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Surgery_Schwartz. Recently, CT enterocolysis has been used, and it was reported to be superior to plain X-ray small bowel contrast studies.TherapySmall bowel obstruction is usually associated with a marked depletion of intravascular volume due to decreased oral intake, vomiting, and sequestration of fluid in bowel lumen and wall. Therefore, fluid resuscitation is integral to treatment. Isotonic fluid should be given intravenously, and an indwelling bladder catheter may be placed to monitor urine output. Central-venous or pulmonary-artery catheter monitoring are not generally indi-cated unless the patient has underlying cardiac disease and severe dehydration. Broad-spectrum antibiotics are not indi-cated unless there is concern for bowel ischemia and surgery is planned.The stomach should be continuously evacuated of air and fluid using a nasogastric (NG) tube. Effective gastric decom-pression decreases nausea, distention, and the risk of vomiting and aspiration. Longer nasoenteric tubes, with tips


Surgery_Schwartz

Surgery_Schwartz. evacuated of air and fluid using a nasogastric (NG) tube. Effective gastric decom-pression decreases nausea, distention, and the risk of vomiting and aspiration. Longer nasoenteric tubes, with tips placed into the jejunum or ileum, were favored in the past but are rarely used today, as they are associated with higher complication rates than NG tubes, with no proven greater efficacy in several studies.While a period of close observation and nonoperative management has been the mainstay of treatment for partial bowel obstruction, the standard therapy for complete small bowel obstruction has generally been expeditious surgery, with the dictum that “the sun should never rise and set on a complete bowel obstruction.” The rationale for favoring early surgical intervention is to minimize the risk for bowel strangu-lation, which is associated with an increased risk for morbidity and mortality. Clinical signs and currently available laboratory tests and imaging studies do not reliably permit


Surgery_Schwartz

Surgery_Schwartz. for bowel strangu-lation, which is associated with an increased risk for morbidity and mortality. Clinical signs and currently available laboratory tests and imaging studies do not reliably permit the distinction between patients with simple obstruction and those with stran-gulated obstruction prior to the onset of irreversible ischemia. Therefore, the goal is to operate before the onset of irreversible ischemia. This treatment approach has, however, undergone significant reassessment in recent years, with many advocating for nonoperative approaches in management of these patients, providing closed-loop obstruction is ruled out and there is no evidence of intestinal ischemia. In a study of 145 patients with CT-diagnosed high-grade compete small bowel obstruction, 46% of the overall cohort were managed nonoperatively. More specifically, of the 104 patients who did not meet criteria for immediate surgery, 66 patients were successfully managed nonoperatively.17Thus, conservative therapy


Surgery_Schwartz

Surgery_Schwartz. were managed nonoperatively. More specifically, of the 104 patients who did not meet criteria for immediate surgery, 66 patients were successfully managed nonoperatively.17Thus, conservative therapy in the form of NG decompres-sion and fluid resuscitation is now commonly recommended in the initial management of nonischemic bowel obstruction. Non-operative management has been documented to be successful in 65% to 81% of patients with partial small bowel obstruction. Of those successfully treated nonoperatively, only 5% to 15% have been reported to have symptoms that were not substantially improved within 48 hours after initiation of therapy. Therefore, most patients with partial small obstruction whose symptoms do not improve within 48 hours after initiation of nonopera-tive therapy should be considered for surgery. In a study using the National Inpatient Sample, this principle was further high-lighted. The authors concluded that a 2-day limit of watchful waiting before surgery is not


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Surgery_Schwartz. be considered for surgery. In a study using the National Inpatient Sample, this principle was further high-lighted. The authors concluded that a 2-day limit of watchful waiting before surgery is not associated with an increase in mortality or postoperative morbidity, although inpatient costs were higher.18The observation that administration of water-soluble oral contrast has not only diagnostic but also therapeutic and prog-nostic value has led to the creation of several protocols and path-ways for management of patients presenting with small bowel obstruction. An example of such a pathway that is utilized at our institution is outlined in Fig. 28-16. Several studies and subsequent meta-analyses have shown that use of water-soluble contrast not only predicts likelihood of success of nonoperative management but also reduces the need for surgery (odds ratio 0.44), length of stay by about 2 days, and time to resolution by about 28 hours, without an increase in morbidity or


Surgery_Schwartz

Surgery_Schwartz. of nonoperative management but also reduces the need for surgery (odds ratio 0.44), length of stay by about 2 days, and time to resolution by about 28 hours, without an increase in morbidity or mortality.16The operative procedure performed for small bowel obstruction varies according to the etiology of the obstruc-tion. For example, adhesions are lysed, tumors are resected, and hernias are reduced and repaired. Regardless of the etiol-ogy, the affected intestine should be examined, and nonviable bowel should be resected. Criteria suggesting viability are nor-mal color, peristalsis, and marginal arterial pulsations. Usu-ally, visual inspection alone is adequate in judging viability. In borderline cases, a Doppler probe may be used to check for pulsatile flow to the bowel, and arterial perfusion can be veri-fied by visualizing intravenously administered fluorescein dye in the bowel wall under ultraviolet illumination. Neither tech-nique has, however, been found to be superior to


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Surgery_Schwartz. perfusion can be veri-fied by visualizing intravenously administered fluorescein dye in the bowel wall under ultraviolet illumination. Neither tech-nique has, however, been found to be superior to clinical judg-ment. In general, if the patient is hemodynamically stable, short lengths of bowel of questionable viability should be resected, and primary anastomosis of the remaining intestine should be performed. However, if the viability of a large proportion of the intestine is in question, a concerted effort to preserve intestinal tissue should be made. In such situations, the bowel of uncertain viability should be left intact and the patient reexplored in 24 to 48 hours in a “second-look” operation. At that time, definitive resection of nonviable bowel is completed.Brunicardi_Ch28_p1219-p1258.indd 123123/02/19 2:24 PM 1232SPECIFIC CONSIDERATIONSPART IINoNoYesYesAdhesive smallbowel obstructionSigns and symptomsof strangulation andintestinal ischemia?Operating roomfor


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Surgery_Schwartz. 123123/02/19 2:24 PM 1232SPECIFIC CONSIDERATIONSPART IINoNoYesYesAdhesive smallbowel obstructionSigns and symptomsof strangulation andintestinal ischemia?Operating roomfor explorationNPOIVFNG tubeSerial abdominal exam100 mL of water-solublecontrast through NGKUB after 8 hoursHas contrastreached colon?High likelihood for nonoperativeresolution of bowel obstructionRemove NGStart sipsRepeat KUBafter 24 hoursHas contrastreached colon?Strongly consider surgerywithin 72 hours of admissionYesFigure 28-16. Management of small bowel obstruction.Successful laparoscopic surgery for bowel obstruction is being reported with greater frequency. In a propensity score-matched study of patients who underwent adhesiolysis for small bowel obstruction, the laparoscopic approach was associated with significantly lower rates of overall complications, surgical site infections, and a shorter length of hospital stay (4 vs. 10 days).19 Since distended loops of bowel can interfere with adequate


Surgery_Schwartz

Surgery_Schwartz. with significantly lower rates of overall complications, surgical site infections, and a shorter length of hospital stay (4 vs. 10 days).19 Since distended loops of bowel can interfere with adequate visualization, early cases of proximal small bowel obstruction that are likely due to a single adhesive band are best suited for this approach. Presence of bowel distention and multiple adhesions can cause these procedures to be difficult, with a reported conversion rate of 17% to 33%. One of the major concerns with the laparoscopic approach has been the risk of iatrogenic bowel injury. A pooled analysis of 11 nonrandomized comparative studies has, however, shown that the risk of bowel injury and reoperation were not different between the two procedures, although the laparoscopic approach was associated with greater surgical time.20OutcomesThe perioperative mortality rate associated with surgery for nonstrangulating small bowel obstruction is less than 5%, with most deaths occurring in


Surgery_Schwartz

Surgery_Schwartz. associated with greater surgical time.20OutcomesThe perioperative mortality rate associated with surgery for nonstrangulating small bowel obstruction is less than 5%, with most deaths occurring in elderly patients with significant comorbidities. Mortality rates associated with surgery for stran-gulated obstruction is higher, highlighting the need for prompt intervention in this group. Long-term prognosis is related to the etiology of obstruction. Many patients who are treated conser-vatively for adhesive small bowel obstruction do not require future readmissions; less than 20% of such patients will have a readmission over the subsequent 5 years with another episode of bowel obstruction.In a study of 286 patients who had undergone surgical intervention for adhesive small bowel obstruction, the risk of recurrent obstruction was 5.5% at 1 year, 11.3% at 3 years, and 13.5% at 5 years. The risk of reoperation for recurrent obstruction was 3.7% at 1 year, 4.8% at 3 years, and 5.8% at 5


Surgery_Schwartz

Surgery_Schwartz. the risk of recurrent obstruction was 5.5% at 1 year, 11.3% at 3 years, and 13.5% at 5 years. The risk of reoperation for recurrent obstruction was 3.7% at 1 year, 4.8% at 3 years, and 5.8% at 5 years.21 Considering the frequency of small bowel obstruction and the varied degree of clinical severity and presentation, there is often variation in the care of patients admitted with bowel obstruction. Studies have shown that a standard hospital-wide policy can help improve care of patients with bowel obstruction, reducing their time to surgery and shortening their length of hospital stay.22Brunicardi_Ch28_p1219-p1258.indd 123223/02/19 2:24 PM 1233SMALL INTESTINECHAPTER 28PreventionWith adhesive small bowel obstruction representing a large therapeutic burden, prevention of postoperative adhesions has become an area of great interest. Good surgical technique, careful handling of tissue, and minimal use and exposure of peritoneum to foreign bodies, forms the cornerstone of adhe-sion


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Surgery_Schwartz. adhesions has become an area of great interest. Good surgical technique, careful handling of tissue, and minimal use and exposure of peritoneum to foreign bodies, forms the cornerstone of adhe-sion prevention. These measures alone are often inadequate. In patients undergoing colorectal or pelvic surgery, hospital read-mission rates of greater than 30% over the subsequent 10 years have been reported for adhesive small bowel obstruction.23Use of laparoscopic surgery, when possible, has been strongly promoted. A recent study using the Swedish National Inpatient Register has shown that, compared to laparoscopy, open surgery is associated with a fourfold increase in risk of small bowel obstruction within 5 years of the index procedure, even after accounting for other risk factors such as age, comor-bidity, and previous abdominal surgery.24In those undergoing open surgery, several strategies for adhesion prevention have been tried; however, the only therapy that has shown some success has


