Final Design

Anchor 3 is a model that was developed based on the design flaws that the team faced once putting together the physical prototype with Anchor 2. The section of the anchor that has the valve hole went in between the vertebral body but when assembled with the PTFE enclosure, the hydrogel wasn't able to fill completely which can lead to a mechanical instability that wasn't picked up in the SolidWorks FEA. This model accounts for the defects with a T-shape that matches the curvature of both the vertebral body (~10 degrees) and its top face. The change to one screw also allows proper security with the small extrusions around it to keep it in place with fewer holes being drilled into the bone.

The final design consists of a PTFE enclosure filled through a Qosina one-way valve with a hydrogel. This sac was hand-sewn and sealed with Permabond to prevent leakage and covered half of the area of the spinal disc. These seams will not be included in the final design. Rather, the enclosure will be made of a single sheet of heat-sealed plastic. The current enclosure was able to withstand over 530N of force despite the seams. The material for the sack will likely be changed to a less slick material which will be easier to work with.

With the help of Watershed Idea Foundry and their Renishaw Titanium Printer, the team was able to get a 1:1 scale titanium model of both Anchors 2 and 3, which were presented during the UCSD Bioengineering Day Conference.