Curr Pro Sur Enfe Divert

8/12/2019 Curr Pro Sur Enfe Divert

1/56


2/56

World War, there was an increased acknowledgment of the prevalence of

this disease. In 1907, Dr William Mayo reported 5 cases of diverticulitisto the American Surgical Association and demonstrated a modern

understanding of the disease, stating that the surgical treatment depended

on specific clinical factors and that, if significant obstruction or infectionwas present, a temporary artificial anus should be made.5 He advocated

primary resection, stating that it was better to perform a primaryresection of the affected part of the bowel, before abscess and fistula

supervened. Following Mayos modern day understanding of the dis-

ease, the trend in the USA and the UK reverted back to a 3-stageprocedure as advocated by both Smithwick in 1942 and Lockhart-

Mummery in 1938.6,7 Staged resection with initial colostomy anddrainage followed by resection of the involved segment and interval

closure of the colostomy remained the standard treatment for diverticulitis

for decades. The increased morbidity and disability for patients who hadundergone staged procedures gave impetus to the initial resection of the

affected segment, the current standard surgical treatment for patients with

diverticulitis. More recently, reports of primary laparoscopic lavagewithout resection of the involved segment are challenging this dictum.8,9

IncidenceDiverticulosis is one of the most common colonic conditions in Western

populations. Since the 20th century, an increasing prevalence of diver-

ticular disease has been noted, particularly in industrialized nations.

Diverticulosis is rare under the age of 30. Thereafter, the incidence of thediverticulosis is such that more than 40% develop diverticula by the age

of 60 years and more than 60% of those aged 80 years or older are

affected.10,11

The exact incidence of diverticulosis is difficult to determine but could

presumably be determined by a combination of autopsy, radiographic,and endoscopic series. These data sources all have a number of limita-

tions. The incidence in autopsy series varies with the interest of the

individual pathologist in reporting the prevalence of diverticulosis. In thepostmortem state, diverticula may only be detected by careful examina-

tion of the colon to detect small diverticula or diverticula obscured by

mesenteric fat. The true prevalence of diverticulosis could theoretically bedetermined by performing barium enema studies on a large segment of

the population. However, such studies are not ethically possible in anasymptomatic population because of the dose of radiation required.

Colonoscopy and flexible sigmoidoscopy series may also provide data on

the prevalence of diverticulosis; however, many of the procedures are

Curr Probl Surg, September 2010 681


3/56


4/56

vasa recta penetrate the circular muscle layer, providing the blood supply

for the mucous membrane. These herniations occur at well-defined points

around the circumference of the colon along either side of the mesenterictenia and on the mesenteric border of the 2 antimesenteric teniae25 (Fig 2).

When there is no inflammatory process, diverticula are soft and com-

pressible, allowing a free communication between the diverticulum andthe colonic lumen. Microscopic studies of areas of the colon with early

small diverticula demonstrate areas of thinning due to presumed focalmicroscopic muscle atrophy.12 With progression, a clear-cut defect in the

muscle occurs, usually at the site of penetration of a vessel through gapsin the circular muscle layer.

FIG 1.(A) Diverticulitis discharges (uncomplicated and complicated) in Nationwide Inpatient Samplefrom 1991 to 2005. (B) Proportion of patient discharges for free diverticular perforation among allpatients with diverticulitis in Nationwide Inpatient Sample from 1991 to 2005. (Reprinted withpermission from Ricciardi et al.24).



5/56

The exact pathogenesis of diverticulitis is uncertain. Similar to the devel-

opment of acute appendicitis, it is postulated that stasis or obstruction of thediverticulum lead to bacterial overgrowth, localized tissue inflammation, and

ischemia. Once the colonic mucosa is injured, ulceration can occur, leading

to a contained perforation and formation of a peridiverticular abscess or free

perforation with peritonitis. The inflammatory process can also fistulize into

adjacent organs such as the small bowel, bladder, and vagina. The most

commonly isolated organisms are anaerobic bacteria, includingBacteroides,

Peptostreptococcus, Clostridium, and Fusobacterium species and Gram-

negative aerobes, especially Escherichia coli.26

Microscopic features of diverticulitis include thickening of the lamina

propria secondary to influx of lymphocytes. Mucin depletion and Paneth cell

hyperplasia can also be observed in addition to crypt abscesses and ulcer-

ation.27 Many of the histologic features are similar to those associated with

inflammatory bowel disease.28

FIG 2. Vasa recta penetrate the colonic wall at tenia libera, omentalis, and mesocolica. Thisallows herniation of mucosa and submucosa at these sites. (Color version of figure is availableonline.)

684 Curr Probl Surg, September 2010


6/56

Pathophysiologic FeaturesThe pathophysiology of the development of diverticulitis has focused

on the structural abnormalities of the colon wall (termed a tenia specificelastosis), disordered motility and generation of high intracolonic pres-

sures (segmentation), and the role of dietary fiber.

SegmentationAlthough the colon does represent a continuous column of gas and

stool, high regional pressures can be generated within individual colonic

segments. This process has been called segmentation and likened to the

development of small compartments or segments within the sigmoidcolon. This mechanism presumably leads to mucosal herniation and the

development of diverticulosis.29,30

Painter and colleagues performed sigmoid manometry and cineradiog-

raphy in patients with and without diverticular disease.29 The highest

pressures were generated in the sigmoid colon. Patients with normal

colons and patients with diverticular disease had similar resting luminal

pressures29,31 but high-pressure waves occurred in patients with divertic-

ular disease. In addition, patients with diverticular disease generatedhigher luminal pressures in response to a pharmaceutical stimulus such as

the administration of morphine sulfate but not to meperidine. In subse-

quent studies, increased colonic motility (as evidenced by the number and

amplitude of contractions) was noted in the sigmoid colon in patients with

left-sided diverticular disease.32,33

The studies performed by Painter and others have a number of shortcom-

ings. There were methodologic differences related to bowel preparation and

the type of sensors used. A study period of 2 hours is relatively short and upto 24 hours may be needed to draw meaningful conclusions. The studies also

involved a small number of patients and failed to account for age, gender,

physical activities, or body fat percentage. Some have suggested that

pressure-sensitive transducers that can be swallowed and allowed to pass

through the gastrointestinal tract will give a more comprehensive measure of

colonic physiology in diverticular disease.34

Other investigators have focused on myoelectrical activity in the colon

to explain the development of diverticulosis. Myoelectrical studies haveshown distinct slow wave motility patterns of patients with diverticular

disease compared with irritable bowel syndrome.35 Patients with diver-

ticular disease had abnormal slow wave motility patterns of 12 to 18

cycles/min, whereas patients with irritable bowel syndrome had a 3 cycle

per minute motility pattern.35,36 Administration of bran had no effect on



7/56

the motility of patients with irritable bowel syndrome, but in patients with

diverticular disease administration of bran caused the motility patterns toreturn to normal.37 Of note, the abnormal motility patterns persisted in

patients with diverticular disease despite sigmoid resection.38

Further physiologic studies demonstrate increased pressures and exag-gerated motility indexes in patients with symptomatic diverticular dis-

ease.33,39 Patients with diverticular disease who are subjected to 24-hourmanometric monitoring demonstrate abnormal propulsive activities that

are specific to the affected regions of the colon.33 It is unclear, however,

whether these motility and propulsion abnormalities are a byproduct ofcolonic disease or merely represent symptoms of diverticulitis.40

Role of FiberDiverticular disease has been called a fiber-deficiency disease of

Western civilization. Early studies of diverticular disease comparedpopulations in sub-Saharan Africa and the UK and concluded that the

much higher incidence of diverticular disease in the UK was because of

the amount of dietary fiber consumed.41 Painter and Burkitt studied

colonic transit times and stool weights in more than 1000 individuals in

the UK and sub-Saharan Africa. Longer transit times and lower stoolweights were seen in the UK population compared with the Ugandan

population. A high fiber diet was felt to be the major contributing factor

to faster colonic transit times, larger stool volumes, and more frequentbowel movements. Painter and Burkitt reasoned that the rising incidence

of diverticular disease in the Western world could be due to a gradualdecrease in consumption of dietary fiber over the course of the 20th

century. Specifically, the advent of roller milling and the process of

refining sugar during the Industrial Revolution removed a large source offiber from the Western diet. The life expectancy of Western populations

has increased over the 20th century and therefore one would anticipate an

increase in the prevalence of diverticular disease with increasing age. Lifeexpectancy remains low on the African continent and, therefore, as

smaller numbers of the population reach older ages, a lower prevalence of

diverticular disease should be expected.42 As Africans have adopted a

more Western diet, authors have noted an increasing prevalence of

diverticular disease has been noted.43Animal studies have supported the role of dietary fiber in the develop-

ment of diverticular disease. In a prospective randomized trial of theeffects of differing amounts of fiber in 1800 rats, Fisher and colleagues

demonstrated a dramatic increase in the number of rats with diverticulosiswhen fed low fiber diets compared with those fed high fiber diets.44



8/56

Approximately 45% of the rats on the lowest fiber diet developed

diverticula compared with 9% of the rats on the highest fiber diet.Two studies have examined dietary factors in large populations of

patients with and without diverticular disease.45,46 Both studies have

demonstrated significantly lower consumption of dietary fiber in patientswith diverticular disease when compared with their healthy counterparts.

