Appendectomy

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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).

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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.

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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

I. History

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 is present when pain is elicited by extending the right hip with the patient lying on the left side. The presence of a psoas sign suggests a retrocecal appendix.
3. The obturator sign is present when pain is elicited by flexing and internally rotating the rig, and suggests a pelvic appendix.

III. Laboratory Tests

A. Leukocytosis may accompany appendicitis. A white blood cell count of greater than 18,000 cells/mm3 is unusual in the absence of perforation or an abscess.
B. Urinalysis is helpful in excluding alternative diagnoses; however, red and white blood cells are sometimes detected in the urine during appendicitis when the inflamed appendix abuts the right ureter or bladder.

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Figure 15-3 Variable position of the appendix.

(From Kelly HA, Hurdon E: The Vermiform Appendix and Its Diseases. Philadelphia, WB Saunders, 1905.)

Does your patient exhibit signs or symptoms consistent with appendiceal perforation?

IV. Radiographic Studies

A. Abdominal radiographs are frequently obtained but are rarely helpful in the diagnosis of appendicitis. They may, however, point to alternative diagnoses (e.g., renal or ureteral calculi). Rarely, a radio-opaque fecalith in the right lower quadrant or free intraperitoneal air from an appendiceal perforation is visible.
B. Ultrasonography is both sensitive and specific for the diagnosis of appendicitis but is highly operator dependent. Ultrasonographic findings suggestive of appendicitis include a noncompressible appendix, an appendix with an anteroposterior diameter of 7 mm or greater, the presence of a fecalith, and periappendiceal fluid.
C. CT scanning of the abdomen and pelvis with intravenous and oral contrast has a sensitivity and specificity of greater than 95% for the diagnosis of appendicitis. Periappendiceal inflammation and appendiceal wall thickening are diagnostic of appendicitis (Fig. 15-4). CT scanning is also of utility in identifying abscesses or phlegmons associated with perforated appendicitis.

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Figure 15-4 Evaluation for suspected appendicitis. CBC, complete blood count; CT, computed tomography; PE, physical examination; U/A, urinalysis.

(Adapted from Feldman M, Friedman LS, Brandt LJ [eds]: Sleisenger and Fordtran’s Gastrointestinal and Liver Disease, 8th ed. Philadelphia, Saunders, 2006.)

COMPONENTS OF THE PROCEDURE AND APPLIED ANATOMY

Preoperative Considerations

I. Once the diagnosis of acute appendicitis is established, broad-spectrum antibiotic therapy should be initiated.
II. Before laparoscopy, an orogastric tube and a urinary catheter should be placed for decompression of the stomach and urinary bladder, respectively.

Open Appendectomy

I. Incision and Exposure

A. Open appendectomy is most often performed through either a transverse (Rocky-Davis) or an oblique (McBurney) incision (Fig. 15-5). If greater exposure is required, the transverse incision can more readily be extended past the lateral edge of the rectus sheath than can the oblique incision. Therefore a transverse incision is generally preferred.
B. Regardless of whether a transverse or an oblique incision is chosen, a muscle-splitting (sparing) technique is used. Subcutaneous fat is bluntly dissected away to expose the external oblique aponeurosis. The external and internal oblique aponeuroses are sharply divided. The transversus abdominis muscle fibers are retracted to expose the underlying transversalis fascia, which, along with the underlying peritoneum, is sharply incised.
C. If murky or purulent fluid is encountered on entry into the peritoneal cavity, it is sampled and sent for Gram stain and culture to aid in postoperative antibiotic selection if postoperative antibiotic therapy is indicated.
D. The appendix is delivered into the wound with a gentle finger sweep from lateral to medial in the right paracolic gutter. Alternatively, the teniae of the right colon are followed to their convergence to identify the base of the appendix.

II. Appendectomy

A. The mesoappendix, which contains the appendiceal artery, is divided between ties (Fig. 15-6). The base of the appendix is then divided between clamps. The base is ligated, and the appendix is removed.
B. The mucosa of the appendiceal stump is cauterized to prevent mucocele formation.
C. The appendiceal stump can be inverted by placement of a Z-stitch (Fig. 15-7) or a purse-string suture.

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Figure 15-5 Common incisions for open appendectomy (dashed lines).

(From Ortega JM, Ricardo AE: Surgery of the appendix and colon. In Moody FG [ed]: Atlas of Ambulatory Surgery. Philadelphia, WB Saunders, 1999.)

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Figure 15-6 Division of the mesoappendix.

(From Ortega JM, Ricardo AE: Surgery of the appendix and colon. In Moody FG [ed]: Atlas of Ambulatory Surgery. Philadelphia, WB Saunders, 1999.)

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Figure 15-7 Division of the appendix. A, The appendix is divided after ligation. B, A Z- or purse-string stitch is placed in the cecum. C, The appendiceal stump is inverted.

(From Ortega JM, Ricardo AE: Surgery of the appendix and colon. In Moody FG [ed]: Atlas of Ambulatory Surgery. Philadelphia, WB Saunders, 1999.)

Inversion of the appendiceal stump is controversial because the resulting bulge in the cecal wall can be mistaken for a polypoid lesion on subsequent colonoscopy.

III. Irrigation and Closure

A. The right lower quadrant is irrigated, and the transversalis fascia and peritoneum, internal oblique aponeurosis, and external oblique aponeurosis are closed in three layers.
B. If the appendix was nonperforated, the skin is typically closed. If the appendix was perforated, the skin is either left open, left to close secondarily, or loosely closed with staples.

