Deformation tends to be greatest within Tango Filament at the highest point of the support base, which is the front of the lumbar vertebrae (T12). Deformation is lowest towards the back of the lumbar vertebrae (L5). A compressive load of 50 lbs was applied across the support base.

Stress tends to be greatest within Tango Filament at the lowest point of the support base, which is the center of the spine phantom (L3). Everywhere else along the support base seems to produce very minimal stress.

The top surface of the sacrum was altered to appear smooth in order to produce a more uniform load. The area of interest is along the I-Beam pin itself. This area shows very minimal deformation with a compressive load of 5 lbs.

The stress of the I-Beam pin can be assumed as zero psi when a load of 5 lbs is applied to it. The load was picked as an approximate measure of load that may be applied to the sacrum due to it only being a reference point for the rest of the lumbar region, and not a load-bearing item. In conclusion, the pin will hold up under the load.

This was the first iteration design of the dual road pins. With a 6 lb load force applied, the side pin would not be able to hold up due to deformation appearing extreme for a non-compliant part, so redesign was needed.

This was the first iteration design of the dual road pins. With a 6 lb load force applied, the side pin would not be able to hold up due to the stress concentration at the interface being extremely high, so redesign was needed.

This was the second iteration design of the dual rod pins. With the same 6 lb load force applied, for comparison, the side pin appears to hold up due to minimal deformation, so manufacturing of this was moved forward.

This was the second iteration design of the dual rod pins. With the same 6 lb load force applied, for comparison, the side pin appears to have half of the stress as the circular dual rod pins, so manufacturing of this was moved forward. The stress is noticed to be very localized at a point along the interface.

This was the third and final iteration design of the dual rod pins. With the same 6 lb load force applied, for comparison, the side pin appears to hold up due to minimal deformation, and was in fact on average slightly lower than the previous iteration. Manufacturing of this part has not been completed for this project, but Medtronic will move forward with the design.

This was the third and final iteration design of the dual rod pins. With the same 6 lb load force applied, for comparison, the side pin appears to have approximately the same stress as the previous iteration. The difference is that this stress is dispersed over a larger surface area. Manufacturing of this part has not been completed for this project, but Medtronic will move forward with the design.

The top dual rod pins will be placed within the vertebrae to maintain accurate home-positioning. With a compressive load of 20 lbs being applied to the top pins, deformation appears to be very minimal. Therefore, manufacturing was moved forward since 20 lbs of force seemed to be greater than anything that we thought may be applied to these pins.

The top dual rod pins will be placed within the vertebrae to maintain accurate home-positioning. With a compressive load of 20 lbs being applied to the top pins, stress appears to be very higher at the top interface of the pins, so durability testing needed to be considered.

This was the second iteration design of the top pins. The top pins were tapered instead of cylindrical in hopes of reducing potential failure. With a compressive load of 20 lbs being applied to the top pins, deformation appears to be very minimal and even less than the previous iteration.

This was the second iteration design of the top pins. The top pins were tapered instead of cylindrical in hopes of reducing potential failure. With a compressive load of 20 lbs being applied to the top pins, stress appears to be approximately half of what the previous iteration stress was.