Appendectomy – Open

Overview

Historically, it is believed that British surgeon Claudius Amyand performed the first appendectomy during the repair of an inguinal hernia in 1735. However, inflammation of the appendix, including subsequent clinical sequelae of abscess and perforation, was first described in 1886 by Reginald Fitz.

Today, acute appendicitis is the most common surgical emergency of the abdomen, with more than 250,000 appendectomies performed annually in the United States. Although the diagnosis of appendicitis in a young man with acute abdominal pain localized to the right lower quadrant can be clear-cut, the clinical diagnosis may be less straightforward in women of childbearing age and in those at the extremes of age. In these patients, appendicitis can still be a challenging clinical entity to diagnose in a timely, accurate, and cost-effective manner.

Important considerations for surgeons and areas of debate include investigative radiology tests, such as computed tomography (CT) and ultrasonography, and the use of laparoscopy as a diagnostic and therapeutic approach. As with other etiologies of the acute abdomen, early and accurate recognition of patients requiring urgent operative repair should be the overriding principle in the workup and treatment of patients with suspected appendicitis. Delayed diagnosis in the treatment of acute appendicitis is associated with higher rates of perforation with resultant increased morbidity and mortality.

Presentation of Illness

Appendicitis is most frequently a disease of young and healthy individuals. The location, timing, and character of pain and associated symptoms are key factors to elicit in understanding the presentation of the disease. The classic symptoms are cramping and intermittent abdominal pain that usually begins in the periumbilical or epigastric region with subsequent migration to the right lower quadrant. As the course of appendicitis progresses, pain progresses from intermittent and cramping to constant and sharp in nature. If the appendix does not lie in an anterior or pelvic position, the diagnosis of appendicitis may be more difficult, leading to potential delay. In particular, a retrocecal appendix may not cause local signs of peritonitis.

The timing of nausea can also help to distinguish appendicitis, in which nausea follows the pain, from gastroenteritis, in which nausea typically precedes pain. In addition, most patients with gastroenteritis show evidence of anorexia. A low-grade fever is often present in uncomplicated appendicitis; high fevers are atypical for simple appendicitis and may be a sign of perforation, appendiceal abscess, or another disease process. Other clinical entities to be considered in the differential diagnosis include urinary tract infection, renal calculi, gastroenteritis, gynecologic diagnoses such as ruptured ovarian cyst or pelvic inflammatory disease, cholecystitis, diverticulitis, or small bowel obstruction.

Pathophysiology

The exact pathophysiology of acute appendicitis is not entirely clear, but the prevailing theory is that appendiceal luminal obstruction is the key mechanism. In children, lymphoid hyperplasia, often in the setting of infection or dehydration, is thought to be the most common etiology of obstruction.

In the adult population, fecaliths are the main causes of obstruction leading to acute appendicitis; other causes are scarring, which is rare, or tumor. Obstruction causes distension of the lumen of the appendix, yielding increased intramural and intraluminal pressures. This leads to lymphatic and vascular compromise with ischemia and then necrosis of the appendix with associated bacterial overgrowth. In the first 24 hours, the great majority of patients have inflammation and possibly necrosis, with perforation uncommon. Approximately two thirds of patients with perforated appendicitis have had symptoms for more than 48 hours. Early in appendicitis, the most common bacteria are aerobic organisms. In contrast, late appendicitis is associated with mixed infections. Common organisms associated with late appendicitis are Escherichia coli, Streptococcus spp., Proteus spp., Bacteroides fragilis, and Pseudomonas spp.

Diagnosis