title: Clinical guidelines, computed tomography scan, and negative appendectomies: a case series.
abstract: BACKGROUND
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Resurrection Emergency Medicine Residency Program, Resurrection Medical Center, Chicago, IL 60631, USA.
authors.forename: Chad
authors.initials: C
authors.lastname: Harswick
authors.forename: Amy Archer
authors.initials: AA
authors.lastname: Uyenishi
authors.forename: Mary Frances
authors.initials: MF
authors.lastname: Kordick
authors.forename: Shu B
authors.initials: SB
authors.lastname: Chan
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000855:Anorexia / Q000209:etiology; D001062:Appendectomy; D001064:Appendicitis / Q000150:complications* / Q000000981:diagnostic imaging* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed