shown in Table 33-2.17
TABLE 33-2AAST Colon Injury Scale ||Download (.pdf) TABLE 33-2 AAST Colon Injury Scale
|Grade ||Injury description |
|I || |
(a) Contusion or hematoma without devascularization
(b) Partial thickness laceration
|II ||Laceration ≤50% of circumference |
|III ||Laceration >50% of circumference |
|IV || |
Transection of the colon
|V || |
Transection of the colon with segmental tissue loss
The first guidelines regarding the management of colon injuries were published by the US Surgeon General and mandated colostomy for all colon wounds. This unusual directive was initiated because of the exceedingly high mortality associated with colorectal injuries, in excess of 50%,18,19 during the early years of World War II. Although these guidelines were not based on any scientific evidence, they were credited for the improved outcomes seen in the last years of the war. However, during this period many other major advances such as faster evacuation from the battlefield, improved resuscitation, and introduction of penicillin and sulfadiazine may have contributed to the reduction in mortality. The policy of mandatory colostomy remained the unchallenged standard of care until late 1970s. Stone and Fabian reported the first major scientific challenge of this policy in 1979.20 A prospective randomized study, which excluded patients with hypotension, multiple associated injuries, destructive colon injuries, and delayed operations, concluded that primary repair was associated with fewer complications than colostomy.
The validity of these “standard” contraindications for primary repair or resection and anastomosis was challenged in subsequent studies. New prospective randomized studies with no exclusion criteria demonstrated the safety of primary repair for nondestructive colon injuries. By the 1990s and 2000s primary repair gained widespread acceptance and the role of colostomy was challenged, even in cases with these perceived risk factors. Today, the vast majority of injuries are primarily repaired however, in specific cases where there is a highly destructive blast injury, or staged treatment under austere combat conditions or where the patient is profoundly malnourished or has immunosuppression due to HIV or chemotherapy, diversion may be warranted malnourished or immunosupressed.
Contemporary Management of Nondestructive Colon Injuries
Nondestructive injuries include those involving less than 50% of the bowel wall and without devascularization. There is now sufficient class I evidence supporting primary repair in all nondestructive colon injuries irrespective of risk factors. Chappuis2 in a randomized study of 56 patients with no exclusion criteria concluded that primary repair should be considered in all colon injuries irrespective of the presence of risk factors. In a subsequent study in 1995, Sasaki21 randomized 71 patients with colon injuries to either primary repair or diversion, again without any exclusion criteria. The overall complication rate was 19% in the primary repair group and 36% in the diversion group. In addition, the complication rate associated with colostomy closure was 7%. The study concluded that primary repair should be performed in all civilian penetrating colon injuries irrespective of any associated risk factors.
In another prospective randomized study in 1996, Gonzalez5 randomized 109 patients with penetrating colon injuries to primary repair or diversion. The sepsis-related complication rate was 20% in the primary repair group and 25% in the diversion group. The authors continued their study and the series increased to 181 patients.22 They concluded again that all civilian penetrating colon injuries should be primarily repaired.
Overall, a collective review of all published prospective randomized studies identified 160 patients (Table 33-3) with primary repair and 143 patients treated with diversion. The abdominal sepsis complication rate was 13.1% and 21.7%, respectively. In addition, numerous prospective observational studies also support routine primary repair in nondestructive injuries.1,3,4,22 In conclusion, there is sufficient class I and II data to support the routine primary repair of all nondestructive colon injuries, irrespective of the presence or absence of risk factors.
