Desenvolvimento de implantes personalizados para artrodese da coluna vertebral fabricados via manufatura aditiva por extrusão de PEEK

Abstract

Spinal fusion surgery is the standard treatment for when the intervertebral disc is degenerated and non-surgical methods have failed. In this treatment, an intervertebral device or spinal cage is introduced in the place of the disc, giving support and trying to promote the fusion of the adjacent vertebrae. Proper fitting of the implant with the vertebrae is essential for the patient’s recovery. Medical imaging technologies such as computed tomography (CT) already allow a virtual reconstruction of the internal anatomy of the patient to be treated. On the other hand, additive manufacturing (AM) by material extrusion allows a virtual model to be easily materialized. The recent introduction of the biocompatible PEEK polymer in material extrusion technology makes it possible to develop patient-specific implants (PSI). PEEK is already used in spine implants and shows some advantages such as radiolucency and mechanical properties close to human bone. The present research work proposes and applies a methodology in the development of custom spinal implants of the interbody spacer type that combines CT and AM technologies by PEEK extrusion. The purpose of the study is to show evidence of the feasibility of using this material and method for producing custom implants. Spine implants were designed and modeled according to the geometry and needs of five case studies. Prototypes of the custom implants were manufactured in PEEK via material extrusion AM and then underwent annealing and sterilization. The dimensional properties of the prototypes were collected between each stage. The implant prototypes proved to be accurate, without significant geometric changes. The methodology, implant design and technologies used proved to be viable for the production of personalized implants.