MRI and 3D imaging of the mimic musculature

It is known that (elective) surgery can lead to changes in facial expressions.
A disturbance in the normal anatomy might be the cause of this problem. A
change in the location of the origo or insertion of a muscle can result in a
change in the course of that muscle. As a result of this, the vector by which a
muscle exerts its force will change, thereby also changing its function in
facial expressions.

After surgery, some patients report the above-mentioned change in facial
expressions even after complete healing. This change is most of the time
unexpected and unpredicted and thereby unwanted by the patient as well as by
the surgeon. This seems in particular to be the truth after a Le Fort 1
osteotomy, for cleft-, and non-cleft cases. Although these patients are
convinced that their faces look more attractive after having the surgery done,
they don*t appreciate the change in facial expressions. Especially a reduced
ability to smile broadly, a very important way of non-verbal communication,
seems to be the cause for disappointment. In severe cases it may even be that
patients no longer recognize their own faces as a result of the changed facial
expressions.

Placing back the mimic muscles to the correct anatomical site seems to be
important in order to prevent the occurrence of any undesirable changes in
facial expressions after elective surgery. Detailed knowledge about the exact
position and the course of the mimic muscles from origin to insertion is
therefore considered essential.

A lot of research has been done recently regarding the (change in) position (of
parts) the facial skeleton after trauma and surgery by using three-dimensional
imaging techniques and CT-scans. However, still very little is known about the
mimic muscles of the face and their exact position and function.

The purpose of this research project is to learn all the details about the
mimic muscles. The aim is to find out whether it is possible to identify all
the small mimic muscles independently of each other (instead of identifying
mimic muscles as a group) and to determine their exact anatomical position from
origo to insertion to reveal their function based on their anatomical position
by using MRI and three-dimensional imaging.

With the results of this research project reference values could be made
regarding muscles positions and average excursions in facial expressions. These
reference values could be helpful to place back the muscles to their original
anatomic site during surgery in order to preserve or restore the facial
expressions of the patient in the best possible way and to quantify the changes
in facial expressions after trauma or surgery.

This study has multiple purposes:

Primary objective:
1: to investigate whether it is possible to identify the small mimic muscles
independently of each other and to determine the exact position of the origin
and insertion of the mimic muscles on 7 Tesla MRI images, thereby defining the
course of these muscles and revealing their functions in facial expression.

Secondary objectives:
2: to investigate whether localization of the origins and insertions of the
mimic muscles of the face using MRI images, can be standardized.

3: to investigate whether it is possible to superimpose MRI images and 3D
photographs using the computer program3dMedX, as done previously with CT scans.

4: to determine which muscles cause a specific facial expression by researching
the vectors of facial landmarks and compare these to the vectors of the mimic
muscles, thereby trying to connect the course of a muscle with the facial
expression to reveal the function of a muscle.

5: to determine the duration a volunteer can hold a certain facial expression.

Feasibility study

There are no risks for healthy volunteers associated with participation in this
study. The extend of the burden is minimal, there will only be a time
investment of approximately 60 minutes.