Interoperative BIOmechanical Surgical Splint BIOSS Interoperative BIOmechanical Surgical Splint By: Nick Schlewitz Department of Biomedical Engineering Vanderbilt University Advisors: Dr. Paul King, Vanderbilt University; Dr. Edward Glaser, D.P.M

What’s a Bunion? A bunion is calcium deposit which occurs at the head of the first metatarsal. The extra calcium causes a separation of the first and second metatarsals. The big toe commonly crosses over the second toe if left untreated. The greater the separation, the more severe the operation to correct it.

Fix My Bunion There are more than 171,000 bunion surgeries performed each year, and nearly 20,000 of those are so severe they require restructuring of the first metatarsal. This is called a closing wedge osteotomy. Closing wedge osteotomies are major operations and carry severe complications, sometimes crippling the patient. Radiograph of a patient’s first metatarsal following a closing wedge osteotomy. A pin has been inserted to align the first metatarsal in the correct position.

Complications? The most common complication resulting from a closing wedge osteotomy is called Metatarsus Primus Elevatus (MPE). MPE is best described as an elevation of the big toe. The toe becomes fixated in this position and becomes rigid or completely immobile. MPE, the big toe is clearly raised as a result of a closing wedge osteotomy This condition can be crippling and/or lead to future operations.

Why MPE? How do we treat it? MPE is caused by one of two reasons Surgical technique, which involves the precision of the cut in the bone. Post-operative weight bearing Both causes can be addressed during the healing stages, when the foot is bandaged with a splint that holds the toe in the correct position and sustains its mobility.

What’s Next? Introduce Splint Discuss mechanisms of function Discuss manufacturing technique Marketing and future goals