Designing a 3d printed bone simulant for wire navigation training

Medical simulation has risen in popularity as a method of improving surgical outcomes for less experienced practitioners. In orthopedic surgery, haptic feedback is an essential element of simulation. In the case of Kirschner wire navigation, for example, a steel pin is drilled through cortical bone and into cancellous bone. Currently, many orthopedic simulations use Sawbones polyurethane foam surrogates as a bone simulant (Sawbones, Vashon Island, WA). When designing a simulator, however, creating or modifying an existing mold for cast parts is costly, which can be a critical limitation. A relatively low- cost alternative is 3D printing prototype bone surrogates. In this experiment, three rapid-prototyped bone samples were printed from light-weight polylactic acid, each with different material densities based on their printing temperature. In a blind test, orthopedic surgeons were asked to drill a Kirschner wire into four bone simulants: three made from polylactic acid, each prepared with different printing temperatures, and a Sawbones control. The surgeons rated their experience with the surface engagement, drill feel, and ability to redirect their wire. The survey found that the densest sample, printed at the lowest temperature, received the highest surgeon rating, with an average score of 13.5/15 +/- 2.60; the Sawbones control received the worst rating: 6.5/15 +/- 2.96.