TABLE 33-3Primary Repair Versus Diversion: Prospective Randomized Studies with No Exclusion Criteria ||Download (.pdf) TABLE 33-3 Primary Repair Versus Diversion: Prospective Randomized Studies with No Exclusion Criteria
|Study ||Primary repair ||Diversion |
|No. of patients ||Abdominal septic complications ||No. of patients ||Abdominal complications |
|Chappuis et al2 || 28 || 4 (14.3%) || 28 || 5 (17.9%) |
|Sasaki22 || 43 || 1 (2.3%) || 28 || 8 (28.6%) |
|Gonzalez23 || 89 ||16 (18%) || 87 ||18 (21%) |
|Total ||160 ||21 (13.1%) ||143 ||31 (21.7%) |
Despite the available scientific evidence, many surgeons still consider colostomy as the safest procedure in high-risk colon injuries. In a survey of 317 Canadian surgeons in 1996, 75% of them chose colostomy in low-velocity gunshot wounds to the colon.23 In another survey in 1998, of 342 American trauma surgeons, members of the AAST, a colostomy was the procedure of choice in 3% of injuries with minimal spillage, in 43% of injuries with gross spillage, in 18% of injuries involving greater than 50% of the colon wall, and in 33% of cases with colon transection.24 Clearly old habits still play a significant role in modern surgical practice.
Contemporary Management of Destructive Colon Injuries
Destructive colon injuries include those with loss of more than 50% of the bowel wall circumference or with devascularization (see Fig. 33-2) and require a segmental colonic resection. Destructive injuries were traditionally managed with diversion because of the perceived high risk for intra-abdominal sepsis. Small prospective studies in the 1990s suggested that primary anastomosis may be safe. Collectively, these studies included only 36 patients with colon resection and anastomosis. The incidence of anastomotic leak was 2.5% and no deaths occurred. These studies concluded that primary anastomosis is the procedure of choice irrespective of the presence of any risk factors for abdominal complications.2,5,21 However, a prospective observational study with 25 patients treated by resection and anastomosis reported two fatal anastomotic leaks (8%) directly attributed to suture line breakdown.8 The study concluded that some high-risk patients (PATI >25 or ≥6 U of blood transfusions or delayed operation) with destructive colon injuries may benefit from diversion. The study included very few patients who were diverted, making any comparison with the primary anastomosis group impossible.
There were also two retrospective studies which included only destructive colon injuries requiring resection. In an analysis of 43 patients who were managed by resection and anastomosis Stewart25 reported an overall anastomotic leak rate of 14%. However, in the subgroup of patients with blood transfusion greater than 6 U the leak rate was 33%. The study suggested that diversion should be considered in patients receiving massive blood transfusions or in the presence of underlying medical illness. In another retrospective study of 140 patients with destructive colon injuries requiring resection Murray26 reported similar intra-abdominal sepsis rates with primary anastomosis or diversion. Univariate analysis identified Abdominal Trauma Index greater than or equal to 25 or hypotension in the emergency room to be associated with increased risk of anastomotic leak. The study suggested that diversion be considered in these high-risk subgroups of patients.
In summary, the available prospective randomized data to this point, which included only a small number of cases, recommended resection with anastomosis irrespective of risk factors. Two larger retrospective studies suggested that diversion should be considered in selected patients with PATI greater than or equal to 25, multiple blood transfusions, or associated medical comorbidities.25,26
In order to address these limitations, the AAST sponsored a prospective multicenter study to evaluate the safety of primary anastomosis or diversion and identify independent risk factors for colon-related complications in patients with penetrating destructive colon injuries.6 The study included 297 patients with penetrating colon injuries requiring resection who survived at least 72 hours. Rectal injuries were excluded. The overall colon-related mortality was 1.3% (four deaths) and all deaths occurred in the diversion group (P = .01). The most common abdominal complication was an intra-abdominal abscess (19% of patients) followed by fascia dehiscence (9%). The incidence of anastomotic leak was 6.6% and no deaths occurred in the group with an anastomosis. Multivariate analysis identified severe fecal contamination, greater than or equal to 4 U of blood transfusions within the first 24 hours, and inappropriate antibiotic prophylaxis as independent risk factors for abdominal complications. In the presence of all three of these risk factors, the incidence of abdominal complications was approximately 60%, in the presence of two factors the complication rate was 34%, in the presence of only one factor the rate was approximately 20%, and with no risk factors it was 13%. The method of colon management (anastomosis or diversion), delay in operation, shock at admission, site of colon injury, PATI greater than 25, ISS greater than 20, or associated intra-abdominal injuries were not found to be independent risk factors for developing a complication. The study also compared colon-related outcomes in high-risk patients (hypotension at admission, blood transfusions >6 U, delay of operation >6 hours, severe peritoneal contamination, or PATI >25) after primary anastomosis or colostomy. These risk factors have been suggested by many surgeons as an indication for diversion. The colon-related mortality in this high-risk group was 4.5% (4 of 88 patients) for the colostomy group and zero in the 121 patients who underwent primary anastomosis (P = .03). The adjusted relative risk of abdominal septic complications was similar when comparing colostomy to primary anastomosis, in both the low- and high-risk patients (Table 33-4). There was a trend toward longer ICU and hospital stay in the colostomy group. The study concluded that because “colon diversion is associated with worse quality of life and requires an additional operation for closure, colon injuries requiring resection should be managed by primary repair, irrespective of risk factors.”6 As mentioned earlier in this section, there may be some notable exceptions to the widely accepted practice of primary anastomosis. For example, the patient who sustains a destructive injury secondary to a blast mechanism, such as that seen after an improvised explosive device. In these patients, the more liberal utilization of diversion may be warranted.27
TABLE 33-4AAST Study of Destructive Colon Injuries: Comparison of Abdominal Complications Between Primary Anastomosis and Diversion in High- and Low-Risk Patients6 ||Download (.pdf) TABLE 33-4 AAST Study of Destructive Colon Injuries: Comparison of Abdominal Complications Between Primary Anastomosis and Diversion in High- and Low-Risk Patients6
|Patient population (N = 297) ||Abdominal complications (%) ||Adjusted relative risk (95% CI) ||P-value |
|Primary anastomosis ||Diversion |
|All patients ||22 ||27 ||0.81 (0.55–1.41) ||0.69 |
|Low-risk patientsa ||13 || 8 ||1.26 (0.21–8.39) ||0.82 |
|High-risk patientsa ||28 ||30 ||0.90 (0.53–1.40) ||0.67 |
The optimal management of colon injuries in patients undergoing a damage control procedure has been actively investigated over the last several years. If colonic continuity could not be reestablished at the index operation, it has been suggested that a delayed anastomosis may be safe because follow-up reexploration would identify any anastomotic problems and fecal diversion can be performed at this stage. In addition, there are some theoretical disadvantages of having a colostomy, because it is a source of fecal material, near an open abdomen. In addition, the subsequent closure of the colostomy, especially end colostomy, might be a major technical challenge because of the hostile intra-abdominal environment. In a series of uncontrolled retrospective studies comparing delayed anastomosis to anastomosis at the index operation or diversion, there was a similar or increased rate of complications but no increase in colon related deaths.28,29,30,31,32 The general conclusion from this work was that anastomosis remains an acceptable treatment option and avoids the need for a colostomy and the subsequent operation to restore continuity. There may be an increase in the leak rate, which would then result in a colostomy; however, this is the same result that would be expected if the colostomy was performed at the index operation.
In one retrospective series of 174 patients by Ott,33 the leak rate was 27% for anastomosis versus 6% for diversion. In their regression, transfusion requirement and left sided anastomosis were found to be risk factors associated with leakage. Other authors have also identified specific risk factors that may preclude safe delayed anastomosis and favor diversion. In a retrospective series from Fischer,34 patients requiring the use of vasopressors quadrupled the leak rate. The time taken to achieve fascial closure may also impact the complication rate. In a retrospective series from Anjaria,35 although primary repair or delayed anastomosis was found to be acceptable if fascial closure could be achieved, if this could not be accomplished by the second take-back operation, diversion was recommended as there was an 8 fold increase in the leak rate. Similarly in a Western Trauma Association multicenter trial36 that looked at all enteric anastomoses, the leak rate was highest for the left colon. Like the previous study, as the time to closure increased, so did the leak rate. Closure after day 5 was associated with a fourfold increase in the leak rate. They recommended, however, that repair or anastomosis be considered for all patients. Therefore for the majority of patients who are physiologically ready for their take-back operation, and therefore able to tolerate the anastomosis, if the colonic wall is healthy, our practice is to perform an anastomosis without the routine use of diversion.
