Print Close Window

Note: Large images and tables on this page may necessitate printing in landscape mode.

Copyright © The McGraw-Hill Companies. All rights reserved.

Schwartz's Principles of Surgery > Chapter 30. The Appendix >

KEY POINTS

1. Appendectomy for appendicitis is the most commonly performed emergency operation in

the world.

2. Despite the increased use of ultrasonography, computed tomographic scanning, and

laparoscopy, the rate of misdiagnosis of appendicitis has remained constant (15.3%), as has

the rate of appendiceal rupture. The percentage of misdiagnosed cases of appendicitis is

significantly higher among women than among men.

3. Appendicitis is a polymicrobial infection, with some series reporting up to 14 different

organisms cultured in patients with perforation. The principal organisms seen in the normal

appendix, in acute appendicitis, and in perforated appendicitis are Escherichia coli and

Bacteroides fragilis.

4. Antibiotic prophylaxis is effective in the prevention of postoperative wound infection and

intra-abdominal abscess. Antibiotic coverage is limited to 24 to 48 hours in cases of

nonperforated appendicitis. For perforated appendicitis, 7 to 10 days of treatment is

recommended.

5. Compared with younger patients, elderly patients with appendicitis often pose a more

difficult diagnostic problem because of the atypical presentation, expanded differential

diagnosis, and communication difficulty. These factors contribute to the disproportionately

high perforation rate seen in the elderly.

6. The overall incidence of fetal loss after appendectomy is 4% and the risk of early delivery

is 7%. Rates of fetal loss are considerably higher in women with complex appendicitis than in

those with negative appendectomy and those with simple appendicitis. Removing a normal

appendix is associated with a 4% risk of fetal loss and 10% risk of early delivery.

7. Recent data on appendiceal malignancies from the Surveillance, Epidemiology, and End

Results program identified mucinous adenocarcinoma as the most frequent histologic

diagnosis, followed by adenocarcinoma, carcinoid, goblet cell carcinoma, and signet-ring cell

carcinoma.

ANATOMY AND FUNCTION

The appendix first becomes visible in the eighth week of embryologic development as a

protuberance off the terminal portion of the cecum. During both antenatal and postnatal

development, the growth rate of the cecum exceeds that of the appendix, so that the

development, the growth rate of the cecum exceeds that of the appendix, so that the

appendix is displaced medially toward the ileocecal valve. The relationship of the base of the

appendix to the cecum remains constant, whereas the tip can be found in a retrocecal, pelvic,

subcecal, preileal, or right pericolic position (Fig. 30-1). These anatomic considerations have

significant clinical importance in the context of acute appendicitis. The three taeniae coli

converge at the junction of the cecum with the appendix and can be a useful landmark to

identify the appendix. The appendix can vary in length from <1 cm to >30 cm; most

appendices are 6 to 9 cm long. Appendiceal absence, duplication, and diverticula have all

been described.1â!“4

Fig. 30-1.

Various anatomic positions of the vermiform appendix.

For many years, the appendix was erroneously viewed as a vestigial organ with no known

function. It is now well recognized that the appendix is an immunologic organ that actively

participates in the secretion of immunoglobulins, particularly immunoglobulin A. Although

there is no clear role for the appendix in the development of human disease, recent studies

demonstrate a potential correlation between appendectomy and the development of

inflammatory bowel disease. There appears to be a negative age-related association between

inflammatory bowel disease. There appears to be a negative age-related association between

prior appendectomy and subsequent development of ulcerative colitis. In addition,

comparative analysis clearly shows that prior appendectomy is associated with a more benign

phenotype in ulcerative colitis and a delay in onset of disease. The association between

Crohn's disease and appendectomy is less clear. Although earlier studies suggested that

appendectomy increases the risk of developing Crohn's disease, more recent studies that

carefully assessed the timing of appendectomy in relation to the onset of Crohn's disease

demonstrated a negative correlation. These data suggest that appendectomy may protect

against the subsequent development of inflammatory bowel disease; however, the mechanism

is unclear.4

Lymphoid tissue first appears in the appendix approximately 2 weeks after birth. The amount

of lymphoid tissue increases throughout puberty, remains steady for the next decade, and

then begins a steady decrease with age. After the age of 60 years, virtually no lymphoid

tissue remains within the appendix, and complete obliteration of the appendiceal lumen is

common.1â!“4

ACUTE APPENDICITIS

Historical BackgroundAlthough ancient texts have scattered descriptions of surgery being undertaken for ailments

sounding like appendicitis, credit for performing the first appendectomy goes to Claudius

Amyand, a surgeon at St. George's Hospital in London and Sergeant Surgeon to Queen Ann,

King George I, and King George II. In 1736, he operated on an 11-year-old boy with a

scrotal hernia and a fecal fistula. Within the hernial sac, Amyand found the appendix

perforated by a pin. He successfully removed the appendix and repaired the hernia.5

The appendix was not identified as an organ capable of causing disease until the nineteenth

century. In 1824, Louyer-Villermay presented a paper before the Royal Academy of Medicine

in Paris. He reported on two autopsy cases of appendicitis and emphasized the importance of

the condition. In 1827, François Melier, a French physician, expounded on Louyer-

Villermay's work. He reported six autopsy cases and was the first to suggest the antemortem

recognition of appendicitis.5 This work was discounted by many physicians of the era,

including Baron Guillaume Dupuytren. Dupuytren believed that inflammation of the cecum

was the main cause of pathology of the right lower quadrant. The term typhlitis or

perityphlitis was used to describe right lower quadrant inflammation. In 1839, a textbook

authored by Bright and Addison entitled Elements of Practical Medicine described the

symptoms of appendicitis and identified the primary cause of inflammatory processes of the

right lower quadrant.6 Reginald Fitz, a professor of pathologic anatomy at Harvard, is credited

with coining the term appendicitis. His landmark paper definitively identified the appendix as

the primary cause of right lower quadrant inflammation.7

Initial surgical therapy for appendicitis was primarily designed to drain right lower quadrant

abscesses that occurred secondary to appendiceal perforation. It appears that the first

abscesses that occurred secondary to appendiceal perforation. It appears that the first

surgical treatment for appendicitis or perityphlitis without abscess was carried out by Hancock

in 1848. He incised the peritoneum and drained the right lower quadrant without removing

the appendix. The first published account of appendectomy for appendicitis was by Krönlein

in 1886. However, this patient died 2 days after operation. Fergus, in Canada, performed the

first elective appendectomy in 1883.5

The greatest contributor to the advancement in the treatment of appendicitis was Charles

McBurney. In 1889, he published his landmark paper in the New York State Medical Journal

describing the indications for early laparotomy for the treatment of appendicitis. It is in this

paper that he described the McBurney point as follows: "maximum tenderness, when one

examines with the fingertips is, in adults, one half to two inches inside the right anterior

spinous process of the ilium on a line drawn to the umbilicus."8 McBurney subsequently

published a paper in 1894 describing the incision that bears his name.9 However, McBurney

later credited McArthur with first describing this incision. Semm is widely credited with

performing the first successful laparoscopic appendectomy in 1982.10

The surgical treatment of appendicitis is one of the great public health advances of the last

150 years. Appendectomy for appendicitis is the most commonly performed emergency

operation in the world. Appendicitis is a disease of the young, with 40% of cases occurring in

patients between the ages of 10 and 29 years.11 In 1886, Fitz reported the associated

mortality rate of appendicitis to be at least 67% without surgical therapy.7 Currently, the

mortality rate for acute appendicitis with treatment is reported to be <1%.12

IncidenceThe lifetime rate of appendectomy is 12% for men and 25% for women, with approximately

7% of all people undergoing appendectomy for acute appendicitis during their lifetime. Over

the 10-year period from 1987 to 1997, the overall appendectomy rate decreased in parallel

with a decrease in incidental appendectomy.11,13 However, the rate of appendectomy for

appendicitis has remained constant at 10 per 10,000 patients per year.14 Appendicitis is most

frequently seen in patients in their second through fourth decades of life, with a mean age of

31.3 years and a median age of 22 years. There is a slight male:female predominance (1.2 to

1.3:1).11,13

Despite the increased use of ultrasonography, computed tomography (CT), and laparoscopy,

the rate of misdiagnosis of appendicitis has remained constant (15.3%), as has the rate of

appendiceal rupture. The percentage of misdiagnosed cases of appendicitis is significantly

higher among women than among men (22.2 vs. 9.3%). The negative appendectomy rate for

women of reproductive age is 23.2%, with the highest rates in women aged 40 to 49 years.

The highest negative appendectomy rate is reported for women >80 years of age (Fig. 30-

2).13,14

Fig. 30-2.

Rate of negative appendectomy by age group.

(Adapted from Flum et al.13,14)

Etiology and PathogenesisObstruction of the lumen is the dominant etiologic factor in acute appendicitis. Fecaliths are

the most common cause of appendiceal obstruction. Less common causes are hypertrophy of

lymphoid tissue, inspissated barium from previous x-ray studies, tumors, vegetable and fruit

seeds, and intestinal parasites. The frequency of obstruction rises with the severity of the

inflammatory process. Fecaliths are found in 40% of cases of simple acute appendicitis, in

65% of cases of gangrenous appendicitis without rupture, and in nearly 90% of cases of

gangrenous appendicitis with rupture.

Traditionally the belief has been that there is a predictable sequence of events leading to

eventual appendiceal rupture. The proximal obstruction of the appendiceal lumen produces a

closed-loop obstruction, and continuing normal secretion by the appendiceal mucosa rapidly

produces distention. The luminal capacity of the normal appendix is only 0.1 mL. Secretion of

as little as 0.5 mL of fluid distal to an obstruction raises the intraluminal pressure to 60 cm

H2O. Distention of the appendix stimulates the nerve endings of visceral afferent stretch

fibers, producing vague, dull, diffuse pain in the midabdomen or lower epigastrium. Peristalsis

also is stimulated by the rather sudden distention, so that some cramping may be

superimposed on the visceral pain early in the course of appendicitis. Distention increases

from continued mucosal secretion and from rapid multiplication of the resident bacteria of the

appendix. Distention of this magnitude usually causes reflex nausea and vomiting, and the

appendix. Distention of this magnitude usually causes reflex nausea and vomiting, and the

diffuse visceral pain becomes more severe. As pressure in the organ increases, venous

pressure is exceeded. Capillaries and venules are occluded, but arteriolar inflow continues,

resulting in engorgement and vascular congestion. The inflammatory process soon involves

the serosa of the appendix and in turn parietal peritoneum in the region, which produces the

characteristic shift in pain to the right lower quadrant.

The mucosa of the GI tract, including the appendix, is susceptible to impairment of blood

supply; thus its integrity is compromised early in the process, which allows bacterial invasion.

As progressive distention encroaches on first the venous return and subsequently the

arteriolar inflow, the area with the poorest blood supply suffers most: ellipsoidal infarcts

develop in the antimesenteric border. As distention, bacterial invasion, compromise of

vascular supply, and infarction progress, perforation occurs, usually through one of the

infarcted areas on the antimesenteric border. Perforation generally occurs just beyond the

point of obstruction rather than at the tip because of the effect of diameter on intraluminal

tension.

This sequence is not inevitable, however, and some episodes of acute appendicitis apparently

subside spontaneously. Many patients who are found at operation to have acute appendicitis

give a history of previous similar, but less severe, attacks of right lower quadrant pain.

Pathologic examination of the appendices removed from these patients often reveals

thickening and scarring, suggesting old, healed acute inflammation.15,16 The strong

association between delay in presentation and appendiceal perforation supported the

proposition that appendiceal perforation is the advanced stage of acute appendicitis; however,

recent epidemiologic studies have suggested that nonperforated and perforated appendicitis

may, in fact, be different diseases.17

BacteriologyThe bacterial population of the normal appendix is similar to that of the normal colon. The

appendiceal flora remains constant throughout life with the exception of Porphyromonas

gingivalis. This bacterium is seen only in adults.18 The bacteria cultured in cases of

appendicitis are therefore similar to those seen in other colonic infections such as

diverticulitis. The principal organisms seen in the normal appendix, in acute appendicitis, and

in perforated appendicitis are Escherichia coli and Bacteroides fragilis.18â!“21 However, a wide

variety of both facultative and anaerobic bacteria and mycobacteria may be present (Table

30-1). Appendicitis is a polymicrobial infection, with some series reporting the culture of up

to 14 different organisms in patients with perforation.18

Table 30-1 Common Organisms Seen in Patients with AcuteAppendicitis

Aerobic and Facultative Anaerobic

Gram-negative bacilli Gram-negative bacilli

Escherichia coli Bacteroides fragilis

Pseudomonas aeruginosa Other Bacteroides species

Klebsiella species Fusobacterium species

Gram-positive cocci Gram-positive cocci

Streptococcus anginosus Peptostreptococcus species

Other Streptococcus species Gram-positive bacilli

Enterococcus species Clostridium species

The routine culture of intraperitoneal samples in patients with either perforated or

nonperforated appendicitis is questionable. As discussed earlier, the flora is known, and

therefore broad-spectrum antibiotics are indicated. By the time culture results are available,

the patient often has recovered from the illness. In addition, the number of organisms

cultured and the ability of a specific laboratory to culture anaerobic organisms vary greatly.

