improved outcomes in colon and rectal surgery and that was reliable in the acute postinjury setting as opposed to other etiologies for critical illness (i.e. sepsis or major operation). Three hundred sixty patients undergoing laparotomy for pen- etrating trauma were the basis of this study. Each intraabdominal organ was assigned a weight in terms of potential for developing complications, and a sub-grading from 1–5 based on severity of the injury. A PATI cutoff of 25 separated a substantial increase in complication rates (17% vs. 50% for stab wounds, and 12% vs. 44% for gunshot wounds). Notably, this scale provided a basis for the development of the Organ Injury Scale of the American Association for the Surgery of Trauma (AAST). In 1987, Dr. Donald Trunkey, the president of the AAST at that time, appointed the Organ Injury Scaling Committee to derive an injury scaling system that unified several previously proposed scoring systems for the purposes of conducting higher-quality research, and to provide a common parlance amongst centers and authors (Trunkey, DD, personal communication). This commit- tee cites the results of 2 prior studies of penetrating colon injuries (47, 48), in which scoring systems proved useful to guide manage- ment, as support for creating this scoring system for all abdomi- nal organs. Their work utilized some of the structure of the PATI proposed by Moore, as previously discussed. The AAST Colon Injury Scale is shown in Table 35.2.(49) MANAGEMENT OF PENETRATING COLON INJURY The argument for primary repair The management of penetrating colon injury has undergone sig- nificant changes during the past 50 years. Today, primary repair is considered the treatment of choice for most colon injuries. Stone and Fabian’s seminal paper set the stage for this strategy. Earlier authors recognized that a strategy mandated during wartime, under combat conditions, and practiced by surgeons with vary- ing levels of experience may not be applicable to modern civilian conditions. As an example, Pontius, Creech, and DeBakey (50) reported their experience with 122 civilian colon injuries in 1957. They reviewed military series between WWII and the Korean con- flict, noting a drop in mortality from 53% to 15%, and civilian series during the same era, noting a drop in mortality from 62% to 14%. These authors primarily repaired 83 colon injuries with 8% mortality and diverted 36 colon injuries with 25% mortality. They acknowledge that primary repair was only attempted in patients without extensive fecal contamination, complete destruction of a segment of bowel or rectal injuries. In addition, they note that, of all survivors in both groups, there was a 20% complication rate, including only 3 intraabdominal abscesses. This complication rate is similar to rates seen half a century later. The modern era of data supporting primary repair for pen- etrating colon injuries includes several randomized controlled tri- als (RCT). The next RCT examining this issue after the work of Stone and Fabian was not published until 1991 by Chappuis and colleagues.(14) Although there are several methodological limita- tions, this study was important in that it excluded only patients with rectal injuries and attempted to answer the question that Stone and Fabian did not address, which is whether primary repair was equivalent in more severely injured patients with a greater degree of colon injury. Stone and Fabian (9) excluded almost half of the patients with colon injuries due to preoperative shock, multiple organs injured, gross contamination, greater than 8 hours from injury to repair, blood loss >1 L, and destructive injury. Chappuis and colleagues randomized 56 patients into either a primary repair or a diversion group, with 28 patients in each group. There were similar grades of colon injury (primarily grade III), PATI (26 and 23.9), transfusion rates (43% and 39%), complication rates (32% and 35%), and numbers of intraabdominal abscess (3 and 4) in the primary repair and diversion groups respectively. However, the sample size was small, and the authors reported no statistics. Although the PATI was indicative of severe intraabdominal injury, only four patients were admitted in hemorrhagic shock (defined as a systolic blood pressure less than 80 mm Hg). Additionally, only 13 total patients (5 in the primary repair group and 8 in the diver- sion group) required more than 4 units of packed red blood cells (PRBC). Thus, although this series represented an unselected pop- ulation, the sample size was insufficient to conclude that primary repair is equivalent to diversion in severely injured patients. Since these two reports, there have been four other RCT that support primary repair in most situations.(23, 25, 26, 51) Although Gonzalez and colleagues published the results of their first 109 patients in 1996 (24), the authors state that this study was continued in order to assess complication rates associated Table 35.1 Flint grades of colonic injury. Grade Mortality a Complications a 1 Isolated colon injury, minimal contamination, 4% 0% no shock, minimal delay 2 Through-and-through perforation, lacerations, 20% 20% moderate contamination 3 Severe tissue loss, devascularization, heavy 25% 31% contamination a. n = 137. Table 35.2 AAST grades of colon and rectal injury. Grade a Description ICD-9 b Organ injury scale: Colon I Hematoma Contusion/hematoma without 863.40 – .44 devascularization Laceration Partial thickness, no perforation 863.40 – .44 II Laceration Laceration <50% circumference 863.50 – .54 III Laceration Laceration ≥50% circumference 863.50 – .54 IV Laceration Transection of the colon 863.50 – .54 V Laceration Transection with segmental 863.50 –.54 tissue loss Vascular Devascularized segment 863.50 – .54 Organ injury scale: Rectum I Hematoma Contusion/hematoma without 863.45 devascularization Laceration Partial thickness, no perforation 863.45 II Laceration Laceration <50% circumference 863.55 III Laceration Laceration ≥50% circumference 863.55 IV Laceration Full thickness laceration extending 863.55 into perineum V Vascular Devascularized segment 863.55 a. Advance one grade for multiple injuries to the same organ. b. .41 & .51 = Ascending; .42 & .52 = Transverse; .43 & .53 = Descending; .44 & .54 = Rectum. colorectal trauma with destructive injuries requiring resection and anastomo- sis.(25) Table 35.3 summarizes the findings from these studies, excluding the preliminary 1996 data generated by Gonzalez. Falcone et al. (51), also had stringent exclusion criteria, and had a small sample size of 22 patients. The other studies excluded only extraperitoneal rectal injury.