title: Third place: Flank position is associated with higher skin-to-surface interface pressures in men versus women: implications for laparoscopic renal surgery and the risk of rhabdomyolysis.
abstract: OBJECTIVE
  There have been several reports of rhabdomyolysis occurring after prolonged laparoscopic procedures in the flank position. Accordingly, we evaluated interface pressures between the skin and three commonly used operating room table surfaces. The aim of our study was to determine if pressure changes could be related to body mass index (BMI), sex, position, and/or the table surface material.
  
  
  METHODS
  Ten men and 10 women were grouped according to BMI <25 or >or=25, with five participants in each group. Subjects were placed in the left lateral decubitus position with the operating table flat, half flexed, fully flexed, half flexed with the kidney rest elevated, and fully flexed with the kidney rest elevated. Interface pressures were recorded, using an X-Sensor pressure sensing mat, for 5-minute periods in each of the described positions on each surface.
  
  
  RESULTS
  Sex and BMI were statistically significant predictors of increased pressures (P= 0.0042 and 0.0402, respectively). The parameter estimate for the difference between men and women was 4.63 mm Hg (P= 0.0002), and the difference for BMI >or= 25 compared with <25 was also significant (P < 0.0209). Full table flexion (50-degree) produced significantly higher pressures than both flat (P= 0.0001) and the half-flexed (25-degree) position (P < 0.0001). Positions with the kidney rest elevated were associated with significantly higher pressures than without elevation (P < 0.0001). With regard to the surface used, egg crate provided lower pressures than gel pads (P= 0.0117).
  
  
  CONCLUSIONS
  Women have significantly lower interface pressures when compared with men. BMI >or= 25 also increases interface pressures. The use of the kidney rest is associated with markedly increased pressure; use of a half-flexed position is preferable to a full-flexed position. These data have implications for patient positioning and identification of persons at risk for rhabdomyolysis during laparoscopic renal surgery.
authors.affiliation: Department of Urology, University of California-Irvine, Irvine, California 92868, USA.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Deane
authors.forename: Hak J
authors.initials: HJ
authors.lastname: Lee
authors.forename: Geoffrey N
authors.initials: GN
authors.lastname: Box
authors.forename: Jose Benito A
authors.initials: JB
authors.lastname: Abraham
authors.forename: Corollos S
authors.initials: CS
authors.lastname: Abdelshehid
authors.forename: Erick R
authors.initials: ER
authors.lastname: Elchico
authors.forename: Reza
authors.initials: R
authors.lastname: Alipanah
authors.forename: James F
authors.initials: JF
authors.lastname: Borin
authors.forename: Royce W
authors.initials: RW
authors.lastname: Johnson
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Jackson
authors.forename: Elspeth M
authors.initials: EM
authors.lastname: McDougall
authors.forename: Ralph V
authors.initials: RV
authors.lastname: Clayman
mesh_terms: D001363:Awards and Prizes; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology / Q000601:surgery; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D011187:Posture / Q000502:physiology*; D011312:Pressure; D012206:Rhabdomyolysis / Q000209:etiology* / Q000503:physiopathology*; D012307:Risk Factors; D012727:Sex Characteristics; D012867:Skin / Q000503:physiopathology*