Peritoneal culture should be reserved for patients who are immunosuppressed, as a result of

either illness or medication, and for patients who develop an abscess after the treatment of

appendicitis.20â!“22 Antibiotic prophylaxis is effective in the prevention of postoperative

wound infection and intra-abdominal abscess.23 Antibiotic coverage is limited to 24 to 48

hours in cases of nonperforated appendicitis. For perforated appendicitis, 7 to 10 days of

therapy is recommended. IV antibiotics are usually given until the white blood cell count is

normal and the patient is afebrile for 24 hours. Antibiotic irrigation of the peritoneal cavity

and the use of transperitoneal drainage through the wound are controversial.24

Clinical Manifestations

SYMPTOMSAbdominal pain is the prime symptom of acute appendicitis. Classically, pain is initially

diffusely centered in the lower epigastrium or umbilical area, is moderately severe, and is

steady, sometimes with intermittent cramping superimposed. After a period varying from 1 to

12 hours, but usually within 4 to 6 hours, the pain localizes to the right lower quadrant. This

classic pain sequence, although usual, is not invariable. In some patients, the pain of

appendicitis begins in the right lower quadrant and remains there. Variations in the anatomic

location of the appendix account for many of the variations in the principal locus of the

somatic phase of the pain. For example, a long appendix with the inflamed tip in the left

lower quadrant causes pain in that area. A retrocecal appendix may cause principally flank or

back pain; a pelvic appendix, principally suprapubic pain; and a retroileal appendix, testicular

pain, presumably from irritation of the spermatic artery and ureter. Intestinal malrotation also

is responsible for puzzling pain patterns. The visceral component is in the normal location, but

the somatic component is felt in that part of the abdomen where the cecum has been

arrested in rotation.

Anorexia nearly always accompanies appendicitis. It is so constant that the diagnosis should

be questioned if the patient is not anorectic. Although vomiting occurs in nearly 75% of

patients, it is neither prominent nor prolonged, and most patients vomit only once or twice.

Vomiting is caused by both neural stimulation and the presence of ileus.

Most patients give a history of obstipation beginning before the onset of abdominal pain, and

many feel that defecation would relieve their abdominal pain. Diarrhea occurs in some

patients, however, particularly children, so that the pattern of bowel function is of little

differential diagnostic value.

The sequence of symptom appearance has great significance for the differential diagnosis. In

>95% of patients with acute appendicitis, anorexia is the first symptom, followed by

abdominal pain, which is followed, in turn, by vomiting (if vomiting occurs). If vomiting

precedes the onset of pain, the diagnosis of appendicitis should be questioned.

SIGNSPhysical findings are determined principally by what the anatomic position of the inflamed

appendix is, as well as by whether the organ has already ruptured when the patient is first

examined.

Vital signs are minimally changed by uncomplicated appendicitis. Temperature elevation is

rarely >1°C (1.8°F) and the pulse rate is normal or slightly elevated. Changes of greater

magnitude usually indicate that a complication has occurred or that another diagnosis should

be considered.25

Patients with appendicitis usually prefer to lie supine, with the thighs, particularly the right

thigh, drawn up, because any motion increases pain. If asked to move, they do so slowly and

with caution.

The classic right lower quadrant physical signs are present when the inflamed appendix lies in

the anterior position. Tenderness often is maximal at or near the McBurney point.8 Direct

rebound tenderness usually is present. In addition, referred or indirect rebound tenderness is

present. This referred tenderness is felt maximally in the right lower quadrant, which

indicates localized peritoneal irritation.25 The Rovsing signâ!”pain in the right lower quadrant

when palpatory pressure is exerted in the left lower quadrantâ!”also indicates the site of

peritoneal irritation. Cutaneous hyperesthesia in the area supplied by the spinal nerves on the

right at T10, T11, and T12 frequently accompanies acute appendicitis. In patients with

obvious appendicitis, this sign is superfluous, but in some early cases, it may be the first

positive sign. Hyperesthesia is elicited either by needle prick or by gently picking up the skin

between the forefinger and thumb.

Muscular resistance to palpation of the abdominal wall roughly parallels the severity of the

inflammatory process. Early in the disease, resistance, if present, consists mainly of voluntary

guarding. As peritoneal irritation progresses, muscle spasm increases and becomes largely

involuntary, that is, true reflex rigidity due to contraction of muscles directly beneath the

inflamed parietal peritoneum.

Anatomic variations in the position of the inflamed appendix lead to deviations in the usual

physical findings. With a retrocecal appendix, the anterior abdominal findings are less striking,

and tenderness may be most marked in the flank. When the inflamed appendix hangs into the

pelvis, abdominal findings may be entirely absent, and the diagnosis may be missed unless

the rectum is examined. As the examining finger exerts pressure on the peritoneum of

Douglas' cul-de-sac, pain is felt in the suprapubic area as well as locally within the rectum.

Signs of localized muscle irritation also may be present. The psoas sign indicates an irritative

focus in proximity to that muscle. The test is performed by having the patient lie on the left

side as the examiner slowly extends the patient's right thigh, thus stretching the iliopsoas

muscle. The test result is positive if extension produces pain. Similarly, a positive obturator

sign of hypogastric pain on stretching the obturator internus indicates irritation in the pelvis.

The test is performed by passive internal rotation of the flexed right thigh with the patient

supine.

LABORATORY FINDINGS

Mild leukocytosis, ranging from 10,000 to 18,000 cells/mm3, usually is present in patients

with acute, uncomplicated appendicitis and often is accompanied by a moderate

polymorphonuclear predominance. White blood cell counts are variable, however. It is unusual

for the white blood cell count to be >18,000 cells/mm3 in uncomplicated appendicitis. White

blood cell counts above this level raise the possibility of a perforated appendix with or without

an abscess. Urinalysis can be useful to rule out the urinary tract as the source of infection.

Although several white or red blood cells can be present from ureteral or bladder irritation as

a result of an inflamed appendix, bacteriuria in a urine specimen obtained via catheter

generally is not seen in acute appendicitis.26

Imaging StudiesPlain films of the abdomen, although frequently obtained as part of the general evaluation of

a patient with an acute abdomen, rarely are helpful in diagnosing acute appendicitis.

However, plain radiographs can be of significant benefit in ruling out other pathology. In

patients with acute appendicitis, one often sees an abnormal bowel gas pattern, which is a

nonspecific finding. The presence of a fecalith is rarely noted on plain films but, if present, is

highly suggestive of the diagnosis. A chest radiograph is sometimes indicated to rule out

referred pain from a right lower lobe pneumonic process.

Additional radiographic studies include barium enema examination and radioactively labeled

leukocyte scans. If the appendix fills on barium enema, appendicitis is excluded. On the other

hand, if the appendix does not fill, no determination can be made.27 To date, there has not

been enough experience with radionuclide scans to assess their utility.

Graded compression sonography has been suggested as an accurate way to establish the

diagnosis of appendicitis. The technique is inexpensive, can be performed rapidly, does not

require a contrast medium, and can be used even in pregnant patients. Sonographically, the

appendix is identified as a blind-ending, nonperistaltic bowel loop originating from the cecum.

With maximal compression, the diameter of the appendix is measured in the anteroposterior

With maximal compression, the diameter of the appendix is measured in the anteroposterior

dimension. Scan results are considered positive if a noncompressible appendix ≥6 mm in

the anteroposterior direction is demonstrated (Fig. 30-3). The presence of an appendicolith

establishes the diagnosis. Thickening of the appendiceal wall and the presence of

periappendiceal fluid is highly suggestive. Sonographic demonstration of a normal appendix,

which is an easily compressible, blind-ending tubular structure measuring ≤5 mm in

diameter, excludes the diagnosis of acute appendicitis. The study results are considered

inconclusive if the appendix is not visualized and there is no pericecal fluid or mass. When the

diagnosis of acute appendicitis is excluded by sonography, a brief survey of the remainder of

the abdominal cavity should be performed to establish an alternative diagnosis. In females of

childbearing age, the pelvic organs must be adequately visualized either by transabdominal or

endovaginal ultrasonography to exclude gynecologic pathology as a cause of acute abdominal

pain. The sonographic diagnosis of acute appendicitis has a reported sensitivity of 55 to 96%

and a specificity of 85 to 98%.28â!“30 Sonography is similarly effective in children and

pregnant women, although its application is somewhat limited in late pregnancy.

Fig. 30-3.

Sonogram of a 10-year-old girl who presented with nausea, vomiting, and abdominal pain. Theappendix measured 10.0 mm in maximal anteroposterior diameter in both the noncompression (A)and compression (B) views.

Although sonography can easily identify abscesses in cases of perforation, the technique has

limitations and results are user dependent. A false-positive scan result can occur in the

presence of periappendicitis from surrounding inflammation, a dilated fallopian tube can be

mistaken for an inflamed appendix, inspissated stool can mimic an appendicolith, and, in

obese patients, the appendix may not be compressible because of overlying fat. False-

negative sonogram results can occur if appendicitis is confined to the appendiceal tip, the

appendix is retrocecal, the appendix is markedly enlarged and mistaken for small bowel, or

the appendix is perforated and therefore compressible.31

Some studies have reported that graded compression sonography improved the diagnosis of

appendicitis over clinical examination, specifically decreasing the percentage of negative

explorations for appendectomies from 37 to 13%.32 Sonography also decreases the time

before operation. Sonography identified appendicitis in 10% of patients who were believed to

have a low likelihood of the disease on physical examination.33 The positive and negative

predictive values of ultrasonography have impressively been reported as 91 and 92%,

respectively. However, in a recent prospective multicenter study, routine ultrasonography did

respectively. However, in a recent prospective multicenter study, routine ultrasonography did

not improve diagnostic accuracy or rates of negative appendectomy or perforation compared

with clinical assessment.

High-resolution helical CT also has been used to diagnose appendicitis. On CT scan, the

inflamed appendix appears dilated (>5 cm) and the wall is thickened. There is usually

evidence of inflammation, with "dirty fat," thickened mesoappendix, and even an obvious

phlegmon (Fig. 30-4). Fecaliths can be easily visualized, but their presence is not necessarily

pathognomonic of appendicitis. An important suggestive abnormality is the arrowhead sign.

This is caused by thickening of the cecum, which funnels contrast agent toward the orifice of

the inflamed appendix. CT scanning is also an excellent technique for identifying other

inflammatory processes masquerading as appendicitis.

Fig. 30-4.

Computed tomographic scans with findings positive for appendicitis. Note the thick-walled anddilated appendix (A) and mesenteric streaking and "dirty fat" (B).

Several CT techniques have been used, including focused and nonfocused CT scans and

enhanced and nonenhanced helical CT scanning. Nonenhanced helical CT scanning is

important, because one of the disadvantages of using CT scanning in the evaluation of right

lower quadrant pain is dye allergy. Surprisingly, all of these techniques have yielded

essentially identical rates of diagnostic accuracy: 92 to 97% sensitivity, 85 to 94% specificity,

90 to 98% accuracy, and 75 to 95% positive and 95 to 99% negative predictive values.34â

!“36 The additional use of a rectally administered contrast agent did not improve the results

of CT scanning.

A number of studies have documented improvement in diagnostic accuracy with the liberal

use of CT scanning in the work-up of suspected appendicitis. CT lowered the rate of negative

appendectomies from 19 to 12% in one study,37 and the incidence of negative

appendectomies in women from 24 to 5% in another.38 The use of this imaging study altered

the care of 24% of patients studied and provided alternative diagnoses in half of the patients

with normal appendices on CT scan.39

Despite the potential usefulness of this technique, there are significant disadvantages. CT

scanning is expensive, exposes the patient to significant radiation, and cannot be used during

pregnancy. Allergy contraindicates the administration of IV contrast agents in some patients,

and others cannot tolerate the oral ingestion of luminal dye, particularly in the presence of

nausea and vomiting. Finally, not all studies have documented the utility of CT scanning in all

nausea and vomiting. Finally, not all studies have documented the utility of CT scanning in all

patients with right lower quadrant pain.40

A number of studies have compared the effectiveness of graded compression sonography and

helical CT in establishing the diagnosis of appendicitis. Although the differences are rather

small, CT scanning has consistently proven superior. For example, in one study, 600

ultrasounds and 317 CT scans demonstrated sensitivity of 80 and 97%, specificity of 93 and

94%, diagnostic accuracy of 89 and 95%, positive predictive value of 91 and 92%, and

negative predictive value of 88 and 98%, respectively.30 In another study, ultrasound

positively impacted the management of 19% of patients, compared with 73% of patients for

CT. Finally, in a third study, the negative appendix rate was 17% for patients studied by

ultrasonography compared with a negative appendix rate of 2% for patients who underwent

helical CT scanning.41 One concern about ultrasonography is the high intraobserver

variability.42

One issue that has not been resolved is which patients are candidates for imaging studies.43

This question may be moot, because CT scanning routinely is ordered by emergency

physicians before surgeons are even consulted. The concept that all patients with right lower

quadrant pain should undergo CT scanning has been strongly supported by two reports by

Rao and his colleagues at the Massachusetts General Hospital. In one, this group documented

that CT scanning led to a fall in the negative appendectomy rate from 20 to 7% and a decline

in the perforation rate from 22 to 14%, as well as establishment of an alternative diagnosis in

50% of patients.44 In the second study, published in the New England Journal of Medicine,

Rao and associates documented that CT scanning prevented 13 unnecessary appendectomies,

saved 50 inpatient hospital days, and lowered the per-patient cost by $447.45 In contrast,

several other studies failed to prove an advantage of routine CT scanning, documenting that

surgeon accuracy approached that of the imaging study and expressing concern that the

imaging studies could adversely delay appendectomy in affected patients.46,47

The rational approach is the selective use of CT scanning. This has been documented by

several studies in which imaging was performed based on an algorithm or protocol.48 The

likelihood of appendicitis can be ascertained using the Alvarado scale (Table 30-2).49 This

scoring system was designed to improve the diagnosis of appendicitis and was devised by

giving relative weight to specific clinical manifestation. Table 30-2 lists the eight specific

indicators identified. Patients with scores of 9 or 10 are almost certain to have appendicitis;

there is little advantage in further work-up, and they should go to the operating room.

