UM Focus

Lower rates of unnecessary appendectomies

Helical CT scanners present fewer surprises

By Elgin K. Kennedy, MD

Editor, The Assertive Utilization and Quality Report

A recent study from Massachusetts General Hospital shows that routine use of helical computed tomography (CT) scans of the appendix in patients with suspected appendicitis simultaneously saves money and improves quality of care.1,2 The diagnosis of appendicitis is initially missed in about 20% of patients, and missed appendicitis is the most frequently successful malpractice claim against emergency department (ED) physicians. Delay increases the risk of appendiceal perforation, and perforation increases the risk of postoperative complications from 8% to 39%.

Also, of those undergoing emergency surgery for appendicitis, the appendix is normal in 20% of patients. Some conditions that can mimic acute appendicitis are right-sided kidney stones, acute cholecystitis, ovarian cyst, pelvic inflammatory disease, mesenteric adenitis, and food poisoning.

Patients with classic acute appendicitis initially will have epigastric or central abdominal pain, followed by anorexia, nausea, and vomiting. Pain and tenderness then move to the right lower quadrant, followed by a low-grade fever, and finally leukocytosis. However, many appendicitis patients have atypical findings due to the fact that fever and leukocytosis do not always present, and to the difficulty in assessing and locating pain. It is difficult for clinicians to make accurate diagnoses on clinical grounds alone.

The investigators assessed 100 consecutive ED patients to be admitted for suspected appendicitis based on history, physical examination, and laboratory tests. They gave each patient an appendiceal CT scan. The physician treatment plans made before the CT scans were compared with the patients' actual treatments once the CT results were known. The helical scans were 98% accurate in confirming or ruling out appendicitis as determined by surgical pathology or clinical follow-up after two months.

Appendicitis constituted the final diagnosis in only 53 of the 100 patients. Learning the results of the CT scans led to changes in the treatment of more than half the patients, including the prevention of an unnecessary appendectomy in 13. At a cost of $3,647 per appendectomy, this is a total savings of $47,281. Add to that the savings associated with avoided admissions for observation, and the total savings are $67,531. The appendiceal CT cost is $228 per patient. Subtracting that $22,800 from $67,531 leaves a cost savings of $44,731, or $447 per patient.

The helical CT has an accuracy of 93% to 98% in confirming or ruling out appendicitis. By contrast, ultrasonography's accuracy is 83%. The CT completes a scan in one breath (15 seconds) and provides superior images with no motion artifact. Radiologic interpretation can be available within an hour.

A helical CT scanner costs about $1.5 million and has been available for only a few years. Many smaller-to-medium-sized facilities do not have one. In addition, your ED physicians and surgeons must be willing to order the scans, and on-call radiologists must be willing to provide the tests on an emergency basis. All may agree when it comes down to reducing the rate of unnecessary appendectomies from the national average of 20% to less than 5%.


1. Rao PM, Rhea JT, Novelline RA, et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med 1998; 338:141-146.

2. McColl I. More precision in diagnosing appendicitis (editorial). N Engl J Med 1998; 338:190-191.

[Editor's note: The preceding article was first published in the September 1997 issue of The Assertive Utilization and Quality Report - $60 per year (12 issues). For more information, contact Elgin Kennedy, MD, at 204 Second Ave., #334, San Mateo, CA 94401. Telephone: (415) 348-3647.]