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Surgery_Schwartz. comor-bidity, and previous abdominal surgery.24In those undergoing open surgery, several strategies for adhesion prevention have been tried; however, the only therapy that has shown some success has been the use of hyaluronan-based agents, such as Sperafilm. The use of this barrier has been clearly shown to reduce the incidence of postoperative bowel adhesions; however, their effect in actually reducing the inci-dence of small bowel obstruction remains less well defined.25 The use of these products is often left to the discretion of the surgeon and the clinical context. Wrapping of an intestinal anas-tomosis with the material may be associated with increased leak rates and is generally discouraged.26Other Causes of Small Bowel ObstructionEarly postoperative bowel obstruction, as defined by signs, symptoms, and radiographic signs of SBO occurring within 30 days following surgery, been reported to occur in 0.7% to 9% of patients, with a higher rate in patients undergoing pelvic


Surgery_Schwartz

Surgery_Schwartz. by signs, symptoms, and radiographic signs of SBO occurring within 30 days following surgery, been reported to occur in 0.7% to 9% of patients, with a higher rate in patients undergoing pelvic sur-gery, especially colorectal procedures.27 CT scanning or small bowel series is often required to make the diagnosis. Obstruc-tion that occurs in the early postoperative period is usually par-tial and only rarely is associated with strangulation. Therefore, a period of extended nonoperative therapy (2–3 weeks) consist-ing of bowel rest, hydration, and TPN administration is usually warranted. However, if complete obstruction is demonstrated or if signs suggestive of peritonitis are detected, expeditious reop-eration should be undertaken without delay. In a series of 180 patients undergoing anterior resection for rectal cancer, 12.8% developed early postoperative bowel obstruction on the median postoperative day 5, with 4 requiring surgical exploration at a median interval of 2 weeks from the


Surgery_Schwartz

Surgery_Schwartz. resection for rectal cancer, 12.8% developed early postoperative bowel obstruction on the median postoperative day 5, with 4 requiring surgical exploration at a median interval of 2 weeks from the index case.27Crohn’s disease as a cause of small bowel obstruction is discussed in more detail later in this chapter in the “Crohn’s Disease” section.Malignant small bowel obstruction can be a challenging problem. Although it often indicates advanced disease with poor prognosis, 25% to 33% of patients with a history of cancer who present with small bowel obstruction have adhesions as the etiol-ogy of their obstruction and therefore should not be denied appro-priate therapy. Even in cases in which the obstruction is related to recurrent malignancy, palliative resection or bypass can be performed, and in select cases these procedures lead to improved quality of life. In a series of 81 patients with small bowel obstruc-tion, palliation was achieved in over 80% of patients, with over 70% able to


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Surgery_Schwartz. and in select cases these procedures lead to improved quality of life. In a series of 81 patients with small bowel obstruc-tion, palliation was achieved in over 80% of patients, with over 70% able to reestablish oral intake. In this series, the surgical mor-bidity was high, with 7% developing an enterocutaneous fistula/Table 28-4Ileus: common etiologiesAbdominal surgeryInfection Sepsis Intra-abdominal abscess Peritonitis PneumoniaElectrolyte abnormalities Hypokalemia Hypomagnesemia Hypermagnesemia HyponatremiaMedications Anticholinergics Opiates Phenothiazines Calcium channel blockers Tricyclic antidepressantsHypothyroidismUreteral colicRetroperitoneal hemorrhageSpinal cord injuryMyocardial infarctionMesenteric ischemiaanastomotic leak and a 30-day mortality rate of 6%.28 Patients with obvious carcinomatosis and multifocal obstruction pose a difficult challenge, given their limited prognosis. Thus, management must be tailored to an individual patient’s prognosis and desires. At the


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Surgery_Schwartz. obvious carcinomatosis and multifocal obstruction pose a difficult challenge, given their limited prognosis. Thus, management must be tailored to an individual patient’s prognosis and desires. At the time of surgery, relief of the obstruction may be best achieved by a bypass procedure, avoiding a potentially difficult bowel resection, and even if that is not feasible, a palliative gastrostomy tube can be considered to help resolve nausea and vomiting.ILEUS AND OTHER DISORDERS OF INTESTINAL MOTILITYIleus and intestinal pseudo-obstruction are clinical syndromes caused by impaired intestinal motility and are characterized by symptoms and signs of intestinal obstruction in the absence of a lesion-causing mechanical obstruction. Ileus is a temporary motility disorder that is reversed with time as the inciting factor is corrected. In contrast, chronic intestinal pseudo-obstruction comprises a spectrum of specific disorders associated with irre-versible intestinal dysmotility.Ileus is a


Surgery_Schwartz

Surgery_Schwartz. time as the inciting factor is corrected. In contrast, chronic intestinal pseudo-obstruction comprises a spectrum of specific disorders associated with irre-versible intestinal dysmotility.Ileus is a major cause of morbidity in hospitalized patients. A degree of intestinal ileus is a normal physiological response to abdominal surgery, which often resolves quickly without any long-term sequela. However, when postoperative ileus is pro-longed, it can cause significant morbidity and cost. Prolonged postoperative ileus is the most frequently implicated cause of delayed discharge following abdominal operations, and its eco-nomic impact has been estimated to be between $750 million and $1 billion annually in the United States.29PathophysiologyNumerous factors capable of impairing intestinal motility, and thus inciting ileus, have been described (Table 28-4). The most Brunicardi_Ch28_p1219-p1258.indd 123323/02/19 2:24 PM 1234SPECIFIC CONSIDERATIONSPART IIfrequently encountered factors


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Surgery_Schwartz. and thus inciting ileus, have been described (Table 28-4). The most Brunicardi_Ch28_p1219-p1258.indd 123323/02/19 2:24 PM 1234SPECIFIC CONSIDERATIONSPART IIfrequently encountered factors are abdominal operations, infec-tion and inflammation, electrolyte abnormalities, and drugs.Following most abdominal operations or injuries, the motility of the gastrointestinal tract is transiently impaired. Among the proposed mechanisms responsible for this dysmotility are surgical stress-induced sympathetic reflexes, inflammatory response mediator release, and anesthetic/analgesic side effects; each of which can inhibit intestinal motility. The return of normal motility generally follows a characteristic temporal sequence, with small-intestinal motility returning to normal within the first 24 hours after laparotomy and gastric and colonic motility returning to normal by 48 hours and 2 to 5 days, respectively. Since small bowel motility is returned before colonic and gastric motility, listening


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Surgery_Schwartz. after laparotomy and gastric and colonic motility returning to normal by 48 hours and 2 to 5 days, respectively. Since small bowel motility is returned before colonic and gastric motility, listening for bowel sounds is not a reliable indicator that ileus has fully resolved. Functional evidence of coordinated gastrointestinal motility in the form of passing flatus or bowel movement is a more useful indicator. Resolution of ileus may be delayed in the presence of other factors capable of inciting ileus such as the presence of intra-abdominal abscesses or electrolyte abnormalities.Chronic intestinal pseudo-obstruction can be caused by a large number of specific abnormalities affecting intestinal smooth muscle, the myenteric plexus, or the extraintestinal nervous system (Table 28-5). Visceral myopathies constitute a group of diseases characterized by degeneration and fibro-sis of the intestinal muscularis propria. Visceral neuropathies encompass a variety of degenerative disorders of the


Surgery_Schwartz

Surgery_Schwartz. myopathies constitute a group of diseases characterized by degeneration and fibro-sis of the intestinal muscularis propria. Visceral neuropathies encompass a variety of degenerative disorders of the myenteric and submucosal plexuses. Both sporadic and familial forms of visceral myopathies and neuropathies exist. Systemic disor-ders involving the smooth muscle such as progressive systemic sclerosis and progressive muscular dystrophy, and neurologi-cal diseases such as Parkinson’s disease, can also be compli-cated by chronic intestinal pseudo-obstruction. In addition, viral infections, such as those associated with cytomegalovirus and Epstein-Barr virus, can cause intestinal pseudo-obstruction.Table 28-5Chronic intestinal pseudo-obstruction: etiologiesPrimary CausesFamilial types Familial visceral myopathies (types I, II, and III) Familial visceral neuropathies (types I and II) Childhood visceral myopathies (types I and II)Sporadic types Visceral myopathies Visceral


Surgery_Schwartz

Surgery_Schwartz. types Familial visceral myopathies (types I, II, and III) Familial visceral neuropathies (types I and II) Childhood visceral myopathies (types I and II)Sporadic types Visceral myopathies Visceral neuropathiesSecondary CausesSmooth muscle disorders Collagen vascular diseases (e.g., scleroderma) Muscular dystrophies (e.g., myotonic dystrophy) AmyloidosisNeurological disorders Chagas disease, Parkinson’s disease, spinal cord injuryEndocrine disorders Diabetes, hypothyroidism, hypoparathyroidismMiscellaneous disorders Radiation enteritisPharmacological causes E.g., phenothiazines and tricyclic antidepressantsViral infectionsClinical PresentationThe clinical presentation of ileus resembles that of small bowel obstruction. Inability to tolerate liquids and solids by mouth, nausea, and lack of flatus or bowel movements are the most common symptoms. Vomiting and abdominal distension may occur. Although bowel sound characteristics are not diagnostic, they are usually diminished or absent, in


Surgery_Schwartz

Surgery_Schwartz. flatus or bowel movements are the most common symptoms. Vomiting and abdominal distension may occur. Although bowel sound characteristics are not diagnostic, they are usually diminished or absent, in contrast to the hyper-active bowel sounds that usually accompany mechanical small bowel obstruction. The clinical manifestations of chronic intes-tinal pseudo-obstruction include variable degrees of nausea and vomiting and abdominal pain and distention.DiagnosisRoutine postoperative ileus should be expected and requires no diagnostic evaluation. Definition of prolonged postoperative ileus has been varied but generally diagnosed if ileus persists beyond 5 days postoperatively. A recent global survey synthesized the results of the data to define postoperative ileus as “interval from surgery until passage of flatus/stool AND tolerance of an oral diet,” with prolonged postoperative ileus being defined as “two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of


Surgery_Schwartz

Surgery_Schwartz. passage of flatus/stool AND tolerance of an oral diet,” with prolonged postoperative ileus being defined as “two or more of nausea/vomiting, inability to tolerate oral diet over 24 h, absence of flatus over 24 h, distension, radiologic confirmation occurring on or after day 4 postoperatively without prior resolu-tion of postoperative ileus.”30 Prolonged ileus is reported to occur in 10% to 15% of patients undergoing intestinal surgery.31Once suspected, diagnostic evaluation to detect specific underlying factors capable of inciting ileus and to rule out the presence of mechanical obstruction is warranted.Patient medication lists should be reviewed for the pres-ence of drugs, especially opiates, known to be associated with impaired intestinal motility. Measurement of serum electrolytes may demonstrate electrolyte abnormalities commonly associ-ated with ileus. Abdominal radiographs are often obtained, but the distinction between ileus and mechanical obstruction may be difficult based on


