 improved outcomes in colon and rectal surgery determine which method is superior, a recent meta-analysis of the available literature was used to compare the treatment out- come using EMG vs. pressure biofeedback.(87) EMG biofeed- back was primarily used in 18 studies (442 subjects) with a mean success rate (improved symptoms) of 70%. Pressure biofeedback training was used in 13 studies (275 subjects) with a mean success rate of 78%. These results showed a significantly better outcome in patients with pressure biofeedback protocols. Further analy- sis compared intraanal to perianal EMG biofeedback and their results showed no significant difference between the two sub- groups (69% vs. 72%, respectively). Overall, these data show suc- cess rates ranging from 69 to 78%, regardless of which protocol or what instrumentation is used; however, without controlled trials, the optimal protocol for subjects with dyssynergic-type constipa- tion remains unclear. The role of other factors on the outcome of biofeedback therapy in patients with pelvic dyssynergy has been studied. In one study, the only predictor of successful outcome was the number of ses- sions attended (5 or more) and whether the therapist discharged the patient (63% success rate) rather than the patient terminating treatment prematurely (25% success rate).(90) To date, research- ers have not been able to identify any physiologic (manometry and balloon expulsion test), anatomic (rectocele, intussusception, or abnormal perineal descent), or demographic (age, gender, duration of symptoms) variables that influence treatment out- come; however, many investigators do suggest that psychopathol- ogy may influence biofeedback treatment outcome. Anxiety and psychological distress are commonly associated with pelvic floor dyssynergy. One study showed that patients with pelvic floor dys- synergic-type constipation or rectal pain showed a tendency to use somatization as a defense mechanism to manage psychologi- cal distress.(91) This pattern was not seen in a comparison group of patients with fecal incontinence. Others have suggested that there may be a psychosomatic basis for chronic idiopathic con- stipation, including pelvic floor dyssynergy.(92, 93) Studies have reported up to 65% of constipated subjects were diagnosed with various psychological disorders (94); however, there is significant debate whether the psychopathology is a cause or a consequence of dyssynergic constipation. In a study of patients with slow-tran- sit constipation without pelvic dyssynergy 60% of subjects had a concurrent affective disorder, with 66% reporting having a previous affective disorder.(95) Others have shown a high incidence of sexual or physical abuse in patients suffering from constipation. Given these results, it is of no surprise that psychological treatment for subjects with constipation is frequently recommended in addi- tion to biofeedback therapy. Establishment of an effective psycho- therapeutic relationship may be critical for success. Biofeedback therapy has been used for the treatment of slow- transit constipation. A single case series reported the successful treatment of 4 patients with slow-transit constipation without pelvic floor dyssynergy using biofeedback therapy (96); how- ever, two of the four patients continued to require laxative use despite improved symptoms, and there was no objective confirm- atory evidence (repeat colonic transit study) to support physi- ologic improvement. A recent study has compared the benefits of biofeedback therapy in patients with slow-transit constipa- tion to those with pelvic dyssynergia-type constipation.(97) At 6 months, the dyssynergic group had greater satisfaction (71% vs. 8%), and more frequently reported ≥ 3 bowel movements per week (76% vs. 8%) than the slow-transit group following a 5 weekly biofeedback sessions. These data indicate that pelvic floor biofeedback benefits patients with pelvic floor dyssyner- gia, but not patients with slow transit constipation. Biofeedback therapy has been suggested as the initial therapy for patients with outlet obstruction associated with pelvic floor dyssynergy. This concept is supported by a recent randomized, controlled trial of patients with pelvic floor dyssynergy where biofeedback was shown to be more effective than laxative therapy with PEG.(98) Further well designed prospective randomized controlled trials are necessary to establish biofeedback therapy as the primary treatment for patients with this condition. Failure of biofeedback therapy poses a significant treatment problem as most patients do not improve with surgical interven- tion. Division of the puborectalis muscle in the posterior midline has been reported in patients with intractable pelvic dyssynergy. However, results are disappointing with very few patients obtain- ing any benefit from the procedure.