Biomechanical Analysis of 2 Versus 4 Rods Across the Cervicothoracic Junction in a Human Cadaveric Model

Area of Science:

• Spinal biomechanics
• Orthopedic surgery
• Biomaterials science

Background:

• Cervicothoracic junction reconstruction presents biomechanical challenges due to spinal transition and alignment changes.
• Destabilization necessitates robust surgical techniques for spinal stability.

Purpose of the Study:

• To compare rod strain and multidirectional flexibility of cervicothoracic junction reconstructions.
• Evaluate the efficacy of 4-rod versus traditional 2-rod constructs.

Main Methods:

• Human cadaveric cervicothoracic specimens were used for multidirectional flexibility testing.
• Specimens underwent destabilization and subsequent reconstruction with various rod configurations (titanium and cobalt chrome).
• Range of motion and rod strain were quantified for each construct.

Main Results:

• Accessory rods significantly improved biomechanical stability for titanium and cobalt chrome constructs.
• Cobalt chrome rods demonstrated greater stability and less strain compared to titanium rods.
• The addition of accessory rods did not significantly reduce rod strain but improved overall stability.

Conclusions:

• Supplemental accessory rods enhance the stability of cervicothoracic reconstructions.
• Cobalt chrome rods provide superior stability and reduced strain over titanium rods.
• Four-rod constructs offer improved biomechanical support for the cervicothoracic spine.