by Christopher Kolb
October 16, 2020


Wearable to Prevent Deep Vein Thrombosis


OsciFlex is developing a wearable medical device to prevent the occurrence of hospital-acquired deep vein thrombosis (blood clots) in the legs. Deep vein thrombosis is a condition that affects hundreds of thousands of patients each year, which results in tens of thousands of premature deaths and billions of dollars in associated healthcare costs. The founder of OsciFlex, John Welsh, is an experienced researcher in vascular biology, coagulation, and thrombotic diseases. The device John created is an ankle brace with an integrated air bladder in the base. The bladder inflates at specific intervals to keep a patient’s feet active during a long term hospital stay. Direct imaging has identified that this type of sustained motion is effective in creating optimal blood flow patterns to prevent this condition.

Project Scope

OsciFlex brought in NextFab’s Product Development team to produce a series of fully functional prototypes used during clinical testing. The current standard for preventing hospital-acquired deep vein thrombosis is a compression boot. It’s often removed by the patient because of discomfort, making the fit and comfort of OsciFlex’s device a crucial element in the design. We created several different leg braces varying in shape and size, which were then wrapped in a soft textile and fitted with custom-designed air bladders. The prototypes were adjusted and modified using direct user feedback from clinical testing done by the OsciFlex team.

NextFab created parametric (measurement or dimension based) 3D models in SolidWorks using surfacing and Design for Injection Molding parameters so the foot brace would be ready to move into production when the final fit was decided upon. The prototype boot models were 3D printed at full scale in order for the OsciFlex team to test for comfort and efficacy prior to clinical trials. NextFab also prototyped different air bladder shapes and sizes, as well as boot coverings and strap designs.


NextFab industrial designer Chris Kolb and product design engineer Walt Barger teamed up on the project. They started by working with the client to explore and ultimately select a few leg brace concepts to pursue. That led to the creation of several different leg brace CAD models that were 3D printed at full scale using a large format 3D printer. The braces were then wrapped in a soft textile and fitted with custom-designed air bladders, which Chris fabricated on-site at NextFab. The prototypes were tested in a clinical setting to solicit direct user feedback from both patients and caregivers. Given the importance of comfort, NextFab’s team went through several iterations of the design until it was comfortable and lightweight enough for long-term patient use.

At the conclusion of the project, NextFab provided a fully functional prototype that will be used in future clinical trials.

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