Spinal fusion surgery often requires that bone be harvested from the patient, reduced to a small and consistent size, and reintroduced into the patient to promote bone growth. Stryker identified an opportunity to replace this painstaking, manual process with an efficient powered solution. Stryker challenged M3 to design a best in class bone mill for surgeons and scrub nurses that met their needs and fit within their existing work-flow. The critical technical issues were how to consistently mill the desired sized bone chips while ensuring maximum cell viability and integrating with Stryker’s existing capital equipment products.
The effort was broken into two parallel activities. First, potential bone reducing techniques were researched and prototyped with the primary goal of finding a solution that minimized the detrimental effects to the bone’s integrity from the milling process. Second, contextual research was performed to identify key interaction points and develop an optimized work-flow before focusing on form. The results of these activities were then brought together to develop the initial product architecture. The design was then prototyped and refined until the final product was suitable for manufacture.
Bone mills allow surgeons to utilize patient’s bone in fusion surgeries without the need for expensive bone graft substitutes. The patented Stryker Mill efficiently and consistently reduces harvested autologous bone into appropriately sized particles with a single pass cutting action. This means that the milling operation is now performed with much less effort and time by the surgical team while providing consistent sized bone that is viable. Resulting Bone Mill sales were triple Stryker’s original expectations for the first year and shut the door on competitors who were trying to use Stryker’s previous lack of a bone mill product to enter Stryker accounts.
STRATEGY: M3 Design observed surgical teams in the O.R. environment to obtain rich contextual data. Surgeons, scrub techs and nurses walked the M3 team through the bone harvesting process as it was being performed. M3 quickly realized that the critical user issue was that the process yielded inconsistent results. A competitive product evaluation uncovered the key technical issue: current bone reducing methods often cut the bone fragments more than once, which may compromise bone viability.
CONCEPT: Multiple bone reduction techniques and product architectures were evaluated to determine the milling solution that would use a single cutting action to consistently reduce the bone to the desired size M3 identified key user interaction points and used them to develop an optimized work-flow which informed the system’s component arrangement. M3 followed these explorations with multiple sketch sessions and which resulted in a final form that met the product’s design and usability criteria.
DEVELOPMENT: M3 built prototypes and ran extensive lab experiments to determine the disc cutter’s torque “sweet-spot” requirement. Multiple versions of the blade’s cutting features were built and evaluated to achieve optimal bone consistency. System prototypes were also used to evaluate human factors and work-flow to ensure the product was easy to use. The final product design was delivered to Stryker and integrated into their supply chain after multiple and extensive design reviews.