Patients with diverticulosis also tended to eat greater quantities of red

meat and fats. Aldoori and colleagues studied 51,529 male healthprofessionals and over a 6-year period there were 384 (0.75%) new cases

of diverticular disease. The risk of the development of diverticular diseasewas inversely associated with insoluble dietary fiber intake. The relative

risks associated with fruit and vegetable fiber were 0.62 (95% CI

0.45-0.86) and 0.55 (95% CI 0.37-0.84).45 Fiber found in fruits and

vegetables conferred the most protective effect (compared with fiber from

cereal) and a high intake of total fat and red meat increased the incidenceof diverticular disease. Manousus and colleagues46 compared a cohort of

individuals who were predominantly vegetarians to a cohort who pre-

dominantly ate meat and consumed very few vegetables. Diverticulosiswas defined as the presence of 3 of more diverticula on barium enema

study. In this study, 100 patients with radiographically confirmed diver-ticulosis and 110 control patients were compared using a structured

interview that included questions pertaining to dietary intake, demo-

graphic, and socioeconomic factors; they concluded that higher reportedconsumption of meat and dairy products was associated with develop-

ment of diverticulitis. The risk of developing diverticular disease was

50-fold greater in meat eaters. Although these studies have potentialconfounding variables including detection and recall bias, they support

the role of dietary fiber. Furthermore, in a large cohort study of 47,228men, popcorn, nut, and seed consumption was inversely correlated with

diverticulosis or diverticular complications.47 This study refutes the adagethat nuts, corn, seeds, and popcorn cause diverticulitis and should be

avoided in patients who have had an attack of diverticulitis.47

Colonic Wall Abnormalities and Tenia Specific ElastosisAlternative theories to the traditional low fiber hypothesis have been

proposed. Some investigators have suggested that the smooth muscle ofthe rectosigmoid behaves differently from other muscles in the colon

wall. This was theorized because often wall thickening was the onlyabnormality in the absence of inflammation.48 Early necropsy studies

describe increased bowel wall thickness in patients with diverticulardisease.25 Although this was initially felt to be from muscular hypertro-



9/56

phy, multiple subsequent studies have shown that there is no evidence of

either hypertrophy or hyperplasia. Whiteway and Morson proposed that

this thickening was due to elastin deposition within the tenia.

49

Whitewayand Morson studied the muscularis propria in patients with uncomplicated

diverticulosis and found that the tenia were thickened due to elastin

deposition. There was an increase of over 200% in elastin in these patients

compared with controls. The elastin was laid down in a contracted form,

leading to bunching of the tenia and apparent foreshortening of the bowel.

Furthermore, with progressive scarring in diverticulitis, the ratio of type

I to type III collagen is altered in both the serosa and the submucosa.50

Some have postulated that this effect is secondary to aberrant activity ofmatrix metalloproeinases and tissue inhibitors of the matrix metallopro-

teinases.51 It remains to be seen whether the role of matrix metalloproe-

inases and tissue inhibitors of the matrix metalloproteinases is specific to

acute inflammation or to diverticular disease.52

Despite the grossly increased muscle wall thickness, patients with

diverticulosis remain more susceptible to herniation. The role of collagen

and the tensile strength of the colonic wall have been investigated. Wess

and colleagues analyzed colonic collagen content in an attempt todetermine if a lack of collagen is responsible for this apparent weakness

of the muscle wall.53 Since the collagen content does not change with age

or the presence of diverticula, the changes are more likely to be qualitative

than quantitative. Collagen fibrils demonstrate increased cross-linking with

increased age; this process seems to increase most dramatically after 40 years

of age, the age at which the incidence of diverticular disease also appears to

increase. This same study demonstrated that patients with diverticulosis

have an abnormally high amount of collagen cross-linkage in the colonwall. This difference persists even when patients were compared with

age-matched controls. Increased cross-linkage of collagen fibers likely

causes the tissues to become stiffer and less resistant to stretching. The

loss of compliance of the colonic submucosa, the layer primarily

responsible for tensile strength, may make the submucosa more suscep-

tible to small tears when subjected to the higher intraluminal pressures

triggered by segmentation. Any tear in this layer could potentially then

lead to mucosal herniations and the formation of diverticulosis.A possible genetic connective tissue defect has also been suggested

because of reports of diverticular disease in young patients with Marfan

syndrome or EhlersDanlos syndrome.54-56 It is likely that a number of

processes including impaired motility, low fiber intake, inflammation, and

elastin deposition contribute to the pathogenesis of diverticular disease.



10/56

Additional Risk FactorsAge. From a historical standpoint, diverticulitis in younger patients

(under the age of 50 years) has been described as more virulent and morelikely to be associated with complications and more likely to require

resection.57,58 Young patients have been variably defined as under 50

years in some series and under 40 or 45 years old in other series. Despite

the definition of what age defines young patients, all series of younger

patients with acute diverticulitis have noted a striking male predominance

in contrast to older series, which have a slight female predominance.59

Earlier series of young patients in the pre-computed tomography (CT)

scan era have had a large percentage of patients undergoing resection,presumably since the patients were frequently diagnosed preoperatively

with appendicitis. These patients then underwent laparotomy and subse-

quent resection when diverticulitis and not appendicitis was encountered.

Currently, such patients would most likely be diagnosed with acute

diverticulitis on CT scan preoperatively and treated with initial medical

management of bowel rest and antibiotics. The current management of

young patients with diverticulitis continues to be a source of considerable

controversy and is discussed later in this text.

Sex. Diverticular disease tends to affect patients during middle age as

the incidence rises from 5% at age 40 to 80% by age 80.60 The prevalence

of the disease among the sexes has been estimated to be between a 2:3 and

3:1 male-to-female ratio.21,61 Other authors have reported that patients

with symptomatic diverticular disease younger than the age of 65 tend to

be male. Hall and colleagues demonstrated that younger male patients

may present with more severe CT findings of diverticulitis than femalepatients.62 Recent data suggest that men have a higher incidence of

diverticular bleeding, whereas obstructions are more common among

women.63

Geographic Factors. Geographic location also appears to play an

important role in the incidence of diverticulitis. Diverticulitis appears to

be much less common in Asian populations.41 When diverticulitis does

occur, it tends to involve the right-sided colon in contrast to the sigmoid

colon as is common in Western populations.56

There is a clear relation-ship between increasing industrialization and incidence of this disease.

Several studies have documented the low prevalence of the disease in

African nations.64-66 Other authors have noted increased rates of diver-

ticulitis in Africans with increased penetration of Western lifestyle

patterns.67 Reports from both Japan and Singapore have reported in-



11/56

creases in prevalence approaching 20%. This is thought to be due to the

increased acceptance of Western diets.68,69

Physical Activity.Two studies have examined the effect of exercise on

the development of diverticular disease.70,71 The risk of developing

diverticular disease and levels of physical activity appear to be inverselyrelated. This difference persisted even when the authors adjusted differ-

ences in dietary fiber intake. A potential drawback of the study is that the

differences may have arisen from the fact that ability to exercise mighthave been impaired or prohibited by symptoms of diverticular disease.70

Smoking. The potential association between diverticular disease andsmoking is contradictory. One large case-control study demonstrated that

smokers had 3 times the risk of developing complications from divertic-

ular disease than did nonsmokers.72 Another large cohort study of 46,000

men in the USA failed to show a similar association.71

Nonsteroidal Anti-Inflammatory Agents. The use of nonsteroidalanti-inflammatory agents (NSAIDs) has been associated with the devel-

opment of multiple gastrointestinal complications. Evidence suggests that

chronic NSAID use is almost twice as common in patients with diverticulardisease as healthy controls with no known colonic disease.73,74 While the

health professionals follow-up study showed an increased incidence ofuncomplicated diverticular disease in patients who used NSAIDs compared

with their asymptomatic counterparts, additional studies have noted an

increased risk of complicated diverticulitis with NSAID use.75 A retro-

spective study by Corder demonstrated a 23% higher risk of perforating

diverticulitis in patients who took NSAIDs regularly compared withpatients with diverticular disease who did not take NSAIDs.76 An

additional study of hospitalized patients demonstrated chronic NSAID

use to be much higher in patients admitted with diverticular disease thanthe population as a whole. In addition these patients were 4 times more

likely to develop perforated diverticulitis than patients with no history ofNSAID use.77

