Non-invasively extendable megaprosthesis
NIH
GRANITE MEDICAL, LLC
ABSTRACT This project is the development of a non-invasively extending distal femur replacement (DFR) for children and adolescents subsequent to bone tumor resection. Each year in the US there are 200-250 malignant bone tumor diagnoses in the distal femurs of patients 15 years and younger. With advances in chemotherapy, limb salvage surgery utilizing a megaprosthesis has increasingly become the treatment of choice. For growing patients these megaprostheses are required to extend so they can “grow” as the contralateral limb grows. Only one non-invasively lengthened DFR is FDA approved to treat these patients. The implant is actuated with a large electromagnetic appliance in a clinical setting. It is exceedingly complex and the average revision rate has been reported at 48%, including revisions for: insufficient lengthening capacity, lengthening mechanism failure, implant fracture, aseptic loosening and infection. MRI is contraindicated and the implant is extremely expensive. Our device is non-invasively, manually extended by pressing on the patient's skin. It's designed for a significantly reduced complication rate, the mechanism is simple and robust, it's MRI compatible and can be lengthened at home for a more gradual growth and constant leg length equality. It is capable of up to 240% of the extension that its sole US competitor offers and is easier and less expensive to manufacture so it can be offered at a reduced price to a greater population. The specific aims of the project are to (1) complete the implant design, (2) design specialized surgical instruments for implantation and (3) conduct non- clinical bench testing in preparation for FDA submission. PROJECT NARRATIVE This project is the development of a non-invasively extending distal femur replacement for children and adolescents undergoing bone tumor resection for maintaining limb length equality. Each year in the US there are 200-250 malignant bone tumor diagnoses in the distal femurs of patients 15 years and younger. Our device is simple, robust, MRI compatible, can be extended more gradually at home, has far more extension capability and is designed for a reduced complication rate when compared to its sole US competitor.
SBIR/STTR