title: The impact of days off between cases on perioperative outcomes for robotic-assisted laparoscopic prostatectomy.
abstract: OBJECTIVE
  To examine the effect of days off between cases on perioperative outcomes for robotic-assisted laparoscopic prostatectomy (RALP).
  
  
  METHODS
  We analyzed a single-surgeon series of 2036 RALP cases between 2003 and 2014. Days between cases (DBC) was calculated as the number of days elapsed since the surgeon's previous RALP with the second start cases assigned 0 DBC. Surgeon experience was assessed by dividing sequential case experience into cases 0-99, cases 100-249, cases 250-999, and cases 1000+ based on previously reported learning curve data for RALP. Outcomes included estimated blood loss (EBL), operative time (OT), and positive surgical margins (PSMs). Multiple linear regression was used to assess the impact of the DBC and surgeon experience on EBL, OT, and PSM, while controlling for patient characteristics, surgical technique, and pathologic variables.
  
  
  RESULTS
  Overall median DBC was 1 day (0-3) and declined with increasing surgeon case experience. Multiple linear regression demonstrated that each additional DBC was independently associated with increased EBL [β = 3.7, 95% CI (1.3-6.2), p < 0.01] and OT [β = 2.3 (1.4-3.2), p < 0.01], but was not associated with rate of PSM [β = 0.004 (-0.003-0.010), p = 0.2]. Increased experience was also associated with reductions in EBL and OT (p < 0.01). Surgeon experience of 1000+ cases was associated with a 10% reduction in PSM rate (p = 0.03) compared to cases 0-99.
  
  
  CONCLUSIONS
  In a large single-surgeon RALP series, DBC was associated with increased blood loss and operative time, but not associated with positive surgical margins, when controlling for surgeon experience.
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA. pearce.shane@gmail.com.
authors.forename: Shane M
authors.identifier: http://orcid.org/0000-0002-1898-3565
authors.initials: SM
authors.lastname: Pearce
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Pariser
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA.
authors.forename: Sanjay G
authors.initials: SG
authors.lastname: Patel
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA.
authors.forename: Blake B
authors.initials: BB
authors.lastname: Anderson
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Eggener
authors.affiliation: Section of Urology, Department of Surgery, University of Chicago Medicine and Biological Sciences, 5841 S. Maryland Ave., MC 6038, Chicago, IL, 60637, USA.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Zagaja
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D002983:Clinical Competence; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D061646:Operative Time; D011468:Prostatectomy / Q000193:education* / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D012371:Robotics / Q000379:methods*; D025321:Surgery, Computer-Assisted
keywords: Outcomes; Prostatectomy; Prostatic neoplasm; Skill depreciation; Surgeon volume