Appendectomy

Published on 11/04/2015 by admin

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CHAPTER 15 Appendectomy

Joseph Anthony P. Rodriguez, Robert E. Roses, Benjamin Braslow

Case Study

A 19-year-old male presents to the emergency room complaining of severe right-sided lower abdominal pain, nausea, and anorexia, which began 24 hours earlier. On physical examination, he has a fever of 100.5°F. His abdomen is focally tender on palpation of the right lower quadrant. His white blood cell count is within the normal range. A computed tomography (CT) scan of the abdomen and pelvis shows a thickened appendix and periappendiceal inflammation (Fig. 15-1).

Figure 15-1 Computed tomography scan showing a thickened appendix (A) and adjacent inflammation (B).

(From Rakel RE [ed]: Textbook of Family Medicine, 7th ed. Philadelphia, Saunders, 2007, courtesy of Dr. Perry Pernicano, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI.)

BACKGROUND

The appendix is a blind-ended tubular structure arising from the cecum approximately 2 cm below the ileocecal valve (Fig. 15-2). Obstruction of the lumen of the appendix by fecal material (i.e., fecalith), a tumor, or lymphoid hyperplasia may result in elevated intraluminal pressures, vascular congestion, stasis, bacterial overgrowth, and inflammation. Without intervention, the resulting appendicitis may progress to wall necrosis and appendiceal perforation. Prompt diagnosis and management are critical to the successful treatment of appendicitis. Despite the high incidence of appendicitis, however, its diagnosis is not always straightforward. The differential diagnosis of appendicitis is broad and may include gastroenteritis, Meckel’s diverticulitis, colonic diverticulitis, inflammatory bowel disease, urinary tract infection, epididymitis, and gastrointestinal and reproductive tract malignancies. Women of childbearing age who present with abdominal pain pose a particular diagnostic challenge because pelvic inflammatory disease, ovarian cysts, and ovarian torsion can also mimic appendicitis.

Figure 15-2 The appendix and mesoappendix. The appendix is located at the confluence of the three taenia coli, at the base of the cecum. The mesoappendix, containing the appendiceal vessels, suspends the appendix from the terminal ileum.

(From Drake RL, Vogl W, Mitchell AWM: Gray’s Anatomy for Students. Philadelphia, Churchill Livingstone, 2005.)

This chapter focuses on the perioperative and operative management of diseases of the appendix. Both laparoscopic and open approaches to appendectomy are frequently in use and are discussed.

INDICATIONS FOR SURGERY

I. Appendicitis: Appendectomy is indicated in all cases of suspected nonperforated appendicitis. Laparoscopic and open approaches are largely equivalent; however, each approach has advantages in selected situations. The open technique is generally less costly and is associated with shorter operative times. Laparoscopy allows for superior visualization of the peritoneal cavity and exclusion of other pathology when the diagnosis of appendicitis is equivocal. For this reason, laparoscopic appendectomy is often the preferred operation in women of childbearing age in whom the differential diagnosis for appendicitis is especially broad. Obese patients particularly benefit from the superior visualization and smaller incisions afforded by the laparoscopic approach as well.

II. In cases of perforated appendicitis, a role for nonoperative management, coupled with percutaneous drainage of periappendiceal collections, has emerged. Such an approach is supported by the relatively high complication rates and long recovery times associated with immediate operative management. Clinically stable patients with well-circumscribed abscesses at the time of presentation are typical candidates for such an approach. Most surgeons will perform an interval appendectomy, usually 6 to 8 weeks later. However, some have advocated forgoing this in light of the relatively low frequency and typically mild course of recurrent appendicitis in patients managed nonoperatively.

III. Neoplasm: Tumors of the appendix are present in approximately 5% of specimens after appendectomy for appendicitis, but are rarely diagnosed preoperatively. Carcinoid tumors are the most common malignancy of the appendix; most of these are small (<1 cm) and are adequately treated with simple appendectomy. Carcinoid tumors larger than 2 cm are associated with higher rates of metastases and should be treated with right hemicolectomy, as should tumors of any size located at the base of the appendix. Adenocarcinomas of the appendix are extremely rare and are generally treated with right hemicolectomy.

PREOPERATIVE EVALUATION

A. Patients with acute appendicitis typically provide a history of initial vague periumbilical or epigastric pain, reflecting distention of the appendix and stimulation of the visceral fibers of the autonomic nervous system. The pain subsequently becomes more severe and localizes to the right lower quadrant of the abdomen as the appendix becomes progressively more inflamed and irritates the adjacent peritoneum. Appendicitis is usually associated with anorexia. Nausea, emesis, and low-grade fever may also be present and typically follow the onset of pain.

B. Appendiceal perforation may be heralded by high fever, tachycardia, and more diffuse pain. Alternatively, some patients experience an interval of decreased pain and nausea immediately after perforation as a result of decompression of the distended appendix. Very young or elderly patients are more likely to present atypically and to be diagnosed after appendiceal perforation.

Is your patient hungry?

II. Physical Examination

A. Patients with appendicitis typically have a low-grade fever. High fevers (>101°F) are more common in the setting of appendiceal perforation. Focal tenderness in the right lower quadrant is usually present. McBurney’s point, located two thirds of the distance between the umbilicus and the anterior superior iliac crest, typically overlies the appendix and is, therefore, the point of maximal tenderness. Importantly, tenderness may be remote from McBurney’s point, reflecting the variable position of the appendix (Fig. 15-3).

B. Other signs associated with appendicitis include Rovsing’s sign, the psoas sign, and the obturator sign.

1. Rovsing’s sign is positive when right lower quadrant abdominal pain is exacerbated by palpating the left lower quadrant, reflecting the site of local peritoneal irritation.

2. The psoas sign

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