Expansion System Stabilizes and Restores Vertebral Body

A novel spinal implant provides a fully controlled and comprehensive solution for the reduction of painful osteoporotic vertebral compression fractures (VCFs).

The Stryker (Kalamazoo, MI, USA) SpineJack implantable fracture reduction system is based on a modifiable titanium expander designed to realize the biomechnical restoration of a VCF by simultaneously restoring sagittal and coronal balance, coronal angulation, and endplate restoration. The procedure involves placement using a percutaneous transpedicular approach with fluoroscopic guidance, followed by a controlled anatomical cranio-caudal expansion that preserves the surrounding bone trabeculae.

During expansion, a 500-Newton distraction force is applied along the cranio-caudal axis, similar to a car jack. Device expansion is achieved using a specific tool that pulls the two ends of the implant towards each other, shortening the device and deploying the central titanium component. A rack-and-pinion system blocks the expansion of the implant at the desired height, preventing loss of correction before low-pressure injection of polymethylmethacrylate (PMMA) bone cement, which envelops the implants, ensuring definitive stabilization of the fracture.

By optimizing biomaterial positioning and interdigitation, the Spinejack system provides controlled uni-directional cranio-caudal expansion to restore sagittal and coronal balance; adaptation of the implant’s expansion to restore coronal angulation, and adaptation of implant positioning for endplate restoration. The SpineJack implantable fracture reduction system is available in three sizes (5.8, 5, and 4.2 mm), and includes three dimensional (3D) mapping software that uses computerized tomography (CT) scans to evaluate the anatomical restoration.

Non-operative treatment of VCF is often poorly tolerated, and surgical options include percutaneous vertebroplasty and kyphoplasty. Vertebroplasty is associated with higher rates of procedure-related complications and cement leakage, while kyphoplasty can result in significant loss of restored vertebral height after balloon deflation. The Spinejack system, developed originally by Vexim (Toulouse, France), which was recently acquired by Stryker, has been shown to overcome both problems and provide superior clinical results.