(229) Biomechanical modeling of cervical support during pregnancy: implications for the treatment of cervical insufficiency

A cerclage supports the cervix by applying compression to the cervical stroma. However, the biomechanics of cervical compression are not well understood. In this study, we aimed to investigate the biomechanics of cerclage support by modeling cerclage compression. We also examined cervical compression using the Cx Device, a medical device currently in development as an alternative to cerclage. The Cx Device is designed to distribute cervical compression over a larger contact area. Our hypothesis was that our models would show a wider distribution of compression with the Cx Device compared to the cerclage.

Study Design:

Three-dimensional ultrasound measurements of the uterus and cervix were taken from a patient at 21 weeks of gestation. The ultrasound anatomy was then converted into a computer-aided design (CAD) model, which included the cervix, uterus, fetal membranes, and abdomen. The model was meshed using tetrahedral elements in Hypermesh and imported into FEBio for finite element analysis. Material properties for the maternal reproductive tissue were assigned based on previously published mechanical data, and appropriate boundary conditions were applied. A force of 0.85 N was applied to the areas where the Cx Device and cerclage contact the cervix. The distribution of tissue stretch and stress in the cervix was computed for both the cerclage and Cx Device, allowing for a comparison of their biomechanical function.

Results:

Biomechanical modeling shows that cerclage is associated with areas of high stress concentration in the region where the suture is placed (Figure). Cervical compression is concentrated over a distance of 5 mm with a cerclage (blue color). In contrast, the Cx Device spreads cervical compression over a wider distance of 21 mm (green color), resulting in decreased stress concentrations.

Conclusion:

Biomechanical modeling has demonstrated that the distribution of cervical compression is directly influenced by the method of cervical support used. This study provides valuable insight into the mechanism of mechanical support for the cervix.