(14, 23, 25, 26) Notably, Sasaki and colleagues (23) noted more patients in shock defined as a systolic blood pressure (SBP) <80 mm Hg (28% vs. 4%), a higher degree of gross contamination (60% moderate or heavy contamination vs. 25%), and more patients requiring more than 4 units of blood (16% vs. 4%) in the primary repair group as compared to the diversion group. The authors report that all of these comparisons were statistically significant, although p values were not reported. Despite these differences, and despite similar PATI scores of 25.5 and 23.4 for primary repair and diversion respectively, they found an increase in the likelihood of complications in the diver- sion group (odds ratio of 1.99, p = 0.02). Using a multivariate regression model, they analyzed the exclusion criteria of previous studies (associated organ injury, shock on admission, fecal con- tamination, location of colon injury, age, transfusion requirement, delay of operation, extent of colon injury, abdominal wall loss, and mechanism of injury) as potential risk factors for complica- tions. They found that only the PATI score was an independent predictor for complications but this was regardless of the type of repair. Gonzalez et al. (25) found no difference in complication rate, and noted that this lack of difference persisted when patients with a PATI >25 in each group were compared. Kamwendo and colleagues (26) randomized 240 patients to diversion or pri- mary repair, and also further stratified these groups into those that underwent operation before and after 12 hours postinjury. They found no differences in overall complication rate, mortality, number of patients in shock or requiring transfusion, or septic complications between the primary repair and diversion groups. Further, they found no difference in complication rate between the early and late repair groups. Two meta-analyses have been published on this topic. Singer and Nelson (22) published a systematic review of the litera- ture in 2002. They pooled data from five RCTs (9, 14, 23, 25, 51), totaling 467 patients. The following year, the Cochrane Collaboration (21) pooled data from six RCTs, including five Table 35.3 Randomized trials investigating primary repair versus diversion in colon injury. Complication Mortality Author(s) Year n d PR Div PR Div Exclusion Criteria Comment Stone (9) 1979 139 1% a 10% a 1.5% 1.4% Preoperative BP < 80/60 PR lower total and BL > 1000 ml infectious complication >2 organs injured rate. Gross contamination Excluded group: More Operation >8 hr post-injury infectious complications, Destructive injury higher mortality. Loss of abdominal wall Chappuis (14) 1991 56 32% 35% 0% 0% Extraperitoneal rectal 1 st study with broad injury inclusion criteria. Low N in shock (3 PR, 1 Div) but PATI scores equivalent (26 & 24). Falcone (51) 1992 22 8/11 b 10/9 b 9% 0% Death < 24 hr post-injury Used intracolonic bypass. Admit > 8 hr post-injury Operation at another institution Deemed inadmissible Sasaki (23) 1995 71 19% a 36% a NR NR Extraperitoneal rectal PR more shock, gross injury contamination, transfusions, left-sided injury (p < 0.05). PATI >25 independent risk for complications. Div OR 1.99 for complications vs. PR. Gonzalez (25) 2000 176 18% 21% 2% 1% Extraperitoneal rectal PATI > 25 subgroup no injury difference PR vs. Div Kamwendo (26) 2002 240 37% 26% 0% 1.7% Extraperitoneal rectal Equivalent complication injury rate PR vs. Div: • Overall • Early vs. late (cutoff 12hr post-injury) Note: PR = Primary repair, Div = Diverted, NR = Not reported, PATI = Penetrating Abdominal Trauma Index. a. Significantly different. b. Total number of complications was reported, p = 0.516. c. Reported as significantly different but no p values reported. d. Number randomized. improved outcomes in colon and rectal surgery of the studies addressed in their prior meta-analysis (9, 14, 23, 25, 26, 51), comparing 361 patients in the primary repair group with 344 patients in the diversion group. They noted that the PATI was reported in five of the six trials, and although statisti- cal analysis could not be performed on this data, the primary repair group had higher mean PATI scores (29 vs. 26). Their analysis revealed a lower overall complication rate in patients undergoing primary repair. The authors conducted a rigorous analysis in which data that contributed to possible heterogene- ity were excluded. This resulted in a strengthening of the odds ratio favoring primary repair. When considering intraabdomi- nal infection, there were no significant differences between the two groups, although when sensitivity analysis was performed, the remaining data generated an odds ratio (OR) that favored primary repair (0.59, CI 0.37–0.94). Thus, meta-analysis showed a decreased risk of complications, and an either equivalent or lower risk of intraabdominal infection with primary repair. Neither analysis found any differences in mortality between the two groups, with rates of <3%. A summary of these 2 meta-analyses is pre- sented in Table 35.4. Both meta-analyses were authored by Nelson and Singer, and both were conducted in the same fashion by the authors. The Cochrane review included the report by Kamwendo (26), and noted that these were the only data from outside the United States. Although differences in resources, transport time, and patient population may have implications for including this data in the meta-analysis, similar findings amongst such a potentially differ- ent population support the generalizability of primary repair. In general, these analyses do not include the complication rate from subsequent ostomy takedown. Injuries requiring resection and anastomosis Current evidence clearly supports primary repair in the set- ting of uncomplicated colon injury defined as injuries easily repaired by direct suture, without significant devascularization or a destructive component. The summary of existing prospec- tive, randomized data suggests that this is the method of choice even in the setting of significant hypotension, high transfusion requirement, associated injury, gross contamination, and delay to operation. The issue of performing primary repair in the sub- set of injuries requiring resection and anastomosis is less clear. The data still favor primary resection and anastomosis without proximal diversion in the sense that all of the RCTs classified these repairs as primary repair. A review of these studies finds only 43 cases of resection and anastomosis without diversion in 6 randomized studies, which is a potential source of type II error. The most well-documented data in a randomized set- ting comes from Sasaki and colleagues (23), who noted patient characteristics, complications, and outcomes in the subset of 12 patient who underwent resection and anastomosis versus Table 35.4 Meta-analyses investigating primary repair vs. diversion in colon injury. Author Singer 2002 (Ref) Nelson 2003 (Ref) Comment N (patients) 467 705 Patients analyzed in an intention to treat manner N (trials) 5 6 Nelson added 1 trial to Singer review (REF) Injury severity by PATI for PR 28.9 28.9 Only 4 trials (REFS) reported PATI Variance not provided, thus statistical analysis could not be performed PR included higher PATI patients Injury severity by PATI for Div 25.8 25.8 OR (CI) for mortality 1.7 (0.51 – 5.7) 1.22 (0.4 – 3.74) Mortality low for both groups (1.7-2.9%) No heterogeneity among trials Intervention favored Neither Neither OR (CI) for all complications 0.28 (0.18 – 0.42) 0.54 (0.39 – 0.76) P value for heterogeneity < 0.01 Intervention favored PR PR OR (CI) for all complications (excluding heterogeneous study) 0.13 (0.08 – 0.23) 0.13 (0.08 – 0.23) P value for heterogeneity = 0.16 Study by Gonzalez, et al (REF) contributed the heterogeneity to the meta-analysis Intervention favored PR PR OR (CI) for all infectious complications 0.41 (0.27 – 0.63) 0.44 (0.17 – 1.1) Including intra-abdominal abscess, anastomotic leak, peristomal abscess, sepsis, wound infection, and abdominal wound dehiscence Intervention favored PR Neither * OR (CI) for abdominal infection (including wound dehiscence) 0.59 (0.38 – 0.94) 0.67 (0.35 – 1.3) Including all of the above except sepsis. Kamwendo study contributed heterogeneity. OR values same as Singer review favoring PR when this trial excluded Intervention favored PR Neither OR (CI) for abdominal infection (excluding wound dehiscence) 0.52 (0.31 – 0.86) 0.69 (0.32 – 1.39) Intervention favored PR Neither OR (CI) for wound complications (including wound dehiscence) 0.55 (0.34 – 0.89) 0.55 (0.34 – 0.9) Including peristomal abscess, wound infection, and abdominal wound dehiscence No heterogeneity among trials Intervention favored PR PR OR (CI) for wound complications (excluding wound dehiscence) 0.43 (0.25 – 0.76) 0.43 (0.24 – 0.77) Intervention favored PR PR * When the heterogeneous study was excluded, the OR (CI) became 0.24 (0.14 – 0.40), favoring primary