The Barrow Biomimetic Spine: Fluoroscopic Analysis of a Synthetic Spine Model Made of Variable 3D-printed Materials and Print Parameters.

STUDY DESIGN: Objective and subjective fluoroscopic assessments of a new synthetic spine model.

OBJECTIVE: The aim of this study was to analyze the fluoroscopic performance and fidelity to human tissue of a new synthetic spine model.

SUMMARY OF BACKGROUND DATA: The Barrow Biomimetic Spine project aims to develop a 3-dimensional (3D) printed, synthetic spine model that will one day replace cadaveric tissue in spine biomechanical research. A crucial component to any biomimetic spine model is that it performs similarly to cadaveric tissue on standard diagnostic imaging modalities.

METHODS: Numerous L5 vertebral bodies (VBs) were 3D printed with variable shell thicknesses and internal densities, and fluoroscopic images were taken of these models to measure cortical thickness and gray-scale density. An L3-L5 spinal segment was then printed, and fluoroscopic films were obtained at variable C-arm angles. Three spine surgeons subjectively scored these images for human fidelity. Pedicle screws were then placed into the L3-L5 segment to demonstrate successful or breached placement. Standard anteroposterior (AP) and lateral films were taken, and three spine surgeons were tested and scored on correctly identifying screw placement.

RESULTS: Cortical thickness and gray-scale density testing demonstrated an upward trend with increases in relevant print settings. Subjective scoring demonstrated nearly perfect fidelity for the L3-L5 model. Surgeon identification of screw placement on the AP and lateral fluoroscopic views also demonstrated nearly perfect fidelity.

CONCLUSION: This study is the first to demonstrate that 3D-printed VB and segmental spine models accurately mimic human tissue on C-arm fluoroscopy, not only in respect to their anatomical appearance in standard views but also in their response to surgical manipulation and the variations in C-arm angle that commonly occur in the operating room. As such, these spine models have the potential to serve as an excellent platform for future research and surgical education programs.

LEVEL OF EVIDENCE: N/A.