(99) These data suggest that this procedure has no role in the treatment of patients with this condition. Botulinum toxin injection has been proposed as an alternative therapeutic modality for these patients with refrac- tory pelvic floor dyssynergy. Injection of the toxin is directed into the puborectalis muscle and external anal sphincter. Symptom improvement was reported in up to 75% of patients with benefit lasting from 1 to 3 months. Fecal incontinence was reported in 25% of patients, and was transient lasting only 1 to 3 months after injection.(100–101) Others have reported similar beneficial effects of botulinum toxin injection for dyssynergic-type con- stipation.(102) However, because the effects of the toxin wear off within 3 months of administration, repeated injections are necessary to maintain symptomatic improvement. Furthermore, given the expense of this drug, this treatment modality should be reserved for those patients with severe symptomatic pelvic dys- synergia that has failed all other therapies. sURgeRY OPtiOns Surgical intervention for functional constipation is limited to patients with documented severe slow-transit constipation that is refractory to medical management. Patient selection is criti- cal for success. Minimal evaluation requires colon transit studies to document slow-transit constipation, and pelvic floor physiol- ogy testing to rule out pelvic floor dysfunction. Operative proce- dures performed for the treatment of slow-transit constipation include segmental colectomy, subtotal colectomy with ileosig- moid anastamosis, and total abdominal colectomy with ileorec- tal anastamosis. Each procedure has its champions; however, the overwhelming body of literature indicates superiority of total abdominal colectomy with ileorectal anastamosis. Total abdominal colectomy with ileorectal anastamosis is the treatment of choice for patients with slow-transit constipation. The anastamosis is usually performed in the proximal rectum at or near the sacral promontory. At this level, the anastamosis is easier to perform, eliminates the risks associated with rectal mobilization, and bowel diameter does not limit the size of the anastomotic lumen.(103)  operative and nonoperative therapy for chronic constipation Timing of surgery is best decided by the patient, as this sur- gery is an irreversible step in the treatment of constipation. Most patients are accepting of surgical intervention when all conserva- tive measures have failed to result in an acceptable quality of life. In addition to standard operative risk for colectomy, patients should be counseled that abdominal pain and bloating may persist postoperatively even after normalization of bowel fre- quency. This is significant as a recent report showed that persist- ent abdominal pain had the strongest correlation with quality of life scores following colectomy in these patients.(104) Standard bowel preparations may not be sufficient as many patients with slow-transit constipation have one bowel-movement per week and are already taking PEG products to assist with bowel func- tion. A clear liquid diet for 48 hours along with multiple enemas and laxatives may be necessary to adequately evacuate the colon and rectum of stool. Perioperative antibiotics are given accord- ing to current standards (intravenous) and physician preference (oral) as described in Chapter 2. Overall success of total abdominal colectomy with ileorectal anas- tamosis for slow-transit constipation is approximately 90%, and reported rates of symptomatic improvement ranges from 50% to 100%.(104, 105) This variability may be the direct result of how suc- cess after surgery is defined.(104) Many studies use patient satisfaction as criteria for success; however, patient derived subjective assessment is an inaccurate measurement of surgical outcome and likely varies between patients and studies. In a review of the literature evaluating subtotal colectomy for slow-transit constipation, Knowles et al. found that only half of the 31 studies that documented success or satisfaction reported the method of data acquisition.(19) Furthermore, in these studies success rate was based on patient judgment in 14, on function in 6, and on a combination of both in 5. Criteria used to assess suc- cess or satisfaction was not reported in 6 studies. Patient satisfaction and gastrointestinal functional outcomes (i.e. bowel-movement fre- quency) do not correlate with quality of life.(104, 106) A recent report showed a significant increase in bowel-movement frequency after subtotal colectomy; however, the persistence of abdominal pain and the development of postoperative incontinence or diarrhea adversely affected quality of life scores.(104) The authors concluded that bowel movement frequency alone does not provide an accurate assessment of patient’s outcome. This has led investigators to suggest the use of standardized outcome measures such as questionnaire-based proto- cols that assess quality of life.