Static Analysis and Design of Innovative Porous Lumbar Interbody Cages

Interbody discs play a major role in maintaining the spine and skeleton structures which may undergo damage. If damage is so severe that the disc cannot be repaired, implants, known as “interbody cages”, should be used.

The present study aimed to propose a novel design with proper strength and resistance against axial disc torques.

The design and analysis of innovative anatomical cages comprised two stages, namely, cage design according to three different models and finite element analysis (FEA). The designs were based on the spine of a 15-year-old teenager without lumbar disc disease. To model the vertebrae, computed tomography )CT( scans and Digital Imaging and Communications in Medicine (DICOM) files were entered into Mimics Version 10.01 (Materialise Inc., Leuven, Belgium); then, the L4 and L5 spinal segments were modeled.

The implants were fixed to the bottom level and subjected to a net force of 1000 N. Additionally, a moment load of 7.5 Nm in flexion, extension, axial rotation, and lateral bending was applied in these three cage models. Considering the application of 1000-N force, maximum and minimum stress and strain distribution rates were presented in three honeycomb, Islamic architecture, and porous gyroid cages.

Novel designs for lumbar cages were considered to achieve damping capacity, light weight, and high resistance. Considering the characteristics of the honeycomb, Islamic architecture, and gyroid structures, optimal designs were proposed for lumbar cages to achieve adequate strength and resistance against axial disc torques under normal conditions.