Caffeine Ingestion.Caffeine intake has been investigated as a possible

contributing factor to the development of diverticular disease as caffeinestimulates small bowel secretion and may also affect colonic transit

time.78 When caffeine consumption was evaluated in groups of patients

with and without diverticular disease, no difference was identified.71Obesity.Several retrospective case series have noted a striking prepon-

derance of obese patients with diverticulitis, particularly patients underthe age of 40.58,79,80 In addition, 2 prospective cohort studies (the Health

Professionals Follow-up Study and a Swedish study) have shown anassociation between body mass index (BMI) and diverticular dis-



12/56

ease.71,81,82 The USA Health Professionals study has shown an increased

risk of diverticulitis and diverticular bleeding not only with increasingBMI, but also waist circumference and waist-to-hip ratio.81 Obesity has

been linked not only to inflammation but also to differences in the

intestinal flora, which may be potential mechanisms for the increased riskof diverticulitis.83-85

Development of SymptomsAlthough most patients with diverticulosis remain asymptomatic, ap-

proximately 10% to 25% of patients develop symptoms ranging frommild abdominal pain to peritonitis and signs of sepsis. The pathophysio-

logic factors underlying the differential presentations of this disease are

unknown. Several authors have proposed that the development ofsymptoms involves several inter-related processes including muscular

dysfunction, inflammation, and visceral hypersensitivity.86-88

The degree of inflammation present with diverticulitis is variable and

has been difficult to correlate with symptoms. Horgan and colleagues

retrospectively reviewed 47 patients who underwent resection for diver-ticular disease.89 They reported a syndrome of smoldering diverticulitis

that occurred in patients with chronic left lower quadrant pain but did nothave associated fever or leukocytosis. Seven patients had previously

undetected pericolic abscesses and 76% had evidence of acute and

chronic mucosal inflammation. More than three quarters of patients hadresolution of symptoms after resection. There was no correlation between

the extent of resection, the duration of symptoms, and the preoperativeendoscopic evidence of inflammation. Similarly, Morson found no

evidence of colonic inflammation in one third of patients who had

resection for diverticular disease.48 Although some patients may haveresolved the inflammatory change before elective resection, this finding

suggests a weak correlation at best between the degree of inflammationand symptoms in diverticular disease.

Inflammation. Inflammatory change associated with diverticulitis is

most often termed acute diverticulitis, describing systemic symptomsassociated with peritoneal inflammation including left lower quadrant

pain, fever, and leukocytosis. Luminal mucosal inflammation may also be

associated with colonic diverticula and have some features of inflamma-tory bowel disease.90 This entity has also been called segmental colitis,

sigmoiditis, and diverticular colitis.91-93 The clinical significance of thisentity is not known and the incidence is low; the finding has been noted

in 0.25% to 1.5% of colonoscopies performed.90,94 However, due to lackof an established definition and variation in reporting, the exact clinical



13/56

course of diverticular colitis is difficult to determine. It has been

suggested that diverticular-associated colitis is a distinct entity, althoughthe clinical manifestations overlap inflammatory bowel disease.95

Visceral Hypersensitivity and Post InflammatoryNeuronal Damage

Persistent colonic symptoms, especially abdominal pain, have been

reported after resolution of infectious enteritis and inflammatory bowel

disease and may also occur after resolution of an episode of acutediverticulitis. It has been suggested that the sharp pain represents visceral

hypersensitivity of excessive perception or an excessive afferent responseto stimuli.87 The pain appears to be related temporally to contractions in

the sigmoid colon and has been noted in patients with symptomatic

disease. This type of pain has not been observed in patients withotherwise asymptomatic diverticulosis.33,96,97 Thus, persistent symptoms

after resolution of an episode of diverticulitis may represent visceral

hypersensitivity and not ongoing inflammation.Patients with acute diverticulitis have also been noted to have increased

nerve staining in the muscularis propria compared with control patients,in addition to increased staining in the mucosa and submucosa.86 The

neurons are of smaller diameter, suggesting proliferation in response to

inflammation. Nerve damage in patients who have had diverticulitis hasbeen documented and it is postulated that this may represent regeneration

and hyperinnervation and contribute to ongoing symptoms.86,98,99 Pa-tients with diverticular disease have been shown to have increased

neuropeptides in mucosal biopsies, which may also represent prior

inflammation.

100

Clinical Manifestations of Diverticular DiseaseThere are 3 main clinical presentations of diverticular disease (Table 1).

The most common clinical presentation of diverticulitis is left-sided

abdominal pain with or without an associated mass, fever, and leukocy-tosis. Patients generally resolve the acute episode after treatment with

antibiotics. Another manifestation is smoldering disease that only par-

tially improves with antibiotics and medical therapy. Such patients haverecurrent symptoms that can manifest with ongoing low grade fever and

left-sided abdominal pain. CT scans on such patients generally willdemonstrate a persistent phlegmon and these patients require resection for

ongoing symptoms. Many patients present with associated obstruction,

abscess, fistula, or perforation. The approach to these patients is discussed



14/56

in the section on complicated diverticular disease. Finally, a small groupof patients may have atypical presentations for diverticulitis. These

patients may have chronic left lower quadrant pain and diverticulosis but

lack objective evidence of diverticulitis such as fever leukocytosis orobjective findings on CT scan. There is considerable overlap with irritable

bowel syndrome in this group of patients, who are challenging both todiagnose and to manage.

Clinical Symptoms and Physical ExamThe clinical presentation of diverticular disease is dependent on the

extent of the disease process. Patients with acute diverticulitis typically

present with left-sided abdominal pain, fever, and leukocytosis. With asignificant phlegmon or abscess, an abdominal mass may be appreciated

on rectal or pelvic examination. The tenderness is often associated with

some degree of abdominal distention or signs of ileus. Patients with aredundant sigmoid colon may have predominant right-sided tenderness.

Free perforation is associated with diffuse abdominal pain and sometimesreferred pain in the shoulder. Patients often describe changes in their

bowel habits such as diarrhea or an alteration in stool caliber. Rectal

bleeding is uncommon and, if present, is more consistent with ischemiccolitis or inflammatory bowel disease than diverticulitis. Nausea and

vomiting may be seen with associated small or large bowel obstruction.

Patients with fistulas may have minimal abdominal complaints and maypresent initially to a urologist or gynecologist. Patients who develop

complications of diverticular disease such as colovesical fistulas maypresent with pneumaturia, pyuria, or fecaluria, whereas patients with

colovaginal fistulas may present with vaginal discharge, vaginal air, or

stool per vagina.

TABLE 1. Typical presentation patterns of diverticulitis

Acute diverticulitis

Typical, relapsing (chronic)

SubacuteComplicated diverticulitis

Obstruction

Mass/abscess

Fistula

Hemorrhage

Perforation

Chronic diverticulitis

Atypical

Atypical site (transverse, ascending)



15/56

A number of patients with chronic diverticular disease will present

with pain as their predominant symptom in the absence of other physicalfindings. The pain is typically persistent and boring, remaining constant

over long periods. It does not tend to be crampy in nature as in patients

with irritable bowel syndrome, but is difficult to distinguish from thisentity. These patients have diverticulosis on contrast examination or CT

scans but seldom have features of obstruction, perforation, stricture, or

abscess formation. Most authors have suggested that these patients shouldhave symptoms for 6 months before meriting a resection.89

Differential DiagnosisThe differential diagnosis for patients with suspected diverticular

disease includes appendicitis, bowel obstruction, colorectal cancer, gyne-cologic disease, inflammatory bowel disease (especially Crohns disease),

irritable bowel syndrome, ischemic colitis, and pyelonephritis. Other

diagnoses that should be entertained depending on the clinical scenarioinclude tubo-ovarian abscess, pelvic inflammatory disease, ureteral cal-

culi, volvulus, stercoral ulcer, ovarian torsion, and endometriosis. Modern

cross-sectional imaging is often helpful in diagnosing many of theseclinical entities. The most important diagnosis to exclude on initial

presentation is colorectal cancer. CT scanning confirms a diagnosis ofdiverticular disease but is also helpful in excluding other intra-abdominal

clinical entities.

