title: Modeling manual perineal protection during vaginal delivery.
abstract: OBJECTIVE
  We compared hands-on manual perineal protection (MPP) and hands-off delivery techniques using the basic principles of mechanics and assessed the tension of perineal structures using a novel biomechanical model of the perineum. We also measured the effect of the thumb and index finger of the accoucheur's dominant-posterior hand on perineal tissue tension when a modified Viennese method of MPP is performed.
  
  
  METHODS
  Hands-off and two variations of hands-on manual perineal protection during vaginal delivery were simulated using a biomechanical model, with the main outcome measure being strain/tension throughout the perineal body during vaginal delivery.
  
  
  RESULTS
  Stress distribution with the hands-on model shows that when using MPP, the value of highest stress was decreased by 39 % (model B) and by 30 % (model C) compared with the hands-off model A. On the cross section there is a significant decrease in areas of equal tension throughout the perineal body in both hands-on models. Simulation of the modified Viennese MPP significantly reduces the maximum tension on the inner surface of the perineum measured at intervals of 2 mm from the posterior fourchette.
  
  
  CONCLUSIONS
  In a biomechanical assessment with a finite element model of vaginal delivery, appropriate application of the thumb and index finger of the accoucheur's dominant-posterior hand to the surface of the perineum during the second stage of delivery significantly reduces tissue tension throughout the entire thickness of the perineum; thus, this intervention might help reduce obstetric perineal trauma.
authors.affiliation: New Technologies-Research Centre, University of West Bohemia, Pilsen, Czech Republic.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Jansova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kalis
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Rusavy
authors.forename: Robert
authors.initials: R
authors.lastname: Zemcik
authors.forename: Libor
authors.initials: L
authors.lastname: Lobovsky
authors.forename: Katariina
authors.initials: K
authors.lastname: Laine
mesh_terms: D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D006801:Humans; D008954:Models, Biological; D010502:Perineum / Q000502:physiology*; D011247:Pregnancy; D013314:Stress, Mechanical