Instrumentation of the cervicothoracic junction after destabilization

Area of Science:

• Spinal biomechanics
• Orthopedic surgery
• Biomedical engineering

Background:

• Cervicothoracic junction instabilities require effective surgical management.
• Existing instrumentation techniques lack evaluation at the cervicothoracic junction.
• The biomechanical properties of different constructs at this junction are not well understood.

Purpose of the Study:

• To evaluate the biomechanics of three distinct instrumentation constructs.
• To determine the most efficient method for restoring cervicothoracic junction stability.
• To assess construct efficacy with and without laminectomy.

Main Methods:

• Biomechanical testing of six human spines under axial torsion, flexion, and extension.
• Simulation of a Stage 3 cervical spinal injury (distractive-flexion) between C7 and T1.
• Sequential testing of posterior Synthes lateral mass plate, posterior Cotrel-Dubousset rod system, and anterior Synthes cervical locking plate.

Main Results:

• Posterior stabilization techniques exhibited statistically greater stiffness than anterior plates.
• The Cotrel-Dubousset system provided the highest stiffness ratio (instrumented/intact) in all tested motions.
• No significant difference in stiffness was found between posterior plates and the Cotrel-Dubousset system.

Conclusions:

• Anterior plates, posterior plates, and posterior hook-rod constructs can efficiently restore cervicothoracic junction instability.
• Posterior constructs offer enhanced spinal stiffness compared to anterior plates.
• The choice of construct should consider the specific biomechanical demands of the cervicothoracic junction.