Biomechanical simulation of the fetal descent without imposed theoretical trajectory

Abstract

Abstract-The medical training concerning childbirth for young obstetricians involves performing real deliveries, under supervision. This medical procedure becomes more complicated when instrumented deliveries requiring the use of forceps or suction cups become necessary. For this reason, the use of a versatile, configurable childbirth simulator, taking into account different anatomical and pathological cases, would provide an important benefit in the training of obstetricians, and improve medical procedures. The production of this type of simulator should be generally based on a computerized birth simulation, enabling the computation of the reproductive organs of the parturient woman and fetal interactions as well as the calculation of efforts produced during the second stage of labor. However, apart from the commercially available robotized dummy simulators, very few virtual training tools using computational technologies have been developed. Unfortunately, all of these simulators approximate the expulsive forces of childbirth by imposing a pre-computed fetal trajectory. They have rather limited possibilities and would be unlikely to meet the versatility requirements described above. Besides, much research work has been carried out to simulate precisely birth-induced pelvic floor dysfunction and organ prolapse, with damage to levator ani muscles. All these simulators perform a detailed modeling of the levator ani muscles in interaction with a rigid fetal head, at high computational cost. However, they do not take into consideration many pelvic organs involved in the process of childbirth.To reconcile the accuracy of results and computation time, we propose an approach that lies between the two classes of simulator described above in order to perform a realistic simulation of the descent of the fetus through the birth canal. In this paper we present the first stage of this work by focusing on the geometrical and biomechanical modeling of the main organs involved (i. e. the uterus, abdomen and pelvis of the parturient woman interacting with the fetus) based on the laws of continuum mechanics. At this stage, to verify the correctness of our hypothesis, we use finite element analysis, because of its reliability, precision and stability. In sum, our study improves work performed on childbirth simulators because:• our childbirth model takes into account all the major organs involved in birth process, thus enabling many childbirth scenarios to be considered, • fetal head is not treated as a rigid body and its motion is computed by taking into account realistic boundary conditions, i. e. we do not impose a pre-computed fetal trajectory, • we take into account the cyclic uterine contractions as well as voluntary efforts produced by the muscles of the abdomen, • a slight pressure is added inside the abdomen, representing the residual muscle tone.

Fast computation of soft tissue deformations in real-time simulation with Hyper-Elastic Mass Links

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A new design for the BirthSIM simulator to improve realism

“…These cylinders have been sized according to the results from [11] and [12] which showed that the maximal applied force to extract the fetus is about 200N. The stroke of these cylinders have been chosen according to the trajectory extracted from Buttin et al [13] which is similar to the one introduced in Fig. 2.…”

Mathematical modeling of the female reproductive system: from oocyte to delivery

“…However, the number of research groups that are working in this area has increased and many are directly confronting these issues. More anatomical structures have been incorporated into modeling frameworks, less prescription for fetal head descent, and in some cases, fetal head molding has been taken into account . Population based models have also recently been developed for both the ‘passageway’ and the ‘passenger.’ These advances in the modeling frameworks are beginning to enable quantitative analysis of the mechanics of vaginal birth in order to identify the contributions of various anatomical structures to birth outcomes.…”