Patients with scores of 7 or 8 have a high likelihood of appendicitis, whereas scores of 5 or 6

are compatible with, but not diagnostic of, appendicitis. CT scanning is certainly appropriate

for patients with Alvarado scores of 5 and 6, and a case can be built for imaging for those

with scores of 7 and 8. On the other hand, it is difficult to justify the expense, radiation

exposure, and possible complications of CT scanning in patients whose scores of 0 to 4 make

it extremely unlikely (but not impossible) that they have appendicitis.

Table 30-2 Alvarado Scale for the Diagnosis of Appendicitis

Manifestations Value

Symptoms Migration of pain 1

Anorexia 1

Nausea and/or vomiting 1

Signs Right lower quadrant tenderness 2

Rebound 1

Elevated temperature 1

Laboratory values Leukocytosis 2

Left shift in leukocyte count 1

Total points 10

Source: Reproduced with permission from Alvarado.49

Selective CT scanning based on the likelihood of appendicitis takes advantage of the clinical

skill of the experienced surgeon and, when indicated, adds the expertise of the radiologist

and his or her imaging study. Figure 30-5 proposes a treatment algorithm addressing the

rational use of diagnostic testing.50

Fig. 30-5.

Clinical algorithm for suspected cases of acute appendicitis. If gynecologic disease is suspected, apelvic and endovaginal ultrasound examination is indicated.

(Reproduced with permission from Paulson et al.50 Copyright © Massachusetts Medical Society.All rights reserved.)

Laparoscopy can serve as both a diagnostic and therapeutic maneuver for patients with acute

abdominal pain and suspected acute appendicitis. Laparoscopy is probably most useful in the

evaluation of females with lower abdominal complaints, because appendectomy is performed

on a normal appendix in as many as 30 to 40% of these patients. Differentiating acute

gynecologic pathology from acute appendicitis can be effectively accomplished using the

laparoscope.

Appendiceal RuptureImmediate appendectomy has long been the recommended treatment for acute appendicitis

because of the presumed risk of progression to rupture. The overall rate of perforated

appendicitis is 25.8%. Children <5 years of age and patients >65 years of age have the

highest rates of perforation (45 and 51%, respectively) (Fig. 30-6).14,15,51 It has been

suggested that delays in presentation are responsible for the majority of perforated

appendices. There is no accurate way of determining when and if an appendix will rupture

before resolution of the inflammatory process. Recent studies suggest that, in selected

patients, observation and antibiotic therapy alone may be an appropriate treatment for acute

appendicitis.17,52

Fig. 30-6.

Rate of appendiceal rupture by age group.

(Personal communication from David Flum, MD.)

Appendiceal rupture occurs most frequently distal to the point of luminal obstruction along the

antimesenteric border of the appendix. Rupture should be suspected in the presence of fever

with a temperature of >39°C (102°F) and a white blood cell count of >18,000 cells/mm3.

In the majority of cases, rupture is contained and patients display localized rebound

tenderness. Generalized peritonitis will be present if the walling-off process is ineffective in

containing the rupture.

In 2 to 6% of cases, an ill-defined mass is detected on physical examination. This could

represent a phlegmon, which consists of matted loops of bowel adherent to the adjacent

inflamed appendix, or a periappendiceal abscess. Patients who present with a mass have

experienced symptoms for a longer duration, usually at least 5 to 7 days. Distinguishing

acute, uncomplicated appendicitis from acute appendicitis with perforation on the basis of

clinical findings is often difficult, but it is important to make the distinction because their

treatment differs. CT scan may be beneficial in guiding therapy. Phlegmons and small

abscesses can be treated conservatively with IV antibiotics; well-localized abscesses can be

managed with percutaneous drainage; complex abscesses should be considered for surgical

drainage. If operative drainage is required, it should be performed using an extraperitoneal

approach, with appendectomy reserved for cases in which the appendix is easily accessible.

Interval appendectomy performed at least 6 weeks after the acute event has classically been

recommended for all patients treated either nonoperatively or with simple drainage of an

abscess.53,54

abscess.53,54

Differential DiagnosisThe differential diagnosis of acute appendicitis is essentially the diagnosis of the acute

abdomen (see Chap. 35). This is because clinical manifestations are not specific for a given

disease but are specific for disturbance of a given physiologic function or functions. Thus, an

essentially identical clinical picture can result from a wide variety of acute processes within

the peritoneal cavity that produce the same alterations of function as does acute appendicitis.

The accuracy of preoperative diagnosis should be approximately 85%. If it is consistently less,

it is likely that some unnecessary operations are being performed, and a more rigorous

preoperative differential diagnosis is in order. A diagnostic accuracy rate that is consistently

>90% should also cause concern, because this may mean that some patients with atypical,

but bona fide, cases of acute appendicitis are being "observed" when they should receive

prompt surgical intervention. The Haller group, however, has shown that this is not invariably

true.55 Before that group's study, the perforation rate at the hospital at which the study took

place was 26.7%, and acute appendicitis was found in 80% of the patients undergoing

operation. By implementing a policy of intensive inhospital observation when the diagnosis of

appendicitis was unclear, the group raised the rate of acute appendicitis found at operation to

94%, but the perforation rate remained unchanged at 27.5%.55 The rate of false-negative

appendectomies is highest in young adult females. A normal appendix is found in 32 to 45%

of appendectomies performed in women 15 to 45 years of age.14

A common error is to make a preoperative diagnosis of acute appendicitis only to find some

other condition (or nothing) at operation. Much less frequently, acute appendicitis is found

after a preoperative diagnosis of another condition. The most common erroneous preoperative

diagnosesâ!”together accounting for >75% of casesâ!”are, in descending order of frequency,

acute mesenteric lymphadenitis, no organic pathologic condition, acute pelvic inflammatory

disease, twisted ovarian cyst or ruptured graafian follicle, and acute gastroenteritis.

The differential diagnosis of acute appendicitis depends on four major factors: the anatomic

location of the inflamed appendix; the stage of the process (i.e., simple or ruptured); the

patient's age; and the patient's sex.56â!“60

ACUTE MESENTERIC ADENITISAcute mesenteric adenitis is the disease most often confused with acute appendicitis in

children. Almost invariably, an upper respiratory tract infection is present or has recently

subsided. The pain usually is diffuse, and tenderness is not as sharply localized as in

appendicitis. Voluntary guarding is sometimes present, but true rigidity is rare. Generalized

lymphadenopathy may be noted. Laboratory procedures are of little help in arriving at the

correct diagnosis, although a relative lymphocytosis, when present, suggests mesenteric

adenitis. Observation for several hours is in order if the diagnosis of mesenteric adenitis

seems likely, because it is a self-limited disease. However, if the differentiation remains in

doubt, immediate exploration is the safest course of action.

Human infection with Yersinia enterocolitica or Yersinia pseudotuberculosis, transmitted

through food contaminated by feces or urine, causes mesenteric adenitis as well as ileitis,

colitis, and acute appendicitis. Many of the infections are mild and self limited, but they may

lead to systemic disease with a high fatality rate if untreated. The organisms are usually

sensitive to tetracyclines, streptomycin, ampicillin, and kanamycin. A preoperative suspicion of

the diagnosis should not delay operative intervention, because appendicitis caused by Yersinia

cannot be clinically distinguished from appendicitis due to other causes. Approximately 6% of

cases of mesenteric adenitis are caused by Yersinia infection.

Salmonella typhimurium infection causes mesenteric adenitis and paralytic ileus with

symptoms similar to those of appendicitis. The diagnosis can be established by serologic

testing. Campylobacter jejuni causes diarrhea and pain that mimics that of appendicitis. The

organism can be cultured from stool.

GYNECOLOGIC DISORDERSDiseases of the female internal reproductive organs that may erroneously be diagnosed as

appendicitis are, in approximate descending order of frequency, pelvic inflammatory disease,

ruptured graafian follicle, twisted ovarian cyst or tumor, endometriosis, and ruptured ectopic

pregnancy.

Pelvic Inflammatory DiseaseIn pelvic inflammatory disease the infection usually is bilateral but, if confined to the right

tube, may mimic acute appendicitis. Nausea and vomiting are present in patients with

appendicitis, but in only approximately 50% of those with pelvic inflammatory disease. Pain

and tenderness are usually lower, and motion of the cervix is exquisitely painful. Intracellular

diplococci may be demonstrable on smear of the purulent vaginal discharge. The ratio of

cases of appendicitis to cases of pelvic inflammatory disease is low in females in the early

phase of the menstrual cycle and high during the luteal phase. The careful clinical use of

these features has reduced the incidence of negative findings on laparoscopy in young women

to 15%.

Ruptured Graafian FollicleOvulation commonly results in the spillage of sufficient amounts of blood and follicular fluid to

produce brief, mild lower abdominal pain. If the amount of fluid is unusually copious and is

from the right ovary, appendicitis may be simulated. Pain and tenderness are rather diffuse.

Leukocytosis and fever are minimal or absent. Because this pain occurs at the midpoint of the

menstrual cycle, it is often called mittelschmerz.

Twisted Ovarian CystSerous cysts of the ovary are common and generally remain asymptomatic. When right-sided

cysts rupture or undergo torsion, the manifestations are similar to those of appendicitis.

Patients develop right lower quadrant pain, tenderness, rebound, fever, and leukocytosis. If

the mass is palpable on physical examination, the diagnosis can be made easily. Both

transvaginal ultrasonography and CT scanning can be diagnostic if a mass is not palpable.

Torsion requires emergent operative treatment. If the torsion is complete or longstanding, the

pedicle undergoes thrombosis, and the ovary and tube become gangrenous and require

resection. Leakage of ovarian cysts resolves spontaneously, however, and is best treated

nonoperatively.24,56â!“61

Ruptured Ectopic PregnancyBlastocysts may implant in the fallopian tube (usually the ampullary portion) and in the ovary.

Rupture of right tubal or ovarian pregnancies can mimic appendicitis. Patients may give a

history of abnormal menses, either missing one or two periods or noting only slight vaginal

bleeding. Unfortunately, patients do not always realize they are pregnant. The development

of right lower quadrant or pelvic pain may be the first symptom. The diagnosis of ruptured

ectopic pregnancy should be relatively easy. The presence of a pelvic mass and elevated

levels of chorionic gonadotropin are characteristic. Although the leukocyte count rises slightly

(to approximately 14,000 cells/mm3), the hematocrit level falls as a consequence of the

intra-abdominal hemorrhage. Vaginal examination reveals cervical motion and adnexal

tenderness, and a more definitive diagnosis can be established by culdocentesis. The

presence of blood and particularly decidual tissue is pathognomonic. The treatment of

ruptured ectopic pregnancy is emergency surgery.

ACUTE GASTROENTERITISAcute gastroenteritis is common but usually can be easily distinguished from acute

appendicitis. Gastroenteritis is characterized by profuse diarrhea, nausea, and vomiting.

Hyperperistaltic abdominal cramps precede the watery stools. The abdomen is relaxed

between cramps, and there are no localizing signs. Laboratory values vary with the specific

cause.

OTHER INTESTINAL DISORDERS

Meckel's DiverticulitisMeckel's diverticulitis gives rise to a clinical picture similar to that of acute appendicitis.

Meckel's diverticulum is located within the distal 2 ft of the ileum. Meckel's diverticulitis is

associated with the same complications as appendicitis and requires the same treatmentâ

!”prompt surgical intervention. Resection of the segment of ileum bearing the diverticulum

with end-to-end anastomosis can nearly always be done through a McBurney incision,

extended if necessary, or laparoscopically.

Crohn's EnteritisThe manifestations of acute regional enteritisâ!”fever, right lower quadrant pain and

tenderness, and leukocytosisâ!”often simulate acute appendicitis. The presence of diarrhea

and the absence of anorexia, nausea, and vomiting favor a diagnosis of enteritis, but this is

not sufficient to exclude acute appendicitis. In an appreciable percentage of patients with

chronic regional enteritis, the diagnosis is first made at the time of operation for presumed

acute appendicitis. In cases of an acutely inflamed distal ileum with no cecal involvement and

a normal appendix, appendectomy is indicated. Progression to chronic Crohn's ileitis is

a normal appendix, appendectomy is indicated. Progression to chronic Crohn's ileitis is

uncommon.