(106) These instruments should be used along with postoperative complications, functional outcome measures as well as gastrointestinal function to provide more uniform outcomes measurement of operative success in these patients. Acute and long-term complications are significant and include prolonged postoperative ileus, recurrent bowel obstruction, abdominal pain and bloating, diarrhea, incontinence, and recur- rent constipation, and are addressed in detail below. These fac- tors all affect quality of life scores with incontinence having the greatest negative impact.(104) In fact, postoperative quality of life assessment after total abdominal colectomy and ileorectal anastamosis showed significantly decreased scores compared to those of the general population (107); however, 93% of patients that met selection criteria for total abdominal colectomy with ile- orectal anastamosis for slow-transit constipation would undergo colectomy again given the chance.(104) Early reports found that if the whole intraabdominal colon was not removed, symptoms often recurred.(108) In fact, results of segmental colectomy have been disappointing with small series reporting up to 100% failure rate.(19) Reports of subtotal colectomy with ileosigmoid anastamosis resulted in an increased incidence of constipation and conversion to total colectomy was necessary in 50% of cases.(109) Other authors support this concept and cite increased incidence of constipation recurrence and persistence resulting in the need to reoperate to remove the remaining colon.(107, 110) Removal of the colon with preserva- tion of the cecum and ileocecal valve has been described; how- ever, long-term results were poor as maintenance of the cecal reservoir resulted in dilatation and recurrence of constipation symptoms.(111) Modifications of colonic transit studies using multiple ingestible markers and scintigraphic defecography have been used to determine segmental colonic inertia.(112) Although the validity of these techniques to determine segmental motility dysfunction has been questioned (113), these tests have been used in recent studies to identify and successfully treat patients with segmental colonic inertia.(105, 114) In one study, 28 patients were treated with segmental resection with a median follow-up of 50 months.(114) Early failure with persistent or recurrent consti- pation occurred in 3 (11%) patients and required further surgery. Patient satisfaction was reported in 23 (82%) patients; however, outcome was reported as excellent in 10 patients, good in 7, fair in 7, poor in 4. If successful outcomes were assigned to the excel- lent and good category, the success rate would fall to 61%. Again, variability in method to define success may play a factor in these results. Another study evaluated 15 patients with slow-transit constipation classifying them into total colonic slow-transit (8 patients) and left slow-transit (7 patients). (105) Total abdominal colectomy or left colectomy was performed according to this clas- sification and resulted in improvement in symptoms (increased daily evacuations) in 8 (100%) and 6 (86%) patients, respectively. The authors report that patients with left colonic slow-transit all had prolonged latency times and were treated with percutaneous nerve evaluation. None received permanent implantation of the device, but it does raise the question as to whether colon transit studies were affected in these patients. The weighted finding of prolonged latency times in patients with left colonic slow-transit is interesting as sacral nerve stimulation has been successful for the treatment of slow-transit and dyssynergic-type constipation. (115) Although segmental colectomy seems promising for the treatment of segmental colonic inertia, controlled data are lack- ing and further studies are needed to verify and support its use. In a small subset of patients with slow-transit constipation ile- ostomy may be necessary due to poor operative risk or in elderly patients with impaired continence. COMMOn COMPliCatiOns Morbidity of colectomy in patients with slow-transit constipation includes several factors. First, the direct risks of colon resection are related to the anastamosis (leak, stricture), infections (wound and intraabdominal abscess), bleeding, and anesthesia. Mortality related to colectomy in this group has been <1%.(103) Long-term compli- cations resulting from colectomy in patients with slow-transit con- stipation are significant, and have been shown to negatively impact  improved outcomes in colon and rectal surgery outcomes with decreased quality of life.(104) Common complica- tions in this group of patients include recurrent bowel obstruction, abdominal pain, diarrhea, incontinence, and recurrent constipa- tion, and warrant further discussion. Recurrence of constipation is addressed in detail in the section to follow. In patients undergoing total abdominal colectomy with ile- orectal anastamosis, the most frequently occurring complication is small bowel obstruction. The reported incidence ranges from 8 to 38% with surgical intervention required in up to 75%.(104, 110, 116) The etiology of obstruction is commonly attributed to adhesions formed from the extensive colectomy; however, others have reported findings of small bowel pseudo-obstruction due to proposed neuropathic disorder of the myenteric plexus affect- ing overall bowel motility.