Date of Award

6-2013

Document Type

Open Access

Degree Name

Bachelor of Science

Department

Mechanical Engineering

First Advisor

Glenn Sanders

Language

English

Keywords

tumors, cancer, implants, bone, surgery

Abstract

Benign and malignant tumors often arise in bone due to metastasizing cancer. Thirty years ago limbs affected by tumors were treated with amputation, now with new technology, limb‐saving surgery is used most of the time; however, these surgical methods have limitations. Research shows a trend of using allografts and metallic implants to fill the bone gap once the tumor is resected. In some cases sections up to one third of the femur can be removed, sometimes disrupting the joint. There are many problems such as the integration and risk of failure in these implants. A more patient specific approach can be beneficial. It is important to create an implant that is optimally porous to promote osseointegration, bony ingrowth through the implant. While porosity is important, the implant must also sustain mechanical loading. We hypothesized that we can reduce the limitations of current bone cancer treatment methods by utilizing novel CAD and manufacturing technology to design a patient‐specific orthopaedic implant. Using a software program called Mimics, we transformed CT scan data of a patient’s cancerous femur into a three‐dimensional model. Using the 3D model, we resected the 15cm tumor through a “virtual surgery”. A custom implant was designed to fill the bone gap and the overall porosity and pore size was optimized to withstand physiologic loading and promote osseointegration. The implant’s stresses and strains will be tested using Finite Element Analysis (FEA) to confirm the mechanical properties. Once the design is optimized, a titanium (Ti6Al4V) implant will be created using Direct Metal Laser Sintering (DMLS), an additive manufacturing (rapid prototyping) technique. Additive manufacturing has recently started to appear in the medical device industry because of the capabilities to create intricate and complex structures and the cost-­‐effectiveness. This process for creating patient-specific implants can greatly improve bone cancer patient’s outcomes by minimizing the surgical resection, avoiding the resection of the (knee) joint, and allowing for improved osseointegration. We also anticipate that bone health will be better maintained as the bone marrow will not be disrupted.

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