# Preclinical evaluation of lateral interbody fusions using 3D printed PEEK or 3D printed titanium cages

## TL;DR

This study compares 3D printed PEEK and titanium cages for spinal fusion in sheep, finding both effective but with imaging advantages for PEEK.

## Contribution

Demonstrates that 3D printed PEEK and titanium cages both support interbody fusion in a preclinical model.

## Key findings

- 3D PEEK cages allowed clear imaging via radiographs and microCT due to their radiolucent properties.
- 3D Ti cages showed image artifacts in microCT and appeared solid in radiographs, complicating fusion evaluation.
- Both cage types supported successful interbody fusion with autograft in sheep models.

## Abstract

PEEK interbody cages are well established. 3D porous PEEK designs can now be produced with additive manufacturing. This study compared the in-vivo response of additive manufactured porous PEEK (3D PEEK) and titanium alloy (3D Ti) cages.

Interbody fusion was performed in 11 adult sheep at 2 levels (L2-3 and L4-5) using 3D PEEK and 3D Ti cages filled with autograft with posterior bilateral pedicle screw fixation. Fusions were evaluated at 8 and 16 weeks via manual palpation, microcomputed tomography (microCT), histology, and histomorphometry.

All animals recovered well following surgery with no adverse events. The radiolucent nature of PEEK allowed the fusions to be evaluated using radiographs and microCT. The 3D Ti cages however appeared solid rather than porous in the radiographs and presented artifacts in the microCT scans which precluded definitive determination of the fusions. Range of motion results improved with time for 3D PEEK and 3D Ti while no differences between designs were detected. Histology and histomorphometry confirmed 3D PEEK and 3D Ti supported fusion in this model using autograft.

Range of motion and histology results were similar for 3D PEEK and 3D Ti. Radiographs and microCT could be used to assess the fusions with 3D PEEK due to the radiolucent nature. 3D Ti appeared solid in the radiographs and had image artifact in microCT which precluded definitive evaluation of the fusions. 3D PEEK and 3D Ti cages both support interbody fusion in this preclinical model.