A Novel Titanium End-Disc-Assisted Allograft Preparation System for Anterior Cervical Corpectomy and Fusion: Development and Preliminary Biomechanical Evaluation.

Background

Allograft bone remains an attractive option for anterior cervical corpectomy and fusion (ACCF), but its use can be limited by variable graft geometry, insufficient endplate contact, and operator-dependent trimming. This study aimed to develop a titanium end-disc-assisted allograft construct with a standardized cutting and assembly system and to preliminarily evaluate its static mechanical integrity under axial compression, compression-shear, and torsional loading.

Methods

The construct consisted of a controlled-length bone graft, two Ti6Al4V end-discs, and four countersunk fixation screws, forming a graft-disc construct with a maximum total height not exceeding 40 mm. The end-discs incorporated angled screw holes, bone-graft filling spaces, and enlarged contact surfaces. A modular preparation system was designed for graft clamping, length definition, guided cutting, alignment, pre-drilling, and screw fixation. Porcine rib specimens were used as an allograft substitute. Native bone and assembled constructs were tested under static compression, compression-shear, and torsion.

Results

The system produced standardized constructs. Except for axial compressive stiffness, the assembled constructs showed numerically higher compressive yield force, shear stiffness, shear yield force, torsional stiffness, and yield torque than native bone; however, these findings were interpreted descriptively because of the limited sample size. Failure occurred mainly within the bone, with no obvious failure at the bone-titanium interface, titanium end-discs, or fixation screws.

Conclusions

The proposed system enabled standardized graft preparation and construct assembly. Further fatigue, subsidence, and clinically relevant cervical spine model testing are required.