Uncomplicated Disease

Laboratory and Diagnostic Imaging

Most patients with acute diverticulitis have an elevated white blood cellcount. Patients with a colovesical fistula may have an abnormal urinalysis

and/or culture. Polymicrobial urine cultures are common.Although several different modalities have been used to evaluate

patients with suspected diverticular disease, CT has emerged as the study

of choice. Flat and upright plain films of the abdomen are commonlyobtained in the evaluation of the patient with acute abdominal pain to

exclude obstruction or free intraperitoneal air. In patients with diverticular

disease the findings of plain films tend to be nonspecific.101Contrast enemas are seldom currently used in the evaluation and

management of diverticulitis. Findings suggestive of diverticulitis oncontrast enema studies include diverticula, fold thickening, spasm,

intramural sinus tract, tethering of the colon wall, and extravasation ofcontrast. Well-performed barium studies are able to distinguish fine



16/56

mucosal detail and can demonstrate muscular rigidity as well as tubular-

ization of the lumen. Water-soluble contrast studies can be of particularutility in acute settings in which there is a potential need for urgent

surgery or a possible perforation is suspected. Barium administration

under these circumstances is relatively contraindicated.102 In patients whopresent with obstipation, water-soluble contrast can assist in relieving a

partial obstruction.In specialized settings, ultrasound has been demonstrated to be an

effective test in the diagnosis of acute diverticulitis. Mural thickening,

extraluminal air, pericolic abscess, and hyperechogenic fat were findingsthat were suggestive of the diagnosis.103 Ultrasound has not gained wide

acceptance in the USA.The most widely available and accurate examination of patients with

acute abdominal pain is the abdominal CT. Advantages of CT scanning

include the ability to make an accurate diagnosis and stage the severity ofdisease, and the therapeutic ability to drain an abscess with CT guidance.

Disadvantages of CT scan include radiation exposure and the cost of the

examinations. For evaluation of acute diverticulitis, CT has an additionalbenefit since it assesses the extraluminal findings, the predominant

findings in acute diverticulitis. CT findings consistent with diverticulitiswere first described more than 25 years ago. These signs included thepresence of diverticula, pericolic fat stranding, colonic wall thickening

more than 4 mm, and abscess formation.104 CT has the added advantage

of detecting other intraperitoneal findings, including hepatic abscesses,

pyelophlebitis, small bowel obstruction, colonic strictures/obstruction,and colovesical fistulas.

Ambrosetti and colleagues first proposed a system for classifying the

severity of diverticulitis on CT findings to guide clinical management.CT findings consistent with mild diverticulitis included localized wall

thickening (5 mm) and inflammation of the pericolic fat. Severe CTfindings were the combination of localized wall thickening and

inflammation of the pericolic fat with abscess, extraluminal air, or

extraluminal contrast (Table 2). Patients with severe CT findingsunderwent operative intervention more frequently than those patients

with mild findings (33% vs 15%). Patients younger than 50 years of

age with severe findings on CT scan were also more likely to haverecurrences or complications.105

These early findings have been evaluated prospectively and confirmedin a cohort of 502 patients. Compared with patients with mild diverticu-

litis, patients with findings of severe diverticulitis on CT scan were morelikely to have recurrent attacks of diverticulitis after an initial attack of



17/56

acute diverticulitis treated with antibiotics (39% vs 14%). In this cohort

of patients, CT was preferable to contrast enema in the diagnosis and

management of acute diverticulitis.106 Poletti and colleagues explored CTand demographic predictors for nonoperative treatment failure in 312

patients with a first episode of left-sided diverticulitis and concluded that

the presence of an abscess or extraluminal air more than 5 mm in diameterwere significant predictors of treatment failure.107

CT findings that are relevant to clinical management were reclassifiedinto a classification system based on the Hinchey classification system

(Table 3). In Grade 0 there is colonic wall thickening but not pericolonic

fat stranding. Grade 1a consists of wall thickening and pericolonic fatstranding, while Grade 1b includes a pericolonic or mesocolic abscess.

Patients with Grade 2 disease have distant intra-abdominal or pelvicabscesses. Patients with Grade 3 and Grade 4 disease have purulent and

fecal peritonitis, respectively. CT is somewhat limited in distinguishing

between patients with Grade 3 and Grade 4 disease since purulent andfecal peritonitis often cannot be distinguished on imaging108 (Figs 3-5).

Although the study power was limited, Kaiser and colleagues found that

disease severity using the modified CT Hinchey classification systemcorrelated with postoperative morbidity and mortality. They also found

that the CT stage correlated with recurrence when patients were managednonoperatively. The presence of a diverticulitis-associated abscess was

1 particular factor that was highly associated with high risk of failure of

nonoperative management. These authors suggested that patients who

TABLE 2. Ambrosetti CT criteria for diverticulitis severity137

Mild diverticulitis Wall thickening (5 mm)

Pericolic fat stranding

Severe diverticulitis Wall thickening (5 mm)Pericolic fat stranding with

Abscess

Extraluminal air

Extraluminal contrast

TABLE 3. Modified Hinchey classification system146

Stage 0 Mild clinical diverticulitis

Stage Ia Confined pericolic inflammation---phlegmonStage Ib Confined pericolic abscess (within sigmoid mesocolon)

Stage II Pelvic, distant intra-abdominal or intraperitoneal abscess

Stage III Generalized purulent peritonitis

Stage IV Fecal peritonitis



18/56

were admitted with a diverticular abscess should receive strong consid-

eration of an elective resection.109

Endoscopic procedures (flexible sigmoidoscopy and colonoscopy) aregenerally not advocated during an acute episode of diverticulitis. A delay of

6 weeks following resolution of symptoms is recommended. This

approach is encouraged to avoid potential conversion of a sealedmicroperforation into a free perforation.110 This approach has been

questioned by other groups who have demonstrated that colonoscopyduring an acute episode of diverticutlitis can be safe. Even when optical

examination of the colon is performed in the acute setting, a substantial

number of the procedures cannot be completed.110,111

Cytoscopy or cystography has been used to identify suspected colovesi-

cal fistulas. In the CT scan era, however, the presence of air in the urinarybladder in the absence of instrumentation is considered diagnostic.112

Treatment of Uncomplicated DiverticulitisMedical Treatment

Antibiotics.The mainstay of therapy for management of uncomplicated

diverticulitis is antibiotic therapy. Despite the broad application ofantibiotics in the operative and nonoperative therapy of diverticulitis,

FIG 3.Modified Hinchey stage Ia diverticulitis. Arrow points to pericolic inflammation and phlegmon.



19/56

there have been few studies examining the optimal administration of these

agents.113 Diverticula are thin-walled structures that are thought toperforate and spill intracolonic contents and bacteria into the surrounding

tissue. Thus, the microflora associated with diverticular disease includethe normal colonic flora such as gram-negative rods, gram-positive rods,

and anaerobic bacteria. The anaerobic bacteria are far more common and

outnumber the aerobic 1000:1.114 When the microbiological profiles of

patients with perforated diverticultis were reviewed, 75% of specimens

were polymicrobial: 71% of patients cultured E. coli,10% of patients had

Group D Streptococcus (Enterococcus), and 50% of the specimensisolated Bacteroides fragilis.26

Patients with minimal systemic symptoms and mild signs of peritonealirritation can typically be treated as outpatients. Patients receive broad

spectrum antibiotics for 7 to 14 days. Despite their common use, there arefew data regarding the optimal length of treatment with antibiotics.

FIG 4.Modified Hinchey stage II diverticulitis. Arrow points to pelvic abscess.



20/56

Patients who present with fever, systemic symptoms, or inability to

tolerate oral intake are usually hospitalized. Parenteral antibiotics are

typically administered until the acute symptoms resolve. Once there isclinical improvement, the antibiotic route is changed to oral adminis-

tration.There are several single and combination antibiotic regimens for the

management of acute diverticulitis. All the regimens have activity against

the colonic flora; however, little is known about their efficacy.114 Kellumand colleagues randomized 51 patients to a regimen of cefoxitin alone

versus gentamicin/clindamycin. Patients in need of an urgent operation

were excluded. These authors concluded that the single-agent regimenexhibited similar efficacy to the 2-agent regimen. They recommended the

use of cefoxitin since this was cost-effective.115

The American College of Gastroenterology guidelines for the treatment

of diverticulitis include cefoxitin or ampicillin/sulbactam as single agents,or a third-generation cephalosporin, aminoglycoside, or monobactam in

FIG 5. (A) Modified Hinchey stage III diverticulitis. Arrow points to free fluid. (B) Modified Hincheystage III diverticulitis. Arrow points to free air. (C) Modified Hinchey stage III diverticulitis.Demonstrates intra-abdominal free fluid. (D) Modified Hinchey stage III diverticulitis. Arrow points topelvic fluid.