repair. PATI= Penetrating abdominal trauma index, PR= Primary repair, Div= Diversion, OR= Odds Ratio, CI= 95% confidence interval. colorectal trauma 31 patients who did not require resection, all within their primary repair group. When these data were independently extracted and analyzed by chi squared analysis and Fisher’s exact test, there were no differences between number of organs injured (p = 1.0), proportion of patients in shock (p = 0.46), presence of either moderate or heavy gross contamination (p = 0.31), proportion of patients needing more than 4 units of PRBC (p = 0.38), left-sided injury (p = 0.75), proportion with PATI > 25 (p = 0.17), or number of complications (p = 0.67). As would be expected, the mean PATI was greater in the resection subgroup, although this was not statistically significant (29 vs. 24). Also as expected, the number of patients with Flint grade 3 injury was higher in the resection subgroup versus the direct repair group (92% vs. 23%, p < 0.001). In their study, the primary repair group as a whole was more ill than the diversion group. Despite this, the diversion group was twice as likely to develop complications as compared to the primary repair group. Within the primary repair group, there were no differences between the resection and non- resection groups. Thus, the analysis above supports resection and anastomosis without diversion. Two caveats to this statement are that the numbers of patients are small, and the study was not powered to make this conclusion definitively. Demetriades et al. (27), conducted a nonrandomized, multi- center prospective review of 297 patients who sustained colon injury that required resection. One-hundred ninety-seven patients underwent primary anastomosis exclusively and 100 patients underwent diversion at 19 trauma centers. The method of repair was left to the discretion of the operating surgeon. The authors identified severe gross contamination, transfusion >4 units of PRBC in the first 24 hours, and single agent antibiotic prophy- laxis as independent risk factors for abdominal complications in a multivariate regression analysis. The presence of all 3 factors was associated with a complication rate of 68%, 2 factors with a rate of 17–38%, one factor with a rate of 17–21%, and none of these factors with a rate of 13%. Subsequently, two sets of analyses were then conducted comparing primary repair with diversion, the first controlling for these 3 independent risk factors, and the second adjusting for ‘traditional’ risk factors commonly found in the literature: hypotension (SBP < 90), transfusion >6 units of PRBC, severe contamination, PATI >25, and delay of operation >6 hours. The authors found similar rates of abdominal compli- cations between the 2 groups, no difference in complication rate by location of repair (e.g. ileocolostomy, colocolostomy, ileos- tomy, colostomy), and no difference in hospital or ICU stay. They noted 24% and 22% overall rates of abdominal and extraabdomi- nal complications respectively. One major limitation of this study was that the diversion group had a higher incidence of delayed operation, shock at admission, left colon injuries, PATI >25, small bowel and liver injuries, transfusion requirement, and severe fecal contamina- tion. Further, the diversion group received antibiotics longer than the primary repair group, although the median duration is not reported. However, the authors performed a separate analy- sis controlling for these factors and again found no difference in abdominal complications, hospital stay, or ICU stay. They did note an increased colon-related mortality with the diversion group (4.5% vs. 0%, p = 0.03), which translated to 4 deaths in this group. Thirteen patients in the primary repair group had an anastomotic leak, compared to one leak from a Hartmann pouch. No risk factors could be identified for leak within the primary repair group, and no patient died as a result of leak. The authors concluded that method of colon management does not influence the development of colon-related abdominal complications, and primary repair should therefore be practiced for all injuries. They also concluded that transfusion, severe contamination, and single agent antibiotic prophylaxis are independent risk factors associ- ated with complications. On the other side of this argument, several retrospective series have been published that present a caution to the concept of uni- form primary repair of all colon injuries. As an example, Stewart et al. (52), published a follow-up study based on their previous experience with 95 direct repairs with no suture line complica- tions and an 11% incidence of abscess.(53) The authors changed their management strategy and repaired all injuries primarily, including destructive wounds requiring resection and anasto- mosis. Forty-three patients undergoing resection and anastomo- sis and 17 undergoing colostomy were analyzed. They noted no statistically significant difference in complication rate. However, when comparing the 6 anastomotic leaks to 37 primary repairs that did not leak, they noted a 12-fold risk of leak in patients that had an underlying illness (e.g. diabetes mellitus, cirrhosis, HIV infection). The need for transfusion was not significantly associ- ated with increased risk, but the combination of transfusion >6 units of PRBC and medical illness resulted in a 14-fold increased risk of leak. The sample size was small, but the authors concluded that a 14% leak rate is excessively high. Other limitations include a shift in practice toward primary repair during the study period and inherent problems with determining underlying illness in the trauma population in general. Although these reports are ret- rospective reviews of a relatively small number of patients, high transfusion requirement (commonly 4 or 6 units) consistently appears as a risk factor for complications.(27, 53) Results of the randomized trials previously discussed did not identify this as a risk factor for complications. Damage Control Data concerning repair of colon injuries in the setting of damage control surgery (DCS) are scarce. There are no randomized data, and literature that specifically describes the management of colon injury in the context of damage control surgery is limited to three reports analyzing 34 patients.(54–56) Miller et al. (54) retrospectively analyzed 17 patients who underwent DCS and subsequent delayed definitive repair of colon injury. All patients had destructive colon injury, under- went abbreviated laparotomy at their initial operation, and were returned to the operating room after correction of acido- sis, coagulopathy, and hypothermia in the ICU. Eleven patients underwent resection and primary anastomosis and 6 under- went diversion. The authors compared the 11 anastomosis after DCS patients to 21 controls, who were patients with traumatic colon injuries undergoing anastomosis at initial operation. There were no leaks in the DCS group and one in the initial anasto- mosis group (p = 0.66). The abscess and colon-related mortality were also similar. As would be expected, the ISS and overall improved outcomes in colon and rectal surgery mortality were higher in the damage control group. The authors then compared the 11 anastomosis after DCS patients to the other 6 patients, who underwent colostomy after damage control. They found no differences in ISS, abscess rate, colon-related mortality, or overall survival. Chavarria-Aguilar et al. (55) reviewed the management of destructive bowel injury in the setting of the open abdomen. The data are heterogeneous, as patients with small bowel injuries are included in the analysis. Of 104 patients with destructive bowel injury requiring resection and anastomosis, 29 underwent tem- porary vacuum closure