title: Renal tumor contact surface area: a novel parameter for predicting complexity and outcomes of partial nephrectomy.
abstract: BACKGROUND
  The contact surface area (CSA) of a tumor with adjacent renal parenchyma may determine the complexity and thus the perioperative outcomes of partial nephrectomy (PN).
  
  
  OBJECTIVE
  We devised a novel imaging parameter, renal tumor CSA, and correlate it with perioperative outcomes in patients undergoing PN.
  
  
  METHODS
  Of 200 patients undergoing PN for a tumor (January 2010 to August 2011), 162 had renal protocol computed tomography scanning data available. CSA was calculated using image-rendering software (Synapse 3D, Fujifilm), and interobserver variability was determined between three independent observers.
  
  
  METHODS
  CSA was correlated to baseline demographics and perioperative outcomes as a continuous and categorical variable using multivariable logistic regression analysis. The ability of CSA to predict adverse perioperative events was compared with demographic factors and nephrometry scoring systems.
  
  
  CONCLUSIONS
  The mean tumor size was 3.1cm; CSA was 18.3 cm(2). CSA ≥20 cm(2) correlated with adverse tumor characteristics (greater tumor size, volume, and complexity) and perioperative outcomes (more parenchymal volume loss, blood loss, and complications) compared with CSA <20 cm(2). On multivariable logistic regression, CSA independently predicted operative time, complications, hospital stay, and renal functional outcomes. This predictive ability of CSA was superior to the other parameters evaluated.
  
  
  CONCLUSIONS
  CSA is a novel imaging parameter that quantifies the CSA of renal tumor with adjacent parenchyma. Our preliminary data indicate that CSA correlates with PN outcomes. If validated externally in a larger cohort, CSA could be incorporated into future versions of nephrometry scoring systems.
  
  
  RESULTS
  In this study we outline the method of calculating the contact surface area (CSA) of renal tumors with the surrounding normal kidney using image-rendering software. We found that CSA correlates with a number of important surgical outcomes including operative time, loss of renal function, and complications.
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Leslie
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Inderbir S
authors.initials: IS
authors.lastname: Gill
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Andre Luis
authors.initials: AL
authors.lastname: de Castro Abreu
authors.affiliation: Department of Radiology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Syed
authors.initials: S
authors.lastname: Rahmanuddin
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Karanvir S
authors.initials: KS
authors.lastname: Gill
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Mike
authors.initials: M
authors.lastname: Nguyen
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Andre K
authors.initials: AK
authors.lastname: Berger
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Alvin C
authors.initials: AC
authors.lastname: Goh
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Cai
authors.affiliation: Department of Radiology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Vinay A
authors.initials: VA
authors.lastname: Duddalwar
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA.
authors.forename: Monish
authors.initials: M
authors.lastname: Aron
authors.affiliation: Catherine and Joseph Aresty Department of Urology, USC Institute of Urology, Los Angeles, CA, USA. Electronic address: adityadesai2003@gmail.com.
authors.forename: Mihir M
authors.initials: MM
authors.lastname: Desai
mesh_terms: D000328:Adult; D000368:Aged; D016063:Blood Loss, Surgical; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009392:Nephrectomy / Q000009:adverse effects; D015588:Observer Variation; D016017:Odds Ratio; D061646:Operative Time; D011183:Postoperative Complications / Q000209:etiology; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012984:Software; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Complications; Kidney; Laparoscopy; Partial nephrectomy; Renal neoplasm; Robotic surgery