Frequently asked questions about Acute Appendicitis

 

Introduction

Acute appendicitis (AA), a common intra-abdominal surgical pathology, requires a comprehensive understanding of its presentation, diagnosis, evaluation, and overall operative management. The overall incidence of AA is approximately 7%, with a mortality rate of 0.2-0.8%. The morbidity and mortality are related to the presenting stage of disease and increases in cases of perforation. Briefly, the pathophysiology and progressive timeline of AA is attributed to luminal obstruction, causing distention, ineffective venous and lymphatic drainage, bacterial invasion, and, finally, perforation with associated leakage of contents into the peritoneal cavity. The presentation, evaluation, and diagnosis of AA are notoriously inconsistent; many factors attribute to these discrepancies. The classic history consists of anorexia and periumbilical pain, followed by nausea, right lower quadrant (RLQ) pain, and vomiting, as well as leukocytosis.

History and physical examination should provide enough clinical information to diagnose AA, with the use of imaging as adjuncts in the assessment. Treatment consists of providing aggressive intravenous fluid resuscitation and antibiotics, placing the patient nil per os and on pain control, and obtaining a general surgical consultation for definitive operative management.

A delay of the time of admission with acute to the time of appendectomy was associated with an increased risk for surgical port site infection among patients with non-perforated appendicitis. As a surgical community, a good laparoscopic surgeon should attempt to decrease the rate of complications of laparoscopic appendectomy. Port site infection has been used as a marker of quality care delivery. Identifying something that we do that increases the rate of port site infection is very relevant. In the retrospective study, the records of patients admitted with appendicitis were reviewed over the eight-year period, 4,529 patients were admitted with appendicitis and 4,108 (91%) underwent appendectomy.

Perforation occurred in 23% (942) of the patients who received laparoscopic appendectomy. A delay to laparoscopic appendectomy was not associated with a higher perforation rate. After adjusting for age, leukocytosis, sex, minimal access surgical technique and perforation, the time from admission to appendectomy greater than six hours was independently associated with an increase in port site infection. Time to appendectomy did not significantly increase port site risk in patients with perforated appendicitis, but it did so in patients without perforation. The average time from admission to appendectomy was 11 hours and 50 minutes. Dr. Teixeira noted that this was “a little long,” although 36% of patients were operated on within six hours.

As with other laparoscopic surgeries, the literature describes decreased pain, earlier resumption of diet, and decreased length of hospital stay for appendectomy. However, this must be objectively contrasted to the open procedure, which already involves minimal risk, extremely short length of hospital stay, and a low rate of complications. Additional disadvantages of laparoscopy include increased cost and longer operating times. The operative technique for AA consists of an appendectomy; however, the choice of either an open or laparoscopic operation continues to be challenged in the medical literature. Historically, the RLQ incision of open appendectomy has persisted essentially unchanged. The use of laparoscopy in the surgical management of AA was first described in 1983, with a continued increasing trend in its use.

Function

Histologically, the walls of the appendix contain not only mucous-secreting goblet cells but lymphoid tissue (developing during the 14th and 15th weeks of gestation), implying immune function in early development. Nevertheless, no specific function in the adult has been determined.

Anatomy

The appendix is an elongated out pouching of the cecum, found at its posteromedial aspect about 2.5 cm below the ileocecal valve. It is derived embryologically from the midgut and first noted between the 5th and 8th weeks of gestation. It subsequently becomes fixed in the RLQ of the abdomen as the gut rotates during development.

Positions of the appendix

The base of the appendix can be identified during surgery by following the convergence of the taenia coli toward the inferior portion of the cecum, forming a continuous muscular layer surrounding the appendix. The position of the appendicular tip is inconstant and can be in various locations, including retrocecal (65%); descending pelvic (31%); transverse and retrocecal (2.5%); ascending, paracecal, and preileal (1%); and ascending, paracecal, and postileal (0.4%). This varied location explains the vast array of presentations.

Blood supply

The blood supply of the appendix is derived from the appendicular artery, originating from the iliac ramus in 35% of cases, the ileocolic artery in 31%, the anterior cecal artery in 20%, the posterior cecal artery in 12%, and the ascending colic ramus in 2%. The venous drainage parallels that of the arterial supply.

Associated structures

Mesoappendix

The mesoappendix consists of the mesentery of the appendix, containing all of the appendicular nerves and vasculature, which is ligated during an appendectomy.

Fold of Treves

The Fold of Treves, another useful anatomic landmark in locating the appendix during surgery, not only represents an a vascular structure but is the only epiploic appendage located at the antimesenteric border of the small intestine. It also serves as a marker indicating the junction of the ileum and cecum.

Indications

To consider the indications for laparoscopic appendectomy, it is more fitting to describe the contraindications, with the notion that all else falls into the indications category.

Contraindications

Absolute contraindications to laparoscopic appendectomy are hemodynamic instability and lack of surgical expertise.

Relative contraindications include severe abdominal distention that causes operative view obstruction or complicates abdominal entry and bowel manipulation, generalized peritonitis, multiple previous surgical procedures, severe pulmonary disease, pregnancy, and extreme obesity. That said, as laparoscopic technology advances and surgeons' expertise increases, many surgeons have successfully performed a multitude of laparoscopic procedures in the presence of these relative contraindications.

If intra-operative complications that cannot be handled using laparoscopy arise during laparoscopic appendectomy, understanding when to convert to an open appendectomy is crucial. Relative indications for conversion include the following:

  • Inability to visualize the appendix
  • Tumor of the appendix extending into base
  • Gangrenous or necrotic base
  • Dense adhesions due to inflammation or prior surgeries
  • Perforated or gangrenous appendicitis
  • Generalized peritonitis
  • Other pathology, including malrotation, carcinoma, diverticula of cecum, endometriosis, pelvic inflammatory diseases, torsion of tubo-ovarian cyst
  • Retrocecal appendix
  • Uncontrolled bleeding
  • Unexpected diagnosi