21/56

combination with an antianaerobic agent.116 The American Society of

Colon and Rectal Surgeons published their practice parameters for themanagement of diverticulitis in 2006. They recommended that antibiotic

therapy be selected to provide adequate coverage of the most common

colonic organisms. The authors maintained that single and combinationregimens were equally effective. Even with appropriate antibiotic ther-

apy, approximately one third of patients will have a recurrence.17

Diet. A high fiber diet increases the bulkiness of stools, decreases

colonic transit time, and therefore decreases intraluminal pressures.40 The

optimal amount of daily fiber is unknown; however, 20 to 30 g is a widelyrecommended figure. Recent evidence supports the notion that individuals

with diets high in fiber have decreased rates of diverticulosis and bear a

lower risk of developing diverticulitis.45-47

Emerging Medical Therapies

Mesalamine.There has been increased interest in the use of immuno-modulatory agents in the management of diverticular disease. 5-ASA

compounds and sulfazalazine are widely used in the management of

inflammatory bowel disease. 5-ASA products alter DNA synthesis andcell cycle progression in lymphocytes. 5-ASA compounds are also

thought to suppress leukotriene and prostaglandin synthesis, as well asdecrease leukocyte adhesion, thus reducing proinflammatory states.117,118

Because a low-grade proinflammatory state is the proposed mechanismunderlying chronic diveriticular disease, a number of small trials have

evaluated the effectiveness of mesalamine-like compounds. In virtually

all of these studies the outcome of interest was symptom severity andchange in bowel habits. In the original description of the use of

mesalamine for the management of diverticulitis, Trespi and colleagues

demonstrated that patients treated with rifaximin, ampicillin/sulbactam,and mesalamine had decreased symtomatology and were less likely to

experience microhemorrhagic phenomenon.119

Another study randomized patients with at least 2 episodes of acute

diverticulitis to a rifaximin-only arm versus a rifaximin/mesalamine arm.

Patients in the rifaximin/mesalamine arm demonstrated significantlyimproved bowel habits, episodes of recurrence, and symptom severity.120

In another study, mesalamine alone was compared with rifaximin alone.

Although there were only 170 patients in the study, the authors compared11 outcome variables including nausea, emesis, dysuria, general illness,

fever, abdominal tenderness, diarrhea, tenesmus, bloating, and abdominalpain/discomfort. Patients treated with mesalamine had statistically signif-

icant lower global score than patients treated with rifaximin alone. Theseauthors concluded that mesalamine is an effective medication for pre-



22/56

venting recurrence of diverticulitis and maintaining remission.121 Other

authors have demonstrated that daily treatment with mesalamine is moreeffective than cyclic treament.122

In a systematic review of 818 patients in 6 randomized trials of 5-ASA

products in the treatment of diverticulitis, patients treated with 5-ASAproducts had better outcomes than those not treated with 5-ASA. They

also concluded, however, that larger trials which had objective confirma-

tion of the diagnosis by endoscopy are needed for confirmation of theinitial data on this type of treatment.123

Probiotics.Probiotics are defined as preparations of naturally occurringcolonic microflora that can exert a beneficial health effect on the host

organism. Patients with diverticular disease are thought to have altered

colonic microflora due to constipation and stasis of fecal matter.124

Administration of these preparations is thought to restore healthy colonic

microflora.Giaccari and colleagues examined the administration of rifaximin

followed by Lactobacillus for 12 months in 79 patients with diverticular

disease. They reported no new complications and adequate symptomcontrol. They concluded that the combination of rifaximin and lactoba-

cillus was an adequate regimen for prophylaxis against the complicationsof diverticular disease.125 In a smaller study (15 patients), investigators

compared administration of nonpathogenicE. coliwith active coal tablets

to coal tablets alone. These authors concluded that the length of remissionwas significantly longer when a probiotic was administered (14 vs 2.4

months).126 Although the initial results are promising, there are only asmall amount of data supporting the use of probiotics and larger,

preferably randomized, trials are needed to confirm the initial results.

Follow-Up After Successful Medical Treatment. Examination of thecolon following a presumed attack of diverticulitis should be carried out

to exclude the presence of malignancy or Crohns disease. Some authorshave demonstrated that CT findings on the patients initial CT scan can be

used to assist in differentiating diverticulitis from a malignancy. Fluid at

the base of the mesentery and vascular engorgement were found to behighly specific for the diagnosis of diverticulitis.127 Chintapalli and

colleagues retrospectively examined the CT scans of patients with known

cancer or diverticulitis. This group determined that enlarged lymph nodeswere observed more frequently in the patients with colorectal cancer

(71% vs 15%).128 In more recent data, other groups have compared theperfusion characteristics of patients with colorectal cancer to those with

diverticular disease. Patients with colorectal cancer tended to have higherblood volume, transit time, and permeability in comparison with patients



23/56

with diverticulitis. This study also confirmed that patients with colorectal

cancer have more pericolonic nodes.129

Optical colonoscopy or flexible sigmoidoscopy combined with contrast

enema are the preferred methods of examining the colon following an

attack of diverticulitis. The American Society of Colon and RectalSurgeons published practice parameters for the management of sigmoid

diverticulitis in 2006.17 The society did not specifically recommend anyspecific time delay for these studies following an attack. Other authors

recommend a delay of 6 weeks following resolution of symptoms. This

approach is encouraged to avoid potential conversion of a sealedmicroperforation into a free perforation.110

Indications for Elective Surgical Management. Until recently, theindications for surgical management of diverticulitis were straightfor-

ward. The goals of surgery for diverticulitis are to resect the sigmoid

colon, restore intestinal continuity, and minimize the chance of anasto-motic complications and recurrent diverticulitis. Elective resection was

advocated after 2 well-documented attacks of uncomplicated diverticulitis

requiring hospitalization, and/or after 1 episode of complicated diverticulitis.In patients younger than 40 years of age, elective resection was recom-

mended after the first attack of complicated or uncomplicated diverticulitissince the disease was generally considered more aggressive in young patients.

These guidelines were endorsed by a number of societies including the

American Society of Colon and Rectal Surgeons, the Society for Surgery ofthe Alimentary Tract, the European Association for Endoscopic Surgery, and

the American College of Gastroenterology.116,130-132

Recently, several of these recommendations have been challenged.

Salem and Flum suggested that waiting until the fourth attack of

uncomplicated diverticular disease would be associated with fewer deathsand fewer intestinal stomas.133 Another decision analysis concluded that

elective resection after the third attack would be more cost-effective.134

Furthermore, a number of large reviews have suggested that the common

practice of operating after the second episode of diverticulitis should be

reconsidered.20,135

The guidelines for surgery have been revised and the American Society

of Colon and Rectal Surgeons currently states that the number of attacks

of uncomplicated diverticulitis is not necessarily an overriding factor indefining the appropriateness of surgery.17 Recommendations should be

influenced by the age and medical condition of the patient, the severityand frequency of the attacks, and the presence of ongoing symptoms.

Furthermore, most patients who present with complicated diverticulitiswill have complicated disease on the first attack; resection after recovery



24/56

from uncomplicated diverticulitis does not prevent the development of

complicated diverticulitis.135,136 Thus, the indications for elective sig-moid resection are determined by the severity of disease, the risk of

subsequent attacks of diverticulitis, and complications of the disease in

addition to the age and other comorbidities of the patient.

Young Patients. Previous recommendations have advocated sigmoid

resection for young patients after 1 well-established attack of diverticu-

litis;132 however, this dictum has been called into question by recent

evidence. The management of young patients with diverticulitis remains

controversial. Several authors have proposed that patients younger than40 to 50 years of age present with a more virulent form of diverticuli-

tis.137 Although younger men are proposed to have severe diverticulitismore often than older men, they required operative intervention less

frequently.105 Other authors have challenged this view, pointing out that

younger patients did not have different rates of conservative management,emergency operation, or mortality.133 In a recent series, patients younger

that 50 years of age were found to present more frequently with evidence

of severe disease on abdominal CT. It is unclear how this fact translatesinto their ultimate clinical outcome.62

Although there is some evidence that young patients present with amore virulent form of the disease, it is not clear that these patients will go

on to have a recurrence. In a study by Guzzo and Hyman, 1 patient out of

196 young patients (50 years) had a free perforation after medicalmanagement of diverticulitis. The median follow-up was 60 months.