Risk Factors for Abdominal Complications After Colon Injuries
The incidence of abdominal complications after colon injuries is very high, with a sepsis rate exceeding 20% (see Table 33-1). Various conditions have been suggested as possible risk factors for colon-related complications but the majority have failed scientific scrutiny.
Left versus right colon injuries: There is a widespread belief that left colon injuries are associated with a higher risk of anastomotic leaks and septic complications following repair or colocolostomy than right colon injuries. In the Western Trauma Association multicenter trial,36 the small bowel leak rate was 3%, right colon 3%, transverse colon 20% and left colon 45% however this was uncontrolled data. In a study of suture line failure after penetrating colon injuries, a regression analysis failed to show any association between injury location and complications.37 The experimental data has not demonstrated any healing differences between the two sides of the colon or any evidence that the two anatomical sides should be treated differently. Experimental work in baboons, which have anatomy and bacteriology very similar to those of humans, showed no difference of the healing properties between the right and left colon.38,39 The healing was evaluated clinically (anastomotic leak or abscess), biochemically (hydroxyproline concentrations), and mechanically (breaking strength of the anastomosis), in both normovolemic and hypovolemic conditions. However, there is strong evidence that ileocolostomy is associated with significantly fewer leaks than colocolostomy and it should be the procedure of choice in cases with right hemicolectomy. Good blood supply is the cornerstone of successful colon healing and this should be taken into account when repairing injuries in the watershed region of the splenic flexure.
Associated abdominal injuries: Earlier retrospective studies suggested that multiple or severe associated intra-abdominal injuries (PATI >25) are associated with a high incidence of anastomotic leaks and therefore in these patients a colostomy should be performed. However, class I and II studies have shown that although multiple associated intra-abdominal injuries are significant risk factors for intra-abdominal sepsis, the method of colon management does not affect the incidence of abdominal sepsis.3,5,6,8,40,41
Shock: There is now sufficient class I and II evidence that preoperative or intraoperative shock is neither an independent risk factor for abdominal sepsis or a contraindication for primary colon repair or anastomosis.3,5,6 The duration and severity of hypotension may be important factors not taken into account in these studies. Practically, patients with sustained intraoperative hypotension will be undergoing damage control laparotomy and the principles of delayed anastomosis as described earlier will apply.
Blood transfusions: Multiple blood transfusions (≥4 U of blood within the first 24 hours) have been shown to be a major independent risk factor for abdominal septic complications.6,33,41 In a large prospective AAST study of 297 patients with penetrating destructive colon injuries multiple blood transfusions were the most important independent risk factor for abdominal sepsis. However, the method of colon management, primary anastomosis or colostomy, did not influence the complication rate in this group of patients.6 In addition to blood, increased infusion of crystalloids was associated with an increase in the leak rate, with a volume of more than 10.5 L over the first 72 hours being associated with a fivefold increase in the leak rate.42 The volume of blood transfusion may in fact be a surrogate marker for shock, and other metrics such as the time to correct base deficit may also be important.
