Chapter 30: The Appendix

KEY POINTS

1. Appendicitis is one of the most common surgical emergencies in contemporary medicine, with a yearly incidence rate of about 100 per 100,000 inhabitants. Lifetime risk for appendicitis is 8.6% for males and 6.7% for females, with the highest incidence in the second decade of life.

2. The natural history of appendicitis is unclear, but it appears that progression to perforation is not predictable and that spontaneous resolution is common, suggesting that nonperforated and perforated appendicitis may, in fact, be different diseases.

3. Right lower quadrant pain, gastrointestinal symptoms starting after the onset of pain, and a systemic inflammatory response with leukocytosis and neutrophilia, increased C-reactive protein concentration, and fever are considered diagnostic of appendicitis. The Appendicitis Inflammatory Response Score or Alvarado score can help improve diagnostic accuracy.

4. Computed tomography scan has improved diagnostic accuracy in individual studies. However, in population-wide studies, the rate of misdiagnosis of appendicitis remains constant. Rates of misdiagnosis are highest in female patients of child-bearing age and patients on the extremes of age (i.e., very young and very old).

5. The role of nonoperative treatment for uncomplicated appendicitis remains controversial. Currently, appendectomy remains the standard of care. Laparoscopic appendectomy has a slight benefit over open appendectomy.

6. Perforated or complicated appendicitis is more common in the very young (age <5 years) and very old (age >65 years).

7. Complicated appendicitis without signs of sepsis or generalized peritonitis may benefit from nonoperative management. The role of interval appendectomy in these cases remains controversial.

8. Single-incision appendectomy provides no obvious advantage over standard laparoscopic appendectomy. Natural orifice transluminal endoscopic surgery remains an investigational procedure.

9. The incidence of fetal loss following normal appendectomy in pregnant patients is 4%, and the risk of premature delivery is 10%. The greatest opportunity to improve fetal outcomes may be through improving diagnostic accuracy and reducing the rate of negative appendectomy.

10. Antibiotic prophylaxis is effective in the prevention of postoperative surgical site infection. Postoperative antibiotics are unnecessary following uncomplicated appendicitis. For complicated appendicitis, a treatment duration of 4 to 7 days is recommended.

11. The role of incidental appendectomy is limited to patients at high risk for misdiagnosis of appendicitis (malrotation, patients unable to respond or react normally), patients at high risk for complications with appendicitis (children ready to undergo chemotherapy), and patients with limited access to modern healthcare.

12. The prevalence of appendiceal malignancy remains at or below 1% of appendectomies. Carcinoid and mucinous adenocarcinoma remain the most frequent histologic diagnosis.

HISTORICAL BACKGROUND

Appendiceal disease is a frequent reason for emergency hospital admission, and appendectomy is one of the most common emergency procedures performed in contemporary medicine. Despite the prevalent role this organ plays in healthcare today, the human appendix was not noted until 1492. Leonardo da Vinci depicted the appendix in his anatomic drawings, but these were not published until the eighteenth century.¹ In 1521, Berengario Da Capri and, in 1543, Andreas Vesalius published drawings recognizing the appendix.²