(104, 117, 118) A retrospective review examined the incidence of postoperative complications follow- ing subtotal colectomy with ileorectal anastamosis in 48 patients with colonic inertia, 30 with Crohn’s disease, and 22 with either Familial Adenomatous Polyposis, or other neoplasia.(119) Small bowel obstruction occurred in 10 to 18% of each group, with no significant difference between groups. Others have reported intestinal obstruction rates of 35% following total abdominal colectomy for slow-transit constipation. In this study, 33% of patients had evidence of a delay in small bowel transit time sug- gesting this disorder is not limited to the colon, but also affects the small bowel. Recent reviews have speculated that routine use of antiadhesive agents such as Seprafilm® may reduce the inci- dence of adhesion induced small bowel obstruction.(103) Postoperative persistence of abdominal pain and alteration in bowel function are significant issues that adversely affect quality of live. A recent retrospective review on quality of life after subto- tal colectomy for slow-transit constipation showed that abdomi- nal pain was persistent in 41% of patients, diarrhea in 52%, and incontinence in 45%.(104) Collectively, these factors had the strongest correlation with quality of life survey, and the devel- opment of incontinence had the most negative impact on the score. As mentioned above, the high rate of persistent abdominal pain after surgery warrants detailed counseling of the patients regarding expectations and outcomes. Patients must be aware that normalization of bowel frequency may not relieve them of their pain. Diarrhea following total abdominal colectomy with ileorectal anastamosis is not uncommon with reported incidence ranging from 0 to 46%.(104) This is not surprising as the colon is effective at water absorption and is responsible for desiccating the stool. Over time intestinal adaptation occurs and normalizes consistency and frequency of the stool, with more than 90% of patients having either solid or semisolid stools by 6 months.(120) During the intestinal adaptation period, diarrhea is treated with fiber, motility agents (loperamide, diphenoxylate and atropine sulfate), and binders (cholestyramine) to reduce bowel frequency. The incidence of postoperative incontinence has been reported in 0% to 52% of patients with a mean of 14%.(104) Intractable diarrhea, especially in the setting of fecal incontinence, may require conversion to a permanent ileostomy. ReCURRenCe It is clear that colectomy for refractory constipation has demon- strated successful outcomes for total abdominal colectomy with ileorectal anastamosis in 89 to 100% after appropriate preop- erative workup, including colon transit study, defecography, and anorectal physiology tests.(19) Therefore, the greatest assurance to success in the operative treatment of constipation starts with appropriate patient selection. Recurrence or persistence of constipation following colectomy has been reported to occur in up to 33% of patients.(104) Patients with combined slow-transit constipation with pelvic floor dyssynergy are less likely to result in successful outcomes after surgery. Outcomes in patients undergoing surgery for slow-transit constipation with or without pelvic floor dyssynergy have been compared.(121) The pres- ence of pelvic floor dysfunction significantly decreased success rates from 78% to 56%. It has been shown that slow-transit constipation with associated pelvic floor dyssynergia can be treated initially with biofeedback therapy followed by surgery with similar improvement in outcomes such as median stool number per day, spontaneous stools, laxative use, and quality of life.(107) Patients with slow-transit constipation are believed to have a glo- bal neuropathic disorder of the myenteric plexus that affects colonic motility.(117) It has been proposed that this neuropathic disorder may extend proximal into the small bowel, or even the entire gas- trointestinal tract resulting in a global gastrointestinal motility dis- order (panenteric inertia). Failure to identify these patients may be a reason for early recurrence of constipation or even the high inci- dence of postoperative bowel obstruction. Preoperative evaluation of whole gastrointestinal transit should be performed in all patients undergoing surgery for slow-transit constipation. Successful iden- tification of these patients should raise question as to whether they will benefit from colectomy. If this entity is identified after surgery, conversion to an ileostomy may be required. Finally, recurrence of constipation may be a direct result of incomplete colonic resection. Segmental colectomy, ileosigmoid anastamosis, and preservation of the cecum and ileocecal valve with cecorectal anastamosis are all associated with a higher inci- dence of constipation recurrence or persistence. Surgical failure in these patients frequently requires reoperation for conversion to