Laparoscopic Appendectomy

I. Port Placement

A. Laparoscopic appendectomy is generally performed through three operative ports: a port for the camera (most often through or below the umbilicus), a 12-mm port through which a surgical stapler can be passed, and an additional port to aid in retraction and dissection. The location of the latter two ports is highly variable.
B. Access to the abdomen is obtained with a Veress needle using a “blind” percutaneous technique or an open technique. The open technique is more commonly used.

THE VERESS NEEDLE APPROACH SHOULD NOT BE USED IN PATIENTS WHO HAVE HAD PREVIOUS ABDOMINAL SURGERY.

C. Open technique for placement of the first port

1. A horizontal incision is made below the umbilicus.
2. Subcutaneous soft tissue is bluntly dissected to expose the linea alba. The fascia and underlying peritoneum are divided at the midline under direct vision.
3. Fascial sutures are placed to secure the port and minimize CO2 leakage and loss of pneumoperitoneum. The port is inserted through the incision with a blunt-tipped trocar.
4. CO2 is insufflated through the port. The abdomen should distend symmetrically and become uniformly tympanic.
5. The laparoscope is inserted through the umbilical port, and the peritoneal cavity is surveyed.

D. Placement of the remaining ports: The remaining two ports are inserted under direct intra-abdominal visualization. Cutting (sharp) introducers are used to penetrate the fascia and enter the peritoneal cavity.

II. Exposure and Appendectomy

A. The abdominal cavity is surveyed before identification of the appendix in the right lower quadrant.
B. The tip of the appendix is retracted anteriorly to expose the mesoappendix. A dissector is used to bluntly create an opening in the mesoappendix adjacent to the base of the appendix.
C. The bottom jaw of a surgical stapler is passed through the opening in the mesoappendix, and the stapler is fired across the base of the appendix. The stapler is then used to divide the mesoappendix separately (Fig. 15-8).

III. Irrigation and Closure

A. The right lower quadrant is irrigated with normal saline and inspected for hemostasis. The umbilical fascia is closed.
B. All skin incisions are closed with absorbable suture.

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Figure 15-8 A, Division of the appendix using an endostapler. B, Division of the mesoappendix with an endostapler.

(From Ortega JM, Ricardo AE: Surgery of the appendix and colon. In Moody FG [ed]: Atlas of Ambulatory Surgery. Philadelphia, WB Saunders, 1999.)

Additional Considerations

I. Appendicitis in Pregnancy

A. Appendicitis is the most common indication for surgery in pregnant patients. The diagnosis of appendicitis is particularly challenging in this setting because early signs and symptoms of appendicitis, including nausea, emesis, and leukocytosis, are also attributable to pregnancy. Additionally, the gravid uterus may push the appendix away from its normal location, resulting in an atypical distribution of pain. As a result, diagnosis is frequently delayed until symptoms become relatively severe.
B. Prompt diagnosis and treatment are particularly important because perforated appendicitis is associated with fetal mortality rates of as high as 35%. Ultrasound poses no risk to the fetus and is frequently used to aid in diagnosis. In contrast, CT scanning should be used judiciously to minimize unnecessary radiation exposure. Magnetic resonance imaging is emerging as a reliable, and likely safe, alternative to CT scanning when the diagnosis of appendicitis is equivocal. Open appendectomy remains the most common approach to appendectomy in the setting of pregnancy, although the laparoscopic approach is increasingly being used as well.

II. The Normal Appendix: When a noninflamed appendix is encountered during open exploration through a right lower quadrant incision, generally, the appendix should still be removed to avoid future diagnostic confusion. It is less clear whether a noninflamed appendix should be removed during laparoscopic exploration.
III. Inflammatory Bowel Disease: Crohn’s disease may mimic appendicitis. Indeed, the diagnosis of inflammatory bowel disease after surgical exploration for appendicitis is not uncommon. When evidence of Crohn’s disease rather than appendicitis is encountered during operative exploration, generally, the appendix should still be removed to avoid future diagnostic confusion. Inflammation involving the cecum and the base of the appendix sometimes precludes safe appendectomy.

POSTOPERATIVE COURSE

Patients typically have little postoperative pain after appendectomy. Urinary catheters should be removed before emergence from anesthesia. A clinically significant postoperative ileus is uncommon, and patients can be fed shortly after recovery from anesthesia. Postoperative antibiotic therapy is unnecessary. Most patients are discharged within 48 hours of surgery.

FORMAL PATHOLOGIC EVALUATION OF THE SURGICAL SPECIMEN SHOULD BE REVIEWED TO EXCLUDE A MISSED NEOPLASM.

Perforated appendicitis is associated with a more protracted postoperative recovery. Ileus is common, and diet should be advanced gradually. Postoperative antibiotic therapy is indicated, at least until the patient is afebrile for more than 24 hours and the white blood cell count normalizes.

COMPLICATIONS

I. Surgical site infections and intra-abdominal abscess formation are particularly common after appendectomy for perforated appendicitis. By leaving the skin open and allowing for closure by secondary intention, the risk of superficial infection is minimized. Intra-abdominal abscesses are usually amenable to percutaneous drainage and rarely require reoperation.
II. Although it is uncommon, significant intraoperative or postoperative bleeding may result from inadequate ligation of the mesoappendix and appendiceal artery.

SUGGESTED READINGS

Lally KP, Cox CS, Andrassy RJ. Appendix. In Townsend CM, Beauchamp RD, Evers BM, Mattox KL, editors: Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice, 17th ed, Philadelphia: Saunders, 2004.

Paulson EK, Kalady MF, Pappas TN. Clinical practice: suspected appendicitis. N Engl J Med. 2003;348:236-242.

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