Colonic LesionsDiverticulitis or perforating carcinoma of the cecum, or of that portion of the sigmoid that lies

in the right side, may be impossible to distinguish from appendicitis. These entities should be

considered in older patients. CT scanning is often helpful in making a diagnosis in older

patients with right lower quadrant pain and atypical clinical presentations.

Epiploic appendagitis probably results from infarction of the colonic appendage(s) secondary

to torsion. Symptoms may be minimal, or there may be continuous abdominal pain in an

area corresponding to the contour of the colon, lasting several days. Pain shift is unusual, and

there is no diagnostic sequence of symptoms. The patient does not look ill, nausea and

vomiting are unusual, and appetite generally is unaffected. Localized tenderness over the site

is usual and often is associated with rebound without rigidity. In 25% of reported cases, pain

persists or recurs until the infarcted epiploic appendage is removed.

OTHER DISEASESDiseases or conditions not mentioned in the preceding sections that must be considered in the

differential diagnosis include foreign body perforations of the bowel, closed-loop intestinal

obstruction, mesenteric vascular infarction, pleuritis of the right lower chest, acute

cholecystitis, acute pancreatitis, hematoma of the abdominal wall, epididymitis, testicular

torsion, urinary tract infection, ureteral stone, primary peritonitis, and Henoch-Schönlein

purpura.

Acute Appendicitis in the YoungThe establishment of a diagnosis of acute appendicitis is more difficult in young children than

in the adult. The inability of young children to give an accurate history, diagnostic delays by

both parents and physicians, and the frequency of GI upset in children are all contributing

factors.62 In children the physical examination findings of maximal tenderness in the right

lower quadrant, the inability to walk or walking with a limp, and pain with percussion,

coughing, and hopping were found to have the highest sensitivity for appendicitis.63

The more rapid progression to rupture and the inability of the underdeveloped greater

omentum to contain a rupture lead to significant morbidity rates in children. Children <5

years of age have a negative appendectomy rate of 25% and an appendiceal perforation rate

of 45%. These rates may be compared with a negative appendectomy rate of <10% and a

perforated appendix rate of 20% for children 5 to 12 years of age.13,14 The incidence of

major complications after appendectomy in children is correlated with appendiceal rupture.

The wound infection rate after the treatment of nonperforated appendicitis in children is 2.8%

compared with a rate of 11% after the treatment of perforated appendicitis. The incidence of

intra-abdominal abscess also is higher after the treatment of perforated appendicitis than

after nonperforated appendicitis (6% vs. 3%).23 The treatment regimen for perforated

appendicitis generally includes immediate appendectomy and irrigation of the peritoneal

appendicitis generally includes immediate appendectomy and irrigation of the peritoneal

cavity. Antibiotic coverage is limited to 24 to 48 hours in cases of nonperforated appendicitis.

For perforated appendicitis IV antibiotics usually are given until the white blood cell count is

normal and the patient is afebrile for 24 hours. The use of antibiotic irrigation of the

peritoneal cavity and transperitoneal drainage through the wound are controversial.

Laparoscopic appendectomy has been shown to be safe and effective for the treatment of

appendicitis in children.64

Acute Appendicitis in the ElderlyCompared with younger patients, elderly patients with appendicitis often pose a more difficult

diagnostic problem because of the atypical presentation, expanded differential diagnosis, and

communication difficulty. These factors may be responsible for the disproportionately high

perforation rate seen in the elderly. In the general population, perforation rates range from

20 to 30%, compared with 50 to 70% in the elderly.65 In addition, the perforation rate

appears to increase with age >80 years.66

Elderly patients usually present with lower abdominal pain, but on clinical examination,

localized right lower quadrant tenderness is present in only 80 to 90% of patients. A history

of periumbilical pain migrating to the right lower quadrant is reported infrequently. The

usefulness of the Alvarado score appears to decline in the elderly. Fewer then 50% of the

elderly with appendicitis have an Alvarado score of ≥7.66 Although currently there are no

criteria that definitively identify elderly patients with acute appendicitis who are at risk of

rupture, prioritization should be given to patients with a temperature of >38°C (100.4°F)

and a shift to the left in leukocyte count of >76%, especially if they are male, are anorectic,

or have had pain of long duration before admission.65

As a result of increased comorbidities and an increased rate of perforation, postoperative

morbidity, mortality, and hospital length of stay are increased in the elderly compared with

younger populations with appendicitis. Although no randomized trials have been conducted, it

appears that elderly patients benefit from a laparoscopic approach to treatment of

appendicitis. The use of laparoscopy in the elderly has significantly increased in recent years.

In general, laparoscopic appendectomy offers elderly patients with appendicitis a shorter

length of hospital stay, a reduction in complication and mortality rates, and a greater chance

of discharge to home (independent of further nursing care or rehabilitation).67

Acute Appendicitis during PregnancyAppendectomy for presumed appendicitis is the most common surgical emergency during

pregnancy. The incidence is approximately 1 in 766 births. Acute appendicitis can occur at

any time during pregnancy.68 The overall negative appendectomy rate during pregnancy is

approximately 25% and appears to be higher than the rate seen in nonpregnant women.68,69

A higher rate of negative appendectomy is seen in the second trimester, and the lowest rate

is in the third trimester. The diversity of clinical presentations and the difficulty in making the

diagnosis of acute appendicitis in pregnant women is well established. This is particularly true

diagnosis of acute appendicitis in pregnant women is well established. This is particularly true

in the late second trimester and the third trimester, when many abdominal symptoms may be

considered pregnancy related. In addition, during pregnancy there are anatomic changes in

the appendix (Fig. 30-7) and increased abdominal laxity that may further complicate clinical

evaluation. There is no association between appendectomy and subsequent fertility.

Fig. 30-7.

Location of the appendix during pregnancy. ASIS = anterior superior iliac spine.

[Reproduced with permission from Metcalf A: The appendix, in Corson JD, Williamson RCN (eds):Surgery. London: Mosby, 2001.]

Appendicitis in pregnancy should be suspected when a pregnant woman complains of

abdominal pain of new onset. The most consistent sign encountered in acute appendicitis

during pregnancy is pain in the right side of the abdomen. Seventy-four percent of patients

report pain located in the right lower abdominal quadrant, with no difference between early

and late pregnancy. Only 57% of patients present with the classic history of diffuse

periumbilical pain migrating to the right lower quadrant. Laboratory evaluation is not helpful

in establishing the diagnosis of acute appendicitis during pregnancy. The physiologic

in establishing the diagnosis of acute appendicitis during pregnancy. The physiologic

leukocytosis of pregnancy has been defined as high as 16,000 cells/mm3. In one series only

38% of patients with appendicitis had a white blood cell count of >16,000 cells/mm3.68

Recent data suggest that the incidence of perforated or complex appendicitis is not increased

in pregnant patients.69

When the diagnosis is in doubt, abdominal ultrasound may be beneficial. Another option is

magnetic resonance imaging, which has no known deleterious effects on the fetus. The

American College of Radiology recommends the use of nonionizing radiation techniques for

front-line imaging in pregnant women.70 Laparoscopy has been advocated in equivocal cases,

especially early in pregnancy; however laparoscopic appendectomy may be associated with an

increase in pregnancy-related complications. In an analysis of outcomes in California using

administrative databases, laparoscopy was found to be associated with a 2.31 increased odds

of fetal loss over open surgery.69

The overall incidence of fetal loss after appendectomy is 4% and the risk of early delivery is

7%. Rates of fetal loss are considerably higher in women with complex appendicitis than in

those with a negative appendectomy and with simple appendicitis. It is important to note that

a negative appendectomy is not a benign procedure. Removing a normal appendix is

associated with a 4% risk of fetal loss and 10% risk of early delivery. Maternal mortality after

appendectomy is extremely rare (0.03%). Because the incidence of ruptured appendix is

similar in pregnant and nonpregnant women and because maternal mortality is so low, it

appears that the greatest opportunity to improve fetal outcomes is by improving diagnostic

accuracy and reducing the rate of negative appendectomy.68â!“71

Appendicitis in Patients with AIDS or HIV InfectionThe incidence of acute appendicitis in HIV-infected patients is reported to be 0.5%. This is

higher than the 0.1 to 0.2% incidence reported for the general population.72 The presentation

of acute appendicitis in HIV-infected patients is similar to that in noninfected patients. The

majority of HIV-infected patients with appendicitis have fever, periumbilical pain radiating to

the right lower quadrant (91%), right lower quadrant tenderness (91%), and rebound

tenderness (74%). HIV-infected patients do not manifest an absolute leukocytosis; however,

if a baseline leukocyte count is available, nearly all HIV-infected patients with appendicitis

demonstrate a relative leukocytosis.72,73

The risk of appendiceal rupture appears to be increased in HIV-infected patients. In one large

series of HIV-infected patients who underwent appendectomy for presumed appendicitis, 43%

of patients were found to have perforated appendicitis at laparotomy.74 The increased risk of

appendiceal rupture may be related to the delay in presentation seen in this patient

population.72,74 The mean duration of symptoms before arrival in the emergency department

has been reported to be increased in HIV-infected patients, with >60% of patients reporting

the duration of symptoms to be longer than 24 hours.72 In early series, significant hospital

delay also may have contributed to high rates of rupture.72 However, with increased

delay also may have contributed to high rates of rupture.72 However, with increased

understanding of abdominal pain in HIV-infected patients, hospital delay has become less

prevalent.72,75 A low CD4 count is also associated with an increased incidence of appendiceal

rupture. In one large series, patients with nonruptured appendices had CD4 counts of 158.75

± 47 cells/mm3 compared with 94.5 ± 32 cells/mm3 in patients with appendiceal

rupture.72

The differential diagnosis of right lower quadrant pain is expanded in HIV-infected patients

compared with the general population. In addition to the conditions discussed elsewhere in

this chapter, opportunistic infections should be considered as a possible cause of right lower

quadrant pain.72â!“75 Such opportunistic infections include cytomegalovirus (CMV) infection,

Kaposi's sarcoma, tuberculosis, lymphoma, and other causes of infectious colitis. CMV

infection may be seen anywhere in the GI tract. CMV infection causes a vasculitis of blood

vessels in the submucosa of the gut, which leads to thrombosis. Mucosal ischemia develops,

leading to ulceration, gangrene of the bowel wall, and perforation. Spontaneous peritonitis

may be caused by opportunistic pathogens, including CMV, Mycobacterium avium-

intracellulare complex, Mycobacterium tuberculosis, Cryptococcus neoformans, and

Strongyloides. Kaposi's sarcoma and non-Hodgkin's lymphoma may present with pain and a

right lower quadrant mass. Viral and bacterial colitis occur with a higher frequency in HIV-

infected patients than in the general population. Colitis should always be considered in HIV-

infected patients presenting with right lower quadrant pain. Neutropenic enterocolitis

(typhlitis) should also be considered in the differential diagnosis of right lower quadrant pain

in HIV-infected patients.73,75

A thorough history and physical examination is important when evaluating any patient with

right lower quadrant pain. In the HIV-infected patient with classic signs and symptoms of

appendicitis, immediate appendectomy is indicated. In those patients with diarrhea as a

prominent symptom, colonoscopy may be warranted. In patients with equivocal findings, CT

scan is usually helpful. The majority of pathologic findings identified in HIV-infected patients

who undergo appendectomy for presumed appendicitis are typical. The negative

appendectomy rate is 5 to 10%. However, in up to 25% of patients AIDS-related entities are

found in the operative specimens, including CMV, Kaposi's sarcoma, and M. avium-

intracellulare complex.72,74

In a retrospective study of 77 HIV-infected patients from 1988 to 1995, the 30-day mortality

rate for patients undergoing appendectomy was reported to be 9.1%.72 More recent series

report 0% mortality in this group of patients.75 Morbidity rates for HIV-infected patients with

nonperforated appendicitis are similar to those seen in the general population. Postoperative

morbidity rates appear to be higher in HIV-infected patients with perforated appendicitis. In

addition, the length of hospital stay for HIV-infected patients undergoing appendectomy is

twice that for the general population.72,75 No series has been reported to date that addresses

the role of laparoscopic appendectomy in the HIV-infected population.

TreatmentDespite the advent of more sophisticated diagnostic modalities, the importance of early

operative intervention should not be minimized. Once the decision to operate for presumed

acute appendicitis has been made, the patient should be prepared for the operating room.

