Cervical facetectomy and its effect on spine strength

Area of Science:

• Orthopedics
• Biomechanics
• Spinal Surgery

Background:

• Facet joints are crucial for cervical spine stability.
• Understanding the impact of facetectomy on spinal mechanics is vital for surgical planning.

Purpose of the Study:

• To evaluate the effect of varying degrees of bilateral facetectomy on the shear strength of cervical spine motion segments.

Main Methods:

• Tested 14 cervical spine motion segments in shear under compression and distraction.
• Specimens underwent 0%, ≤50%, or 70% bilateral facetectomy.
• Shear strength and failure modes were analyzed.

Main Results:

• Facetectomy did not affect compression or distraction stiffness.
• 70% facetectomy led to joint fracture at 159 lbs.
• Specimens with >50% facetectomy showed significantly compromised shear strength.

Conclusions:

• Bilateral resection of over 50% of facet joints compromises cervical spine shear strength.
• This suggests a threshold for safe facetectomy during spinal procedures.