and the rest primary fascial closure. Eight patients with colon injuries underwent resection and delayed anastomosis after initial packing. Two leaks occurred, both from small bowel anastomoses. There were no differences in rate of abdominal abscess between the anastomosis and stoma groups in either the vacuum-closure group or the initial fascial closure group, with rates of 7–21%. These findings led the authors to conclude that resection and anastomosis is safe in the face of destructive injury and an open abdomen and should be consid- ered in most patients. The retrospective nature of the study did not allow causality to be established, and the small sample size did not allow for the identification of risk factors or appropriate candidates for anastomosis versus ostomy. Finally, Johnson and colleagues (56) describe general changes in DCS over an 8-year period and comment on 7 colonic anasto- moses and 2 primary repairs. They report one leak and 3 abscesses, but do not specify if this was within the colon resection group or the 13 small bowel resections performed. The authors of this chapter recently reviewed data collected on soldiers undergoing damage control laparotomy in Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) during 2005–2006 (unpublished data). We found a 51% rate of concomitant colon injury, or 77 of 152 patients. This is more than twice the number of patients studied than in the existing civil- ian literature. The early colon-related complication rate (7 days postinjury) was 14%. These included 5 leaks, 3 abscesses, and 6 cases of ischemia on further evaluation requiring reoperation. Complications were essentially equally distributed among the ostomy and anastomosis groups (p = 0.54). Results are summa- rized in Table 35.5. Further, there were no differences in compli- cations by location of injury (p = 0.58). There were no differences in ISS between colostomy and no colostomy (all primary repairs) and colostomy, direct repair, and resection and anastomosis groups. The colostomy group was more likely to have a massive transfusion, but there were no differences in the complication rate in any comparison. Although follow-up is currently limited to a mean of 7 days postinjury, data collection is ongoing. These results support the conclusion of Chavarria-Auguilar and col- leagues (55), that even in combat settings with massive injury and tissue loss, primary repair is feasible. However, as discussed later in this chapter, war injuries in combat situations may require dif- ferent management than civilian injuries. Practice patterns In an attempt to synthesize the diverse conclusions found in the literature, Miller and colleagues (57) developed a clinical path- way for destructive colon injuries in 1995 and compared patients treated during this period with their experience before its imple- mentation. Primary repair was undertaken in all colon injuries except patients with destructive injuries requiring >6 units of PRBC pre- or intraoperatively, or patients with significant under- lying medical illness. These high-risk patients underwent diver- sion. Two hundred nine patients in the clinical pathway group were compared to 60 prepathway patients. The authors found no difference in abscess, anastomotic leak, or colon related mortality rates between the two time periods. They also found no differ- ence in leak rates between anastomosis and direct repair groups after implementation of the clinical pathway, whereas there was a higher leak rate in the resection group in the prior era. Finally, they found that there was a reduction in the number of patients undergoing diversion from 31% to 9%. This translates to a rela- tive risk reduction of 71%, an absolute risk reduction of 22%, and a number needed to treat of 4.5. That is, for every five patients treated according to the pathway, one colostomy and subsequent takedown was avoided. Further, there were no differences in com- plications with gross contamination, associated injury, or location of colon injury. These results suggest that the authors improved their patient selection for colostomy, and that destructive injury alone is not a contraindication to primary repair. The notable corollary to this conclusion is that there was a role for colostomy in their experience. SUMMARY The treatment of penetrating colon injury has changed markedly in the past 50 years. Level I evidence supports primary repair (with- out diversion) of nondestructive injuries as the method of choice in nearly all circumstances. Specifically these circumstances include hypotension, gross contamination, high transfusion requirement, associated injury, and delay from injury to operative treatment. Level I data also exists supporting primary repair for destructive injuries requiring resection and anastomosis but is more limited. Transfusion requirement, gross contamination, and high penetrat- ing abdominal trauma index have been independently associated with infectious complications by a number of authors, but this has been regardless of the type of management (diversion or primary repair). Data regarding primary repair in the setting of damage Table 35.5 Colon injuries in the setting of damage control surgery during Operation Iraqi Freedom 2005–2006. Colostomy No colostomy (n = 44) (n = 30) p value ISS a 24.7 ± 2.2 24.8 ± 3.2 0.98 Massive 25/44 8/30 0.02 transfusion (56.8%) (26.7%) Complications 9/44 4/31 0.54 (20.5%) (12.9%) Colostomy Direct repair Anastomosis (n = 44) (n = 10) (n = 20) p value ISS a 24.7 ± 2.2 24.4 ± 3.8 24.9 ± 6.0 1.00 Massive 25/44 3/10 5/20 0.04 transfusion (56.8%) (30%) (25%) Complications 9/44 1/10 3/20 0.69 (20.5%) (10.0%) (15%) a. mean ± standard error of the mean. colorectal trauma control is even more limited, and no level I data exists. However, small series, including a recent large review of military injuries sug- gests that primary repair is feasible in the damage control setting. No convincing data exist supporting diversion as superior to pri- mary repair. In severely injured patients, a reasonable strategy is to initiate damage control techniques, including leaving the bowel in discontinuity, and subsequently performing an anastomosis once normal physiology is restored. A low threshold of suspicion is the key to diagnosis in most cases. Most injuries are found intraoperatively, and most are uncomplicated. Thus, primary repair is appropriate for the major- ity of colon injuries. As always, sound judgment, skilled resuscita- tion, and attentive postoperative care are keys to good outcomes. The complication rate is high regardless of method of manage- ment, and providers should be aware of this fact. “… it cannot be emphasized too strongly that the dangers of the abdominal patient are not over when the last stitch has been put in. Recovery depends almost as much on the skill and the duration of the after- care as on the operation itself.” (Ogilvie, 1944) (4) Blunt colon injury Colonic injury is uncommon after blunt abdominal trauma, accounting for only 1–5% of blunt traumatic injury.(58) It is notoriously difficult to diagnose, but a delay in diagnosis is associated with significant morbidity including fatal peritonitis, sepsis, and life-threatening hemorrhage.(59, 60) There are three primary proposed mechanisms in the pathogenesis of blunt colonic injury.(61) The first is crush injury between an object such as a steering wheel, seat belt, or vertebral column. Second, shear injury occurs at points of fixation, particularly the sigmoid mesentery. Third, burst injury can occur when a closed loop is formed at impact. The resultant injury pattern is characteristic and can include mural and mesenteric hematomas, partial thick- ness tears, full thickness perforations, and transection at fixation or contact points. Blunt colonic injury (BCI) is usually partial thickness, with rare exceptions (3%) being full-thickness colonic perforations. (62) The most common cause is motor vehicle crashes, both restrained and unrestrained.