Given the current level of evidence, there is no clear mandate to treatyoung patients with diverticulitis differently from other age groups.138

Several series have noted an increasing percentage of young patients

with diverticulitis. Young patients with diverticulitis have comprised 18%to 34% of recent series62,138-141 compared with 1.3% to 8.2% of patients

in older series.142,143

With the ability of CT scanning to stratify patients with mild or more

severe diverticulitis, several studies have noted that young patients have

more severe disease compared with other cohorts. Chautems and col-leagues compared patients younger than 50 and over the age of 50 with

mild and severe disease. Mild disease was defined as mild inflammatory

change on CT scanning and severe disease was defined as associationwith microperforation, etc. There were 28 patients younger than 50 and

50% had mild disease and 50% had severe disease. Over the age of 50, 74patients had mild disease and 16 patients had severe disease. The risk of

a poor outcome (generally defined as the need for operative intervention)

was 54% in young patients with severe disease and 44% in patients over



25/56

the age of 50 with severe disease. Thus, although the risk of poor outcomewith severe disease in young patients was relatively equivalent to older

patients with severe disease, a higher percentage of young patients had

evidence of severe disease.136 In a review of 932 patients, Hall andcolleagues noted similar findings. Young patients were more likely to

present with evidence of severe disease on CT scan than older patients

(19.3% vs 11.5%).62

The dictum that diverticulitis in young patients has a more virulent

course has been challenged. Vignati and colleagues noted that youngerpatients with diverticulitis had an identical clinical course compared with

older patients.144 In another review of 196 young patients followed for amedian of 60 months, only 1 patient presented with free perforation after

initial medical management of acute diverticulitis. Salem and Flum have

noted that younger patients had no different rates of conservativemanagement, need for emergency operation, or mortality.133

Complicated Diverticular DiseaseComplicated diverticulitis generally refers to diverticulitis associ-

ated with perforation, fistula, abscess, stricture, or obstruction. Diver-ticular bleeding is associated with diverticulosis and not diverticulitis.

In an effort to be able to compare different groups of patients with

perforation/abscess, the Hinchey classification has been used and isdivided into stages I to IV.145 Stage I is diverticulitis associated with

pericolic abscess; stage II is a more distant abscess such as a pelvic orretroperitoneal abscess. Stage III is purulent peritonitis, and stage IV

is fecal peritonitis. Modifications of the Hinchey classification have

been made by Warsavary and colleagues146 (Table 3) and used byothers,109 but the original Hinchey classification remains the most

common classification system used (Table 4). Other scoring systems

such as the Mannheim Peritonitis Index and the colorectal (Cr)-POSSUM (the colorectal physiological and operative severity score

for the enumeration of mortality and morbidity) may be better tools toassess operative risk in the future.147,148

Management of complicated diverticular disease is dependent on theparticular presentation of the disease. Treatment of the complications of

TABLE 4. Hinchey classification system145

Stage I Pericolic or mesenteric abscess

Stage II Pelvic or retroperitoneal abscess

Stage III Purulent peritonitisStage IV Feculent peritonitis



26/56

diverticulitis may range from treatment with bowel rest and parenteral

antibiotics to emergent exploratory laparotomy. We review the treatment

options for each of the complications of diverticulitis separately.

Diverticular AbscessDiverticular abscess occurs in approximately 15% of patients with acute

diverticulitis. Abscesses include pericolic, pelvic, and retroperitoneal

abscesses. In women, involvement of the left ovary may result intubo-ovarian abscesses.149 Data from the Nationwide Inpatient Sample,

the largest source of all-payer hospital discharge information in the USA,

suggests an increase in the number of patients with diverticular abscess inthe last decade24 (Fig 6). This may be due to the widespread use of CT

scanning since previously patients were often treated empirically withantibiotics and small abscesses may not have been detected. Furthermore,

CT scanning on initial presentation may also lead to increased detection

of small fluid collections associated with diverticulitis, which may notnecessarily be abscesses.

In patients with diverticulitis and an associated abscess, the goal has

previously been to treat the inflammatory process and ideally to operateon an elective basis when the risk of infectious complications is

substantially lower, therefore optimizing the ability to safely perform aresection and anastomosis. The management of diverticular abscess

changed in 1986 with the report of Saini and colleagues, who reported

percutaneous drainage of diverticular abscess followed by a single-stage

FIG 6.Proportion of patient discharges for diverticular abscess among all patients with diverticulitisin Nationwide Inpatient Sample from 1991 to 2005. (Reprinted with permission from Ricciardi etal.24)



27/56

resection in 7 of 8 patients.150 The surgical dictum has been to ultimately

perform resection on all patients after percutaneous drainage since morethan 40% will develop recurrent sepsis.109 However, reports of patients

who have undergone percutaneous or operative drainage with no further

septic sequelae have called this practice into question. Franklin andcolleagues reported on 18 patients who underwent laparoscopic drainage

of Hinchey II abscess and, at a follow-up of 4 to 34 months, 15 remained

asymptomatic without the need to undergo resection.151

The debate about the management of diverticular abscesses centers on

determining which patients can be treated with antibiotics alone, whichpatients require percutaneous drainage, and which patients require urgent

or emergent surgery. CT scanning has been the mainstay of diagnosis of

intra-abdominal abscess and also allows for exclusion of other causes ofacute abdominal pain. For patients with mild diverticulitis or confined

pericolic inflammation (phlegmon), there is general consensus that bowelrest and antibiotics are generally effective. Similarly, there is general

consensus that patients with perforated diverticulitis manifested by

purulent peritonitis or feculent peritonitis require operative intervention. Themanagement strategy for patients with pericolic or pelvic abscesses is less

well-defined. By definition, these patients have more severe diverticulitiswith a mortality rate of 5% to 10% and a higher rate of emergency surgery(up to 25%).152 Additional considerations include the success of percutane-ous drainage, the ability to access the abscess, the failure rate and potential

complications of percutaneous drainage, and the ultimate outcome. Assessing

outcome should include a reasonable follow-up period with assessment ofability to perform a resection and primary anastomosis in patients resected

and risk of recurrent sepsis in those patients who are observed.

The initial approach to patients with diverticular abscess includes bowelrest, antibiotics, and close observation. Several possible antibiotic regi-

mens may be employed. Antibiotics are targeted to cover gastrointestinalflora. Small abscesses, particularly in a stable patient without signs of

systemic sepsis, do not require percutaneous drainage. In several reports,

small abscesses (which were defined as those between 2 and 4 cm) oftenresolve with intravenous antibiotics alone without the need for operative

or percutaneous drainage.17,153-155 For those patients with diverticular

abscess who continue with signs of sepsis (fever, abdominal pain, andleukocytosis), percutaneous drainage is preferred. A recent review sug-

gested that 20% to 30% of diverticular abscesses were amenable topercutaneous drainage and the failure rate of percutaneous drainage was

20% to 30%.155 The preferred approach for percutaneous drainage isusually by a transabdominal route with care to avoid the inferior



28/56

epigastric or deep circumflex iliac vessels156 (Fig 7). If the abscess is not

accessible by this route, a transgluteal, transperineal, transvaginal, or

transrectal route may be employed. Transabdominal compared withtransgluteal or transperineal drains tend to be better tolerated in terms of

patient comfort. The success rate with simple unilocular abscesses is upto 80%, whereas more complex abscesses associated with loculations,

fistula, or whose drainage route transverses normal organs are associated

with a higher failure rate.156 The expertise and skill of the interventional

radiologist is also associated with a higher success rate.

The location of abscess influences the chance of success with antibioticsand/or percutaneous drainage. In general, mesocolic or pericolic abscesses

have a better prognosis than pelvic or retroperitoneal abscesses.157,158

Pericolic abscesses may result from earlier disease and local inflammatorychanges with abscess formation in the mesentery, whereas pelvic ab-

scesses may result from larger perforation with the potential to extendfrom the mesentery to the surrounding pelvis and peritoneum. In a study

of 73 cases of diverticular abscess, 59% of cases eventually required

surgery, while 71% of patients with pelvic abscess required resection.157

Both size and location influence the success rate of percutaneous

drainage. One study suggested that the size of an abscess did not

determine the outcome and patients who were managed medically had anidentical outcome to those who underwent drainage159; however, most

studies suggest that abscesses of up to 4 cm can be optimally managed byantibiotics.149,153-155

The use of antibiotics alone versus percutaneous drainage andantibiotics was compared in 1 retrospective study of patients with

FIG 7.Pigtail catheter in a complex diverticular pelvic abscess.



29/56

diverticulitis and CT-confirmed abscesses.149 The outcome of patients

treated with antibiotics alone was equivalent to patients treated withdrainage and antibiotics. The failure rate of percutaneous drainage was

33%. Patients who underwent percutaneous drainage had larger

abscesses and the study was not randomized; however, more than 80%of patients with Hinchey stage II abscesses could be treated success-

fully with antibiotics.