Fecal contamination: Severe fecal spillage is a major independent risk factor for abdominal sepsis.1,6,13,26,43,44 This finding has led some authors to suggest that this condition should be a contraindication to primary repair or anastomosis. However, all prospective randomized studies and recent large prospective observational studies have shown that the method of colon management does not influence the septic complication rate.2,5,6
Time from injury to operation: Although delays in the operative management of colon perforations increase the risk of septic complications, the length of delay over which the complication rate increases is not clear. Some studies suggest that this critical delay is 6 hours, while others have extended it to 12 hours.8,26,45 The degree of contamination is likely more important than the operative delay and the magnitude of the delay by itself should not be used as an absolute criterion for primary repair or diversion.
Retained missiles: There is no evidence that retained bullets, which have passed through the colon, are associated with an increased risk of local sepsis. Removal of the missile does not reduce the risk of infection. In a study of 84 patients with gunshot wounds of the colon, the bullet remained in the body in 40 and was removed in 44. The incidence of local septic complications was 5% and 7%, respectively.46
Closure of the skin wound: Closure of the skin incision after colonic injuries, especially in the presence of fecal spillage, is associated with a high incidence of wound infection that is often complicated by necrotizing soft tissue infection or fascia dehiscence.47 In these cases the skin should be left open at the index operation.
The overall incidence of colon leaks after repair and anastomosis is low. In a collective review of 35 prospective or retrospective studies with 2964 primary repairs, there were 66 (2.2%) leaks.48 Review of the published prospective studies that included 534 patients with colon repair or resection and anastomosis demonstrated a 3.2% leak rate.6,48 Resection and anastomosis is significantly more likely to leak than a simple repair. In a collective review of 362 patients with resection and anastomosis the overall incidence of anastomotic leak was 5.5%.48 In a more recent multicenter prospective study of 197 patients with penetrating colon injuries who underwent resection and primary anastomosis, the leak rate was 6.6%.6
The prognosis for colon leaks is good and the majority of patients can safely be managed nonoperatively with adequate percutaneous drainage with an extremely low associated mortality rate. Reexploration of the abdomen for wide drainage and fecal diversion or resection and reanastomosis should be reserved only for patients with generalized peritonitis or failed percutaneous drainage.
On entering the peritoneal cavity the first step is to control any bleeding followed by addressing ongoing GI tract contamination. The extent of the colon injury is assessed by adequate mobilization of the injured segment and careful inspection of the retroperitoneal wall. Paracolic hematomas due to penetrating trauma should be explored to rule out any underlying perforation. Gentle squeezing of the suspected area may facilitate the diagnosis of any occult injuries by demonstrating the leakage of air or colonic contents. The ureter should always be identified and examined in cases with injuries to the ascending or descending colon. The splenic flexure of the colon is the least accessible segment because of its anatomical location under the left hypochondrium. During its mobilization, caution should be exercised to avoid excessive downward traction of the colon, which may cause avulsion of the splenic capsule and troublesome bleeding (Fig. 33-6). In cases with multiple associated injuries and coagulopathy, these capsular tears may require a splenectomy, which increases the risk of postoperative complications. This iatrogenic complication can be avoided by placing three or four laparotomy pads under the diaphragm, above the spleen. This maneuver aids in the exposure and safe division of the splenocolic ligament.
Excessive downward traction of the splenic flexure of the colon may cause avulsion of the capsule of the spleen and troublesome bleeding.
Adequate debridement of all penetrating wounds, especially gunshot wounds, is critical before any repair is performed. For destructive injuries, the resection margins should result in well perfused wall that is adequately mobilized to allow a tension free anastomosis. The method of anastomosis, handsewn or stapled, does not play a significant role in the incidence of anastomotic leaks. In a prospective AAST study of 207 patients49 with penetrating destructive injuries who underwent resection and anastomosis, 128 cases were handsewn and 79 cases were stapled. The incidence of anastomotic leak was 7.8% and 6.3%, respectively. For handsewn anastomoses, another debated technical issue is the role of a one-layer versus two-layer anastomosis. Numerous studies in the nontrauma setting have concluded that a one-layer anastomosis is as safe as a two-layer anastomosis.50