title: Beware the contracted gallbladder - Ultrasonic predictors of conversion.
abstract: BACKGROUND
  Pre-operative ultrasound is the gold standard pre-operative investigation for patients undergoing a cholecystectomy. Ultrasound provides a sensitive approach for analysing characteristics of the gallbladder. Thus, we aimed to examine the importance of ultrasonic gallbladder characteristics on laparoscopic cholecystectomy conversion rates and then sought to devise a pre-operative predictive score for conversion based on our findings.
  
  
  METHODS
  A retrospective analysis of patients undergoing a laparoscopic cholecystectomy was performed between January 2000 and December 2006. Patient demographic data and pre-operative imaging results from abdominal ultrasounds were analysed. We then devised a pre-operative predictive score for conversion based on independent variables derived from multivariate analysis.
  
  
  RESULTS
  A total of 1061 patients underwent a laparoscopic cholecystectomy. Conversion to an open procedure was required in 58 cases. The overall conversion rate was 5.4%. Univariate analysis revealed male gender (p < 0.0001), gallbladder wall thickness >4 mm (p = 0.0024), a contracted gallbladder (p = 0.005) and a dilated CBD (p = 0.0416) as being significantly associated with conversion. These variables were then evaluated using multivariate analysis and three variables, namely, male gender, a contracted gallbladder and a thickened gallbladder wall were identified as independent predictors. A pre-operative predictive score for conversion was devised from a training cohort (n = 761) and tested on a sub-cohort (n = 300). Patients with a score of 2 or more had a 19.2% risk of conversion (p < 0.001).
  
  
  CONCLUSIONS
  Conversion to an open cholecystectomy shows a strong associated with gallbladder ultrasonic characteristics which are available pre-operatively. The likelihood of conversion can be accurately predicted using a pre-operative scoring system.
authors.affiliation: Department of Surgery, University Hospital Limerick, 4i Centre for Interventions in Infection, Inflammation and Immunity, Graduate Entry Medical School, Limerick, Ireland. donaloleary@rcsi.ie
authors.forename: D P
authors.initials: DP
authors.lastname: O'Leary
authors.forename: E
authors.initials: E
authors.lastname: Myers
authors.forename: D
authors.initials: D
authors.lastname: Waldron
authors.forename: J C
authors.initials: JC
authors.lastname: Coffey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D002769:Cholelithiasis / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D016473:Gallbladder Emptying / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D057234:Preoperative Period; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
keywords: Conversion; Laparoscopic cholecystectomy; Ultrasound