In conclusion, approximately 15% of patients with diverticulitishave an associated pericolic or pelvic abscess. Antibiotics remain the

mainstay of treatment, with percutaneous drainage reserved for largerabscesses with a radiologic window. The decision for surgery should

be approached on a case-by-case basis. Diverticulitis associated with

abscess denotes more severe diverticulitis and a substantial number ofpatients require sigmoid resection. Although 40% to 50% of patients

admitted with diverticular abscesses respond to conservative treat-

ment, sigmoid resection is recommended for selected patients, partic-ularly those with more complex or larger abscesses and those with

recurrent or persistent symptoms.157 Ideally, elective surgery is

performed after initial treatment with antibiotics and/or percutaneous

drainage as indicated.

Perforated DiverticulitisApproximately 1% of patients with diverticulitis develop free perfora-

tion, which may include purulent or fecal peritonitis (Fig 1B). Free

perforation almost exclusively develops on the first attack of diverticulitisand is generally not seen in patients who have had multiple attacks of

diverticulitis. The mainstay of treatment for perforated diverticulitis over

the last several decades has been the Hartmann procedure, which resectsthe disease and eliminates the septic focus. A disadvantage of the

procedure is the requirement for a second major surgical procedure toreverse the colostomy and the attendant morbidity and potential mortality

of the procedure. Data from large administrative databases suggest that at

least one third of patients may never undergo reversal160 and up to 70%of patients older than 77 years may not undergo reversal.161 Women are

less likely than men to undergo Hartmann reversal.160,162 The develop-

ment of a scoring system may assist clinicians in identifying factorspredictive of colostomy reversal.163

There has been renewed interest in performing resection and primaryanastomosis in selected patients with Hinchey III and Hinchey IV

diverticulitis. Several systematic reviews and meta-analyses have sug-gested that primary anastomosis is superior to Hartmann resection for



30/56

patients with perforated diverticulitis; however, there is considerable

selection bias.133,164 In clinical practice, the decision to perform a

primary anastomosis should be made on a case-by-case basis. Severaltechnical and patient-related factors must be considered by the surgeon to

determine if the patient is a good candidate for a primary anastomosis.

Hemodynamic instability, diffuse peritonitis (either purulent or fecal),

ischemia, or significant edema of the bowel at an intended site of

anastomosis and anemia, malnutrition, and immunocompromised state

are general contraindications to a primary anastomosis.165 Although

discussed frequently in the literature, data from the Nationwide Inpatient

Sample have not shown any evidence that primary anastomosis is beingmore commonly used as the preferred procedure for patients who undergo

surgery for acute diverticulitis.23

Recently, alternatives to resection and definitive treatment with laparo-

scopic lavage have been reported. Based on a small series of successful

laparoscopic lavage for treatment of patients with perforated diverticulitis

with purulent peritonitis,166 a prospective multi-institutional study of 100

patients has been reported.9 Patients with perforated diverticulitis and

generalized peritonitis underwent laparoscopic lavage as definitive treat-ment. No effort was made to mobilize and resect the sigmoid colon. The

median age was 62.5 years with a follow-up of 36 months. Eight patients

were found to have fecal peritonitis and converted to an open procedure

and underwent resection. The remaining 92 patients were treated success-

fully with laparoscopic lavage with a 4% morbidity rate and a 3%

mortality rate. Two patients later required intervention for a pelvic

abscess and 2 patients presented with recurrent diverticulitis in the study

period. These data challenge our conventional surgical teaching andsuggest that selected patients with purulent peritonitis from diverticulitis

may be treated successfully with laparoscopic lavage without resection of

the affected segment of colon.

A subsequent review of 8 studies of 213 patients with acute complicated

diverticulitis managed by laparoscopic lavage has noted a 3% conversion

rate. Ten percent of patients had complications and, during a mean

follow-up of 38 months, 38% of patients underwent elective sigmoid

resection with primary anastomosis.8

In the future, this modality maybecome the preferred treatment for perforated peritonitis with associated

purulent peritonitis. Additional concerns include whether many of these

patients required any operative intervention or whether antibiotics, bowel

rest, and drainage by interventional radiology techniques would have

achieved the same outcome.



31/56

FistulasFistulas occur in 2% of patients with diverticular disease.1 The localized

inflammatory process develops into an abscess, which then decompresses

into adjacent viscera (Table 5). Patients who develop fistulas generally donot need emergent intervention as the abscess has decompressed; in fact,

many patients with fistulas may have few abdominal signs and symptoms.Colovesical fistulas are the most common (65%), followed by other types

of fistulas including colovaginal, coloenteric, colouterine, and colocuta-

neous fistulas.167-170

Colovesical Fistulas. Colovesical fistulas are more common in men

than in women. Women affected with a colovesical fistula have usuallyundergone a prior hysterectomy. Patients often present with prominent

urinary symptoms including polymicrobial urinary tract infections, pneu-

maturia, and fecaluria. CT scanning reveals air and/or contrast in thebladder in the absence of prior instrumentation (Fig 8). If performed,

cystoscopy shows inflammation generally at the dome of the bladder and,on occasion, vegetable material in the urine. Colovesical fistulas may also

be associated with locally advanced bladder or primary colon cancer, and

cystoscopy and colonoscopy may be more effective tests to excludemalignancy than CT scanning. Imaging is more helpful to determine the

etiology of a fistula than to document the fistula itself. The surgical

principles for treatment of colovesical fistulas due to diverticular diseaseinclude resection of the affected segment (generally the sigmoid colon)

and pinching off the fistula. The fistula is generally small and may besuture repaired. Ureteral stents are generally not needed. In some cases,

the precise site of the fistula cannot be determined, and pinching it off is

sufficient treatment; sutures are not absolutely necessary. A primary

TABLE 5. Diverticular fistulas

Coloappendiceal

Colocolonic

ColocutaneousColoenteric

Colouterine

Colovenous

Cologastric

Coloperineal

Coloperianal

Coloureteral

Colovaginal

Colovesical

Colovesicovaginal



32/56

anastomosis can usually be performed safely. Omentum is used to

interpose between the anastomosis and the bladder. On occasion, nonop-erative management is used for colovesical fistulas, especially if the

symptoms are minor and the patient has medical comorbidities conferringa significant operative risk. Suppressive antibiotics may be used to

ameliorate symptoms in such cases.171

Colovaginal Fistulas. Colovaginal fistulas occur almost exclusively inwomen who have undergone a prior hysterectomy (Fig 9). Signs and

symptoms include vaginal discharge and passage of air per vagina. Often,

women have seen a gynecologist initially for evaluation of vaginaldischarge. A single-stage sigmoid resection can generally be performed,

pinching off the site of the fistula and interposing omentum.

Colocutaneous Fistula. Colocutaneous fistulas rarely occur de novo

and are generally seen in patients who have undergone prior colectomy or

percutaneous drainage.172 Risk factors for the development of colocuta-

FIG 8.(A) Arrow points to colovesical fistula. (B) Inflamed sigmoid colon adjacent to fistula. (C) Airin noncatheterized bladder consistent with colovesical fistula.



33/56

neous fistula include unsuspected Crohns disease and anastomosis to the

distal sigmoid colon and not the proximal rectum.

Diverticular Stricture/Obstruction. Repeated attacks of diverticulitismay be associated with the development of a sigmoid stricture and

progressive obstructive symptoms. Less commonly, complete large bowelobstruction associated with diverticular disease develops (Fig 10). The

major differential diagnosis is with obstructing colon cancer. Although

large bowel obstruction is most commonly associated with obstructing

FIG 9.Colovaginal fistula. Arrow demonstrates vaginal filling with contrast from pericolonic abscess.

FIG 10. Large sigmoid phlegmon causing a large bowel obstruction. Arrow shows a retrogradeinjection of contrast within the rectum, which is unable to pass the obstruction.



34/56

colon cancer, approximately 10% of large bowel obstructions are attrib-

utable to diverticular disease.173 Colonic stricturing typically developsafter several recurrent attacks leading to fibrosis with the colonic wall.

Small bowel can also become adherent to a focus of inflamed colonic

tissue, leading to associated small bowel obstruction.The approach to management depends on whether the obstruction is

complete or partial. Patients with a partial obstruction that resolves with

bowel rest, intravenous hydration, and antibiotics may be able to undergoelective resection. In some patients, treating the acute inflammatory

phlegmon allows for resolution of the obstruction. Endoscopic or radio-logic evaluation can then be performed and elective resection planned.