Surgery_Schwartz

Surgery_Schwartz. demonstrate electrolyte abnormalities commonly associ-ated with ileus. Abdominal radiographs are often obtained, but the distinction between ileus and mechanical obstruction may be difficult based on this test alone. In the postoperative setting, CT scanning is the test of choice as it can demonstrate the presence of an intra-abdominal abscess or other evidence of peritoneal sepsis that may be causing ileus and can exclude the presence of complete mechanical obstruction. Distinction of postoperative ileus from early postoperative obstruction can be difficult but is helpful in developing the appropriate management plan.The diagnosis of chronic pseudo-obstruction is suggested by clinical features and confirmed by radiographic and mano-metric studies. Diagnostic laparotomy or laparoscopy with full-thickness biopsy of the small intestine may be required to establish the specific underlying cause in cases of suspected neural disorder.TherapyThe management of ileus consists of limiting oral


Surgery_Schwartz

Surgery_Schwartz. full-thickness biopsy of the small intestine may be required to establish the specific underlying cause in cases of suspected neural disorder.TherapyThe management of ileus consists of limiting oral intake and correcting the underlying inciting factor. If vomiting or abdom-inal distention are prominent, the stomach should be decom-pressed using a nasogastric tube. Fluid and electrolytes should be administered intravenously until ileus resolves. If the dura-tion of ileus is prolonged, total parental nutrition (TPN) may be required.Given the frequency of postoperative ileus and its financial impact, many strategies have been tested to reduce its duration. The administration of nonsteroidal anti-inflammatory drugs such as ketorolac and concomitant reductions in opioid dosing have been shown to reduce the duration of ileus in most studies. Similarly, the use of perioperative thoracic epidural anesthesia/analgesia with Brunicardi_Ch28_p1219-p1258.indd 123423/02/19 2:24 PM 1235SMALL


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Surgery_Schwartz. to reduce the duration of ileus in most studies. Similarly, the use of perioperative thoracic epidural anesthesia/analgesia with Brunicardi_Ch28_p1219-p1258.indd 123423/02/19 2:24 PM 1235SMALL INTESTINECHAPTER 28regimens containing local anesthetics combined with limitation or elimination of systemically administered opioids has been shown to reduce duration of postoperative ileus, although they have not reduced the overall length of hospital stay.32 Many studies have also suggested that limiting intraand postoperative fluid administration can also result in reduction of postoperative ileus and shortened hospital stay.33 Furthermore, studies have shown that early postoperative feeding after GI surgery is generally well tolerated and can lead to reduced postoperative ileus and a shorter hospital stay. Table 28-6 summarizes some of the measures used to minimize postoperative ileus. Such data have generated significant interest in Early Recovery After Surgery (ERAS) pathways, which


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Surgery_Schwartz. hospital stay. Table 28-6 summarizes some of the measures used to minimize postoperative ileus. Such data have generated significant interest in Early Recovery After Surgery (ERAS) pathways, which are a collection of steps taken to expedite postoperative recovery in general. ERAS protocols typically involve 15 to 20 steps that involve the pre-, intraand postoperative phases of care and form a multimodal pathway. Although the contribution of each element to the overall outcome has not been well studied, the bundle of steps leads to reduced length of stay and surgical complications. In cases of GI surgery, many of these steps are targeted towards reducing postoperative ileus, which is often the barrier to early discharge.Although prokinetic agents have been tried to pro-mote return of GI motility, they are associated with efficacytoxicity profiles that are too unfavorable to warrant routine use. Recently, administration of alvimopan, a novel, peripherally active mu-opioid receptor


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Surgery_Schwartz. GI motility, they are associated with efficacytoxicity profiles that are too unfavorable to warrant routine use. Recently, administration of alvimopan, a novel, peripherally active mu-opioid receptor antagonist with limited oral absorp-tion, has been shown to reduce duration of postoperative ileus, hospital stay, and rate of readmissions in several prospective, randomized, placebo-controlled trials and the subsequent meta-analysis.34 Any cost savings associated with the use of this drug outside of a clinical trial has, however, been debated.35The therapy of patients with chronic intestinal pseudo-obstruction focuses on palliation of symptoms as well as fluid, electrolyte, and nutritional management. Surgery should be avoided if possible. No standard therapies are curative or delay the natural history of any of the specific disorders causing intes-tinal pseudo-obstruction. Prokinetic agents, such as metoclo-promide and erythromycin, are associated with poor efficacy. Cisapride has been


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Surgery_Schwartz. history of any of the specific disorders causing intes-tinal pseudo-obstruction. Prokinetic agents, such as metoclo-promide and erythromycin, are associated with poor efficacy. Cisapride has been associated with palliation of symptoms; however, because of cardiac toxicity and reported deaths, this agent is restricted to compassionate use in the United States.Patients with refractory disease may require strict limitation of oral intake and long-term TPN administration. Despite these measures, some patients will continue to have severe abdomi-nal pain or such copious intestinal secretions that vomiting and fluid and electrolyte losses remain substantial. These patients may require a decompressive gastrostomy or an extended small bowel Table 28-6Measures to reduce postoperative ileusIntraoperative measures Minimalize handling of the bowel Laparoscopic approach, if possible Restricted intraoperative fluid administrationPostoperative measures Avoid nasogastric tubes Early enteral


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Surgery_Schwartz. measures Minimalize handling of the bowel Laparoscopic approach, if possible Restricted intraoperative fluid administrationPostoperative measures Avoid nasogastric tubes Early enteral feeding Epidural anesthesia, if indicated Restricted IV fluid administration Correct electrolyte abnormalities Consider mu-opiod antagonistsresection to remove abnormal intestine. Small-intestinal trans-plantation has been applied in these patients with increasing fre-quency; the ultimate role of this modality remains to be defined.CROHN’S DISEASECrohn’s disease is a chronic, idiopathic transmural inflamma-tory disease with skip lesions that may affect any part of the alimentary tract, although there is propensity to affect the dis-tal small bowel. Nearly 80% of patients with Crohn’s disease have small bowel involvement, with 30% having terminal ileitis exclusively. Recent studies suggest a prevalence of about 241 cases per 100,000 in the United States.36 The rates of Crohn’s and ulcerative colitis have


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Surgery_Schwartz. involvement, with 30% having terminal ileitis exclusively. Recent studies suggest a prevalence of about 241 cases per 100,000 in the United States.36 The rates of Crohn’s and ulcerative colitis have been increasing globally over the past several decades with substantial regional variations in inci-dence. The highest incidences are reported in western nations and those in northern latitudes, with Canada having the highest reported rates.37 In countries such as China, the prevalence of Crohn’s disease is substantially below that seen in the West, but rates have been rapidly increasing recently.38 The incidence of Crohn’s disease varies among ethnic groups within the same geographic region. For example, members of Eastern European Ashkenazi Jewish population are at a twoto fourfold higher risk of developing Crohn’s disease than members of other popu-lations living in the same location.Most studies suggest that Crohn’s disease is slightly more prevalent in females than in males. The mean


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Surgery_Schwartz. of developing Crohn’s disease than members of other popu-lations living in the same location.Most studies suggest that Crohn’s disease is slightly more prevalent in females than in males. The mean age at which patients are diagnosed with Crohn’s disease falls in the third decade of life years, with a second smaller peak in the sixth decade of life, giv-ing it a bimodal distribution. The age at diagnosis can, however, range from early childhood through the entire lifespan.Both genetic and environmental factors appear to influ-ence the risk for developing Crohn’s disease. The relative risk among first-degree relatives of patients with Crohn’s disease is 14 to 15 times higher than that of the general population, with about 20% of patients reporting a family history. The concor-dance rate among monozygotic twins is as high as 67%; how-ever, Crohn’s disease is not associated with simple Mendelian inheritance patterns. Although there is a tendency within fami-lies for either ulcerative


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Surgery_Schwartz. among monozygotic twins is as high as 67%; how-ever, Crohn’s disease is not associated with simple Mendelian inheritance patterns. Although there is a tendency within fami-lies for either ulcerative colitis or Crohn’s disease to be present exclusively, mixed kindreds also occur, suggesting the presence of some shared genetic traits as a basis for both diseases.Higher socioeconomic status is associated with an increased risk of Crohn’s disease. Most studies have found breastfeeding to be protective against the development of Crohn’s disease. Crohn’s disease is more prevalent among smokers. Furthermore, smoking is associated with the increased risk for both the need for surgery and the risk of relapse after surgery for Crohn’s disease.PathophysiologyCrohn’s disease is characterized by sustained inflammation. Whether this inflammation represents an appropriate response to a yet unrecognized pathogen or an inappropriate response to a normally innocuous stimulus is unknown. Various


Surgery_Schwartz

Surgery_Schwartz. sustained inflammation. Whether this inflammation represents an appropriate response to a yet unrecognized pathogen or an inappropriate response to a normally innocuous stimulus is unknown. Various hypotheses on the roles of environmental and genetic factors in the patho-genesis of Crohn’s disease have been proposed. Many infec-tious agents have been suggested to be the causative organism of Crohn’s disease; however, there has been no conclusive evidence to confirm any. Studies using animal models suggest that in a genetically susceptible host, a nonpathogenic gut microbiome is sufficient to induce a chronic inflammatory response resembling Brunicardi_Ch28_p1219-p1258.indd 123523/02/19 2:24 PM 1236SPECIFIC CONSIDERATIONSPART IIthat associated with Crohn’s disease. In these models, the sus-tained intestinal inflammation is the result of either abnormal epithelial barrier function or immune dysregulation. A full dis-cussion of the role of gut immune system and microbiome in the


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Surgery_Schwartz. the sus-tained intestinal inflammation is the result of either abnormal epithelial barrier function or immune dysregulation. A full dis-cussion of the role of gut immune system and microbiome in the development of Crohn’s disease is beyond the scope of this work, but it is an area of great interest and under investigation. In general, poor barrier function is hypothesized to permit inap-propriate exposure of lamina propria lymphocytes to antigenic stimuli derived from the intestinal lumen. In addition, a variety of defects in immune regulatory mechanisms, e.g., overrespon-siveness of mucosal T cells to enteric flora-derived antigens, can lead to defective immune tolerance and sustained inflammation.Specific genetic defects associated with Crohn’s disease in human patients are beginning to be defined. For example, the presence of a locus on chromosome 16 (the so-called IBD1 locus) has been linked to Crohn’s disease. The IBD1 locus has been identified as the NOD2 gene. Persons with