(62) The left colon is the most fre- quently injured, followed by the right and transverse colon.(62) The diagnosis of blunt colon injury is a diagnostic dilemma, and requires a high index of suspicion. In a retrospective multi- center 5 year review of patients with BCI, the diagnosis was made preoperatively only 5% of the time.(62) These injuries are often diagnosed upon laparotomy for other indications, and although rare, colon injury ranks 4th among injuries found at laparotomy in blunt trauma patients.(60) Physical exam findings are incon- sistent or manifest late after injury and the patient may be diffi- cult to evaluate secondary to traumatic head injury, intoxication, or distracting extraabdominal traumatic injury. The presence of a ‘seat-belt’ sign or a Chance fracture, as described previously, are predictors of hollow viscus injuries. Figure 35.1c demonstrates a blunt colonic injury. Nance et al. (63) studied solid organ injury as a predictor of hollow viscus injury in blunt trauma patients. They found that as the number of solid organ injuries increased, the likelihood that a hollow viscus injury coexisted increased, up to 34.4% in patients with three solid organ injuries. CT scan is currently the most utilized modality for the diagno- sis of blunt colonic injury.(33, 42) Findings suggestive of BCI on CT include evidence of extraluminal air, extraluminal contrast material, bowel wall thickening, streaking of the mesentery, and free fluid in the absence of solid organ injury (Figure 35.1b). Williams et al. (60) studied trauma patients with blunt colonic injury. They evaluated the ability of physical exam, plain radiogra- phy, CT scan, FAST, and DPL to accurately detect BCI. They found that no individual or combination of diagnostic tests was able to accurately detect BCI. For example, the sensitivity of CT findings including free air, contrast extravasation, and free fluid had sensi- tivities ranging from 6–49% and positive predictive values between 50–72%. Ultrasound examination had a sensitivity of 58%, speci- ficity of 44%, a positive predictive value of 61%, and a negative predictive value of 41%. Physical examination findings such as the seat-belt sign, peritoneal signs, and abdominal pain performed similarly, with sensitivity between 21 and 59% and positive predic- tive values between 57 and 63%. Diagnostic peritoneal lavage had a sensitivity of 97% but a specificity of 13%, a positive predictive value of 55% and a negative predictive value of 80%. Malhotra et al. (41) evaluated the accuracy of CT scan in the diagnosis of blunt bowel injury. They found the sensitivity and specificity of CT for these injuries was 88.3% and 99.4%, respec- tively, with an accuracy of 99.9%. The positive and negative predictive values were 53.0% and 99.9%, respectively. The most common finding they reported associated with BCI was unex- plained free fluid. Yegiyants and colleagues (64) found 14 cases of blunt injury with free fluid on CT scan but no evidence of solid organ injury (0.5% of admissions in their review). Eleven of these patients (74%) required laparotomy, with hypotension (3 patients) and peritoneal signs (6 patients) being the two most common triggers. In their series, physical exam was predictive in 43% and FAST exam was positive in 50%. It is possible that the addition of laparoscopy may aid in the management of blunt colonic injuries. As previously noted, Ahmed (44) and Mitsuhide (45) report the avoidance of between 21–75% of laparotomies in blunt abdominal trauma. Figure 35.1c Intraoperative findings in a patient with a “seat-belt sign”. The patient sustained a hematoma in the cecal mesentery and a serosal tear in the sigmoid colon which was primarily repaired. improved outcomes in colon and rectal surgery SUMMARY The management of blunt small bowel injury is relatively straightforward, requiring mainly primary repair or resection and anastomosis.(65) Blunt colonic injury is more complex. In a comprehensive review of the pathophysiology and management of blunt bowel and mesenteric injuries, Hughes and Elton (65) suggest that most blunt colonic injuries should be categorized as high grade (AAST grade V or Flint grade 3, Tables 35.1 and 35.2) and treated accordingly. A high index of suspicion, experi- ence, and appropriate follow-up are the cornerstone to the diag- nosis of this uncommon injury. Currently, physical exam, and CT scanning appear to be the most used methods of diagnosis. Laparoscopy may be a useful adjunct to diagnosis. Devascularized mesentery presents a challenging problem. The viability of the bowel should be assessed if in question and resected if indicated. In cases of severe injury a second look may be considered to assess for progressive ischemia. Once diagnosed, the treatment of blunt colonic injury should follow the guidelines for penetrating colonic injury. Outcomes of colostomy closure Only one RCT included subsequent colostomy takedown in the primary analysis. Chappuis et al. (14), reported 22 closures out of 28 patients in the diversion arm of their RCT with one complica- tion (4.5%), an enterocutanous fistula after ileostomy reversal. The absence of good follow-up limits the conclusions that can be made from this study. It is thus debatable whether this is an appropriate analytical strategy, in that initial management is a separate issue from colostomy closure. However, the risk of subsequent colostomy reversal should be considered when the decision to proceed with diversion is made. This topic is well represented in the literature, with a wide array of heterogeneous conclusions made. Differences in conclusions are due to varied definitions of complications and infections, the inclusion or exclusion of rectal injury, varied indica- tions for original diversion (trauma, cancer, etc), and the retrospec- tive nature of published data.(66–70) Mortality as a consequence of colostomy reversal is sufficiently low (0–3%)(69) that most authors report infectious complications as their primary endpoint. Further, infectious complications remain the major source of mor- bidity after wounding of the abdominal cavity.(71) Two series reviewing stoma closures after diversion for any indication found complication rates of 20–36%.(66,69) These rates are similar despite the reports being separated by 20 years. Factors associated with increased complications range from reversal performed in less than 90 days (66), diverting versus loop colostomy (66), age >55 (69), and use of a silicone drain.(69) While the data is heterogeneous, conclusions that can be made are that colostomy reversal is associated with a high complication rate of approximately 20–30%, and that some retrospective data seem to suggest an increase in complications with diversion (68, 70) which supports at least consideration of primary repair in almost all cases and a more selective use of diversion than what has been taught in previous years. Military perspective The recent military conflicts in Iraq and Afghanistan have raised questions about the applicability of the civilian experience to combat settings and war injuries. In light of this conflict a brief overview of the impact that active wartime has had on trauma surgery—and colon injury specifically—is worthwhile. There is a long history of the lessons of war having a deep and lasting impact on civilian surgical management. One of the clas- sic papers in the trauma literature is Ogilvie’s account of mili- tary surgery during World War II.