Adequate hydration should be ensured, electrolyte abnormalities should be corrected, and

pre-existing cardiac, pulmonary, and renal conditions should be addressed. A large meta-

analysis has demonstrated the efficacy of preoperative antibiotics in lowering the infectious

complications in appendicitis.23 Most surgeons routinely administer antibiotics to all patients

with suspected appendicitis. If simple acute appendicitis is encountered, there is no benefit in

extending antibiotic coverage beyond 24 hours. If perforated or gangrenous appendicitis is

found, antibiotics are continued until the patient is afebrile and has a normal white blood cell

count. For intra-abdominal infections of GI tract origin that are of mild to moderate severity,

the Surgical Infection Society has recommended single-agent therapy with cefoxitin,

cefotetan, or ticarcillin-clavulanic acid. For more severe infections, single-agent therapy with

carbapenems or combination therapy with a third-generation cephalosporin, monobactam, or

aminoglycoside plus anaerobic coverage with clindamycin or metronidazole is indicated.24 The

recommendations are similar for children.76

OPEN APPENDECTOMYFor open appendectomy most surgeons use either a McBurney (oblique) or Rocky-Davis

(transverse) right lower quadrant muscle-splitting incision in patients with suspected

appendicitis. The incision should be centered over either the point of maximal tenderness or a

palpable mass. If an abscess is suspected, a laterally placed incision is imperative to allow

retroperitoneal drainage and to avoid generalized contamination of the peritoneal cavity. If

the diagnosis is in doubt, a lower midline incision is recommended to allow a more extensive

examination of the peritoneal cavity. This is especially relevant in older patients with possible

malignancy or diverticulitis.

Several techniques can be used to locate the appendix. Because the cecum usually is visible

within the incision, the convergence of the taeniae can be followed to the base of the

appendix. A sweeping lateral to medial motion can aid in delivering the appendiceal tip into

the operative field. Occasionally, limited mobilization of the cecum is needed to aid in

adequate visualization. Once identified, the appendix is mobilized by dividing the

mesoappendix, with care taken to ligate the appendiceal artery securely.

The appendiceal stump can be managed by simple ligation or by ligation and inversion with

either a purse-string or Z stitch. As long as the stump is clearly viable and the base of the

cecum is not involved with the inflammatory process, the stump can be safely ligated with a

nonabsorbable suture. The mucosa is frequently obliterated to avoid the development of

mucocele. The peritoneal cavity is irrigated and the wound closed in layers. If perforation or

gangrene is found in adults, the skin and subcutaneous tissue should be left open and allowed

to heal by secondary intent or closed in 4 to 5 days as a delayed primary closure. In children,

who generally have little subcutaneous fat, primary wound closure has not led to an increased

incidence of wound infection.

incidence of wound infection.

If appendicitis is not found, a methodical search must be made for an alternative diagnosis.

The cecum and mesentery should first be inspected. Next, the small bowel should be

examined in a retrograde fashion beginning at the ileocecal valve and extending at least 2 ft.

In females, special attention should be paid to the pelvic organs. An attempt also should be

made to examine the upper abdominal contents. Peritoneal fluid should be sent for Gram's

staining and culture. If purulent fluid is encountered, it is imperative that the source be

identified. A medial extension of the incision (Fowler-Weir), with division of the anterior and

posterior rectus sheath, is acceptable if further evaluation of the lower abdomen is indicated.

If upper abdominal pathology is encountered, the right lower quadrant incision is closed and

an appropriate upper midline incision is made.9

LAPAROSCOPIC APPENDECTOMYSemm first reported successful laparoscopic appendectomy several years before the first

laparoscopic cholecystectomy.10 However, the laparoscopic approach to appendectomy did

not come into widespread use until after the success of laparoscopic cholecystectomy. This

may be due to the fact that appendectomy, by virtue of its small incision, is already a form of

minimal-access surgery.77

Laparoscopic appendectomy is performed under general anesthesia. A nasogastric tube and a

urinary catheter are placed before obtaining a pneumoperitoneum. Laparoscopic

appendectomy usually requires the use of three ports. Four ports may occasionally be

necessary to mobilize a retrocecal appendix. The surgeon usually stands to the patient's left.

One assistant is required to operate the camera. One trocar is placed in the umbilicus (10

mm), and a second trocar is placed in the suprapubic position. Some surgeons place this

second port in the left lower quadrant. The suprapubic trocar is either 10 or 12 mm,

depending on whether or not a linear stapler will be used. The placement of the third trocar

(5 mm) is variable and usually is either in the left lower quadrant, epigastrium, or right upper

quadrant. Placement is based on location of the appendix and surgeon preference. Initially,

the abdomen is thoroughly explored to exclude other pathology. The appendix is identified by

following the anterior taeniae to its base. Dissection at the base of the appendix enables the

surgeon to create a window between the mesentery and the base of the appendix (Fig. 30-

8A). The mesentery and base of the appendix are then secured and divided separately. When

the mesoappendix is involved with the inflammatory process, it is often best to divide the

appendix first with a linear stapler and then to divide the mesoappendix immediately adjacent

to the appendix with clips, electrocautery, Harmonic Scalpel, or staples (Fig. 30-8B and 30-

8C). The base of the appendix is not inverted. The appendix is removed from the abdominal

cavity through a trocar site or within a retrieval bag. The base of the appendix and the

mesoappendix should be evaluated for hemostasis. The right lower quadrant should be

irrigated. Trocars are removed under direct vision.78,79

Fig. 30-8.

Laparoscopic resection of the appendix. Occasionally, if the appendix and mesoappendix areextremely inflamed, it is easier to divide the appendix at its base before division of themesoappendix. A. A window is created in the mesoappendix close to the base of the appendix. B.The linear stapler is then used to divide the appendix at its base. C. Finally the mesoappendix canbe easily divided using the linear stapler.

[Reproduced with permission from Ortega JM, Ricardo AE: Surgery of the appendix and colon, inMoody FG (ed): Atlas of Ambulatory Surgery. Philadelphia: WB Saunders, 1999.]

The utility of laparoscopic appendectomy in the management of acute appendicitis remains

controversial. Surgeons may be hesitant to implement a new technique because the

conventional open approach already has proved to be simple and effective. A number of

articles in peer-reviewed journals have compared laparoscopic and open appendectomy,

including >20 randomized, controlled trials and 6 meta-analyses.64,77,80â!“84 The overall

quality of these randomized, controlled trials has been limited by the failure to blind patients

and providers as to the treatment modality used. Furthermore, investigators have failed to

perform prestudy sample size analysis for the outcomes studied.64 The largest meta-analysis

comparing open to laparoscopic appendectomy included 47 studies, 39 of which were studies

of adult patients. This analysis demonstrated that the duration of surgery and costs of

operation were higher for laparoscopic appendectomy than for open appendectomy. Wound

infections were approximately half as likely after laparoscopic appendectomy as after open

appendectomy. However, the rate of intra-abdominal abscess was three times higher after

laparoscopic appendectomy than after open appendectomy.64

A principal proposed benefit of laparoscopic appendectomy has been decreased postoperative

pain. Patient-reported pain on the first postoperative day is significantly less after

laparoscopic appendectomy. However, the difference has been calculated to be only 8 points

on a 100-point visual analogue scale. This difference is below the level of pain that an

average patient is able to perceive.62 Hospital length of stay also is statistically significantly

less after laparoscopic appendectomy. However, in most studies this difference is <1

day.64,77 It appears that a more important determinant of length of stay after appendectomy

is the pathology found at operationâ!”specifically, whether a patient has perforated or

nonperforated appendicitis. In nearly all studies, laparoscopic appendectomy is associated

with a shorter period before return to normal activity, return to work, and return to

sports.64,77,80â!“84 However, treatment and subject bias may have a significant impact on

the data. Although the majority of studies have been performed in adults, similar data have

been obtained in children.64

There appears to be little benefit to laparoscopic appendectomy over open appendectomy in

thin males between the ages of 15 and 45 years. In these patients, the diagnosis usually is

straightforward. Open appendectomy has been associated with outstanding results for several

decades. Laparoscopic appendectomy should be considered an option in these patients, based

on surgeon and patient preference. Laparoscopic appendectomy may be beneficial in obese

patients, in whom it may be difficult to gain adequate access through a small right lower

quadrant incision. In a retrospective study of 116 patients with a mean body mass index of

35, postoperative length of stay was significantly shorter in the group undergoing laparoscopic

appendectomy, and there were fewer open wounds. In all obese patients in whom the

procedure was completed laparoscopically the incisions closed primarily, whereas the wounds

closed primarily in only 58% of obese patients who underwent open appendectomy. There

was no difference in rates of wound infection; intra-abdominal abscess rates were not

reported.85

Diagnostic laparoscopy has been advocated as a potential tool to decrease the number of

negative appendectomies performed. However, the morbidity associated with laparoscopy and

general anesthesia is acceptable only if pathology requiring surgical treatment is present and

is amenable to treatment using laparoscopic techniques. The question of leaving a normal

appendix in situ is a controversial one. Seventeen to 26% of appendices that appear normal

at exploration are found to have pathologic features on histologic analysis.80 The availability

of diagnostic laparoscopy may actually lower the threshold for exploration and thus adversely

impact the negative appendectomy rate.86 Fertile women with presumed appendicitis

constitute the group of patients most likely to benefit from diagnostic laparoscopy. Up to one

third of these patients do not have appendicitis at exploration. In most of the patients without

appendicitis, gynecologic pathology is identified.87 A large meta-analysis demonstrated that

in fertile women in whom appendectomy was deemed necessary, diagnostic laparoscopy

reduced the number of unnecessary appendectomies.64 In addition, the number of women

without a final diagnosis was smaller. It appears that leaving a normal-appearing appendix in

fertile women with identifiable gynecologic pathology is safe.87

In summary, it has not been resolved whether laparoscopic appendectomy is more effective

in treating acute appendicitis than the time-proven method of open appendectomy. It does

appear that laparoscopic appendectomy is effective in the management of acute appendicitis.

Laparoscopic appendectomy should be considered part of the surgical armamentarium

available to treat acute appendicitis. The decision on how to treat a specific patient with

appendicitis should be based on surgical skill, patient characteristics, clinical scenario, and

patient preference. Additional well-controlled, prospective, blinded studies are needed to

determine which subsets of patients may benefit from any given approach to the treatment of

appendicitis.

NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERYNatural orifice transluminal endoscopic surgery (NOTES) is a new surgical procedure using

flexible endoscopes in the abdominal cavity. In this procedure, access is gained by way of

organs that are reached through a natural, already-existing external orifice. The hoped-for

advantages associated with this method include the reduction of postoperative wound pain,

shorter convalescence, avoidance of wound infection and abdominal-wall hernias, and the

absence of scars. The first case of transvaginal removal of a normal appendix has recently

been reported.88 Much work remains to determine if NOTES provides any additional

advantages over the laparoscopic approach to appendectomy.

ANTIBIOTICS AS DEFINITIVE THERAPYTraditional management of acute appendicitis has emphasized emergent surgical

management. This approach has been based on the theory that, over time, simple

appendicitis will progress to perforation, with resulting increases in morbidity and mortality.

As a result, a relatively high negative appendectomy rate has been accepted to avoid the

possibility of progression to perforation. Recent data suggest that acute appendicitis and

acute appendicitis with perforation may be separate disease entities with distinct

acute appendicitis with perforation may be separate disease entities with distinct

pathophysiology. A time series analysis performed on a 25-year data set did not find a

significant negative relationship between the rates of negative appendectomy and

perforation.17 A study analyzing time to surgery and perforation demonstrated that risk of

rupture is minimal within 36 hours of symptom onset. Beyond this point, there is about a 5%

risk of rupture in each ensuing 12-hour period. However, in many patients the disease will

have an indolent course. In one study 10 of the 18 patients who did not undergo operation for

≥6 days after their symptoms began did not experience rupture.89

Many acute abdominal conditions such as acute diverticulitis and acute cholecystitis are

managed with urgent but not emergent surgery. Moreover, evidence from submarine

personnel who develop appendicitis suggests that nonoperative management of appendicitis

may be a viable treatment option. Sailors who develop appendicitis while stationed on

submarines do not have access to prompt surgical care. They are successfully treated with

antibiotics and fluids days to weeks after the initial attack until the ship can surface and they

can be transferred to a hospital for care.90

A randomized study comparing antibiotic treatment with immediate appendectomy has been

completed. Two hundred and fifty-two men 18 to 50 years of age with the presumptive

diagnosis of appendicitis were enrolled in the study between March 1996 and June 1999. For

patients randomly assigned to antibiotic therapy, if symptoms did not improve within the first

24 hours, an appendectomy was performed. Participants were evaluated after 1 week, 6

weeks, and 1 year. Acute appendicitis was found in 97% of the 124 patients randomly

assigned to surgery. Six patients (5%) had perforated appendices. The complication rate in

the surgery group was 14% (17 of 124). Of the 128 patients enrolled in the antibiotic group,

15 patients (12%) underwent operation within the first 24 hours due to lack of improvement

in symptoms and apparent local peritonitis. At operation seven patients (5%) had perforation.

The rate of recurrence within 1 year was 15% (16 patients) in the group treated with

antibiotics. In five of these patients a perforated appendix was found at operation.52 Although

it initially appears from these data that the use of antibiotics alone may be reasonable

therapy for acute appendicitis, there are several issues to take into account. First, this study

included only men between the ages of 18 and 50 and may not have broad applicability to all

patients with appendicitis, especially those populations known to have higher perforation

rates. Second, the incidence of perforation was 9% in the antibiotic group when patients

requiring operation in both the acute and delayed settings are considered. This compares

unfavorably with the perforation rate of 5% for those patients operated on immediately. In

addition, the study follow-up was only 1 year, which suggests that patients receiving only

antibiotic therapy may still be at risk for the development of appendicitis. Finally, when

patients are treated with antibiotics alone it is possible that diagnoses of significant pathology

such as carcinoid or carcinoma may be delayed.16 Because no laboratory test or clinical

investigation can reliably distinguish patients whose appendicitis is potentially amenable to

conservative treatment, surgery still remains the gold standard of care for patients with acute

appendicitis.

appendicitis.

