Session: 05-06-01 Biomedical Devices I

Paper Number: 70540

Start Time: Friday, 11:45 AM

70540 - Aeromedical Evacuation Skeletal Traction 

The purpose of this project is to design a device that provides skeletal traction to a patient with a fractured femur in an aeromedical evacuation environment. Skeletal traction is typically provided by using weights and cable to provide tension onto a fractured limb. However, in an aeromedical evacuation environment, the forces vary, space is limited, and the environment is not stable, so the traditional method to provide skeletal traction is not suitable. Therefore, we designed and tested a device that could provide skeletal traction to a femoral fracture in an aeromedical evacuation environment.

Skeletal traction provides numerous benefits to a patient. When a patient’s femur is fractured, the fractured ends of the bone push into the patient’s nerves, blood vessels, and soft tissue. This is painful and could cause damage to the patient if not treated. Skeletal traction alleviates the pain and risk by pulling against the bone so that the ends of the bone are not applying pressure to the nerves, blood vessels, and soft tissue. This is typically done by drilling a hole into the tibia, applying a pin through the hole, and providing a force to pull against and elongate the fractured femur.

Aeromedical evacuation has been used increasingly since the 1991 Gulf War. Soldiers who are injured in Iraq or Afghanistan are typically aeromedically evacuated to Germany in a flight that lasts five to seven hours. However, no device currently exists to provides skeletal traction for a femoral fracture that is safe, reliable, and suited for an aeromedical environment. Currently, skin traction can be used as a substitute for skeletal traction. However, the force is applied on the skin using adhesive and straps, which limits the force applied to less than 10 lbs. For comparison, skeletal traction should be able to apply 30 lbs of force to alleviate the negative effects of a fractured femur. Another downside to using skin traction is that soldiers may have received burns and scrapes in addition to their femoral fracture that leave skin traction unsuitable or undesirable.

The requirements for the device include being safe, reliable, and compact. It must maintain a force of 30 lbs on the patient’s leg. Currently, the device is mounted directly onto a litter, the typical method to transport injured patients on an airplane. By using a load cell, linear actuator, and display, the skeletal traction force can be measured, monitored, and adjusted. In its current configuration, the device measures the force and adjusts automatically while displaying the measured weight so the medical care provider can monitor the patient’s treatment. The decision was made to have the device adjust automatically because in-flight effects such as turbulence and the patient sliding may occur too fast to give the medical provider time to adjust the device manually.

A test was conducted that involved attaching a chain to the device to provide resistance and to model the knee. The device was then placed in the bed of a truck and underwent a series of constant accelerations. The results showed the device functions as intended by adjusting to an acceptable level of force.

Presenting Author: Ethan Rabb United States Military Academy

Authors:

Ethan Rabb United States Military Academy
Rebecca Zifchock United States Military Academy
Margaret Nowicki The United States Military Academy
Jeremy Paquin United States Military Academy
Matthew Posner United States Military Academy