title: The impact of body mass index on perioperative outcomes in robot-assisted laparoscopic partial nephrectomy.
abstract: OBJECTIVE
  Obese patients undergoing surgical procedures are at increased risk for perioperative morbidity. The purpose of this study is to determine whether there is an association with body mass index (BMI), clinicopathologic features, and perioperative outcomes and complications in patients undergoing robot-assisted laparoscopic partial nephrectomy (RPN).
  
  
  METHODS
  Medical records of 283 patients who underwent RPN between 2007 and 2012 were reviewed from an Institutional Review Board approved database. We analyzed the association of perioperative outcomes and complications of the surgery with BMI and clinicopathologic features using analysis of variance, Kruskal-Wallis test, t test and chi-square-test. Eventually, independent factors associated with perioperative outcomes and complications were studied using univariate and multivariate regression analysis.
  
  
  RESULTS
  Perioperative outcomes including estimated blood loss (EBL), length of hospital stay (LOS) and operative time (OT) were significantly associated with BMI (P=0.002, P=0.009 and P=0.002, respectively). Warm ischemia time (WIT), perioperative complications, and change in glomerular filtration rate (GFR) before and after surgery were not associated with BMI (P=0.459, P=0.86 and P=0.773). In multivariate analysis, BMI, tumor size≥4 cm, and collecting system invasion were independently associated with EBL and OT. Increased LOS was independently associated with BMI and tumor size ≥4 cm.
  
  
  CONCLUSIONS
  Increasing BMI was not associated with a significant increase in perioperative complications, WIT, or change in GFR in patients undergoing RPN at a high-volume tertiary medical center. Collecting system invasion or tumor size ≥4 cm and BMI were independently associated with higher EBL, LOS, and OT, however.
authors.affiliation: Department of Urology, Hartford Hospital, Hartford, Connecticut 06106, USA. halilkiziloz@gmail.com
authors.forename: Halil
authors.initials: H
authors.lastname: Kiziloz
authors.forename: Ryan
authors.initials: R
authors.lastname: Dorin
authors.forename: Kyle T
authors.initials: KT
authors.lastname: Finnegan
authors.forename: Steven
authors.initials: S
authors.lastname: Shichman
authors.forename: Anoop
authors.initials: A
authors.lastname: Meraney
mesh_terms: D015992:Body Mass Index; D003237:Connecticut / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000150:complications / Q000601:surgery*; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D009392:Nephrectomy / Q000379:methods*; D009765:Obesity / Q000150:complications*; D011183:Postoperative Complications / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D012371:Robotics / Q000379:methods*; D016896:Treatment Outcome