How could engineering software possibly have anything to do with delivering babies?
Engineering, midwifery and obstetrics researchers at Ryerson University and McMaster University are developing an electro-mechanical model of a cervix during labor. They are interested in this model to demonstrate the changes that occur in the cervix in the process of normal labor. In particular, they are studying the changes in the cervix in an unassisted delivery versus when labor is induced. Their goal is to better understand the process so they can develop a training simulator that can be used by students and researchers to demonstrate normal cervical changes in labor and to practise labor induction techniques and study the effectiveness of different induction methods.
Labor is induced in many pregnant women, often when they are overdue and there is risk to the child if it is not born soon. For example, over 20% of all pregnancies in both the United States and the United Kingdom end in induced labor. One induction tool is the Foley catheter. A small balloon is carefully inserted through the opening of the bottom part of the cervix until it reaches just inside the uterus. Then the balloon is filled with saline in order to increase the downward pressure on the top of the cervix, from inside the uterus, mimicking the pressure from the baby's head. The downward pressure triggers the body's natural responses to gradually open the cervix, helping the woman to go into labor.
While this basic technique was first introduced in the 1850s, the precise mechanics are not well quantified. Dr. James Andrew Smith, a Biomedical Engineering researcher and Assistant Professor in Electrical and Computer Engineering at Ryerson University, decided to use MapleSim to create a model of a cervix undergoing induction with a Foley catheter.
Because of the inherent symmetry involved, he modeled a quarter of the cervix, where each section is approximated by a multi-joint arm that moves in response to a tractive force coming down from above. The resulting mathematical model is a double sliding joint, double pin joint, spring-loaded system. He then used MapleSim to extract and analyze the dynamic and kinematic equations governing this system. With this information, he was able to run simulations to experiment with parameters such as the amount and direction of force applied to the cervix and the dimensions of the cervix, and see how the changes affected the length of pre-labor (the amount of time needed to dilate the cervix to the chosen target of 4.5 cm, at which point active labor is often established).
MapleSim model of a cervix undergoing induction with a Foley catheter
By comparing his MapleSim simulation results with the available experimental data, he was able to tune his model to provide a good match. In particular, his model provides a near constant rate of dilation, which is consistent with observed behavior.
Next steps in this project include creating an actual electro-mechanical model of a cervix. This physical training simulator will be used to help train medical and midwifery students in inserting the balloon, and will provide a physical method for testing other dilators in a risk-free environment. It will also be used to develop contact models that help to better understand the friction between the balloon and the cervix, which in turn can be fed back into the virtual MapleSim model to improve its fidelity. Further plans involve using MapleSim to help develop a device that can simulate other birth complications.
"MapleSim is an ideal tool for modeling multidomain systems such as those found in biomedical engineering. Creating models is fast, and the mathematical analysis tools enable me to really understand what is going on in my system, and how to improve it, before building a physical prototype," said Dr. Smith. "Modern engineering has a lot to offer the medical world, and tools like MapleSim make it easier and faster to advance projects like these to the point where they can really help people."
Contact Maplesoft to learn how MapleSim can be used in your classroom.