(4) Although this is the paper most often cited as the impetus behind mandatory colostomy, it describes many classic precepts that were not widely recognized until much later decades. Ogilvie’s paper is remarkable both for his foresight but also the number of principles he describes. These include: the ‘trimodal’ peaks in trauma mortality, damage control, massive transfusion, ARDS, abdominal compartment syndrome, and many of the logistical issues later incorporated into both military and civilian trauma programs. Ogilvie reports a 60% mortality rate from colon inju- ries. Direct suture repair resulted in a 44% mortality rate as opposed to 45–65% for colostomy with and without resection. However, 2 of 2 patients who underwent resection and anas- tomosis died. He attributes the lower mortality with suture repair to less severe injury but nevertheless makes no recom- mendation about selective repair in these cases. Further, he acknowledges the beneficial effects that antibiotics, improved logistics, and liberal use of blood products had on outcomes. Despite these other factors, he strongly advocates for colos- tomy in all cases and states that it is “perhaps the greatest sin- gle factor in the improved results we are able to record”. It is likely that a mandate and automatic action were preferred in the face of the challenges involving resources, evacuation, and ever-changing groups of surgeons of vastly different levels of training and experience. This can be seen in his assertion that “the forward surgeon must have good hands, a stout heart, and not too much philosophy. He is called upon for decision rather than discussion, for action rather than a knowledge of what the best writers think should be done”. Perry and colleagues (2), in a comprehensive review of the military management of colon injury, describe its evolution throughout modern history. Before World War I, laparotomy was discouraged and observation afforded the wounded soldier the best chance of survival. Laparotomy and rapid evacuation dur- ing WWI saw a dramatic decrease in mortality from abdominal injuries from almost 90% to 40%. The changes wrought during WWII have been detailed previously. During the Korean War, air superiority led to improvements in evacuation. Further, the practice of exteriorization, in which the repaired colon was mobi- lized and brought out above the skin for observation, was largely abandoned. Finally, some leeway in the primary repair and anas- tomosis of right colon injuries was allowed. These factors led to a further decline in colon-related mortality from 35% to 16%. Aside from well-documented advances in resuscitation and criti- cal care, the Vietnam War saw improvements in evacuation and antibiotics, as well as more location-specific trends in colon man- agement. Left-sided wounds were diverted, while recommenda- tions for right-sided wounds included resection and primary anastomosis, exteriorization, and resection, ileostomy and mucus fistula. During this time mortality dropped to around 10%. Perry and colleagues stress that the best results with primary repair colorectal trauma are obtained by surgeons experienced in this strategy and when patients remain under the care of the same surgeon. Hudolin and Hudolin (72) reviewed their experience during the Bosnia-Herzegovina conflict in 1992–1995. Two-hundred fifty-nine patients with colonic injury were treated at a single receiving facility with no radiologic capability and a single field generator. Rapid evacuation made long-term follow-up impos- sible. Roughly equal numbers of patients were treated with pri- mary repair and colostomy (47% and 53% respectively). Overall mortality was 7.7% in both treatment groups. There were no dif- ferences in associated injuries, or mechanism of injury (explo- sive or gunshot) between groups. Overall complication rate was similar between groups (27% for primary repair and 30% for colostomy). The authors did not perform statistical analysis on individual complications, citing low numbers, but there were more leaks in the primary repair group (8 vs. 2) and fewer wound complications (7 vs. 15). These authors also cite surgeon experi- ence as an important factor in management with primary repair, but conclude that it is safe even with subsequent rapid evacuation if treatment is undertaken soon after injury and with administra- tion of perioperative antibiotics. Steele and colleagues (73) reviewed the treatment of 175 patients during the 2003–04 period of OIF. Primary repair was undertaken in 53%, the leak rate was 10%, and overall mortality was 17.7%. Only 37% of patients were United States or coalition forces and the rest were local nationals. Mean ISS and AIS were similar among different regions of the colon. Stomas were more frequently performed for rectal or anal sphincter injuries than colonic injuries, and for left-sided versus right-sided or trans- verse injuries. Leaks after primary repair were equally distributed throughout the colon. Although the leak rate was higher in the primary repair group, there was no difference in rate of sepsis or mortality between groups on multivariate analysis. Only ISS >15 was associated with an increase in sepsis, while only rectal or transverse injuries were associated with an increase in mortality. Follow-up is not reported likely due to rapid evacuation and the high proportion of local nationals included in the study. We conducted a review of colon injuries sustained during OIF during 2005–2006 (unpublished data). One hundred thirty- three patients with colon injuries were admitted from Iraq and Afghanistan to Landstuhl Regional Medical Center (LRMC) in Landstuhl, Germany, the tertiary referral center for combat casu- alties in this theater. The average time spent in the three echelons of combat care facilities (battalion aid station, forward surgical team, and combat hospital) was 2 days and the average time spent at LRMC was 4.7 days, translating to about 7 days from injury to echelon V (tertiary US military hospital) care in the United States. Anatomic distribution of injury is depicted in Table 35.6. Primary repair or resection and anastomosis was the ini- tial method of treatment in 34%, colostomy in 45%, and dam- age control consisting of bowel left in discontinuity in 21%. The complication rate was 12% overall and was not related to type of management (p = 0.172). Complications were linked to open abdomen (p = 0.031), increased ICU days (p = 0.015), gunshot wound (p = 0.021), and number of procedures before admission at LRMC (p = 0.008), but not LOS, ISS, mechanism, location of injury, or massive transfusion. These results are limited by the lack of long-term follow-up. Data collection from US sites is ongoing, however, and will be the subject of future publications. SUMMARY These examples demonstrate that the use of primary repair in military series is lower than reported in the civilian literature. (27, 57) Contributing factors include varied training and per- sonal philosophy of treating surgeons, higher number of dam- age control procedures performed, and higher incidence of rectal injury, which in turn results from the contribution of blast and high-energy mechanisms of injury. These differences in combat trauma contribute to the active debate on the method of choice, as is evidenced by recent publications by authors deployed to OIF calling for an expanded role for diversion.(74, 75) To date, how- ever, the experience has been limited to small series and expert opinion. Larger series previously described currently lack long term follow-up. The bulk of the data seems to support primary repair. Antibiotic therapy As previously mentioned, infectious complications are the major source of morbidity after abdominal trauma.(71) Infection is a major contributor to the third peak in the ‘trimodal’ distribution of trauma mortality, which was recognized by Ogilvie in 1944 (4) and described by Trunkey in 1982.