title: The aeromedical risk associated with asymptomatic cholelithiasis in USAF pilots and navigators.
abstract: BACKGROUND
  The U.S. Air Force (USAF) aeromedical policy regarding incidentally discovered, asymptomatic cholelithiasis required the aircrew to undergo cholecystectomy prior to being considered for return to flying duties.
  
  
  OBJECTIVE
  The merit of continuing this USAF policy was evaluated at the request of the U.S. Air Force Surgeon General.
  
  
  METHODS
  A medical literature review of the natural history of cholelithiasis in the general population was completed. The USAF aircrew waiver file (1972-92) and the Ellingson Aerospace Medicine Consultation Service (ACS) data file (1955-92) were reviewed for cases of USAF pilots and navigators with a diagnosis of cholelithiasis or cholecystectomy. Pilot and navigator annual manpower data were obtained from the Air Force Military Personnel Center (1972-92) and used in calculations involving the USAF aircrew waiver file. Surgical morbidity and mortality information was obtained from the Division of Surgery, Wilford Hall Medical Center.
  
  
  RESULTS
  Literature review predicted a 1-4% annual rate of acute events in individuals with previous asymptomatic cholelithiasis. Based on KUB radiographs taken at ACS, the prevalence of asymptomatic cholelithiasis in USAF pilots and navigators was estimated to be 2-3%. Of 11,685 pilots and navigators evaluated at the ACS, 80 (0.7%) were diagnosed with cholelithiasis or cholecystectomy. Between 1972 and 1992, an estimated 16,232 man-years of pilot/navigator exposure to asymptomatic cholelithiasis occurred; however, only 50 cases with a diagnosis of cholecystectomy or cholelithiasis were reported in the USAF waiver file. Mortality and morbidity for cholecystectomy, whether performed by open or laparoscopic technique, were reported as 0.2% and 5%, respectively, in the general population.
  
  
  CONCLUSIONS
  The overall incidence of acute cholecystitis within USAF aircrew would not be changed by aeromedical cholecystectomy being performed on aviators with incidentally detected asymptomatic cholelithiasis.
authors.affiliation: Clinical Sciences Division, Armstrong Laboratory, Brooks Air Force Base, TX 78235-5117, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: Saboe
authors.forename: J W
authors.initials: JW
authors.lastname: Slauson
authors.forename: R
authors.initials: R
authors.lastname: Johnson
authors.forename: T H
authors.initials: TH
authors.lastname: Loecker
mesh_terms: D000328:Adult; D002763:Cholecystectomy; D002769:Cholelithiasis / Q000150:complications* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D012189:Retrospective Studies; D012306:Risk; D014481:United States