ileorectal anastamosis. In patients with recurrent constipation after colectomy, workup is directed at the issues addressed above. First, anatomic evalu- ation of the remaining rectum should be performed. Flexible signoidoscopy is adequate and can be performed in the office after two Fleets enemas. Special attention is made to the anastamosis as stric- ture formation will result in constipation. In the absence of organic disease, pelvic floor physiology testing is repeated to determine the presence of pelvic floor dyssynergia. Presence of this condition requires biofeedback therapy to improve symptoms and outcome. Upper gastrointestinal small bowel follow trough and other tests of whole gut transit will determine whether panenteric inertia is present. In these patients, persistent constipation and pseudo-obstruction are difficult to manage and may require end ileostomy. A careful review of the original operative report will provide evidence as to whether adequate colectomy was performed. Complimentary tests such as colon transit studies (radiopaque markers or scintigraphy) and gastrografin enema (avoid barium if constipation is significant) will help determine if there is residual dysmotile colon remaining. Persistent constipation with evidence of residual colon may require completion colectomy with ileorectal anastamosis.  operative and nonoperative therapy for chronic constipation sUMMaRY Constipation is a common and complex polysymptomatic clini- cal disorder that has multiple etiologies. Successful treatment requires careful workup and patient selection. A careful history and physical exam are the first step. Many medical conditions and medications can cause constipation, and correction of these disorders can improve symptoms. Anatomic evaluation of the colon to rule out neoplasia, stricture, and other organic disease is required. When these secondary causes of constipation are excluded, a functional chronic constipation exists. Functional constipation consists of three overlapping subtypes including slow-transit constipation, dyssynergic defecation, and mixed dis- orders. Initial therapy for all patients includes dietary and lifestyle modification with and without laxatives. Persistent constipation that is refractory to medical management requires further testing. The tests obtained will vary depending on the patients history, surgeons experience, and testing availability. Colonic motility is determined by colon transit studies such as radiopaque markers or scitigraphic defecography. Pelvic floor function and physiology is determined by anal manometry, balloon expulsion test, defec- ography, and electromyography. Isolated slow-transit constipa- tion is successfully treated with total abdominal colectomy with ileorectostomy. Lesser operations result in poor outcome with a high incidence of reoperation. 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Am J Gastroenterol 1995; 90: 748–53.   Colorectal trauma S David Cho, Sharon L Wright, and Martin A Schreiber CHALLENGING CASE A 23-year-old man sustained a through and through gun shot wound to the left lower abdomen. The patient was mildly hypoten- sive on arrival to the emergency room, but responded to admin- istration of 2 L of normal saline. The abdominal exam reveals the bullet holes and moderate tenderness. The rectal exam was normal. Chest and abdominal radiographs were normal except for markers at the gunshot wounds, electrolytes and hemoglobin levels were normal. After administration of a second generation cephalosporin and a type and cross for blood, the patient was taken to the operating room for an abdominal exploration. The only injury found was a lateral injury to the mid sigmoid colon. There was minimal stool contamination of the lower abdomen. CASE MANAGEMENT The colonic wound edges were debrided and the colon was repaired primarily with a two layer suture closure. The abdomen was copiously irrigated. The laparotomy wound was closed and the patient received one dose of antibiotics postoperatively. INTRODUCTION The management of traumatic colon injury has been the sub- ject of much debate and has evolved considerably over the past century. During World War I, primary repair was practiced for all colon injuries, with a resultant mortality in excess of 60%. (1, 2) Civilian series reported similar results, with LoCicero and colleagues reporting a 67% mortality rate from 1927–1942.(3) The mortality rate dropped to approximately 30% during World War II (2) at a time when several changes in management were introduced. Most notably, Ogilvie (4) described exteriorization of colon injuries, leading to the practice of mandatory colostomy, which reduced mortality to about 45%.(4) Mortality dropped further during the Korean and Vietnam conflicts, to about 10% (1), which many attributed to the standardization of colos- tomy. The thinking at that time was that diversion of the fecal stream and avoiding an anastomosis would greatly reduce infec- tious complications.(5) The specter of infection was particularly ominous during a time when antibiotics had just been intro- duced. Many combat surgeons did not have significant training in managing colon injuries, high-velocity wounds, or operating under conditions of resource constraint and combat triage, dur- ing which follow-up of an anastomosis would be difficult.(4, 6) These concepts became incorporated into civilian settings as well and became the standard for at least 30 years. Other innovations during this period included the introduction of antibiotics, and improvements in transport, surgical devices, critical care, and resuscitation (2, 5, 7, 8) that may well have been responsible for the improvements in survival. Despite these factors, colostomy remained the standard of care for the first three-quarters of the twentieth century. This practice was first successfully challenged by the landmark work of Stone and Fabian (9) in 1979, when they published the results of their randomized trial of primary repair without diver- sion versus colostomy in 268 patients with colon injuries. They noted a similar wound infection rate, and a significantly lower peritoneal infection rate with primary repair (15% vs. 29%). Their overall complication rate was 1% for primary repair and 10% for colostomy. Further, they noted an increase in hospital length of stay of approximately 6 days in the colostomy group. Although the study excluded more severely injured patients, it was the first to provide evidence that colostomy was not manda- tory in all cases. Based on this work, a growing body of evidence contributed to a shift toward primary repair of traumatic colon injury during the 1980s and 1990s. Currently, primary repair, defined as a single-staged operation establishing bowel continuity (either by direct suture repair or resection and anastomosis) without proximal diversion, is being increasingly used for most colon injuries in civilian settings.(10, 11) The military conflict in Iraq and Afghanistan has both rein- vigorated the debate between primary repair and diversion, and has brought new perspectives to this issue. Clearly, optimal treat- ment depends not on the uniform application of one technique or the other, but depends on sound judgment and an understand- ing of the current evidence. EPIDEMIOLOGY Colon injury occurs in 30% of abdominal gunshot wounds and 5% of stab wounds, and is the second most common intraabdominal organ injury in civilian penetrating trauma. (12) Penetrating mechanisms cause 85–95% of colon injuries in civilian practice.(6, 13–16) In contrast, in a recent review of colon injuries sustained by American soldiers in Operation Iraqi Freedom over a 2-year period, 71% of injuries were caused by improvised explosive devices (IED) and 24% were caused by gunshot wounds. Blunt injury is rare, with colon involvement in 0.2% of trauma admissions but 20–30% of blunt hollow viscus injuries.(17) Motor vehicle crashes and traffic accidents account for the majority of blunt colorectal injuries.(18, 19) Approximately 80–90% of colon injuries in civilian settings are nondestructive.(20) While mortality has dropped in recent decades to <3% (21, 22), morbidity has remained high. Colon related complications have been consistently reported in 15–30% of cases since 1979. (9, 14, 23–27) PREOPERATIVE ASSESSMENT The initial assessment of any trauma patient always begins with the ABCs (airway, breathing, and circulation) and adherence to Advanced Trauma Life Support (ATLS) principles including the primary and secondary surveys, rapid treatment of immediately  improved outcomes in colon and rectal surgery life-threatening injuries, establishment of appropriate intrave- nous access, and administration of fluids or blood products when appropriate. In cases of severe injury accompanied by marked physiologic derangement, most notably the ‘lethal triad’ (acidosis, hypo- thermia, and coagulopathy) (28) of trauma, the principles of damage control surgery are applicable. These include rapid tri- age, abbreviated laparotomy, and return to the intensive care unit (ICU) for rewarming and correction of acidosis and coagulopa- thy. Intraoperatively the abdomen is packed, massive hemorrhage is controlled, and injured bowel is stapled off and left in disconti- nuity if necessary. In 12 to 24 hours the patient is brought back to the operating room at least once for reexploration and definitive repair.(29) Diagnosis The diagnosis of bowel injury is notoriously difficult. Colon inju- ries are primarily diagnosed intraoperatively.(30) However, diag- nostic techniques warrant a brief discussion. PHYSICAL EXAM Peritoneal signs in the abdominal trauma victim are most often caused by hollow viscus injury. However, physical exam may be dif- ficult to perform in the multisystem trauma patient. Intoxication, traumatic head injury, or distracting injuries may obviate a reli- able physical exam. The “seat belt sign” has been described as a physical exam find- ing that predicts bowel injury. The classic finding is ecchymosis of the anterior abdominal wall secondary to the compressive force of the lap belt (Figure 35.1a). It is associated with a more than doubled (2.9%) relative risk of bowel injury.