Date of Award


Document Type

Open Access

Degree Name

Bachelor of Science


Mechanical Engineering

First Advisor

Glenn Sanders




pain, position, vertrebrate, study, plate


Back pain is often due to the degeneration of intervertebral discs, which can lead to a condition known as spondylolisthesis, whereby a vertebra slips out of position in the anteroposterior direction. There are numerous orthopaedic implants which are used by surgeons to correct this condition; however, there has been no conclusive research conducted in comparing the efficacies of these implants. In the cervical spine, this condition most commonly occurs over two levels. For the purposes of this study, an implant’s efficacy depends on its ability to return the slipped vertebra back into natural position immediately after surgery. To test these implants and accurately compare their efficacies, a test fixture must be designed and constructed that can test both anterior and posterior implant systems and the surgical techniques used to apply them. Two fixtures were fabricated, assembled, and used to test a Zephyr anterior cervical plate based on the two common anterior surgical approaches: a standard three point bending method and a terminal three point bending method. A posterior fixture was fabricated and assembled but no testing was conducted with it due to a lack of availability of posterior implant systems (rod and pedicle screw). It was found that the standard three point bending method pulled the slipped vertebra completely back into position while the terminal three point bending method brought the slipped vertebra 0.80 mm from the corrected position; thus, the standard three point bending method was more effective for the Zephyr plate tested.