Optimum expandable cervical peek cage design by using finite element method

In the thesis study, Cervical PEEK Cage was designed in order to reconstruct height of cervical disc and clearence of neural foramen which lose the characteristic by degeneration.It has been seen that two different applications have been realized in similar problems. The first of these is cervical disc prosthesis. This prosthesis is used with the purpose of preserving mobility and allows all movements in the flexion, extension and rotational direction. The other is PEEK Cage application, which is also a thesis topic. Unlike disk prosthesis, it is a fusion system. It is intended to act as a single vertebrae, ensuring that the vertebrae are locked together. PEEK Cage applications can be expandabled and non-expandabled in two parts. Although expandable PEEK Cage applications offer a more conservative approach, applications allow only one side of the top surface to be widened. It is aimed to overcome this disadvantage by studying the thesis. The first design was realized in CAD environment considering working kinematics and end-plate suitability and then tried to be determined using the static analysis module of ANSYS Workbench, which is a finite element analysis software whether PEEK cage parts undergo plastic deformation during this kinematics. The materials to be used were PEEK (polyether ether ketone) and titanium alloy (Ti4Al6V), which are compatible with human body. Since the problem to be solved during finite element analysis is a nonlinear solution, convergence problems have been encountered and some approaches have been tried to overcome this problem. Different iterations have been applied to two different configurations in the working kinematic to achieve optimum design. After the iteration work, a fully surface expandable PEEK Cage design was developed that can continue its function without undergoing the deformation under the exposed forces. Later, the design was revised to be manufacturable. Assisted hand tools are needed during the implantation of the optimal PEEK cage. The cam which will provide the kinematic part of the titanium alloy part which is to be elevated in order to provide the expansion, and the other is the hand tool which will be used when the PEEK cane is placed in the endplate. In these parts the optimum PEEK design is similar to the methodology used in cage design. Thus, as the surface area is increased for the exposed load by enlarging the entire surface, both tangential stresses are reduced and more holding is provided to the vertebrae. These outputs have made the system more reliable.