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

2. What is BIOSS?
BIOSS is a device aimed at eliminating a common complication, metatarsus primus elevatus,that results from bunion removal surgeries.
The potential market is huge since 304,000 bunion and other toe deformities are repaired a year with around 10% developing the complication that BIOSS addresses.
With 30,400 potential customers a year and no current competition, researching such a device is clearly justified.

3. 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.

4. Fix My Bunion
Many bunions are so severe that 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.
Before (left) and after (right) picture of a bunion that has been removed. (

5. 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.

6. 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
Patients are already told not to bear weight and there is no way to template the cut. However, MPE 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. This is precisely what BIOSS is designed to do.

7. BIOSS: How it Works
BIOSS is designed to alleviate MPE by two mechanisms:
By providing arch support, the plantar fascia ligament will act to pull the big toe down, eliminating elevatus. This mechanism is called the windlass effect.
By incorporating a continuous passive motion device (CPM), the big toe will be well nourished, causing it will heal faster, and it will not stick to the healing bone.

8. The Design
The arrow indicates the arch support which is unique to each persons foot. The entire foot bed and toe guard are made of a polypropylene plastic and connected with a locking nut and bolt.
BIOSS prototype showing the arch support

9. Continuous Passive Motion
In order to continuously move the toe, a 3 RPM geared motor was attached as shown.
By moving the big toe, healing time is reduced and patient satisfaction following the procedure is increased.
BIOSS prototype emphasizing the CPM feature

10. Manufacturing
The conditions necessary for production required that the materials be currently available at Sole Supports.
The plastic used was a polypropylene for its strength, malleability, and cost advantages.

11. Testing
In order to sell the product, the effectiveness of BIOSS must be documented.
Dr. Bud Hawthorn at Summit Medical Center has agreed to use a completed device on his patients following closing wedge osteotomies.

12. Marketing
Using the Sole Supports podiatric clientele, it will be easy to inform and appeal to the podiatric market that BIOSS is designed to attract.
Dr. Glaser is a professional speaker who has spoken at the American Podiatric Medical Association and has the means and ability to bring BIOSS to life.

13. Competition
BIOSS currently has little competition and none specific to the cause of preventing MPE.
Current CPM’s are bulky and expensive, this is the only patented toe CPM.
Only current CPM for toe joint (

14. Economics
Total Bunion and toes deformities operations:
304,000 (NIH 1996)
Production Costs:
Parts and Materials = $30-$40
Labor = $35-$40
Total BIOSS Applicable procedures:
30,400
Projected Price:
$350-$1000
Cost/Benefit ratio:
= 350/80 = 4.375
Total Customers with market share:
3,400
Net Yearly Profit (minimized):
$350 - $80 = $250 (per unit)
X 3,400 (people)
=$ 850K
Start up costs are minimal, allowing for a large profits in a short period of time.
If successful, yearly profits of $850,000 are possible with a 10% market share.
For every dollar spent, $4.38 is returned!

15. Work Completed
A working prototype has been assembled and a manufacturing process has been established.
The prototype has been evaluated by both Dr. Glaser and Dr. Hawthorn with and has passed inspections.
A preliminary economic analysis has been performed and production is likely to begin shortly.

16. Future Work Update prototype to reflect the latest revisions.
Design battery pack and attach to the motor.
Write a patent.
Obtain pre-approval from insurance companies.
Begin sterilization testing and packaging development.
Contact Dr. Hawthorn to begin testing on a real patient.

17. References June 30th interview with Dr. Edward Glaser
July 7th interview with Dr. Bud Hawthorn