title: High negative appendectomy rates are no longer acceptable.
abstract: BACKGROUND
  A 10% to 20% negative appendectomy rate has been accepted in order to minimize the incidence of perforated appendicitis with its increased morbidity. We reviewed our experience with appendicitis in order to determine the incidence of negative appendectomies and perforation, and the role of delay in diagnosis or treatment.
  
  
  METHODS
  We reviewed 659 appendectomies performed over a 12-month period. Incidental and pediatric appendectomies were excluded.
  
  
  RESULTS
  Seventy-five percent of patients were male and 25% female. Nine percent had negative appendectomies and 28% had perforated appendicitis. Perforated appendicitis resulted in increased morbidity and length of stay. Delay in presentation greater than 12 hours after the onset of symptoms significantly increased the perforation rate. In-hospital delay did not affect perforation rate.
  
  
  CONCLUSIONS
  We have achieved a negative appendectomy rate lower than that in other reported series, while maintaining an acceptable perforation rate. In the majority of patients, perforated appendicitis is a result of late presentation.
authors.affiliation: Department of Surgery, University of Southern California School of Medicine, Los Angeles 90033, USA.
authors.forename: M
authors.initials: M
authors.lastname: Colson
authors.forename: K A
authors.initials: KA
authors.lastname: Skinner
authors.forename: G
authors.initials: G
authors.lastname: Dunnington
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001062:Appendectomy; D001064:Appendicitis / Q000175:diagnosis / Q000601:surgery*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007416:Intestinal Perforation / Q000517:prevention & control; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D012189:Retrospective Studies; D012422:Rupture, Spontaneous / Q000517:prevention & control