Clinical guidelines, computed tomography scan, and negative appendectomies: a case series.

INTRODUCTION: Prior studies suggest that preoperative abdominal computed tomography (CT) scan can contribute to a low negative appendectomy rate. Our study objective was to evaluate cases of negative appendectomies for clinical criteria and CT use.

METHODS: Retrospective 1-year study of all negative appendectomies at a community hospital. Data included clinical evidence for appendicitis as well as CT results if performed.

RESULTS: Of 122 cases reviewed, 8 (6.6%) were negative appendectomies. Six were younger than 20 years. Four had a preoperative CT scan. Overall, 106 (87%) of 122 cases received preoperative CT and had a negative appendectomy rate of 3.8%. Sixteen cases did not have preoperative CT and had a negative appendectomy rate of 25% (odds ratio, 8.5; 95% confidence interval, 1.9-38.5; Fisher exact test P = .01).

CONCLUSION: Patients who had a CT scan for suspected appendicitis had a lower rate of negative appendectomies than those who had no CT. Most of the negative appendectomies occurred in patients younger than 20 years.