BIOMED PhD Thesis Defense

Title: 
Fused Filament Fabrication of Polyether-ketone-ketone (PEKK) and Polyether-ether-ketone (PEEK) Lumbar Interbody Fusion Devices: Investigation into the Process Parameters That Enhance Static Strength

Speaker:
Abigail Tetteh, PhD Candidate
School of Biomedical Engineering, Science and Health Systems
Drexel University

Advisor:
Steven Kurtz, PhD 
Research Professor
School of Biomedical Engineering, Science and Health Systems
Drexel University 

Details:
The surgical implantation of lumbar interbody fusion devices (L-IBFDs), often referred to as spinal cages, is the final intervention to facilitate spinal fusion when treating intractable lower back pain. Due to the prevalence of this condition and the significant burden it places on individuals worldwide, the demand for effective spinal cages continues to surge. Careful selection of biomaterials and manufacturing methods for these devices is crucial to ensure successful outcomes.  

For decades, the two biomaterials commonly used for these devices have been titanium (Ti) alloys and polyether-ether-ketone (PEEK) thermoplastic. Although Ti possesses osseointegrative properties, it also poses limitations due to its stiffness and radiopacity, making it less ideal for this application. The use of PEEK addresses these challenges because of its bone-like mechanical properties and radiolucency (which allows for device monitoring post-implantation). However, its hydrophobicity prevents it from achieving osseointegration, which could subsequently lead to device failure. Polyether-ketone-ketone (PEKK), a newer biomaterial in the same thermoplastic family as PEEK, has emerged as a promising alternative. It offers similar bone-like mechanical properties with different surface chemistry that could potentially promote osseointegration. It is also well suited for processing via fused filament fabrication (FFF) printing. This fabrication method is increasingly being utilized in medical device production due to its cost-effectiveness, design flexibility, and low material waste. Specifically for this application, FFF affords the incorporation of intricate features that aid in improving fixation in vivo. 

Effective spinal cages must provide immediate stability and encourage long-term bone integration to prevent complications such as implant migration and failure. Therefore, further investigation is needed to safely utilize the newer PEKK material processed with FFF for permanent implants like lumbar spinal cages. This research aims to examine the behavior of FFF-printed PEKK and benchmark it against the well-established PEEK biomaterial, in an effort to advance knowledge in the development of FFF lumbar spinal devices.

The School of Biomedical Engineering, Science and Health Systems is pleased to announce its 7th Annual Immune Modulation & Engineering Symposium (IMES).