title: Mayo adhesive probability score: an accurate image-based scoring system to predict adherent perinephric fat in partial nephrectomy.
abstract: BACKGROUND
  Image-based renal morphometry scoring systems are used to predict the potential difficulty of partial nephrectomy (PN), but they are centered entirely on tumor-specific factors and neglect other patient-specific factors that may complicate the technical aspects of PN. Adherent perinephric fat (APF) is one such factor known to make PN difficult.
  
  
  OBJECTIVE
  To develop an accurate image-based nephrometry scoring system to predict the presence of APF encountered during robot-assisted partial nephrectomy (RAPN).
  
  
  METHODS
  We prospectively analyzed 100 consecutive RAPNs performed by one surgeon and defined APF as the need for subcapsular renal dissection to isolate the renal tumor for RAPN.
  
  
  METHODS
  The scoring algorithm to predict the presence of APF was developed with a multivariable logistic regression model using a forward selection approach with a focus on improvement in the area under the receiver operating characteristic curve.
  
  
  CONCLUSIONS
  Thirty patients (30%; 95% confidence interval, 21-40) had APF. Single-variable analysis noted an increased likelihood of APF in male patients (p<0.001), higher body mass index (p=0.003), greater posterior perinephric fat thickness (p<0.001), greater lateral perinephric fat thickness (p<0.001), and those with perirenal fat stranding (p<0.001). Two of these variables, posterior perinephric fat thickness and stranding, were most highly predictive of APF in multivariable analysis and were therefore used to create a risk score, termed Mayo Adhesive Probability (MAP) and ranging from 0 to 5, to predict the presence of APF. We observed APF in 6% of patients with a MAP score of 0, 16% with a score of 1, 31% with a score of 2, 73% with a score of 3-4, and 100% of patients with a score of 5.
  
  
  CONCLUSIONS
  MAP score accurately predicts the presence of APF in patients undergoing RAPN. Prospective validation of the MAP score is required.
  
  
  RESULTS
  The Mayo Adhesive Probability score that we we developed is an accurate system that predicts whether or not adherent perinephric, or "sticky," fat is present around the kidney that would make partial nephrectomy difficult.
authors.affiliation: Department of Urology, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Davidiuk
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Parker
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Colleen S
authors.initials: CS
authors.lastname: Thomas
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
authors.affiliation: Department of Urology, Mayo Clinic, Phoenix, AZ, USA.
authors.forename: Erik P
authors.initials: EP
authors.lastname: Castle
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Heckman
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Kaitlynn
authors.initials: K
authors.lastname: Custer
authors.affiliation: Department of Urology, Mayo Clinic, Jacksonville, FL, USA. Electronic address: Thiel.David@mayo.edu.
authors.forename: David D
authors.initials: DD
authors.lastname: Thiel
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000601:surgery; D000368:Aged; D000465:Algorithms; D019540:Area Under Curve; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D065287:Robotic Surgical Procedures; D012737:Sex Factors; D014057:Tomography, X-Ray Computed
keywords: Renal cell carcinoma; Renal morphometry; Robotic partial nephrectomy; Robotic surgery