INTERVAL APPENDECTOMYThe accepted approach for the treatment of appendicitis associated with a palpable or

radiographically documented mass (abscess or phlegmon) is conservative therapy with

interval appendectomy 6 to 10 weeks later. This technique has been quite successful and

produces much lower morbidity and mortality rates than immediate appendectomy.

Unfortunately, this treatment is associated with greater expense and longer hospitalization

time (8 to 13 days vs. 3 to 5 days).91

The initial treatment consists of IV antibiotics and bowel rest. Although this therapy is

generally effective, there is a 9 to 15% failure rate, with operative intervention required at 3

to 5 days after presentation. Percutaneous or operative drainage of abscesses is not

considered a failure of conservative therapy.

Although the second stage of this treatment plan, interval appendectomy, has usually been

carried out, the need for subsequent operation has been questioned. The major argument

against interval appendectomy is that approximately 50% of patients treated conservatively

never develop manifestations of appendicitis, and those who do generally can be treated

nonoperatively. In addition, pathologic examination of the resected appendix shows normal

findings in 20 to 50% of cases.

On the other hand, the data clearly support the need for interval appendectomy. In a

prospective series, 19 of 48 patients (40%) who were successfully treated conservatively

needed appendectomy at an earlier time (mean of 4.3 weeks) than the 10 weeks planned

because of bouts of appendicitis.91 Overall, the rate of late failure as a consequence of acute

disease averages 20%. An additional 14% of patients either continue to have, or redevelop,

right lower quadrant pain. Although the appendix may occasionally be pathologically normal,

persistent periappendiceal abscesses and adhesions are found in 80% of patients. In addition,

almost 50% have histologic evidence of inflammation in the organ itself. Several neoplasms

also have been detected in the resected appendices, even in those of children.16

The timing of interval appendectomy is somewhat controversial. Appendectomy may be

required as early as 3 weeks after conservative therapy. Two thirds of the cases of recurrent

appendicitis occur within 2 years, and this is the outside limit. Interval appendectomy is

associated with a morbidity rate of ≤3% and a hospitalization time of 1 to 3 days. The

laparoscopic approach has been used and has been successful in 68% of procedures.92 In a

more recent study in children, interval appendectomy was performed successfully using the

laparoscopic approach in all 35 patients.93

PrognosisThe mortality from appendicitis in the United States has steadily decreased from a rate of 9.9

per 100,000 in 1939 to 0.2 per 100,000 today. Among the factors responsible are advances

in anesthesia, antibiotics, IV fluids, and blood products. Principal factors influencing mortality

are whether rupture occurs before surgical treatment and the age of the patient. The overall

are whether rupture occurs before surgical treatment and the age of the patient. The overall

mortality rate in acute appendicitis with rupture is approximately 1%. The mortality rate of

appendicitis with rupture in the elderly is approximately 5%â!”a fivefold increase from the

overall rate. Death is usually attributable to uncontrolled sepsisâ!”peritonitis, intra-abdominal

abscesses, or gram-negative septicemia. Pulmonary embolism continues to account for some

deaths.

Morbidity rates parallel mortality rates and are significantly increased by rupture of the

appendix and, to a lesser extent, by old age. In one report, complications occurred in 3% of

patients with nonperforated appendicitis and in 47% of patients with perforations. Most of the

serious early complications are septic and include abscess and wound infection. Wound

infection is common but is nearly always confined to the subcutaneous tissues and responds

promptly to wound drainage, which is accomplished by reopening the skin incision. Wound

infection predisposes the patient to wound dehiscence. The type of incision is relevant;

complete dehiscence rarely occurs in a McBurney incision.

The incidence of intra-abdominal abscess secondary to peritoneal contamination from

gangrenous or perforated appendicitis has decreased markedly since the introduction of

potent antibiotics. The sites of predilection for abscesses are the appendiceal fossa, pouch of

Douglas, the subhepatic space, and between loops of intestine. In the latter site abscesses are

usually multiple. Transrectal drainage is preferred for an abscess that bulges into the rectum.

Fecal fistula is an annoying, but not particularly dangerous, complication of appendectomy

that may be caused by sloughing of the portion of the cecum inside a constricting purse-

string suture; by slipping of the ligature off a tied, but not inverted, appendiceal stump; or by

necrosis from an abscess encroaching on the cecum.

Intestinal obstruction, initially paralytic but sometimes progressing to mechanical obstruction,

may occur with slowly resolving peritonitis with loculated abscesses and exuberant adhesion

formation. Late complications are quite uncommon. Adhesive band intestinal obstruction after

appendectomy does occur, but much less frequently than after pelvic surgical therapy. The

incidence of inguinal hernia is three times higher in patients who have had an appendectomy.

Incisional hernia is like wound dehiscence in that infection predisposes to it, it rarely occurs in

a McBurney incision, and it is not uncommon in a lower right paramedian incision.94

CHRONIC APPENDICITIS

Whether chronic appendicitis is a true clinical entity has been questioned for many years.

However, clinical data document the existence of this uncommon disease.95 Histologic criteria

have been established. Characteristically, the pain lasts longer and is less intense than that of

acute appendicitis but is in the same location. There is a much lower incidence of vomiting,

but anorexia and occasionally nausea, pain with motion, and malaise are characteristic.

Leukocyte counts are predictably normal and CT scans are generally nondiagnostic.

At operation, surgeons can establish the diagnosis with 94% specificity and 78% sensitivity.

There is an excellent correlation between clinical symptomatology, intraoperative findings,

and histologic abnormalities. Laparoscopy can be used effectively in the management of this

and histologic abnormalities. Laparoscopy can be used effectively in the management of this

clinical entity. Appendectomy is curative. Symptoms resolve postoperatively in 82 to 93% of

patients. Many of those whose symptoms are not cured or recur are ultimately diagnosed with

Crohn's disease.95

APPENDICEAL PARASITES

A number of intestinal parasites cause appendicitis. Although Ascaris lumbricoides is the most

common, a wide spectrum of helminths have been implicated, including Enterobius

vermicularis, Strongyloides stercoralis, and Echinococcus granulosis. The live parasites

occlude the appendiceal lumen, causing obstruction. The presence of parasites in the appendix

at operation makes ligation and stapling of the appendix technically difficult. Once

appendectomy has been performed and the patient has recovered, therapy with helminthicide

is necessary to clear the remainder of the GI tract.

Amebiasis also can cause appendicitis. Invasion of the mucosa by trophozoites of Entamoeba

histolytica incites a marked inflammatory process. Appendiceal involvement is a component of

more generalized intestinal amebiasis. Appendectomy must be followed by appropriate

antiamebic therapy (metronidazole).

INCIDENTAL APPENDECTOMY

Decisions regarding the efficacy of incidental appendectomy should be based on the

epidemiology of appendicitis. The best data were published by the Centers for Disease Control

and Prevention based on the period from 1979 to 1984.11 During this period, an average of

250,000 cases of appendicitis occurred annually in the United States. The highest annual

incidence of appendicitis was in patients 9 to 19 years of age (23.3 per 10,000 population).

Males were more likely to develop appendicitis than females. Accordingly, the incidence during

teenage years was 27.6 in males and 20.5 in females per 10,000 population per year. Beyond

age 19 years, the annual incidence fell. Among those >45 years of age, the annual incidence

was 6 in 10,000 males and 4 in 10,000 females. When the life table technique was used, the

data identified a lifetime risk of appendicitis of 8.6% in men and 6.7% in women. Although

men were more likely to develop appendicitis, the preoperative diagnosis was correct in

91.2% of men and 78.6% of women. Similarly, perforation occurred more commonly in men

than in women (19.2 vs. 17.8%). In contrast to the number of cases of appendicitis, 310,000

incidental appendectomies were performed between 1979 and 1984, 62% of the total

appendectomies in men and 17.7% of those in women. Based on these data, 36 incidental

appendectomies had to be performed to prevent one patient from developing appendicitis.96

The financial aspects of the decision to perform incidental appendectomy were assessed.97

For open appendectomy, there was a financial disincentive to perform incidental

appendectomy. On an annual basis, $20,000,000 had to be spent to save the $6,000,000

cost of appendicitis. With the laparoscopic approach, it was cost effective to perform

incidental appendectomy only in patients <25 years of age and only if the reimbursement for

surgeons was 10% of the usual and customary charges. At a higher rate of reimbursement,

surgeons was 10% of the usual and customary charges. At a higher rate of reimbursement,

incidental appendectomy was not cost effective in any age group.

Although incidental appendectomy is generally neither clinically nor economically appropriate,

there are some special patient groups in whom it should be performed during laparotomy or

laparoscopy for other indications. These include children about to undergo chemotherapy, the

disabled who cannot describe symptoms or react normally to abdominal pain, patients with

Crohn's disease in whom the cecum is free of macroscopic disease, and individuals who are

about to travel to remote places where there is no access to medical or surgical care.98

Appendectomy is routinely carried out during performance of Ladd's procedure for

malrotation, because displacement of the cecum into the left upper quadrant would

complicate the diagnosis of subsequent appendicitis.

TUMORS

Appendiceal malignancies are extremely rare. Primary appendiceal cancer is diagnosed in 0.9

to 1.4% of appendectomy specimens.16 These tumors are only rarely suspected

preoperatively. Fewer than 50% of cases are diagnosed at operation.99 Most series report

that carcinoid is the most common appendiceal malignancy, representing >50% of the

primary lesions of the appendix.16,98,99 A review from the National Cancer Institute's

Surveillance, Epidemiology, and End Results (SEER) program found the age-adjusted

incidence of appendiceal malignancies to be 0.12 cases per 1,000,000 people per year.99

Data from the SEER program identified mucinous adenocarcinoma as the most frequent

histologic diagnosis (38% of total reported cases), followed by adenocarcinoma (26%),

carcinoid (17%), goblet cell carcinoma (15%), and signet-ring cell carcinoma (4%).99 Five-

year survival for appendiceal malignancies varies by tumor type. Patients with carcinoid

tumors have the best 5-year survival (83%), whereas those with signet-ring cell cancers have

the lowest (18%).99,100

CarcinoidThe finding of a firm, yellow, bulbar mass in the appendix should raise the suspicion of an

appendiceal carcinoid. The appendix is the most common site of GI carcinoid, followed by the

small bowel and then the rectum. Carcinoid syndrome is rarely associated with appendiceal

carcinoid unless widespread metastases are present, which occur in 2.9% of cases. Symptoms

attributable directly to the carcinoid are rare, although the tumor can occasionally obstruct

the appendiceal lumen much like a fecalith and result in acute appendicitis.16,100,101

The majority of carcinoids are located in the tip of the appendix. Malignant potential is related

to size, with tumors <1 cm rarely resulting in extension outside of the appendix or adjacent

to the mass. The mean tumor size for carcinoids is 2.5 cm.100 Carcinoid tumors usually

present with localized disease (64%). Treatment for tumors ≤1 cm is appendectomy. For

tumors larger than 1 to 2 cm located at the base or with lymph node metastases, right

hemicolectomy is indicated (Fig. 30-9). Despite these recommendations, SEER data indicate

hemicolectomy is indicated (Fig. 30-9). Despite these recommendations, SEER data indicate

that proper surgery for carcinoids is not performed at least 28% of the time.100

Fig. 30-9.

Algorithm for the management of patients with appendiceal carcinoid.

AdenocarcinomaPrimary adenocarcinoma of the appendix is a rare neoplasm with three major histologic

subtypes: mucinous adenocarcinoma, colonic adenocarcinoma, and adenocarcinoid.99 The

most common mode of presentation for appendiceal carcinoma is that of acute appendicitis.

Patients also may present with ascites or a palpable mass, or the neoplasm may be

discovered during an operative procedure for an unrelated cause. The recommended

treatment for all patients with adenocarcinoma of the appendix is a formal right

hemicolectomy. Appendiceal adenocarcinomas have a propensity for early perforation,

although they are not clearly associated with a worsened prognosis.101 Overall 5-year

survival is 55% and varies with stage and grade. Patients with appendiceal adenocarcinoma

are at significant risk for both synchronous and metachronous neoplasms, approximately half

of which will originate from the GI tract.99

MucoceleA mucocele of the appendix is an obstructive dilatation by intraluminal accumulation of

mucoid material. Mucoceles may be caused by one of four processes: retention cysts,

mucosal hyperplasia, cystadenomas, and cystadenocarcinomas. The clinical presentation of a

mucosal hyperplasia, cystadenomas, and cystadenocarcinomas. The clinical presentation of a

mucocele is nonspecific, and often it is an incidental finding at operation for acute

appendicitis. An intact mucocele presents no future risk for the patient; however, the opposite

is true if the mucocele has ruptured and epithelial cells have escaped into the peritoneal

cavity. As a result, when a mucocele is visualized at the time of laparoscopic examination,

conversion to open laparotomy is recommended. Conversion from a laparoscopic approach to

a laparotomy ensures that a benign process will not be converted to a malignant one through

mucocele rupture. In addition, laparotomy allows for thorough abdominal exploration to rule

out the presence of mucoid fluid accumulations.99

The presence of a mucocele of the appendix does not mandate performance of a right

hemicolectomy. The principles of surgery include resection of the appendix, wide resection of

the mesoappendix to include all the appendiceal lymph nodes, collection and cytologic

examination of all intraperitoneal mucus, and careful inspection of the base of the appendix.