Surgery_Schwartz

Surgery_Schwartz. to be defined. For example, the presence of a locus on chromosome 16 (the so-called IBD1 locus) has been linked to Crohn’s disease. The IBD1 locus has been identified as the NOD2 gene. Persons with allelic variants on both chromosomes have a 40-fold relative risk of Crohn’s disease com-pared to those without variant NOD2 genes. The relevance of this gene to the pathogenesis of Crohn’s disease is biologically plau-sible, as the protein product of the NOD2 gene mediates the innate immune response to microbial pathogens. Other putative IBD loci have been identified on other chromosomes (IBD2 on chromose 12q, and IBD3 on chromose 6), and are under investigation.Although appendectomy has been shown to lower the risk of subsequent development of ulcerative colitis, it was suspected that the surgery may increase the risk of developing Crohn’s disease. A meta-analysis has, however, suggested that the observed increased risk of Crohn’s disease in the first few years after an appendectomy may


Surgery_Schwartz

Surgery_Schwartz. may increase the risk of developing Crohn’s disease. A meta-analysis has, however, suggested that the observed increased risk of Crohn’s disease in the first few years after an appendectomy may in fact reflect diagnostic dif-ficulty in a group of patients with incipient Crohn’s.39Although the pathological hallmark of Crohn’s disease is focal, transmural inflammation of the intestine, a spectrum of pathological lesions can be present. The earliest lesion characteristic of Crohn’s disease is the aphthous ulcer. These superficial ulcers are up to 3 mm in diameter and are surrounded by a halo of erythema. In the small intestine, aphthous ulcers typically arise over lymphoid aggregates. Granulomas are highly characteristic of Crohn’s disease and are reported to be present in up to 70% of intestinal specimens obtained during surgical resection. These granulomas are noncaseating and can be found in both areas of active disease and apparently normal intestine, in any layer of the bowel wall,


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Surgery_Schwartz. specimens obtained during surgical resection. These granulomas are noncaseating and can be found in both areas of active disease and apparently normal intestine, in any layer of the bowel wall, and in mesenteric lymph nodes.As disease progresses, aphthae coalesce into larger, stellateshaped ulcers. Linear or serpiginous ulcers may form when multiple ulcers fuse in a direction parallel to the longitudinal axis of the intestine. With transverse coalescence of ulcers, a cobblestoned appearance of the mucosa may arise.With advanced disease, inflammation can be transmural. Serosal involvement results in adhesion of the inflamed bowel to other loops of bowel or other adjacent organs. Transmural inflammation can also result in fibrosis with stricture formation, intra-abdominal abscesses, fistulas, and, rarely, free perforation. Inflammation in Crohn’s disease can affect discontinuous por-tions of intestine, so-called skip lesions that are separated by intervening normal-appearing


Surgery_Schwartz

Surgery_Schwartz. fistulas, and, rarely, free perforation. Inflammation in Crohn’s disease can affect discontinuous por-tions of intestine, so-called skip lesions that are separated by intervening normal-appearing intestine.A feature of Crohn’s disease that is grossly evident and helpful in identifying affected segments of intestine during sur-gery is the presence of fat wrapping, which represents encroach-ment of mesenteric fat onto the serosal surface of the bowel (Fig. 28-17). This finding is virtually pathognomonic of Crohn’s Figure 28-17. Crohn’s disease. This intraoperative photograph demonstrates encroachment of mesenteric fat onto the serosal surface of the intestine (“fat wrapping”) that is characteristic of intestinal segments affected by active Crohn’s’ disease.disease. The presence of fat wrapping correlates well with the presence of underlying acute and chronic inflammation.Features that allow for differentiation between Crohn’s dis-ease of the colon and ulcerative colitis include the


Surgery_Schwartz

Surgery_Schwartz. correlates well with the presence of underlying acute and chronic inflammation.Features that allow for differentiation between Crohn’s dis-ease of the colon and ulcerative colitis include the layers of the bowel wall affected (inflammation in ulcerative colitis is limited to the mucosa and submucosa but may involve the full-thickness of the bowel wall in Crohn’s disease) and the longitudinal extent of inflammation (inflammation is continuous and characteristi-cally affects the rectum in ulcerative colitis but may be discon-tinuous and spare the rectum in Crohn’s disease). In the absence of full expression of features of advanced disease, Crohn’s colitis can sometimes be difficult to distinguish from ulcerative colitis. It is also important to remember that although ulcerative colitis is a disease of the colon, it can be associated with inflammatory changes in the distal ileum (backwash ileitis).Clinical PresentationThe most common symptoms of Crohn’s disease are abdominal pain,


Surgery_Schwartz

Surgery_Schwartz. is a disease of the colon, it can be associated with inflammatory changes in the distal ileum (backwash ileitis).Clinical PresentationThe most common symptoms of Crohn’s disease are abdominal pain, diarrhea, and weight loss. However, the clinical features are highly variable among individual patients and depend on which segment(s) of the gastrointestinal tract is (are) predomi-nantly affected, the intensity of inflammation, and the presence or absence of specific complications. In fact, some patients with Crohn’s disease may have been initially misdiagnosed as having irritable bowel syndrome or celiac disease.Patients can be classified by their predominant clinical manifestation as having primarily (a) fibrostenotic disease, (b) fistulizing disease, and (c) aggressive inflammatory disease. There is substantial overlap among these disease patterns in individual patients, however. The onset of symptoms is insidious, and once present, their severity follows a waxing and waning course.


Surgery_Schwartz

Surgery_Schwartz. There is substantial overlap among these disease patterns in individual patients, however. The onset of symptoms is insidious, and once present, their severity follows a waxing and waning course. Constitutional symptoms, particularly weight loss and fever, or growth retardation in children, may also be prominent and are occasionally the sole presenting features of Crohn’s disease.The disease affects the small bowel in 80% of cases and colon alone in 20%. In those with small bowel disease, the major-ity have ileocecal disease. Isolated perineal and anorectal disease occurs in 5% to 10% of affected patients. Uncommon sites of involvement include the esophagus, stomach, and duodenum.An estimated one-fourth of all patients with Crohn’s disease will have an extraintestinal manifestation of their disease. One Brunicardi_Ch28_p1219-p1258.indd 123623/02/19 2:24 PM 1237SMALL INTESTINECHAPTER 28fourth of those affected will have more than one manifestation. Many of these complications can


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Surgery_Schwartz. disease. One Brunicardi_Ch28_p1219-p1258.indd 123623/02/19 2:24 PM 1237SMALL INTESTINECHAPTER 28fourth of those affected will have more than one manifestation. Many of these complications can be seen with both Crohn’s disease and ulcerative colitis, although they are more prevalent among patients with Crohn’s disease. The most common extraintestinal manifestations are listed in Table 28-7. The clinical severity of some of these manifestations, such as erythema nodosum and peripheral arthritis, are correlated with the severity of intestinal inflammation. The severity of other manifestations, such as pyoderma gangrenosum and ankylosing spondylitis, bear no apparent relationship to the severity of intestinal inflammation.DiagnosisThe diagnosis is usually established with endoscopic findings in a patient with a compatible clinical history. The diagnosis should be considered in those presenting with acute or chronic abdominal pain, especially when localized to the right lower quadrant,


Surgery_Schwartz

Surgery_Schwartz. in a patient with a compatible clinical history. The diagnosis should be considered in those presenting with acute or chronic abdominal pain, especially when localized to the right lower quadrant, chronic diarrhea, evidence of intestinal inflammation on radiography or endoscopy, the discovery of a bowel stricture or fistula arising from the bowel, and evidence of inflamma-tion or granulomas on intestinal histology. Disorders associated with clinical presentations that resemble those of Crohn’s dis-ease include ulcerative colitis, functional bowel disorders such as irritable bowel syndrome, mesenteric ischemia, collagen vascular diseases, carcinoma and lymphoma, diverticular dis-ease, and infectious enteritides. Infectious enteritides are most frequently diagnosed in immunocompromised patients, but they can also occur in patients with normal immune function. Acute ileitis caused by Campylobacter and Yersinia species can be difficult to distinguish from that caused by an acute


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Surgery_Schwartz. patients, but they can also occur in patients with normal immune function. Acute ileitis caused by Campylobacter and Yersinia species can be difficult to distinguish from that caused by an acute presenta-tion of Crohn’s disease. Typhoid enteritis caused by Salmonella Table 28-7Extraintestinal manifestations of Crohn’s diseaseDermatologic Erythema nodosum Pyoderma gangrenosumRheumatologic Peripheral arthritis Ankylosing spondylitis SacroiliitisOcular Conjunctivitis Uveitis/iritis EpiscleritisHepatobiliary Hepatic steatosis Cholelithiasis Primary sclerosing cholangitis PericholangitisUrologic Nephrolithiasis Ureteral obstructionMiscellaneous Thromboembolic disease Vasculitis Osteoporosis Endocarditis, myocarditis, pleuropericarditis Interstitial lung disease Amyloidosis Pancreatitistyphosa can lead to overt intestinal bleeding and perforation, most often affecting the terminal ileum. The distal ileum and cecum are the most common sites of intestinal involvement by infection due to


Surgery_Schwartz

Surgery_Schwartz. can lead to overt intestinal bleeding and perforation, most often affecting the terminal ileum. The distal ileum and cecum are the most common sites of intestinal involvement by infection due to Mycobacterium tuberculosis. This condi-tion can result in intestinal inflammation, strictures, and fistula formation, like those seen in Crohn’s disease. Cytomegalovirus (CMV) can cause intestinal ulcers, bleeding, and perforation.No single symptom, sign, or diagnostic test establishes the diagnosis of Crohn’s disease. Instead, the diagnosis is based on a complete assessment of the clinical presentation with confirmatory findings derived from radiographic, endoscopic, and in most cases, pathologic tests. Patients presenting with a history of Crohn’s disease should have their full blood count, electrolytes and renal function, liver function, iron, B12, ESR, and CRP levels checked. The results may be abnormal, show-ing anemia, but these results are nondiagnostic. Colonoscopy with intubation of


Surgery_Schwartz

Surgery_Schwartz. and renal function, liver function, iron, B12, ESR, and CRP levels checked. The results may be abnormal, show-ing anemia, but these results are nondiagnostic. Colonoscopy with intubation of terminal ileum is the main diagnostic tool and can reveal focal ulcerations adjacent to areas of normal appear-ing mucosa along with polypoid mucosal changes that give a “cobblestone appearance.” Skip areas of involvement are typical with segments of normal-appearing bowel interrupted by large areas of obvious disease; this pattern is different from the con-tinuous involvement in ulcerative colitis. Pseudopolyps, as seen in ulcerative colitis, are also often present. Barium small bowel follow-through, CT enterography, or MR enterography may be used as contrast examinations of the small bowel to reveal strictures or networks of ulcers and fissures. CT scanning may reveal intra-abdominal abscesses and is useful in acute presenta-tions to rule out the presence of other intra-abdominal disorders.


