A Prospective Randomized Study of Clinical Assessment versus Computed Tomography for the Diagnosis of Acute Appendicitis

John J. Hong, Stephen M. Cohn, A. Peter Ekeh, Martin Newman, Moises Salama, Suzanne D. Leblang, for the Miami Appendicitis Group

In This Article

Abstract and Introduction

Background: The objective of this study was to determine if routine use of computed tomography (CT) for the diagnosis of appendicitis is warranted.
Methods: During a one-year study period, all patients who presented to the surgical service with possible appendicitis were studied. One hundred eighty-two patients with possible appendicitis were randomized to clinical assessment (CA) alone, or clinical evaluation and abdominal/pelvic CT. A true-positive case resulted in a laparotomy that revealed a lesion requiring operation. A true-negative case did not require operation at one-week follow-up evaluation. Hospital length of stay, hospital charges, perforation rates, and times to operation were recorded.
Results: The age and gender distributions were similar in both groups. Accuracy was 90% in the CA group and 92% for CT. Sensitivity was 100% for the CA group and 91% for the CT group. Specificity was 73% for CA and 93% for CT. There were no statistically significant differences in hospital length of stay (CA=2.4 ± 3.2 days vs. CT=2.2 ± 2.2 days, p=0.55), hospital charges (CA=$10,728 ± 10,608 vs. CT=$10,317 ± 7,173, p=0.73) or perforation rates (CA=6% vs. CT=9%, p=0.4). Time to the operating room was shorter in the CA group, 10.6 ± 8.4 h vs. CT, 19.0 ± 19.0 h (p < 0.01).
Conclusions: Clinical assessment unaided by CT reliably identifies patients who need operation for acute appendicitis, and they undergo surgery sooner. Routine use of abdominal/pelvic CT is not warranted. Further research is needed to identify sub-groups of patients who may benefit from CT. Computed tomography should not be considered the standard of care for the diagnosis of appendicitis.

The diagnosis of appendicitis remains a clinical dilemma. Reliance on clinical examination with complimentary use of laboratory tests is a time-honored means of diagnosing acute appendicitis. Traditionally, surgeons have operated with a degree of uncertainty, tolerating a number of nontherapeutic appendectomies because of the increased morbidity and mortality associated with delay in diagnosis and consequent perforation.[1,2] This approach has yielded accuracy rates between 80% and 87%.[3,4,5] Lower accuracy has been reported in women of childbearing age, and at both extremes of age regardless of gender.[6,7,8,9] The use of computed tomography (CT) has been studied,[10,11,12,13,14,15,16] with some series reporting the accuracy of appendiceal CT to be more than 95%.[17,18,19] Studies have concluded that CT assists in the diagnosis of appendicitis in patients with atypical or nonspecific findings on clinical examination.[6,20,21] Rao et al. advocate routine use of CT for diagnosis in all patients suspected of having acute appendicitis.[19]

These studies compared accuracy rates before and after introduction of appendiceal CT in a retrospective manner, or characterized prospectively how clinical decision-making was improved by the routine use of appendiceal CT. To date there have been no prospective randomized studies directly comparing clinical assessment (CA) alone to CT for the diagnosis of appendicitis. In our study, we hypothesized that use of CT for the diagnosis of acute appendicitis would not benefit all patients, but may improve accuracy in certain patients, specifically, women of childbearing age.