Right hemicolectomy, or preferably cecectomy, is reserved for patients with a positive margin

at the base of the appendix or positive periappendiceal lymph nodes. Recently, a more

aggressive approach to ruptured appendiceal neoplasms has been advocated. This approach

includes a thorough but minimally aggressive approach at initial laparotomy, as described

earlier, with subsequent referral to a specialized center for consideration of re-exploration and

hyperthermic intraperitoneal chemotherapy.101

Pseudomyxoma PeritoneiPseudomyxoma peritonei is a rare condition in which diffuse collections of gelatinous fluid are

associated with mucinous implants on peritoneal surfaces and omentum. Pseudomyxoma is

two to three times more common in females than in males. Recent immunocytologic and

molecular studies suggest that the appendix is the site of origin for the overwhelming majority

of cases of pseudomyxoma. Pseudomyxoma is invariably caused by neoplastic mucus-

secreting cells within the peritoneum. These cells may be difficult to classify as malignant

because they may be sparse, widely scattered, and have a low-grade cytologic appearance.

Patients with pseudomyxoma usually present with abdominal pain, distention, or a mass.

Primary pseudomyxoma usually does not cause abdominal organ dysfunction. However,

ureteral obstruction and obstruction of venous return can be seen.102 Pseudomyxoma is a

disease that progresses slowly and in which recurrences may take years to develop or

become symptomatic.102 In a series from the Mayo Clinic, 76% of patients developed

recurrences within the abdomen.103 Lymph node metastasis and distant metastasis are

uncommon.

The use of imaging before surgery is advantageous to plan surgery. CT scanning is the

preferred imaging modality. At surgery a variable volume of mucinous ascites is found

together with tumor deposits involving the right hemidiaphragm, right retrohepatic space, left

paracolic gutter, ligament of Treitz, and the ovaries in women. Peritoneal surfaces of the

bowel are usually free of tumor. Thorough surgical debulking is the mainstay of treatment. All

gross disease and the omentum should be removed. If not done previously, appendectomy is

routinely performed. Hysterectomy with bilateral salpingo-oophorectomy is performed in

routinely performed. Hysterectomy with bilateral salpingo-oophorectomy is performed in

women. Survival is better in patients who undergo R0 or R1 resection than in patients who

undergo R2 resection (visible gross disease remaining).104 Because 5-year survival of

mucinous appendiceal neoplasms is only 30%, adjuvant intraperitoneal hyperthermic

chemotherapy is advocated as a standard adjunct to radical cytoreductive surgery.105

Cytoreductive surgery with intraperitoneal hyperthermic chemotherapy is a long, tedious

procedure with operative times of 300 to 1020 minutes reported. In addition, morbidity

(38%) and mortality (6%) are high. Cytoreductive surgery with intraperitoneal hyperthermic

chemotherapy is associated with a 5-year survival of between 53 and 78%. Survival is

associated with initial patient performance status.104â!“106

Any recurrence should be investigated completely. Recurrences are usually treated by

additional surgery. It is important to note that surgery for recurrent disease is usually difficult

and is associated with an increased incidence of unintentional enterotomies, anastomotic

leaks, and fistulas.102,103

LymphomaLymphoma of the appendix is extremely uncommon. The GI tract is the most frequently

involved extranodal site for non-Hodgkin's lymphoma.107 Other types of appendiceal

lymphoma, such as Burkitt's, as well as leukemia, have also been reported.108 Primary

lymphoma of the appendix accounts for 1 to 3% of GI lymphomas. Appendiceal lymphoma

usually presents as acute appendicitis and is rarely suspected preoperatively. Findings on CT

scan of an appendiceal diameter ≥2.5 cm or surrounding soft tissue thickening should

prompt suspicion of an appendiceal lymphoma. The management of appendiceal lymphoma

confined to the appendix is appendectomy. Right hemicolectomy is indicated if tumor extends

beyond the appendix onto the cecum or mesentery. A postoperative staging work-up is

indicated before initiating adjuvant therapy. Adjuvant therapy is not indicated for lymphoma

confined to the appendix.108,109

REFERENCES

Entries Highlighted in Bright Blue Are Key References.1. Geboes K: Appendiceal function and dysfunction: What are the implications for

inflammatory bowel disease? Nat Clin Pract Gastroenterol Hepatol 2:338, 2005. [PMID:

16265384]

2. Ajmani ML, Ajmani K: The position, length and arterial supply of vermiform appendix. Anat

Anz 153:369, 1983. [PMID: 6881534]

3. Fitz RH: Persistent omphalo-mesenteric remains: Their importance in the causation of

intestinal duplication, cyst formation, and obstruction. Am J Med Sci 88:30, 1884.

4. Radford-Smith GL, Edwards JE, Purdie DM, et al. Protective role of appendicectomy on

onset and severity of ulcerative colitis and Crohn's disease. Gut 51:808, 2002. [PMID:

12427781]

5. Ellis H: Appendix, in Schwartz SI (ed): Maingot's Abdominal Operations, 8th ed, vol. 2.

Norwalk, Conn: Appleton-Century-Crofts, 1985, p 1255.

6. Lewis F: Appendix, in Davis JH (ed): Clinical Surgery, 1st ed, vol. 1. St. Louis, Mo: Mosby,

1987, p 1581.

7. Fitz RH: Perforating inflammation of the vermiform appendix: With special reference to its

early diagnosis and treatment. Trans Assoc Am Physicians 1:107, 1886.

8. McBurney C: Experience with early operative interference in cases of disease of the

vermiform appendix. N Y State Med J 50:676, 1889.

9. McBurney C: The incision made in the abdominal wall in cases of appendicitis. Ann Surg

20:38, 1894. [PMID: 17860070]

10. Semm K: Endoscopic appendectomy. Endoscopy 15:59, 1983. [PMID: 6221925]

11. Addiss DG, Shaffer N, Fowler BS, et al: The epidemiology of appendicitis and

appendectomy in the United States. Am J Epidemiol 132:910, 1990. [PMID: 2239906]

12. Hale DA, Molloy M, Pearl RH, et al: Appendectomy: A contemporary appraisal. Ann Surg

225:252, 1997. [PMID: 9060580]

13. Flum DR, Morris A, Koepsell T, et al: Has misdiagnosis of appendicitis decreased over

time? A population-based analysis. JAMA 286:1748, 2001. [PMID: 11594900]

14. Flum DR, Koepsell T: The clinical and economic correlates of misdiagnosed appendicitis:

Nationwide analysis. Arch Surg 137:799, 2002. [PMID: 12093335]

15. Burkitt DP: The aetiology of appendicitis. Br J Surg 58:695, 1971. [PMID: 4937032]

16. Marudanayagam R, Williams GT, Rees BI: Review of the pathological results of 2660

appendicectomy specimens. J Gastroenterol 41:745, 2006. [PMID: 16988762]

17. Livingston EH, Woodward WA, Sarosi GA, et al: Disconnect between incidence of

nonperforated and perforated appendicitis: Implications for pathophysiology and management.

Ann Surg 245:886, 2007. [PMID: 17522514]

18. Rautio M, Saxen H, Siitonen A, et al: Bacteriology of histopathologically defined

appendicitis in children. Pediatr Infect Dis J 19:1078, 2000. [PMID: 11099090]

19. Allo MD, Bennion RS, Kathir K, et al: Ticarcillin/clavulanate versus imipenem/cilastatin for

the treatment of infections associated with gangrenous and perforated appendicitis. Am Surg

65:99, 1999. [PMID: 9926739]

20. Soffer D, Zait S, Klausner J, et al: Peritoneal cultures and antibiotic treatment in patients

with perforated appendicitis. Eur J Surg 167:214, 2001. [PMID: 11316408]

21. Kokoska ER, Silen ML, Tracy TF Jr., et al: The impact of intraoperative culture on

treatment and outcome in children with perforated appendicitis. J Pediatr Surg 34:749, 1999.

[PMID: 10359176]

22. Bilik R, Burnweit C, Shandling B: Is abdominal cavity culture of any value in appendicitis?

Am J Surg 175:267, 1998. [PMID: 9568649]

23. Andersen BR, Kallehave FL, Andersen HK: Antibiotics versus placebo for prevention of

postoperative infection after appendicectomy. Cochrane Database Syst Rev Issue

3:CD001439, 2005.

24. Mazuski JE, Sawyer RG, Nathens AB, et al: The Surgical Infection Society guidelines on

antimicrobial therapy for intra-abdominal infections: An executive summary. Surg Infect

3:161, 2002. [PMID: 12542922]

25. Berry J, Malt RA: Appendicitis near its centenary. Ann Surg 200:567, 1984. [PMID:

6385879]

26. Bower RJ, Bell MJ, Ternberg JL: Diagnostic value of the white blood count and neutrophil

percentage in the evaluation of abdominal pain in children. Surg Gynecol Obstet 152:424,

1981. [PMID: 7209769]

27. Smith DE, Kirchmer NA, Stewart DR: Use of the barium enema in the diagnosis of acute

appendicitis and its complications. Am J Surg 138:829, 1979. [PMID: 507300]

28. Douglas CD, Macpherson NE, Davidson PM, et al: Randomised controlled trial of

ultrasonography in diagnosis of acute appendicitis, incorporating the Alvarado score. Br Med J

321:1, 2000.

29. Franke C, Bohner H, Yang Q, et al: Ultrasonography for diagnosis of acute appendicitis:

Results of a prospective multicenter trial. World J Surg 23:141, 1999. [PMID: 9880422]

30. Kaiser S, Frenckner B, Jorulf HK: Suspected appendicitis in children: US and CTâ!”A

prospective randomized study. Radiology 223:633, 2002. [PMID: 12034928]

31. Jeffrey RB, Jain KA, Nghiem HV: Sonographic diagnosis of acute appendicitis: Interpretive

pitfalls. AJR Am J Roentgenol 162:55, 1994. [PMID: 8273690]

32. Puig S, Hormann M, Rebhandl W, et al: US as a primary diagnostic tool in relation to

negative appendectomy: Six years' experience. Radiology 226:101, 2003. [PMID: 12511675]

33. Rettenbacher T, Hollerweger A, Gritzmann N, et al: Appendicitis: Should diagnostic

imaging be performed if the clinical presentation is highly suggestive of the disease?

Gastroenterology 123:992, 2002. [PMID: 12360459]

34. Funaki B, Grosskreutz SR, Funaki CN: Using unenhanced helical CT with enteric contrast

material for suspected appendicitis in patients treated at a community hospital. AJR Am J

Roentgenol 171:997, 1998. [PMID: 9762983]

35. Raman SS, Lu DSK, Kadell BM, et al: Accuracy of nonfocused helical CT for the diagnosis

of acute appendicitis: A 5-year review. AJR Am J Roentgenol 178:1319, 2002. [PMID:

12034591]

36. Stroman DL, Bayouth CV, Kuhn JA, et al: The role of computed tomography in the

diagnosis of acute appendicitis. Am J Surg 178:485, 1999. [PMID: 10670858]

37. Weyant MJ, Eachempati SR, Maluccio MA, et al: Interpretation of computed tomography

does not correlate with laboratory or pathologic findings in surgically confirmed acute

appendicitis. Surgery 128:145, 2000. [PMID: 10922984]

38. Fuchs JR, Schlamberg JS, Shortsleeve MJ, et al: Impact of abdominal CT imaging on the

management of appendicitis: An update. J Surg Res 106:131, 2002. [PMID: 12127818]

39. Walker S, Haun W, Clark J, et al: The value of limited computed tomography with rectal

contrast in the diagnosis of acute appendicitis. Am J Surg 180:450, 2000. [PMID: 11182396]

40. Ujiki MB, Murayama KM, Cribbins AJ, et al: CT scan in the management of acute

appendicitis. J Surg Res 105:119, 2002. [PMID: 12121697]

41. Applegate KE, Sivit CJ, Salvator AE, et al: Effect of cross-sectional imaging on negative

appendectomy and perforation rates in children. Radiology 220:103, 2001. [PMID: 11425980]

42. Wise SW, Labuski MR, Kasales CJ, et al: Comparative assessment of CT and sonographic

techniques for appendiceal imaging. AJR Am J Roentgenol 176:933, 2001. [PMID: 11264081]

43. Wilson EB, Cole JC, Nipper ML, et al: Computed tomography and ultrasonography in the

diagnosis of appendicitis: When are they indicated? Arch Surg 136:670, 2001. [PMID:

11387006]

44. Rao PM, Rhea JT, Rattner DW, et al: Introduction of appendiceal CT: Impact on negative

appendectomy and appendiceal perforation rates. Ann Surg 229:344, 1999. [PMID:

10077046]

45. Rao PM, Rhea JT, Novelline RA, et al: Effect of computed tomography of the appendix on

treatment of patients and use of hospital resources. N Engl J Med 338:141, 1998. [PMID:

9428814]

46. Morris KT, Kavanagh M, Hansen P, et al: The rational use of computed tomography scans

in the diagnosis of appendicitis. Am J Surg 183:547, 2002. [PMID: 12034390]

47. Lee SL, Walsh AJ, Ho HS: Computed tomography and ultrasonography do not improve

and may delay the diagnosis and treatment of acute appendicitis. Arch Surg 136:556, 2001.

