Modeling manual perineal protection during vaginal delivery
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Introduction and hypothesis
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.
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.
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.
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.
KeywordsManual perineal protection Hands-on Hands-off Modeling Perineal tension Perineal strain
The study was supported by the internal grant project SGS-2013-026 of the University of West Bohemia, by the European Regional Development Fund (ERDF), project “NTIS - New Technologies for the Information Society”, European Centre of Excellence, CZ.1.05/1.1.00/02.0090 and by the Charles University Research Fund (project number P36).
Ethical approval and funding
No formal ethical approval was required for this study; no external funding was obtained.
Conflicts of interest
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