title: Evaluating the learning curve for robot-assisted laparoscopic radical cystectomy.
abstract: OBJECTIVE
  We seek to describe the learning curve of robot-assisted laparoscopic radical cystectomy by evaluating some of the surgical, oncologic, and clinical outcomes in our initial experience with 50 consecutive patients undergoing this novel procedure.
  
  
  METHODS
  Fifty consecutive patients (representing our initial experience with robot-assisted cystectomy) underwent radical cystectomy and urinary diversion from January 2006 to December 2007. Several different metrics were used to evaluate the learning curve of this procedure, including estimated blood loss (EBL), operative (OR) time, pathologic outcomes, and complication rate. We evaluated patients as a continuous variable, divided into five distinct time periods (quintiles), and stratified by first half and second half of robotic experience.
  
  
  RESULTS
  EBL was not significantly lower until the third quintile (patients 21-30), after which further significant reductions were not observed. Mean OR time declined between each quintile for the first 30 patients (1-10 v 11-20 v 21-30). No significant declines occurred after the third quintile (21-30). When evaluated as a continuous variable, the statistical cut point at which no further significant reductions were observed was after patient 20 for OR time. No differences were observed with regard to time to flatus, bowel movement, or hospital discharge. Furthermore, complications were not different between the initial 25 patients and the most recent patients. There has been no case of a positive margin, and there was only one inadvertent bladder entry. Lymph node yield has also not significantly changed over time.
  
  
  CONCLUSIONS
  This report helps to define the learning curve associated with robot-assisted laparoscopic radical cystectomy for bladder cancer. Despite the higher OR times and blood loss that is observed early in the learning curve, no such compromises are observed with regard to these oncologic parameters even early in the experience.
authors.affiliation: Division of Urologic Surgery, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. rpruthi@med.unc.edu
authors.forename: Raj S
authors.initials: RS
authors.lastname: Pruthi
authors.forename: Angela
authors.initials: A
authors.lastname: Smith
authors.forename: Eric M
authors.initials: EM
authors.lastname: Wallen
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical; D002983:Clinical Competence; D015653:Cystectomy / Q000193:education*; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D007858:Learning; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D012371:Robotics / Q000193:education*; D013997:Time Factors; D016896:Treatment Outcome