(31) Flexion distrac- tion injuries of the thoracolumbar spine, termed “Chance frac- tures”, also should raise suspicion for blunt bowel injury.(32) Diagnostic peritoneal lavage Diagnostic peritoneal lavage (DPL) is a rapid and inexpensive test to evaluate the intraperitoneal contents and it remains a diagnostic option in patients with suspected abdominal injury. Via an open or closed technique, the abdominal cavity is lavaged with 1 L of isotonic solution, then aspirated and tested for evi- dence of intraabdominal injury. In blunt trauma, DPL is con- sidered positive if 10 mL of blood is aspirated before instillation of lavage fluid. Microscopic criteria for a positive DPL in blunt trauma include more than 100,000 red blood cells (RBCs)/mm3 or 500 white blood cells/ mm3. The criteria for a positive DPL in penetrating trauma are much less standardized and vary from more than 1,000 RBCs/mm 3 to gross aspiration of >10 cc of blood. In both blunt and penetrating trauma, presence of bile, amylase, bacteria, or particulate matter should indicate visceral injury and need for laparotomy. The accuracy of DPL is 92% to 98%, as reported by the Eastern Association for the Surgery of Trauma guidelines.(33) Otomo et al. (34) posited new criteria specifically designed to diagnose intestinal injuries using DPL. Due to the fact that hemo- peritoneum is not necessarily an indication for operation, they considered the DPL positive when there was a relative increase in the WBC count compared to the RBC indicating peritoneal irrita- tion. They prospectively evaluated 250 patients with blunt abdomi- nal trauma. In addition to other criteria, when the RBC count in the lavage fluid was greater than 10 × 104/mm 3 ), then the DPL was considered positive when the WBC count exceeded the RBC count/150. They report that these criteria have a diagnostic sensi- tivity of 96.6% and specificity of 99.4% for intestinal injury. Advantages of DPL include rapidity, higher sensitivity, lower cost, and immediate performance and interpretation. Unlike computed tomography, performance of DPL does not require transfer to a noncritical area. The major disadvantages are a 1% to 3% risk of iatrogenic intraperitoneal injury and the high sen- sitivity of the test, which may lead to nontherapeutic laparoto- mies.(33) The utility of DPL has significantly decreased in the era of nonoperative management of solid organ injuries and it is primarily used in unstable trauma patients with an unknown source of hemorrhage. However, DPL may diagnose hollow vis- cus injuries that are missed by other modalities. There are relative contraindications to the performance of a DPL which include pregnancy, obesity, and prior celiotomy. Lastly, DPL is primarily of value if the abdominal injury is intraperitoneal. If the injury is confined to the extraperitoneal colon and rectum, DPL may not identify these injuries. Ultrasound Focused abdominal sonography for trauma (FAST) is now a com- monly used modality in the initial diagnostic management of abdominal trauma. FAST has been used as a screening modality for patients with blunt trauma to determine which stable patients should undergo further diagnostic imaging with CT scanning. It has also been used in hemodynamically unstable patients to rap- idly determine presence of intraperitoneal fluid and the need for immediate surgery analogous to the use of gross blood on DPL. In FAST, the ultrasound probe is used to serially evaluate the pericardium, Morison’s pouch (hepatorenal space), splenorenal recess, and the pouch of Douglas (retrovesical portion of the intraperitoneal cavity) for free fluid. A small amount of physi- ologic fluid is occasionally seen in the pelvis, but anything more Figure 35.1a Seat-belt sign. The patient was involved in a roll-over motor vehicle crash.  colorectal trauma should be considered abnormal and should prompt either opera- tive exploration or further investigation. FAST has a sensitivity of 42% to 63%, a specificity of 98% to 100%, a positive predictive value of 67% to 100%, negative pre- dictive value of 93% to 98%, and an accuracy of 92% to 98%. (33–40) Its advantages include rapidity, easy repeatability, its noninvasive nature, the absence of radiation exposure, and low cost. Disadvantages to FAST are interobserver variability and the fact that hollow viscus injuries may not be associated with an adequate volume of free intraabdominal fluid to be diagnosed by FAST. Computed tomography Computed tomography (CT) scanning of the abdomen and pel- vis is the procedure of choice for the evaluation of the hemody- namically stable blunt trauma patient.(33) It is recommended in patients with equivocal physical exam findings, multiple injuries, and neurologic injury. Abdominal CT has a sensitivity of 64% to 88%, specificity of 97% to 99%, and an accuracy of 82% to 99% for the diagno- sis of hollow viscus injury.