title: Vaginal tissue properties versus increased intra-abdominal pressure: a preliminary biomechanical study.
abstract: OBJECTIVE
  This study aims to evaluate the pelvic floor (PF) tension response during simulated increased intra-abdominal pressure (IAP) and the vaginal biomechanical properties.
  
  
  METHODS
  A 3-dimensional computational finite element model for PF was developed based on magnetic resonance imaging from a nulliparous healthy volunteer. The model was used to simulate an IAP of 90 cm H(2)O and to evaluate the PF stresses in the longitudinal and transversal axes. The vaginal samples were obtained from 15 non-prolapsed female cadavers. A uniaxial tensile test to obtain stiffness and maximum stress of vaginal tissue in the longitudinal and transversal axes was performed.
  
  
  RESULTS
  The simulated IAP was associated with a similar PF stress state in the longitudinal and transversal axes. The stiffness and maximum stress in vaginal tissues presented a great variability between subjects. There was no difference in the vaginal tissue elasticity (6.2 ± 1.5 vs. 5.4 ± 1.1 MPa; p = 0.592) and maximum stress (2.3 ± 0.5 vs. 2.6 ± 0.9 MPa; p = 0.692) regarding the measurements in the longitudinal and transversal axes.
  
  
  CONCLUSIONS
  The isotropic biomechanical behavior of vagina is in agreement with the PF stress state response during increased IAP.
authors.affiliation: Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: Pedro A L S
authors.initials: PA
authors.lastname: Martins
authors.forename: Renato M Natal
authors.initials: RM
authors.lastname: Jorge
authors.forename: António J M
authors.initials: AJ
authors.lastname: Ferreia
authors.forename: Cristina S
authors.initials: CS
authors.lastname: Saleme
authors.forename: Thuane
authors.initials: T
authors.lastname: Roza
authors.forename: Marco M P
authors.initials: MM
authors.lastname: Parente
authors.forename: Marcos
authors.initials: M
authors.lastname: Pinotti
authors.forename: Teresa
authors.initials: T
authors.lastname: Mascarenhas
authors.forename: Agostinho
authors.initials: A
authors.lastname: Santos
authors.forename: Liliana
authors.initials: L
authors.lastname: Santos
authors.forename: Agnaldo L
authors.initials: AL
authors.lastname: Silva-Filho
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D008954:Models, Biological; D017773:Pelvic Floor / Q000502:physiology; D011312:Pressure; D013314:Stress, Mechanical; D013718:Tensile Strength; D014621:Vagina / Q000502:physiology*; D055815:Young Adult