Non-Invasive Diagnosis of Compartment Syndrome
At the Orthopaedic Trauma Institute at San Francisco General Hospital, I worked on a wide range of novel orthopaedic technologies, with a focus on mechanical design, fabrication and testing. For each of these testing setups, I built them entirely from scratch using primarily the milling machine and other machine shop tools. Mechanical tests are performed on medical devices, sometimes in cadaveric specimens, in the MTS Bionix 858 (a servohydraulic testing system) along with an Optotrack Tracking System to track movement of test subjects in 3D space.
Compartment Syndrome is a devastating complication of musculoskeletal injury that often leads to significant irreversible disability, and currently can only be detected by mostly unreliable invasive diagnostics or clinical suspicion. We propose to develop a novel non-invasive approach for early detection and prevention of Compartment Syndrome using a combination of ultrasound, video magnification and image processing.
Our first design concept consisted of a box where we can put the patient's legs into, with a platform for each leg to be raised or lowered. On each side of the box is a camera that can be positioned vertically, horizontally and rotated to the part of the leg that needs to be analyzed. This initial prototype allows for the use of any camera, whether it be a digital point-and-shoot camera, SLR, smartphone, or Go Pro.
Part of designing our first prototype also involves considering the experience of the patient and the doctor when performing the diagnostic procedure. We had a couple questions to ask our resident orthopaedic surgeon in order to provide some insight into what happens at the clinic:
- How long do we have to diagnose the patient?
- Can we move the patient? How is the patient positioned?
- Which part of the leg will we be diagnosing?
We learned that patients will be lying on their back, although some will be facing downward. There is no need to lift the leg or move the patient, and there will be a nurse available. For the diagnosis, they just need to open the dressing and expose the leg, and the doctor will stick a needle into the leg at a fixed distance from the patient. For the diagnosis procedure, we have 5-10 seconds to take images of the sides of the legs but can take more images if we need to. Our resident orthopaedic surgeon also noted that the needle is not a very reliable method but it is the best thing they have right now. If the patient doesn't respond to pain narcotics or cannot feel any pain, they are then sent to the OR 1-1.5 hrs after diagnosis.