Surgery_Schwartz

Surgery_Schwartz. strictures or networks of ulcers and fissures. CT scanning may reveal intra-abdominal abscesses and is useful in acute presenta-tions to rule out the presence of other intra-abdominal disorders. Esophagogastroduodenoscopy (EGD) is done for disease of the proximal alimentary tract. Because Crohn’s disease often affects the small bowel, which is difficult to image, capsule endoscopy has been increasing used to make this diagnosis (Fig. 28-18).40Figure 28-18. Crohn’s disease. This image was captured by a wireless capsule endoscope as it was traveling through the small intestine. It demonstrates a superficial ulceration in the small bowel consistent with Crohn’s disease. (Used with permission from Anne T. Wolf, M.D., Department of Medicine, Brigham and Women’s Hospital, Boston, MA.)Brunicardi_Ch28_p1219-p1258.indd 123723/02/19 2:24 PM 1238SPECIFIC CONSIDERATIONSPART IISeveral antibodies have also been identified in patients with inflammatory bowel disease, which may have diagnostic


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Surgery_Schwartz. 123723/02/19 2:24 PM 1238SPECIFIC CONSIDERATIONSPART IISeveral antibodies have also been identified in patients with inflammatory bowel disease, which may have diagnostic value. The most commonly tested antibodies are antineutrophil cytoplasmic antibody (pANCA) and antisaccharmyces cerevi-siae antibody (ASCA). ASCA+/pANCA–, is associated with a diagnosis of Crohn’s disease, while ASCA–/pANCA+, corre-lates with ulcerative colitis. Although these antibody tests have high specificity, their use has been hampered by low test sensi-tivities. There is ongoing interest in developing other antibody tests to diagnose inflammatory bowel disease and help differ-entiate Crohn’s disease from ulcerative colitis. There have been attempts to develop stool tests to diagnose inflammatory bowel disease, and although fecal calprotectin or lactoferrin can iden-tify patients with intestinal inflammation, they are not routinely done in clinical practice.Because of the insidious, and often nonspecific,


Surgery_Schwartz

Surgery_Schwartz. and although fecal calprotectin or lactoferrin can iden-tify patients with intestinal inflammation, they are not routinely done in clinical practice.Because of the insidious, and often nonspecific, presenta-tion of Crohn’s disease, a diagnosis of Crohn’s is typically made only after symptoms have been present for several years. How-ever, in acute presentations, the diagnosis is sometimes made intraoperatively or during surgical evaluation. The initial mani-festation of Crohn’s disease can consist of right lower quadrant abdominal mimicking the presentation of acute appendicitis. In patients with this presentation, Crohn’s disease can be discov-ered for the first time during laparotomy or laparoscopy per-formed for presumed appendicitis. In some patients, the initial manifestation of Crohn’s disease is an acute abdomen related to small bowel obstruction, intra-abdominal abscess, or free intestinal perforation. In other patients, perianal abscesses and fistulas requiring surgical


Surgery_Schwartz

Surgery_Schwartz. Crohn’s disease is an acute abdomen related to small bowel obstruction, intra-abdominal abscess, or free intestinal perforation. In other patients, perianal abscesses and fistulas requiring surgical therapy may be the first manifestation of Crohn’s disease.TherapyBecause no curative therapies are available for Crohn’s dis-ease, the goal of treatment is to palliate symptoms rather than to achieve cure. Medical therapy is used to induce and maintain disease remission. Surgery is reserved for specific indications described later in this chapter. In addition, nutritional support in the form of aggressive enteral regimens or, if necessary, paren-teral nutrition, is used to manage the malnutrition that is com-mon in patients with Crohn’s disease.Medical Therapy. Pharmacologic agents used to treat Crohn’s disease include antibiotics, aminosalicylates, corticosteroids, immunomodulators, and biologic therapies. Antibiotics have an adjunctive role in the treatment of infectious complications


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Surgery_Schwartz. Crohn’s disease include antibiotics, aminosalicylates, corticosteroids, immunomodulators, and biologic therapies. Antibiotics have an adjunctive role in the treatment of infectious complications associated with Crohn’s disease. They are also used to treat patients with perianal disease, enterocutaneous fistulas, and active colonic disease.Crohn’s disease activity is assessed using the Crohn’s dis-ease Activity Index or Harvey-Bradshaw Index, and depending on the scores, it can be categorized as asymptomatic, mild, mod-erate, or severe disease to guide therapy. While patients with mild and moderate disease can be managed on an outpatient basis, those with severe or fulminant disease often require hospitaliza-tion for treatment, bowel rest, and possible nutritional support. There are two general approaches to treating Crohn’s disease: top-down (which starts with the most potent agents to achieve remission with a subsequent decrease in medication) or step-up (starts with less potent and


Surgery_Schwartz

Surgery_Schwartz. approaches to treating Crohn’s disease: top-down (which starts with the most potent agents to achieve remission with a subsequent decrease in medication) or step-up (starts with less potent and often safer drugs, and if symptoms fail to improve advances to the next group of medications).The use of oral 5-aminosalicylic acid (5-ASA) drugs (e.g., mesalamine) is somewhat controversial with mixed results from several randomized studies and meta-analyses. Aminosalicylates are associated with minimal toxicity and are available in a variety of formulations that allow for their delivery to specific regions of the alimentary tract. Thus, many continue to recommend use of mesalamine as an initial step in management of mild symptoms in patients with small bowel Crohn’s disease.Orally administered glucocorticoids are used to treat patients with mild disease that does not respond to aminosalicy-lates, or as initial treatment of patients with moderate disease. Patients with severe active disease


Surgery_Schwartz

Surgery_Schwartz. glucocorticoids are used to treat patients with mild disease that does not respond to aminosalicy-lates, or as initial treatment of patients with moderate disease. Patients with severe active disease usually require intravenous administration of glucocorticoids. Although glucocorticoids are effective in inducing remission, they are ineffective in prevent-ing relapse, and their adverse side-effect profile makes long-term use hazardous. Therefore, they should be tapered once remis-sion is achieved. Some patients are unable to undergo glucocor-ticoid tapering without suffering recurrence of symptoms. Such patients are said to have steroid dependence. These patients, along with those who do not respond to steroids at all (steroid resistant), should be considered for immune modulator therapies. Controlled ileal-released budesonide is an oral steroid with high first-pass hepatic metabolism and few systemic effects that can be tried in those with ileal and colonic Crohn’s disease.For those


Surgery_Schwartz

Surgery_Schwartz. Controlled ileal-released budesonide is an oral steroid with high first-pass hepatic metabolism and few systemic effects that can be tried in those with ileal and colonic Crohn’s disease.For those with severe disease, the thiopurine antimetabo-lites azathioprine and its active metabolite, 6-mercaptopurine, have demonstrated efficacy in inducing remission, maintaining remission, and allowing for glucocorticoid tapering in gluco-corticoid-dependent patients. A response to these medications is usually observed in 3 to 6 months, during which patients may need to continue with steroids. There is also some evidence that they decrease the risk of relapse after intestinal resection for Crohn’s disease. These agents are relatively safe but can induce bone marrow suppression and promote infectious complications. For patients who do not respond to the thiopurines, methotrexate is an alternative that is usually initially given intramuscularly before switching to oral form after achieving


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Surgery_Schwartz. complications. For patients who do not respond to the thiopurines, methotrexate is an alternative that is usually initially given intramuscularly before switching to oral form after achieving symptomatic con-trol. There is little role for cyclosporine in Crohn’s disease; its efficacy/toxicity profile in this disease is poor.The successful introduction of infliximab (Remicade), an anti-TNFα antibody, heralded the era of biological therapies for inflammatory bowel disease. Infliximab is a chimeric monoclo-nal antitumor necrosis-factor alpha (TNFα) antibody that has been shown to have efficacy in inducing remission and in pro-moting closure of enterocutaneous fistulae. There are two other anti-TNFα antibodies, with no randomized studies comparing efficacy of the drugs head to head. In general, it is thought that there is no significant difference in efficacy between them. While infliximab is a mouse-human chimeric antibody, adalimumab (Humira) is a fully human antibody. Certolizumab


Surgery_Schwartz

Surgery_Schwartz. it is thought that there is no significant difference in efficacy between them. While infliximab is a mouse-human chimeric antibody, adalimumab (Humira) is a fully human antibody. Certolizumab pegol (Cimzia) is a PEGylated Fab fragment of a humanized TNF inhibitor mono-clonal antibody. These agents are generally used for patients who are resistant to standard therapy, to help taper steroid dosage. They are generally well tolerated, but they should not be used in patients with ongoing septic processes, such as undrained intra-abdomi-nal abscesses. Antibodies against other targets in this inflamma-tory pathway have also been developed, including vedolizumab (Entyvio), a humanized anti–α4β7 integrin monoclonal antibody, with more specific anti-inflammatory effect in the intestine.For patients with perianal disease, antibiotic therapy with metronidazole or ciprofloxacin is the primary step. Two to 4 weeks of therapy is needed before improvements are seen, and often long-term therapy is


Surgery_Schwartz

Surgery_Schwartz. with perianal disease, antibiotic therapy with metronidazole or ciprofloxacin is the primary step. Two to 4 weeks of therapy is needed before improvements are seen, and often long-term therapy is required to prevent relapse. In cases of relapse, azathioprine can be considered. In patients with fis-tulas, infliximab and azathiprine are drugs of choice.Brunicardi_Ch28_p1219-p1258.indd 123823/02/19 2:24 PM 1239SMALL INTESTINECHAPTER 28Surgical Therapy. With introduction of new treatments, the need for surgery for Crohn’s disease has decreased steadily over the past few decades. Recent meta-analysis estimated the risk of surgery to be 16.3%, 33.3%, and 46.6% at 1, 5, and 10 years respectively.41 Surgery is generally reserved for patients whose disease is unresponsive to aggressive medical therapy or who develop complications of their disease (Table 28-8). Failure of medical management may be the indication for surgery if symp-toms persist despite aggressive therapy for several months


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Surgery_Schwartz. therapy or who develop complications of their disease (Table 28-8). Failure of medical management may be the indication for surgery if symp-toms persist despite aggressive therapy for several months or if symptoms recur whenever aggressive therapy is tapered. Sur-gery should be considered if medication-induced complications arise, specifically corticosteroid-related complications, such as cushingoid features, cataracts, glaucoma, systemic hyperten-sion, compression fractures, or aseptic necrosis of the femoral head. Growth retardation constitutes an indication for surgery in 30% of children with Crohn’s disease.One of the most common indications for surgical interven-tion is intestinal obstruction. Abscesses and fistulas are frequently encountered during operations performed for intestinal obstruc-tion in these patients, but they are rarely the only indication for surgery. Most abscesses are amenable to percutaneous drain-age, and fistulas, unless associated with symptoms or metabolic