(76) Causes can be sepa- rated into two broad categories, those related to the patient or the disease process and those related to treatment. The latter are the modifiable factors. A number of disease-related factors have been reported to contribute to infectious complications. In a recent, comprehen- sive review of the literature addressing infections in penetrating abdominal trauma, Fabian (71) describes colon injury, rate of transfusion, shock (generally SBP < 90 mm Hg), and PATI >25 as well-investigated independent risk factors. Treatment related factors include careful attention to measures that contribute to improved outcomes in the trauma and critically ill population in general; aggressive efforts to achieve normothermia (77), correc- tion of coagulopathy and acidosis, euglycemia (78), minimiza- tion of transfusions (79–81), and careful attention to nutrition. (82–85) Choice, timing, and duration of antibiotic therapy have been well studied and deserve a brief comment. The efficacy of prein- tervention versus posttreatment (postoperative) therapy is well established.(85, 86) In addition, the choice of antibiotic does not seem to matter as much as the adequacy of anaerobic and gram- negative coverage. The only study that appeared to have generated Table 35.6 Anatomic distribution of colon injuries during Operation Iraqi Freedom 2005–2006. Location Number a Percent a Ascending 28 21% Transverse 20 15% Descending 28 21% Sigmoid 36 27% Rectum 33 25% a. Totals exceed 100% due to multiple injuries in some patients. improved outcomes in colon and rectal surgery data favoring multiple agent therapy was the prospective nonran- domized study of colon injury requiring resection and anastomo- sis conducted by Demetriades and colleagues that was discussed previously.(27) In this report, single agent antibiotic therapy was an independent risk factor for abdominal complications, with an RR of 1.89 (p = 0.004) and an RR of 1.12 when adjusted for trans- fusion of 4 or more units of PRBC, severe fecal contamination, or method of colon injury management. However, the most recent guidelines published by the Surgical Infection Society in 2002 rec- ommend 24 hours of organism-specific coverage in instances of peritoneal contamination due to traumatic bowel injury repaired within 12 hours.(87) There is sufficient class I evidence to recom- mend 24 hours of an appropriate antibiotic for the minimization of infectious morbidity in colon trauma.(88–90) Bozorgzadeh et al. (88) randomized 300 patients to either 24 hours or 5 days of therapy with cefoxitin after penetrating abdominal injury. There were no exclusion criteria and patients with colon injury (32%), shock on admission (31%), and multiple abdominal organ injuries (19%) were included. The overall infec- tion rate was 25%, while deep surgical site infections occurred in 6%. There were no differences in complications or length of stay between groups. In addition, multivariate analysis found only colon injury to be independently associated with infection and increased length of stay. One limitation of this study was that the 5 day group had a higher incidence of intraoperative shock, mul- tiple organ injury, and intraoperative blood loss. Cornwell and co-workers (89) randomized patients with full- thickness, penetrating colon injury and one risk factor consisting of PATI>25, transfusion of 6 or more units of PRBC, or greater than 4 hours from injury. Sixty three patients were randomized to either 24 hours or 5 days of cefoxitin therapy. There were no differences in severity of injury or other baseline characteristics, infectious complications, length of stay, or mortality. Overall abdominal infection rate was 29% and overall mortality was 9.5%. Although the sample size was adequate by power analysis, there were a small number of patients in each group. Kirton and colleagues (90) performed a multicenter, double blinded, placebo-controlled RCT in which 317 patients with pen- etrating hollow viscus injury were randomized to receive either 24 hours of ampicillin/sulbactam followed by 4 days of saline placebo, or 5 days of antibiotic therapy. The proportion of colon injuries (50%), AAST grade of colon injury, distributions of solid organ injury, ISS, PATI, and infection rates were similar in each group. The overall infection rate was 19%, with 9% surgical site infections. Mortality was 1.6% overall. On multivariate analy- sis only total number of PRBC transfused and PATI >25 were independent contributors to infectious complications. Both the Cornwell and Kirton studies identified gram-negative bacilli as the most common isolates. Although this topic has been well studied, the demonstrated risk of infection with colon injury may predispose some prac- titioners to inappropriately prolong the duration of antibiotic therapy. The rising incidence of resistant bacterial strains makes this a critical issue. Adherence to evidence-based guidelines and support on an individual, practice, hospital, and national level is essential in minimizing the incidence of multiply resistant noso- comial infections. Retained fragments The traditional teaching regarding retained fragments is that they should be left in place unless they traverse the colon, in which case they should be removed and the tract debrided. Data regard- ing this subject is scarce. For example, four reports specifically addressing infectious complications after missile injury to the colon have been published since 1990.(91–96) Sarmiento and colleagues, who report the largest experience on this subject, reference six other publications on this topic since 1892.(93) Flint et al. (95) reported a series of seven patients with gun- shot wounds through the colon who developed abscesses, two of whom died (28%). They noted that abscess culture revealed E. Coli, Klebsiella, Bacteroides, and pseudomonal species in every case, leading to the conclusion that contaminated material was inoculating the wound tract, and that retained fragments should be removed. Based on a small series, Flint refuted the belief held at that time that bullets and missile tracts were sterile due to the heat and friction generated by the projectile.(91) Poret (91) reviewed 151 patients with gunshot wounds traversing the colon and found a 26% rate of septic complications when the bullet or fragment was retained and a 16% rate when there was no retained fragment (p = 0.15). Although not statistically significant the authors note clinical significance, and conclude that the retained missile is a nidus for infection. In contrast, Demetriades and Charalambides (92) reviewed their experience with 84 patients with gunshot wounds to the abdomen traversing the colon. Bullets were removed only if they were pal- pable. In 48% of patients the bullet was retained, while in 52% it was either removed or had exited the body. The two groups were matched in severity of injury, site of injury, number of colonic per- forations, and method of repair (primary versus colostomy). The overall abdominal complication rate was 14% and the incidence of missile tract infection was 4% with no differences between groups. Antibiotics were given for 48 hours. The authors concluded that missiles should only be removed if they are easily palpable. Edwards et al. (93) studied the effects of low-velocity, small-fragment injury in a porcine model designed to simulate injury from antipersonnel devices in combat. They fired steel fragments through the unpre- pared colons of swine into a gelatin medium, then cultured several points along the missile tract, as well as the fragment itself. No cul- ture reached 1 × 10 5 organisms and average tract size was 5 cm long by <1 mm in diameter. The authors concluded that small-fragment