[PMID: 11343547]

48. Garcia Pena BM, Taylor GA, Fishman SJ, et al: Effect of an imaging protocol on clinical

outcomes among pediatric patients with appendicitis. Pediatrics 110:1088, 2002.

49. Alvarado A: A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med

15:557, 1986. [PMID: 3963537]

50. Paulson EK, Kalady MF, Pappas TN: Clinical practice. Suspected appendicitis. N Engl J Med

348:236, 2003. [PMID: 12529465]

51. Owings MF, Kozak LJ: Ambulatory and Inpatient Procedures in the United States, 1996.

National Center for Health Statistics Series 13, No. 139. Hyattsville, Md: Department of Health

and Human Services, Centers for Disease Control and Prevention, National Center for Health

Statistics, 2004.

52. Styrud J, Eriksson S, Nilsson I, et al: Appendectomy versus antibiotic treatment in acute

appendicitis: A prospective multicenter randomized controlled trial. World J Surg 30:1033,

2006.

53. Tingstedt B, Bexe-Lindskog E, Ekelund M, et al: Management of appendiceal masses. Eur

J Surg 168:579, 2002. [PMID: 12699091]

54. Willemsen PJ, Hoorntje LE, Eddes EH, et al: The need for interval appendectomy after

resolution of an appendiceal mass questioned. Dig Surg 19:216, 2002. [PMID: 12119525]

resolution of an appendiceal mass questioned. Dig Surg 19:216, 2002. [PMID: 12119525]

55. Haller JA Jr., Shaker IJ, Donahoo JS, et al: Peritoneal drainage versus non-drainage for

generalized peritonitis from ruptured appendicitis in children: A prospective study. Ann Surg

177:595, 1973. [PMID: 4704043]

56. Bongard F, Landers DV, Lewis F: Differential diagnosis of appendicitis and pelvic

inflammatory disease. A prospective analysis. Am J Surg 150:90, 1985. [PMID: 3160252]

57. Jepsen OB, Korner B, Lauritsen KB, et al: Yersinia enterocolitica infection in patients with

acute surgical abdominal disease. A prospective study. Scand J Infect Dis 8:189, 1976.

[PMID: 788144]

58. Knight PJ, Vassy LE: Specific diseases mimicking appendicitis in childhood. Arch Surg

116:744, 1981. [PMID: 7235971]

59. McDonald JC: Nonspecific mesenteric lymphadenitis: Collective review. Surg Gynecol

Obstet 116:409, 1963.

60. Morrison JD: Yersinia and viruses in acute non-specific abdominal pain and appendicitis.

Br J Surg 68:284, 1981. [PMID: 7225744]

61. Droegemueller W: Upper genital tract infections, in Herbst AL, Mishell DR, Stenchever

MW, et al (eds): Comprehensive Gynecology, 2nd ed. St. Louis, Mo: Mosbyâ!“Year Book,

1992, p 691.

62. Bundy DG, Byerley JS, Liles EA, et al: Does this child have appendicitis? JAMA 298:438,

2007. [PMID: 17652298]

63. Colvin JM, Bachur R, Kharbanda A: The presentation of appendicitis in preadolescent

children. Pediatr Emerg Care 23:849, 2007. [PMID: 18091591]

64. Sauerland S, Lefering R, Neugebauer EA: Laparoscopic versus open surgery for suspected

appendicitis. Cochrane Database Syst Rev Issue 4:CD001546, 2004.

65. Sheu B-F, Chiu T-E, Chen J-C, et al: Risk factors associated with perforated appendicitis

in elderly patients presenting with signs and symptoms of acute appendicitis. ANZ J Surg

77:662, 2007. [PMID: 17635280]

66. Young Y-R, Chiu T-F, Chen J-C, et al: Acute appendicitis in the octogenarians and beyond:

A comparison with younger geriatric patients. Am J Med Sci 334:255, 2007. [PMID:

18030181]

67. Harrell AG, Lincourt AE, Novitsky YW, et al: Advantages of laparoscopic appendectomy in

the elderly. Am Surg 72:474, 2006. [PMID: 16808197]

68. Andersen B, Nielsen TF: Appendicitis in pregnancy: Diagnosis, management and

complications. Acta Obstet Gynecol Scand 78:758, 1999. [PMID: 10535336]

69. McGory ML, Zingmond DS, Tillou A, et al: Negative appendectomy in pregnant women is

associated with a substantial risk of fetal loss. J Am Coll Surg 205:534, 2007. [PMID:

17903726]

70. Bree RL, Ralls PW, Bafle DM, et al: Evaluation of patients with acute right upper quadrant

pain. American College of Radiology. ACR Appropriateness Criteria. Radiology 215 Suppl:153,

2000.

71. Bailey LE, Finley RK Jr., Miller SF, et al: Acute appendicitis during pregnancy. Am Surg

52:218, 1986. [PMID: 3954275]

72. Flum DR, Steinberg SD, Sarkis AY, et al: Appendicitis in patients with acquired

immunodeficiency syndrome. J Am Coll Surg 184:481, 1997. [PMID: 9145068]

73. Mueller GP, Williams RA: Surgical infections in AIDS patients. Am J Surg 169(5A

Suppl):34S, 1995.

74. Bova R, Meagher A: Appendicitis in HIV-positive patients. Aust N Z J Surg 68:337, 1998.

[PMID: 9631905]

75. Lowy AM, Barie PS: Laparotomy in patients infected with human immunodeficiency virus:

Indications and outcome. Br J Surg 81:942, 1994. [PMID: 7922084]

76. Nadler EP, Gaines BA: The Surgical Infection Society guidelines on antimicrobial therapy

for children with appendicitis. Surg Infect (Larchmt) 9:75, 2008. [PMID: 18363471]

77. Golub R, Siddiqui F, Pohl D: Laparoscopic versus open appendectomy: A meta-analysis. J

Am Coll Surg 186:545, 1998. [PMID: 9583695]

78. Hunter JG: Advanced laparoscopic surgery. Am J Surg 173:14, 1997. [PMID: 9046878]

79. Scott-Conner CE: Laparoscopic gastrointestinal surgery. Med Clin North Am 86:1401,

2002. [PMID: 12510458]

80. Fingerhut A, Millat B, Borrie F: Laparoscopic versus open appendectomy: Time to decide.

World J Surg 23:835, 1999. [PMID: 10415210]

World J Surg 23:835, 1999. [PMID: 10415210]

81. Hunter JG: Clinical trials and the development of laparoscopic surgery. Surg Endosc 15:1,

2001. [PMID: 11178752]

82. McCall JL, Sharples K, Jadallah F: Systematic review of randomized controlled trials

comparing laparoscopic with open appendicectomy. Br J Surg 84:1045, 1997. [PMID:

9278639]

83. Ortega AE, Hunter JG, Peters JH, et al: A prospective, randomized comparison of

laparoscopic appendectomy with open appendectomy. Laparoscopic Appendectomy Study

Group. Am J Surg 169:208, 1995. [PMID: 7840381]

84. Pedersen AG, Petersen OB, Wara P, et al: Randomized clinical trial of laparoscopic versus

open appendicectomy. Br J Surg 88:200, 2001. [PMID: 11167866]

85. Corneille MG, Steigelman MB, Myers, JG, et al: Laparoscopic appendectomy is superior to

open appendectomy in obese patients. Am J Surg 194:877, 2007. [PMID: 18005788]

86. McGreevy JM, Finlayson SR, Alvarado R, et al: Laparoscopy may be lowering the threshold

to operate on patients with suspected appendicitis. Surg Endosc 16:1046, 2002. [PMID:

12165820]

87. Borgstein PJ, Gordijn RV, Eijsbouts QA, et al: Acute appendicitisâ!”a clear-cut case in

men, a guessing game in young women. A prospective study on the role of laparoscopy. Surg

Endosc 11:923, 1997. [PMID: 9294274]

88. Bernhardt J, Gerber B, Schober H-C, et al: NOTESâ!”case report of a unidirectional

flexible appendectomy. Int J Colorectal Dis 23:547, 2008. [PMID: 18256848]

89. Bickell NA, Aufses AA Jr., Rojas M, et al: How time affects the risk of rupture in

appendicitis. J Am Coll Surg 202:401, 2006. [PMID: 16500243]

90. Campbell MR, Johnston, SL III, Marshburn T, et al: Nonoperative treatment of suspected

appendicitis in remote medical care environments: Implications for future spaceflight medical

care. J Am Coll Surg 198:822, 2004. [PMID: 15110816]

91. Samuel M, Hosie G, Holmes K: Prospective evaluation of nonsurgical versus surgical

management of appendiceal mass. J Pediatr Surg 37:882, 2002. [PMID: 12037755]

92. Yamini D, Vargas H, Klein S, et al: Perforated appendicitis: Is it truly a surgical urgency?

Am Surg 64:970, 1998. [PMID: 9764704]

93. Owen A, Moore O, Marven S, et al: Interval laparoscopic appendectomy in children. J

Laparoendosc Adv Surg Tech A 16:308, 2006. [PMID: 16796448]

94. Cooperman M: Complications of appendectomy. Surg Clin North Am 63:1233, 1983.

[PMID: 6359499]

95. Mussack T, Schmidbauer S, Nerlich A, et al: Chronic appendicitis as an independent

clinical entity. Chirurg 73:710, 2002. [PMID: 12242981]

96. Wang HT, Sax HC: Incidental appendectomy in the era of managed care and laparoscopy.

J Am Coll Surg 192:182, 2001. [PMID: 11220718]

97. Sugimoto T, Edwards D: Incidence and costs of incidental appendectomy as a preventive

measure. Am J Public Health 77:471, 1987. [PMID: 3826467]

98. Fisher KS, Ross DS: Guidelines for therapeutic decision in incidental appendectomy. Surg

Gynecol Obstet 171:95, 1990. [PMID: 2193415]

99. McCusker ME, Cote TR, Clegg LX, et al: Primary malignant neoplasms of the appendix: A

population-based study from the Surveillance, Epidemiology and End Results program, 1973â

!“1998. Cancer 94:3307, 2002. [PMID: 12115365]

100. McGory ML, Maggard MA, Kang H, et al: Malignancies of the appendix: Beyond case

series reports. Dis Colon Rectum 48:2264, 2005. [PMID: 16258711]

101. Dhage-Ivatury S, Sugarbaker PH: Update on the surgical approach to mucocele of the

appendix. J Am Coll Surg 202:680, 2006. [PMID: 16571440]

102. Hinson FL, Ambrose NS: Pseudomyxoma peritonei. Br J Surg 85:1332, 1998. [PMID:

9782010]

103. Gough DB, Donohue JH, Schutt AJ, et al: Pseudomyxoma peritonei. Long-term patient

survival with an aggressive regional approach. Ann Surg 219:112, 1994. [PMID: 8129481]

104. Stewart JH IV, Shen P, Russell GB, et al: Appendiceal neoplasms with peritoneal

dissemination: Outcomes after cytoreductive surgery and intraperitoneal hyperthermic

chemotherapy. Ann Surg Oncol 13:624, 2006. [PMID: 16538401]

105. Sugarbaker PH: New standard of care for appendiceal epithelial neoplasms and

pseudomyxoma peritonei syndrome? Lancet Oncol 7:69, 2006. [PMID: 16389186]

106. McQuellon RP, Russell GB, Shen P, et al: Survival and health outcomes after

cytoreductive surgery with intraperitoneal hyperthermic chemotherapy for disseminated

peritoneal cancer of appendiceal origin. Ann Surg Oncol 15:125, 2008. [PMID: 18030535]

107. Crump M, Gospodarowicz M, Shepherd FA: Lymphoma of the gastrointestinal tract.

Semin Oncol 26:324, 1999. [PMID: 10375089]

108. Pickhardt PJ, Levy AD, Rohrmann CA Jr., et al: Non-Hodgkin's lymphoma of the

appendix: Clinical and CT findings with pathologic correlation. AJR Am J Roentgenol

178:1123, 2002. [PMID: 11959713]

109. Muller G, Dargent JL, Duwel V, et al: Leukaemia and lymphoma of the appendix

presenting as acute appendicitis or acute abdomen. Four case reports with a review of the

literature. J Cancer Res Clin Oncol 123:560, 1997. [PMID: 9393590]

Copyright © The McGraw-Hill Companies. All rights reserved.Privacy Notice. Any use is subject to the Terms of Use and Notice.