Surgery_Schwartz

Surgery_Schwartz. obstruc-tion in these patients, but they are rarely the only indication for surgery. Most abscesses are amenable to percutaneous drain-age, and fistulas, unless associated with symptoms or metabolic derangements, do not require surgical intervention. Less common complications that require surgical intervention are acute gastro-intestinal hemorrhage, perforations, and development of cancer.Although surgery for Crohn’s disease is usually planned, an uncommon, but not rare, scenario is the intraoperative dis-covery of inflammation limited to the terminal ileum during operations performed for presumed appendicitis. This scenario can result from an acute presentation of Crohn’s disease or from acute ileitis caused by bacteria such as Yersinia or Campylo-bacter. Both conditions should be treated medically; ileal resec-tion is not generally indicated. However, the appendix, even if normal appearing, should be removed (unless the cecum is inflamed, increasing the potential morbidity of this


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Surgery_Schwartz. medically; ileal resec-tion is not generally indicated. However, the appendix, even if normal appearing, should be removed (unless the cecum is inflamed, increasing the potential morbidity of this procedure) to eliminate appendicitis from the differential diagnosis of abdominal pain in these patients, particularly those with Crohn’s disease who may be destined to have recurring symptoms.When the diagnosis of Crohn’s disease is known and sur-gery is planned, a thorough examination of the entire intestine should be performed. The presence of active disease is suggested by thickening of the bowel wall, narrowing of the lumen, serosal inflammation and coverage by creeping fat, and thickening of Table 28-8Indications for surgical intervention in Crohn’s diseaseAcute onset of severe disease: Crohn’s colitis +/− toxic megacolon (rare)Failure of medical therapy: Persistent symptoms despite long-term steroid use Recurrence of symptoms when high-dose steroids are tapered Drug-induced


Surgery_Schwartz

Surgery_Schwartz. colitis +/− toxic megacolon (rare)Failure of medical therapy: Persistent symptoms despite long-term steroid use Recurrence of symptoms when high-dose steroids are tapered Drug-induced complications (Cushing’s disease, hypertension)Development of disease complications: Obstruction Perforation Complicated fistulas Hemorrhage Malignancy riskthe mesentery. Skip lesions are present in approximately 20% of cases and should be sought. The length of uninvolved small intestine should be noted.Segmental intestinal resection of grossly evident disease followed by primary anastomosis is the usual procedure of choice. Microscopic evidence of Crohn’s disease at the resection margins does not compromise a safe anastomosis, and frozen section analysis of resection margins is unnecessary. In a ran-domized prospective trial, the effects of achieving 2-cm resec-tion margins beyond grossly evident disease were compared with achieving 12-cm resection margins.42 There were no evident dif-ferences with


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Surgery_Schwartz. prospective trial, the effects of achieving 2-cm resec-tion margins beyond grossly evident disease were compared with achieving 12-cm resection margins.42 There were no evident dif-ferences with respect to clinical recurrence rates or anastomotic recurrences. Recurrence rates were similar whether margins were histologically free of or involved with Crohn’s disease. An area of controversy in surgical management of Crohn’s disease has been the ideal anastomotic technique for the bowel after intestinal resection. This issue was addressed in a randomized study of 139 patients undergoing an ileocolic resection for Crohn’s disease, with a mean follow-up of 11.9 months. There were no differ-ences in endoscopic or symptomatic disease recurrence between the groups reconstructed using end-to-end sutured (2-0 PDS) anastomosis versus those with side-to-side staples anastomosis.43An alternative to segmental resection for obstructing lesions is stricturoplasty (Fig. 28-19). This technique allows


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Surgery_Schwartz. sutured (2-0 PDS) anastomosis versus those with side-to-side staples anastomosis.43An alternative to segmental resection for obstructing lesions is stricturoplasty (Fig. 28-19). This technique allows for preservation of intestinal surface area and is especially well suited to patients with extensive disease and fibrotic stric-tures who may have undergone previous resection and are at risk for developing short bowel syndrome. In this technique, the bowel is opened longitudinally to expose the lumen. Any ABFigure 28-19. Stricturoplasty. The wall of the strictured bowel is incised longitudinally. Reconstruction is performed by closing the defect transversely in a manner similar to the Heinecke-Mickulicz pyloroplasty for short strictures (A), or the Finney pyloroplasty for longer strictures (B).Brunicardi_Ch28_p1219-p1258.indd 123923/02/19 2:24 PM 1240SPECIFIC CONSIDERATIONSPART IIintraluminal ulcerations should be biopsied to rule out the pres-ence of neoplasia. Depending on the


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Surgery_Schwartz. (B).Brunicardi_Ch28_p1219-p1258.indd 123923/02/19 2:24 PM 1240SPECIFIC CONSIDERATIONSPART IIintraluminal ulcerations should be biopsied to rule out the pres-ence of neoplasia. Depending on the length of the stricture, the reconstruction can be fashioned in a manner similar to the Heinecke-Mickulicz pyloroplasty (for strictures less than 12 cm in length) or the Finney pyloroplasty (for longer strictures as much as 25 cm in length). For longer strictures, variations on the standard stricturoplasty, namely the side-to-side isoperistaltic enteroenterostomy, have been advocated and used for strictures with mean lengths of 50 cm.44 Stricturoplasty sites should be marked with metallic clips to facilitate their identification on radiographs and during subsequent operations. Stricturoplasty is associated with recurrence rates that are no different from those associated with segmental resection. Because the affected bowel is left in situ rather than resected, there is the potential for


Surgery_Schwartz

Surgery_Schwartz. is associated with recurrence rates that are no different from those associated with segmental resection. Because the affected bowel is left in situ rather than resected, there is the potential for cancer developing at the stricturoplasty site. However, as data on this complication are limited to anecdotes, this risk remains a theo-retical one. Stricturoplasty is contraindicated in patients with intra-abdominal abscesses or intestinal fistulas. The presence of a solitary stricture relatively close to a segment for which resection is planned is a relative contraindication. In general, stricturoplasty is performed in cases where single or multiple strictures are identified in diffusely involved segments of bowel, or where previous resections have been performed and mainte-nance of intestinal length is of great importance.Intestinal bypass procedures are sometimes required in the presence of intramesenteric abscesses or if the diseased bowel is coalesced in the form of a dense


Surgery_Schwartz

Surgery_Schwartz. intestinal length is of great importance.Intestinal bypass procedures are sometimes required in the presence of intramesenteric abscesses or if the diseased bowel is coalesced in the form of a dense inflammatory mass, making its mobilization unsafe. Bypass procedures (gastrojejunostomy) are also used in the presence of duodenal strictures, for which stric-turoplasty and segmental resection can be technically difficult.Since the 1990s, laparoscopic surgical techniques have been applied to patients with Crohn’s disease. The inflamma-tory changes associated with Crohn’s disease such as thickened and for eshortened mesentery, obliterated tissue planes, and fri-able tissues with engorged vasculature can make laparoscopic approach challenging. Randomized studies and a meta-analysis have confirmed that laparoscopic surgery for Crohn’s disease is associated with less postoperative pain, shorter duration of ileus, and a shorter hospital stay. The rates of disease recurrence were similar


Surgery_Schwartz

Surgery_Schwartz. that laparoscopic surgery for Crohn’s disease is associated with less postoperative pain, shorter duration of ileus, and a shorter hospital stay. The rates of disease recurrence were similar between the two groups.45OutcomesOverall complication rates following surgery for Crohn’s dis-ease range from 15% to 30%. Wound infections, postoperative intra-abdominal abscesses, and anastomotic leaks account for most of these complications.Surgery is not a curative intervention in Crohn’s disease, and many patients develop recurrence. If recurrence is defined endoscopically, 70% recur within 1 year of a bowel resection and 85% by 3 years.46 Clinical recurrence, defined as the return of symptoms confirmed as being due to Crohn’s disease, affects 60% of patients by 5 years and 94% by 15 years after intestinal resection. Reoperation becomes necessary in approximately one-third of patients by 5 years after the initial operation, with a median time to reoperation of 7 to 10 years.47 Of


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Surgery_Schwartz. years after intestinal resection. Reoperation becomes necessary in approximately one-third of patients by 5 years after the initial operation, with a median time to reoperation of 7 to 10 years.47 Of patient-modifying factors, smoking is a strong risk factor for disease recurrence.INTESTINAL FISTULASA fistula is defined as an abnormal communication between two epithelialized surfaces. The communication occurs between two parts of the gastrointestinal tract or adjacent organs in an internal fistula (e.g., enterocolonic fistula or colovesicular fistula). An external fistula (e.g., enterocutaneous fistula or rectovaginal fistula) involves the skin or another external surface epithelium. Enterocutaneous fistulas that drain less than 200 mL of fluid per day are known as low-output fistulas, whereas those that drain more than 500 mL of fluid per day are known as high-output fistulas.Over 80% of enterocutaneous fistulas represent iatrogenic complications that occur as the result of


Surgery_Schwartz

Surgery_Schwartz. whereas those that drain more than 500 mL of fluid per day are known as high-output fistulas.Over 80% of enterocutaneous fistulas represent iatrogenic complications that occur as the result of enterotomies or intes-tinal anastomotic dehiscences. Fistulas that arise spontaneously without antecedent iatrogenic injury are usually manifestations of progression of underlying Crohn’s disease or cancer.PathophysiologyThe manifestations of fistulas depend on which structures are involved. Low-resistance enteroenteric fistulas, which allow luminal contents to bypass a significant proportion of the small intestine, may result in clinically-significant malabsorption. Enterovesicular fistulas often cause recurrent urinary tract infec-tions. The drainage emanating from enterocutaneous fistulas are irritating to the skin and cause excoriation. The loss of enteric luminal contents, particularly from high-output fistulas originat-ing from the proximal small intestine, results in dehydration,


Surgery_Schwartz

Surgery_Schwartz. are irritating to the skin and cause excoriation. The loss of enteric luminal contents, particularly from high-output fistulas originat-ing from the proximal small intestine, results in dehydration, electrolyte abnormalities, and malnutrition.Fistulas have the potential to close spontaneously. Factors inhibiting spontaneous closure, however, include malnutrition, sepsis, inflammatory bowel disease, cancer, radiation, obstruc-tion of the intestine distal to the origin of the fistula, foreign bodies, high output, short fistulous tract (<2 cm) and epitheli-alization of the fistula tract (Table 28-9).Clinical PresentationIatrogenic enterocutaneous fistulas usually become clinically evident between the fifth and tenth postoperative days. Fever, leukocytosis, prolonged ileus, abdominal tenderness, and wound infection are the initial signs. The diagnosis becomes obvious when drainage of enteric material through the abdominal wound or through existing drains occurs. These fistulas are often


