Chapter 30

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.

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 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.1–4

###### 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 ...

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