H.11 Bone thickness measuring device for accurate bony fixation screw selection

Internal fixation of the mandible is a surgical procedure often done by head and neck surgeons (including oral and maxillofacial surgery, ENT and plastic surgery) to provide stability of a fractured mandible. A fractured mandible is encountered in the setting of trauma, mandible pathology that requires resection and controlled fracture by the surgeon for repositioning of the mandible. During the fixation stage, we utilize plates and screws to hold the fractured pieces together. One of the challenges in this procedure is to select the correct screw length after the holes are drilled. Our goal is to select the screw length that matches the thickness of the mandible. However, with different patient anatomy and plate location, the screw length is impossible to predict and must be measured in the operating room.  

The current measuring system available is a depth gauge, which is a retractable metal rod with a hock at the end. The rod goes through the pre-drilled hole while the hock hocks onto the inner cortex of the mandible. The gauge must be positioned perpendicular to the mandible for the retractable rod to pass through the pre-drilled holes. It is not an effective system since the surgical access is usually done through a small incision in the mouth with deep dissection. Perpendicular placement of the gauge is challenging. The small hock often fail to hold on to the inner cortex of the mandible due to difficult positioning. Despite wanting surgical accuracy, this measuring step is often skipped. 

The goal of this project is to design a robust measuring device that can be inserted into deep tissue pocket while obtaining measurement of the bone thickness at the level of the pre-drilled hole. The measurement needs to be accurate to within a millimeter and easy to read. The device needs to be able to access any pre-drilled holes in the jawbone regardless of the position and depth from the surgical incision and easily sterilizable for surgery. 

This project will be sponsored by Dr. Joyce Xu, current resident physician of the Emory Oral and Maxillofacial Surgery program with supervision of my faculty physician Dr. Steven Roser affiliated with Emory Oral and Maxillofacial Surgery.