Surgery_Schwartz

Surgery_Schwartz. and wound infection are the initial signs. The diagnosis becomes obvious when drainage of enteric material through the abdominal wound or through existing drains occurs. These fistulas are often asso-ciated with intra-abdominal abscesses.DiagnosisCT scanning following the administration of enteral contrast is the most useful initial test. Leakage of contrast material from the intestinal lumen can be observed. Intra-abdominal abscesses Table 28-9Factors negatively impacting enteric fistula closurePatient factors Poor nutrition Medications such as steroidsEtiological factors Malignant fistula Fistula related to Crohn’s disease Fistula in radiated fieldsFistula site Gastric DuodenalLocal Factors Persistence of local inflammation and sepsis Presence of a foreign body (e.g., meshes or sutures) Epithelialization of fistula tract Fistula tract <2 cm Distal obstruction to the fistula siteBrunicardi_Ch28_p1219-p1258.indd 124023/02/19 2:24 PM 1241SMALL INTESTINECHAPTER 28should be sought


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Surgery_Schwartz. of fistula tract Fistula tract <2 cm Distal obstruction to the fistula siteBrunicardi_Ch28_p1219-p1258.indd 124023/02/19 2:24 PM 1241SMALL INTESTINECHAPTER 28should be sought and drained percutaneously. If the anatomy of the fistula is not clear on CT scanning, a small bowel series or enteroclysis examination can be obtained to demonstrate the fistula’s site of origin in the bowel. This study is also useful to rule out the presence of intestinal obstruction distal to the site of origin. Occasionally, contrast administered into the intestine does not demonstrate the fistula tract. A fistulogram, in which contrast is injected under pressure through a catheter placed per-cutaneously into the fistula tract, may offer greater sensitivity in localizing the fistula origin.TherapyThe treatment of enterocutaneous fistulas should proceed through an orderly sequence of steps48:1. Stabilization. Fluid and electrolyte resuscitation is begun. Nutrition is provided, usually through the


Surgery_Schwartz

Surgery_Schwartz. treatment of enterocutaneous fistulas should proceed through an orderly sequence of steps48:1. Stabilization. Fluid and electrolyte resuscitation is begun. Nutrition is provided, usually through the parenteral route initially. Sepsis is controlled with antibiotics and drainage of abscesses. The skin is protected from the fistula effluent with ostomy appliances or fistula drains.2. Investigation. The anatomy of the fistula is defined using the aforementioned studies.3. Decision. The available treatment options are considered, and a time line for conservative measures is determined.4. Definitive Management. This entails the surgical procedure and requires appropriate preoperative planning and surgical experience.5. Rehabilitation.The overall objectives are to increase the probability of spontaneous closure. Nutrition and time are the key components of this approach. Most patients will require TPN; however, a trial of oral or enteral nutrition should be attempted in patients with


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Surgery_Schwartz. of spontaneous closure. Nutrition and time are the key components of this approach. Most patients will require TPN; however, a trial of oral or enteral nutrition should be attempted in patients with low-output fistulas originating from the distal intestine. The somatostatin analogue octreotide is a useful adjunct, par-ticularly in patients with high-output fistulas. A meta-analysis of several randomized studies confirmed that somatostatin treatment reduced length of hospital stay and time to closure of fistulas; however, its administration did not lead to a significant differ-ence in fistula closure rates.49 Use of negative pressure wound therapy has increased in management of enterocutaneous fistulas. The system can allow better management of the fistula output. In a study of 91 patients with enterocutaneous fistulas, 40% of fis-tulae reached minimal output within a week, and with an average follow-up of 90 days, spontaneous closure rate was 46%.50Timing of Surgical


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Surgery_Schwartz. of 91 patients with enterocutaneous fistulas, 40% of fis-tulae reached minimal output within a week, and with an average follow-up of 90 days, spontaneous closure rate was 46%.50Timing of Surgical Intervention. Most surgeons would pur-sue 2 to 3 months of conservative therapy before considering surgical intervention. This approach is based on evidence that 90% of fistulas that are going to close do so within 5 weeks and that surgical intervention after this period is associated with bet-ter outcomes and lower morbidity.51If the fistula fails to resolve during this period, surgery may be required, during which the fistula tract, together with the segment of intestine from which it originates, should be resected. Simple closure of the opening in the intestine from which the fistula originates is associated with high recurrence rates. Patients with intestinal fistulas typically have extensive and dense intra-abdominal adhesions. Thus, operations per-formed for nonhealing fistulas can


Surgery_Schwartz

Surgery_Schwartz. is associated with high recurrence rates. Patients with intestinal fistulas typically have extensive and dense intra-abdominal adhesions. Thus, operations per-formed for nonhealing fistulas can present formidable chal-lenges. Successful applications of alternative therapies to close intestinal fistulas such as the use of biologic sealants have been reported. The indications for their use remain to be defined.OutcomesOver 50% of intestinal fistulas close spontaneously. A useful mnemonic designates factors that inhibit spontaneous closure of intestinal fistulas: “FRIEND” (Foreign body within the fistula tract, Radiation enteritis, Infection/Inflammation at the fistula origin, Epithelialization of the fistula tract, Neoplasm at the fis-tula origin, Distal obstruction of the intestine).In a 23-year old retrospective review of 153 cases of enterocutaneous fistulas that were treated surgically, most fis-tulas were found to originate from the small bowel and be iat-rogenic in nature, with


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Surgery_Schwartz. 23-year old retrospective review of 153 cases of enterocutaneous fistulas that were treated surgically, most fis-tulas were found to originate from the small bowel and be iat-rogenic in nature, with patients having undergone five or more previous abdominal surgeries. Operative repair was associated with a 30-day mortality of approximately 4% and a 1-year mor-tality of 15%. Morbidity was over 80%. First attempt at surgical repair was successful in 70% of cases, with an overall closure rate of 84% and some patients requiring up to 3 attempts at surgical repair. The authors identified closure of the abdominal fascia as an important factor in reducing rates of refistulization and postoperative mortality.52 In another similar study, fistula recurrence rates of 30% were documented and were indepen-dently associated with high output fistulas and the type of surgi-cal treatment: operations not involving resection of the fistula had a much higher rate of recurrence.53SMALL BOWEL


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Surgery_Schwartz. and were indepen-dently associated with high output fistulas and the type of surgi-cal treatment: operations not involving resection of the fistula had a much higher rate of recurrence.53SMALL BOWEL NEOPLASMSAdenomas are the most common benign neoplasm of the small intestine. Other benign tumors include fibromas, lipomas, hemangiomas, lymphangiomas, and neurofibromas. The prevalence of small bowel tumors identified at autopsy is 0.2% to 0.3%, which is significantly higher than the rate of operation for small bowel tumors. This suggests that majority of small bowel tumors are asymptomatic. These lesions are most frequently encountered in the duodenum as incidental findings during esophagogastroduodenoscopic (EGD) examinations (Fig. 28-20). The reported prevalence of Figure 28-20. Duodenal polyp. This polyp was incidentally encountered during EGD. It was biopsied and found to be an adenoma.Brunicardi_Ch28_p1219-p1258.indd 124123/02/19 2:24 PM 1242SPECIFIC


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Surgery_Schwartz. of Figure 28-20. Duodenal polyp. This polyp was incidentally encountered during EGD. It was biopsied and found to be an adenoma.Brunicardi_Ch28_p1219-p1258.indd 124123/02/19 2:24 PM 1242SPECIFIC CONSIDERATIONSPART IIduodenal polyps, as detected during EGD performed for other reasons, range from 0.3% to 4.6%.Benign neoplasms account for 30% to 50% of small bowel tumors and include adenomas, lipomas, hematomas, and hemangiomas. Primary small bowel cancers are rare but have been increasing in incidence, with an estimated incidence of 10,190 cases in 2017 in the United States. Among small bowel cancers, adenocarcinomas comprise 35% to 50% of all cases, carcinoid tumors comprise 20% to 40%, and lymphomas comprise approximately 10% to 15%. In a retrospective review of a large U.S. database (SEER) between 1992 and 2006, of a total number of 10,945 small intestine cancers, 4315 were neuroendocrine in origin, 3412 were carcinomas, 2023 were lymphomas, and 1084 were sarcomas.54


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Surgery_Schwartz. database (SEER) between 1992 and 2006, of a total number of 10,945 small intestine cancers, 4315 were neuroendocrine in origin, 3412 were carcinomas, 2023 were lymphomas, and 1084 were sarcomas.54 Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising in the small intestine and comprise the vast majority of tumors that were formerly classified as leiomyomas, leiomyosarcomas, and smooth muscle tumors of the intestine. The small intestine is frequently affected by metastases from or local invasion by cancers originating at other sites. Melanoma, in particular, is associated with a propensity for metastasis to the small intestine.Most patients with small-intestinal cancers are in their fifth or sixth decade of life. Reported risk factors for developing small-intestinal cancers include consumption of red meat, inges-tion of smoked or cured foods, Crohn’s disease, celiac sprue, hereditary nonpolyposis colorectal cancer (HNPCC), familial adenomatous polyposis


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Surgery_Schwartz. cancers include consumption of red meat, inges-tion of smoked or cured foods, Crohn’s disease, celiac sprue, hereditary nonpolyposis colorectal cancer (HNPCC), familial adenomatous polyposis (FAP), and Peutz-Jeghers syndrome.PathophysiologyThe small intestine contains over 90% of the mucosal surface area of the gastrointestinal tract but only 1.1% to 2.4% of all gastrointestinal malignancies. Proposed explanations for the low frequency of small-intestinal neoplasms include (a) dilu-tion of environmental carcinogens in the liquid chyme present in the small-intestinal lumen; (b) rapid transit of chyme, limiting the contact time between carcinogens and the intestinal mucosa; (c) a relatively low concentration of bacteria in small-intestinal chyme and, therefore, a relatively low concentration of carcino-genic products of bacterial metabolism; (d) mucosal protection by secretory IgA and hydrolases such as benzpyrene hydroxy-lase that may render carcinogens less active; and (e) efficient


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Surgery_Schwartz. of carcino-genic products of bacterial metabolism; (d) mucosal protection by secretory IgA and hydrolases such as benzpyrene hydroxy-lase that may render carcinogens less active; and (e) efficient epithelial cellular apoptotic mechanisms that serve to eliminate clones harboring genetic mutations.Recent advances have begun to clarify the molecular pathogenesis of small-intestinal adenocarcinomas and GISTs; there has been less progress with respect to the pathogen-esis of the other small-intestinal malignancies (Table 28-10). Small-intestinal adenocarcinomas are believed to arise from Table 28-10Features of small intestinal malignanciesTUMOR TYPECELL OF ORIGINFREQUENCYaPREDOMINANT SITEAdenocarcinomaEpithelial cell35–50%DuodenumCarcinoidEnterochromaffin cell20–40%IleumLymphomaLymphocyte10–15%IleumGISTInterstitial cell of Cajal10–15%–aFrequencies given as percentages of small intestinal malignancies comprised by each of the tumor types. Gastrointestinal stromal tumors (GISTs) display no