For patients with complete obstruction, there are a number of surgical

options. In the past, persistence of obstruction after treatment withantibiotics typically required sigmoid resection, end colostomy, and

Hartmann closure of the rectum because of concern about the increased

risk of anastomotic leakage in patients who had dilated and edematousbowel or who were not able to undergo preoperative mechanical bowel

preparation. Although the Hartmann resection is still an excellent optionin selected patients, other options include sigmoid resection with primary

anastomosis and diverting proximal stoma (usually a loop ileostomy), ontable lavage and primary anastomosis, or colonic stent placement fol-lowed by semielective sigmoid resection.

On-table lavage is a technique that allows for cleansing of the fecal

laden, obstructed colon before potential anastomosis. The technique hasbeen described by Murray and colleagues174 and involves mobilization ofthe splenic flexure and at times the hepatic flexure. A Foley catheter

attached to warm irrigation fluid is introduced through the appendix. If

surgically absent, the catheter may be placed through a cecotomy orileostomy. Corrugated anesthesia tubing is placed through the distal colon

and secured with umbilical tape. The colon is lavaged until the returns areclear. The technique may be used in selected patients who are hemody-

namically stable and in whom there is minimal contamination. Although

the need for mechanical bowel preparation has been called into questionfor elective colon resection, this claim has not been critically evaluated in

patients with bowel obstruction.175 Lee and colleagues described the use

of on-table lavage and sigmoid resection with primary anastomosis in 33patients with diverticular disease who underwent nonelective resection.

There were no anastomotic leaks in this series, but there was a significant(18%) incidence of wound infection.176

Several authors have demonstrated that treatment of acute colonicobstruction with self-expanding metal stents is a viable option, particu-



35/56

larly in patients with obstructing colon cancer.177,178 Colonic stenting for

benign obstructions is associated with a high rate of stent migration aswell as other delayed complications. In a series of 104 procedures from

1 center, 8 patients had obstruction from a benign etiology.179 After

colonic stenting, many required reinterventions and only 3 patientsachieved a benefit from stenting. From a technical standpoint, stenting a

diverticular stricture which is potentially longer or more angulated may

be more difficult than stenting a short segment stricture from coloncancer. Colonic stenting in benign disease remains a controversial

procedure and should be embarked on with caution.180-182

Diverticular Hemorrhage.Diverticular hemorrhage is the most com-

mon form of lower gastrointestinal hemorrhage and is responsible for30% to 40% of episodes of lower gastrointestinal hemorrhage.183 It does

not typically occur in association with acute diverticulitis. Most divertic-

ular bleeding is typically painless but often manifests with signs andsymptoms of hemodynamic instability.

Diverticula represent herniation of the colonic wall at sites where vasa

recta penetrate the colonic wall. The vasa recta are subject to sheer forcesas they are draped over the diverticulum. This makes them susceptible to

disruption and bleeding. Inflammation does not play a role in this process.Because the right colon is thin walled, diverticular bleeding tends to occur

more frequently in the ascending colon.184

Blood loss can be massive in up to 20% patients presenting with

diverticular hemorrhage.185,186 All patients presenting with symptoms

suggestive of this diagnosis should have adequate intravenous access andhemodynamic monitoring. Patients should be fully resuscitated with

intravenous fluid and blood products if necessary.

Diagnostic evaluation begins with nasogastric tube lavage and bedsideproctoscopy. These maneuvers easily exclude upper gastrointestinal and

hemorrhoidal bleeding as potential sources. While resuscitation contin-ues, it is imperative to make attempts to localize the bleeding source.

Following a full mechanical bowel preparation, patients should be

evaluated with optical colonoscopy. Colonoscopy is the preferred initialtest because it can localize bleeding but also excludes other sources of

hemorrhage such as carcinoma. There are small case series describing

successful endoscopic intervention for the management of diverticularbleeding including injection of epinephrine, cautery, and placement of

clips.187-189

If colonoscopy has not successfully identified a bleeding site, a

technetium99-labeled red blood cell scan should be the next study. Thisnuclear medicine study has several advantages. If there is active bleeding,



36/56

then the nuclear scan will demonstrate extravasation of the radiolabeled

red blood cells into the lumen of the colon. One advantage of radiolabeled

red blood cells is that they circulate for 48 hours, allowing for repetitionof the scan if there are repeated bleeding episodes. In addition, this study

can detect bleeding at rates as low as 0.1 mL/min.190 Sulfur colloid canalso be labeled with technetium but has a very short half-life and therefore

is not useful for the detection of intermittent bleeding.

Mesenteric angiography involves the selective catheterization of the

superior and inferior mesenteric arteries and their tributaries. Extravasa-

tion of contrast in the lumen of the colon is diagnostic. Mesentericangiography can typically detect bleeding rates of 1 to 3 mL/min. If

bleeding is detected, the procedure is potentially therapeutic as coils or

foam can be injected in an attempt to thrombose the bleeding vessel andcontrol bleeding.191,192 A catheter can also be left in place for adminis-

tration of vasopressin or to assist the surgeon in identification of the

bleeding site.

Surgical intervention is seldom necessary as bleeding is self-limited ingreater than 80% of cases.193 Indications for surgical resection include

persistent transfusion requirements, hemodynamic instability, or recurrent

hemorrhage. If a bleeding site is localized, then segmental colectomy isthe preferred surgical procedure. It should be noted that even when

bleeding is localized preoperatively, segmental resection is associated

with a rebleeding rate of 14%.194 In patients in whom a bleeding site has

not been localized, subtotal colectomy is suggested; however, this isassociated with a high degree of morbidity and mortality.195,196

Operative Therapy

Elective ManagementOpen sigmoid resection is generally performed through a midline

incision. Preoperativemechanical bowel preparation is not necessary but

is often performed.175 Preoperative intravenous antibiotics are adminis-

tered. The sigmoid colon is mobilized and proximal and distal pointsselected for resection. The proximal resection margin should be in soft

pliable bowel and it is not necessary to resect all proximal diverticula. The

distal resection margin is the proximal rectum since anastomosis to thedistal sigmoid is associated with a higher risk of recurrent diverticuli-tis.197,198 It may be necessary to mobilize the splenic flexure to perform

a tension-free anastomosis; alternatively, rectal mobilization will also

afford additional length. One study suggested that an inframesentericdissection with preservation of the inferior mesenteric artery decreased



37/56

the incidence of anastomotic leak.199 A hand-sewn or stapled anastomosis

is performed. The anastomosis is most often performed with an end to endanastomosis stapler.

In cases of fistulas to the bladder or the vagina, the fistula may be simply

pinched off and a resection of bladder and/or vagina is not necessary.Once a fistula is pinched off, omentum can be used to interpose between

the bladder and/or vagina and the colon.

Ureteral stents are generally not necessary but may be used in selectedcases. Although they do not prevent ureteral injuries, they permit easy

recognition and repair of such injuries.200 A technique that may be helpfulin mobilization includes proximal to distal resection in which the colon

is divided proximal to the phlegmon with a linear stapler, and the colon

is dissected proximal to distal, rather than performing a lateral to medicaldissection.201 This technique may facilitate easier identification of the

ureter and avoid injury.Although the rectum is not primarily involved with diverticulitis,

inflammation of the proximal rectum may be encountered from the

diverticular phlegmon or from an associated pelvic abscess or diverticularperforation. In such cases, based on sound surgical judgment and specific

intraoperative factors, primary anastomosis potentially to the mid rectumwith proximal fecal diversion may be performed.

Minimally Invasive ColectomyThe advent of laparoscopic surgery has ushered in a new era in the

surgical management of diverticular disease. In the last decade, increasingnumbers of resections for diverticular disease have been performed

laparoscopically. Conventional laparoscopic techniques allow the surgeon

to perform all the major portions of the case, including the anastomosis,through small 5- or 12-mm trocars (Fig 9).

A commonly practiced technique involves the use of a hand-assistedtechnique. In this type of approach the surgeons hand is placed into the

abdomen through a small vertical lower midline or Pfannensteil incision

to assist in the mobilization of the colon. The dissection can be carried outin a medial to lateral or lateral to medial approach.

In the medial to lateral approach a plane is made below the inferior

mesenteric artery. The ureter, gonadal vessels, and other retroperitonealstructures are swept away. The inferior mesenteric artery is then divided

using a stapler or energy device. The sigmoid colon can then be mobilizedup to the level of the splenic flexure by sweeping down the attachments

of the left colonic mesocolon to Gerotas fascia and retroperitoneum. It

may be necessary to mobilize the splenic flexure to perform a tension-free



38/56

anastomosis and there is evidence that suggests that the incidence of

splenic injury is lower with a laparoscopic approach.202 Proximal and

distal resection margins can then be chosen. A hand-sewn or stapledanastomosis is performed. The anastomosis can be performed in intra-

corporeal fashion. Alte

Documents

Curr Pro Sur Enfe Divert