removal and debridement of wound tracts would not present an increased risk of infection if antibiotics were administered soon after injury. Sarmiento et al. (93) retrospectively reviewed 185 patients who sustained gunshot wounds in which the bullet had traversed the colon and extraperitoneal soft tissue only. The decision to extract the bullet was according to the discretion of the operating sur- geon at the time of initial laparotomy. There was a fivefold lower incidence of infection in those in whom the bullet was extracted compared to retained (5% vs. 25%, p = 0.06). They also found no difference in risk of infection for injuries that traversed the right and transverse colon compared to the left colon and rectum. In summary, the evidence is sparse on this topic, but seems to sup- port extraction of bullets, debridement of wound tracts and early antibiotic administration with retained fragments that traverse the colorectal trauma colon and embed in soft tissue. This is consistent with the basic gen- eral surgical principle of not leaving foreign material in the presence of the open gastrointestinal tract. Small-fragment injury poses an additional problem, in that debridement of multiple small-diameter tracks may be a significantly morbid procedure.(94) Rectal injury The classic components of managing rectal injury include the three (or sometimes four) D’s: diversion, presacral drainage, dis- tal rectal washout, and sometimes direct repair.(30, 96) These maneuvers were established during WWII and the Vietnam war (2), and were credited with decreasing mortality from 67% dur- ing WWI to essentially zero during the Vietnam war, and decreas- ing morbidity from approximately 70% to 10% during the same period.(1, 30, 96) Mortality in recent series is low. In a review of 39 civilian studies, Merlino and Reynolds (96) identified 42 deaths in 1105 patients with rectal injury, 10 of which (0.9%) were attributed to the rectal injury itself. They also report a range of 1.3 to 4.5 associated injuries per patient, making associated injury the rule rather than the exception. Genitourinary injury is the most commonly associated injury given the anatomic prox- imity of these organs. The rectum is protected by the bony pelvis and soft tissue, which makes injury less frequent, but exposure more difficult. It is mostly accessible from the anus but is only covered by peri- toneum along its proximal one-third and anteriorly along the middle one-third, facilitating both repair and intraperitoneal contamination. Penetrating injury accounts for 85% of reported injuries, with the majority of these being gunshot wounds.(96) A rare source of rectal injury is iatrogenic perforation, which reportedly occur in approximately 0.1–0.2% of cases.(97, 98) Diagnosis Rectal injuries present a diagnostic challenge. Injuries to the bony pelvis should be rapidly diagnosed, and an unstable pel- vis should be addressed first. Careful perineal and digital rectal examination is the next step and should be accompanied by a high clinical suspicion with risk factors outlined in Table 35.7. Sphincter tone and injuries to the sphincter complex should be carefully noted at this point as well. Digital rectal exam has a reported accuracy of 64–96%.(99–102) Sigmoidoscopy (blood or lesion visualized) for the diagnosis of rectal perforation has an accuracy of 89–100%.(99–101, 103, 104) Blood on digital exam is an indication to further assess the rectum either by proctoscopy or sigmoidoscopy.(103, 104) Intraluminal hem- orrhage identified by endoscopy should lead to the presump- tive diagnosis of rectal injury and management should follow accordingly.(102–104) Contrast-enhanced CT scan and contrast studies are useful adjuncts in equivocal cases.(105) Diagnostic laparoscopy has been described for hemodynamically stable patients with evidence of extraperitoneal rectal injury (blood on rectal exam and proctoscopy), no peritonitis, and no intra- peritoneal injury.(103, 106, 107) Management Traditionally, the cornerstone of rectal injury management is fecal diversion.(96) In distinction to colon injury, diversion is more often indicated for rectal injury. This is partly due to a lack of class I data confirming the safety and feasibility of primary repair alone with rectal injuries, combined with increased difficulty in dissection and exposure, as well as lack of a serosa for much of its extent.(104) Overall mortality rates are low, between 0–9% (99–104, 108–111), including six modern series published since 1996 with a <2% death rate. The infrequency of this injury makes it unlikely that an RCT with sufficient power will be performed. The safety of colostomy in rectal injuries has been documented. In a review of complications related to colostomy, Berne and colleagues (68) reported a 55% inci- dence of complications when colostomy was performed for colon injury versus a 13% incidence when performed for rectal injury. A number of reports have challenged the routine practice of distal irrigation and presacral drainage (101, 103, 108, 110–112), the majority of which cite the differences between civilian and military penetrating trauma as the primary indication for devia- tion from the classic teaching. Only one RCT exists on this topic, conducted by Gonzalez and colleagues.(110) Forty-eight patients were randomized to diver- sion and either presacral drainage or no drainage. Distal irriga- tion was not performed on any patient. There was no mortality attributable to rectal injury, and complications occurred in two patients in the drainage group and one in the nondrainage group (p > 0.05). The authors acknowledge that their study was under- powered to detect a difference in complication rates. Others have argued that with unrepaired extraperitoneal injury the risk of overwhelming pelvic sepsis developing within a closed space is high, and in this case presacral drainage is indicated.(96, 108) In the absence of convincing data, this argument represents a rea- sonable approach. Distal washout has largely been abandoned, as many authors have consistently failed to demonstrate any advantage to its use. Most authors cite the difference between high-energy, military rectal wounds, and lower-energy civilian injuries as the pri- mary difference in results between the original reports from the Vietnam war and contemporary experience (96, 101–104, 108, 110). There may be a role for distal irrigation in wartime and with injuries resembling combat injuries. One useful convention is to approach rectal injury along ana- tomic lines. Intraperitoneal injury can be safely treated in a simi- lar fashion to colon injury, as several authors have demonstrated the feasibility of primary repair without proximal diversion.(96, 101, 108) The exception is in the case of extensive contamination and tissue loss, for which most authors divert the fecal stream. Table 35.7 High-risk factors for rectal injury. Gunshot wound to pelvis, buttocks, lower back or abdomen Wound in which injury tract is directed caudad Penetrating gluteal injury Blast injury to perineal area Complex perineal laceration Pelvic fracture Lower genitourinary tract injury Sexual assault Erotic anal penetration Gross blood per rectum High-energy blunt injury to lower abdomen . multiple injuries in some patients. improved outcomes in colon and rectal surgery data favoring multiple agent therapy was the prospective nonran- domized study of colon injury requiring resection. sign”. The patient sustained a hematoma in the cecal mesentery and a serosal tear in the sigmoid colon which was primarily repaired. improved outcomes in colon and rectal surgery SUMMARY The. improved outcomes in colon and rectal surgery and that was reliable in the acute postinjury setting as opposed to other etiologies for critical