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Surgery_Schwartz. cell of Cajal10–15%–aFrequencies given as percentages of small intestinal malignancies comprised by each of the tumor types. Gastrointestinal stromal tumors (GISTs) display no regional variation in prevalence within the small intestine.preexisting adenomas through a sequential accumulation of genetic abnormalities in a model like that described for the pathogenesis of colorectal cancer. Adenomas are histologi-cally classified as tubular, villous, and tubulovillous. Tubular adenomas have the least aggressive features. Villous adenomas have the most aggressive features and tend to be large, sessile, and located in the second portion of the duodenum. Malignant degeneration has been reported to be present in up to 45% of vil-lous adenomas by the time of diagnosis. Patients with FAP have a nearly 100% cumulative lifetime risk of developing duodenal adenomas that have the potential to undergo malignant trans-formation. The risk of duodenal cancer in these patients is over 100-fold greater


Surgery_Schwartz

Surgery_Schwartz. 100% cumulative lifetime risk of developing duodenal adenomas that have the potential to undergo malignant trans-formation. The risk of duodenal cancer in these patients is over 100-fold greater than in the general population. Indeed, duode-nal cancer is the leading cause of cancer-related death among patients with FAP who have undergone colectomy. Patients with Peutz-Jeghers syndrome develop hamartomatous polyps; however, these polyps can contain adenomatous foci that can undergo malignant transformation (Fig. 28-21).A defining feature of GISTs is their gain of function mutation of proto-oncogene KIT, a receptor tyrosine kinase. Figure 28-21. Small bowel polyp in Peutz-Jeghers syndrome. This image was captured by a wireless capsule endoscope as it was traveling through the small intestine. (Used with permission from Anne T. Wolf, M.D., Department of Medicine, Brigham and Women’s Hospital, Boston, MA.)Brunicardi_Ch28_p1219-p1258.indd 124223/02/19 2:24 PM 1243SMALL INTESTINECHAPTER


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Surgery_Schwartz. (Used with permission from Anne T. Wolf, M.D., Department of Medicine, Brigham and Women’s Hospital, Boston, MA.)Brunicardi_Ch28_p1219-p1258.indd 124223/02/19 2:24 PM 1243SMALL INTESTINECHAPTER 28Pathological KIT signal transduction is believed to be a cen-tral event in GIST pathogenesis. The majority of GISTs have activating mutations in the c-kit proto-oncogene, which cause KIT to become constitutively activated, presumably leading to persistence of cellular growth or survival signals. Because the interstitial cells of Cajal normally express KIT, these cells have been implicated as the cell of origin for GISTs. KIT expression is assessed by staining the tissues for CD117 antigen, which is part of the KIT receptor and is present in 95% of GISTs.Clinical PresentationMost small-intestinal neoplasms are asymptomatic until they become large. Partial small bowel obstruction, with associ-ated symptoms of crampy abdominal pain and distention, nau-sea, and vomiting, is the most common


Surgery_Schwartz

Surgery_Schwartz. neoplasms are asymptomatic until they become large. Partial small bowel obstruction, with associ-ated symptoms of crampy abdominal pain and distention, nau-sea, and vomiting, is the most common mode of presentation. Obstruction can be the result of either luminal narrowing by the tumor itself or intussusception, with the tumor serving as the lead point. Hemorrhage, usually indolent, is the second most common mode of presentation.Physical examination may be unrevealing, but it also may reveal a palpable abdominal mass in those with large tumors. Findings of intestinal obstruction may be present in some patients. A fecal occult blood test may be positive. Jaundice secondary to biliary obstruction or hepatic metastasis may be present. Cachexia, hepatomegaly, and ascites may be present with advanced disease.Although the clinical presentation is usually not specific for tumor type, some general comments are appropriate. Adeno-carcinomas, as well as adenomas (from which most are believed to


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Surgery_Schwartz. disease.Although the clinical presentation is usually not specific for tumor type, some general comments are appropriate. Adeno-carcinomas, as well as adenomas (from which most are believed to arise), are most commonly found in the duodenum, except in patients with Crohn’s disease, in whom most are found in the ileum. Lesions in the periampullary location can cause obstruc-tive jaundice or pancreatitis. Adenocarcinomas located in the duodenum tend to be diagnosed earlier in their progression than those located in the jejunum or ileum, which are rarely diagnosed prior to the onset of locally advanced or metastatic disease.Carcinoid tumors of the small intestine are also usually diagnosed after the development of metastatic disease. These tumors are associated with a more aggressive behavior than the more common appendiceal carcinoid tumors. Approximately 25% to 50% of patients with carcinoid tumor-derived liver metastases will develop manifestations of the carcinoid syn-drome. These


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Surgery_Schwartz. than the more common appendiceal carcinoid tumors. Approximately 25% to 50% of patients with carcinoid tumor-derived liver metastases will develop manifestations of the carcinoid syn-drome. These manifestations include diarrhea, flushing, hypo-tension, tachycardia, and fibrosis of the endocardium and valves the right heart. Candidate tumor-derived mediators of the car-cinoid syndrome such as serotonin, bradykinin, and substance P undergo nearly complete metabolism during the first passage through the liver. As a result, symptoms of carcinoid syndrome are rare in the absence of liver metastases.Lymphoma may involve the small intestine primarily or as a manifestation of disseminated systemic disease. Primary small-intestinal lymphomas are most commonly located in the ileum, which contains the highest concentration of lymphoid tissue in the intestine. Although partial small bowel obstruction is the most common mode of presentation, 10% of patients with small-intestinal lymphoma present


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Surgery_Schwartz. the highest concentration of lymphoid tissue in the intestine. Although partial small bowel obstruction is the most common mode of presentation, 10% of patients with small-intestinal lymphoma present with bowel perforation.The small intestine is the second most common site of GIST tumors after the stomach, containing 25% to 35% of GISTs. There appears to be no regional variation in the preva-lence of GISTs within the small intestine. GISTs have a greater propensity to be associated with overt hemorrhage than the other small-intestinal malignancies (Fig. 28-22).Metastatic tumors involving the small intestine can induce intestinal obstruction and bleeding.DiagnosisBecause of the absent or nonspecific symptoms associated with most small-intestinal neoplasms, these lesions are rarely diagnosed preoperatively. Laboratory tests are nonspecific, except for elevated urinary 5-hydroxyindole acetic acid (5-HIAA) and serum chromogranin A (CgA) levels in patients with carcinoid syndrome, both of


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Surgery_Schwartz. preoperatively. Laboratory tests are nonspecific, except for elevated urinary 5-hydroxyindole acetic acid (5-HIAA) and serum chromogranin A (CgA) levels in patients with carcinoid syndrome, both of which have low sensitivity. Elevated carcinoembryonic antigen (CEA) levels are associated with small-intestinal adenocarcinomas, but only in the presence of liver metastases.Contrast radiography of the small intestine may demon-strate benign and malignant lesions. Enterocolysis is reported to have a sensitivity of over 90% in the detection of small bowel tumors and is the test of choice, particularly for tumors located in the distal small bowel. Upper GI with small bowel follow-through examinations have reported sensitivities ranging from only 30% to 44% (Fig. 28-23). CT scanning can detect abnor-malities in 70% to 80% of cases with small bowel tumor and assess for metastatic spread. Tumors associated with significant bleeding can be localized with angiography or radioisotope-tagged red


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Surgery_Schwartz. abnor-malities in 70% to 80% of cases with small bowel tumor and assess for metastatic spread. Tumors associated with significant bleeding can be localized with angiography or radioisotope-tagged red blood cell (RBC) scans.Tumors located in the duodenum can be visualized and biopsied on EGD. In addition, endoscopic ultrasonography (EUS) can offer additional information such as the layers of the intestinal wall involved by the lesion. Occasionally, the distal ileum can suc-cessfully be visualized during colonoscopy. Intraoperative enter-oscopy can be used to directly visualize small-intestinal tumors beyond the reach of standard endoscopic techniques. For more distal small bowel lesions, capsule endoscopy and double-balloon Figure 28-22. Jejunal gastrointestinal stromal tumor (GIST). This patient presented with overt obscure GI bleeding and was found to have a 7-cm jejunal GIST. The picture represents the laparo-scopic view of the mass (black arrow), arising from the antimesenteric


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Surgery_Schwartz. patient presented with overt obscure GI bleeding and was found to have a 7-cm jejunal GIST. The picture represents the laparo-scopic view of the mass (black arrow), arising from the antimesenteric side of the small bowel (*). He underwent a successful laparoscopic resection.Brunicardi_Ch28_p1219-p1258.indd 124323/02/19 2:24 PM 1244SPECIFIC CONSIDERATIONSPART IIFigure 28-23. Small bowel lesion identified during a small bowel follow-through (arrow). This patient had previously had a metastatic renal lesion to his duodenum requiring a Whipple procedure. During follow-up imaging 3 years later, he was found to have this new lesion in his jejunum. He underwent a laparoscopic small bowel resection. Pathology revealed a benign jejunal sessile polyp.endoscopy have been used to evaluate small bowel. CT and MR enterography are also increasing utilized as noninvasive tests to look for small bowel masses. PET scans can also help assess metabolic activity of lesions and risk of


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Surgery_Schwartz. evaluate small bowel. CT and MR enterography are also increasing utilized as noninvasive tests to look for small bowel masses. PET scans can also help assess metabolic activity of lesions and risk of malignancy.TherapyBenign neoplasms of the small intestine that are symptomatic should be surgically resected or removed endoscopically, if fea-sible. Tumors located in the duodenum, including asymptomatic lesions incidentally found during EGD, can pose the great-est therapeutic challenges. These lesions should be biopsied; symptomatic tumors and adenomas, because of their malignant potential, should be removed. In general, duodenal tumors less than 1 cm in diameter are amenable to endoscopic polypectomy. Lesions greater than 2 cm in diameter are technically difficult to remove endoscopically and may need to be removed surgi-cally. Surgical options include transduodenal polypectomy and segmental duodenal resection. Tumors located in the second portion of the duodenum near the ampulla of


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Surgery_Schwartz. and may need to be removed surgi-cally. Surgical options include transduodenal polypectomy and segmental duodenal resection. Tumors located in the second portion of the duodenum near the ampulla of Vater may require pancreaticoduodenectomy. EUS may offer utility for duodenal tumors ranging in size between 1 and 2 cm in diameter, with those limited to the mucosa being amenable to endoscopic pol-ypectomy. Endoscopic resection of biopsy-proven benign duo-denal periampullary adenomas leads to equivalent efficacy to surgery but with lower morbidity. Adenomas can recur; there-fore, surveillance endoscopy is required after these procedures.55Duodenal adenomas occurring in the setting of FAP require an especially aggressive approach to management. Patients with FAP should undergo screening EGD starting sometime during their second or third decade of life. Adenomas detected should be removed endoscopically, if possible, followed by surveillance endoscopy in 6 months and yearly thereafter, in