(41, 42) Disadvantages include high cost, radiation exposure, and the need to transport patients to the radiology suite. Signs of bowel trauma seen on CT include mesenteric strand- ing, free intraperitoneal fluid in the absence of solid organ injury, extraluminal air or contrast material, and bowel wall thickening. (43) Figure 35.1b demonstrates these findings. Improvements in CT technology have led to increasing sensitivity of CT in the detection of the more subtle signs of injury to the bowel. Laparoscopy Laparoscopy has been evaluated in the diagnosis of intraabdomi- nal injury in a selected group of trauma patients as a method to evaluate penetrating injuries. Potential advantages include avoid- ing nontherapeutic laparotomy and diagnosing and treating blunt bowel injuries that are otherwise missed by imaging techniques. In patients with penetrating abdominal trauma, stable vital signs, intact sensorium without evidence of raised intracranial pres- sure, and absence of contraindications for pneumoperitoneum, Ahmed et al. found that exploratory laparoscopy is safe and accu- rate in the diagnosis of penetrating abdominal injuries, and iden- tified those injuries that necessitated open repair.(44) In their study, they report avoiding nontherapeutic exploratory laparo- tomy in 75% of their patients. The authors describe laparoscopy as having the advantage of identifying injuries to the peritoneum, diaphragm, mesentery and omentum. Mitsuhide et al. (45), prospectively evaluated the use of diag- nostic laparoscopy in conjunction with CT scan in patients with blunt abdominal injury. Diagnostic laparoscopy was performed in hemodynamically stable patients who had either local peri- toneal signs and indirect CT signs (bowel thickening or isolated intraperitoneal fluid), an increase in abdominal pain or tender- ness, or intraperitoneal fluid increased on serial CT scan. A total of 25 laparotomies were performed in 399 patients, 14 based on physical exam or CT findings and another 11 after laparoscopy. In total, 17 laparoscopic examinations were completed and 10 injuries were repaired. Thus, in these 399 patients, laparoscopy detected 1 mesenteric laceration and 7 bowel injuries that were not diagnosed on CT scan. There were no nontherapeutic lapa- rotomies, and 7 laparotomies were avoided. They concluded that laparoscopy can prevent nontherapeutic laparotomy and delayed diagnosis in patients with suspected blunt bowel injury. Risks of laparoscopy in trauma patients include tension pneu- mothorax upon CO2 insufflation, which can be decreased by limiting initial insufflation pressures to 8 mmHg.(45) Other risks include hypotension following insufflation secondary to intra- vascular volume depletion, and gas embolism in patients with intraabdominal solid viscus injury. Injury scales In the effort to standardize assessment of traumatic injuries and potentially predict outcomes, a number of scoring systems have been published. While these scales do not attempt to replace sound judgment, experience and individualization of treatment, they are useful as a common means of assessment and commu- nication amongst surgeons caring for patients with these inju- ries. The three most commonly used in association with colonic injury are briefly discussed here. Flint and colleagues (16) described three grades of colonic injury (Table 35.1), derived from a series of 137 patients. Interestingly, this report appears to have been at least in part generated by the discussion begun by Stone and Fabian (9) just 2 years earlier. The aim of their study was to determine if selection of candidates for primary repair could be based on the severity of colon injury. They noted an increase in mortality from 4% to 25% between injury grades 1 and 3, and no complications for grade 1 versus a 31% complication rate for grade 3 injury. Although no statistics were reported, the authors concluded that primary repair was safe for injury grade 1, while colostomy was the procedure of choice for grades 2 and 3. Moore and co-workers proposed a Penetrating Abdominal Trauma Index (PATI) in 1981.(46) These authors cited a need for an injury severity index that specifically addressed intraabdomi- nal injury, one that focused on morbidity rather than mortality, Figure 35.1b CT scan of a patient with colon injury who demonstrated a “seat- belt” sign. Note the presence of free fluid (arrow) consistent with blood in the abdominal cavity. Of note, this patient did not have a solid organ injury raising suspicion of a hollow viscus injury. . Life Support (ATLS) principles including the primary and secondary surveys, rapid treatment of immediately  improved outcomes in colon and rectal surgery life-threatening injuries, establishment. organ injury in civilian penetrating trauma. (12) Penetrating mechanisms cause 85–95% of colon injuries in civilian practice.(6, 13–16) In contrast, in a recent review of colon injuries sustained. abdominal pain and bloating, diarrhea, incontinence, and recur- rent constipation, and are addressed in detail below. These fac- tors all affect quality of life scores with incontinence having