Comparing cervical spine motion with different halo devices in a cadaveric cervical instability model

Area of Science:

• Orthopedic biomechanics
• Spinal instrumentation
• Cadaveric studies

Background:

• Conventional halo (CH) use in cervical spine injuries is effective but associated with pin site complications.
• The noninvasive halo (NIH) was developed to mitigate CH-related complications.
• Limited biomechanical data exists comparing NIH and CH efficacy in restricting cervical spine motion.

Purpose of the Study:

• To biomechanically compare the immobilization capabilities of the CH and NIH.
• To evaluate performance at C1-C2 and C5-C6 instability levels.
• To assess motion during donning, log rolling, and sit-up maneuvers.

Main Methods:

• Biomechanical evaluation using cadaveric models with induced C1-C2 and C5-C6 instability.
• Measurement of relative vertebral motion during specific maneuvers (donning, log roll, sit-up).
• Comparison of motion under CH and NIH conditions.

Main Results:

• NIH application resulted in significantly less cervical spine motion compared to CH.
• CH provided superior immobilization for C5-C6 instability during log rolling (lateral bending, axial translation).
• CH offered greater frontal plane immobilization at C1-C2 during log rolling; no significant differences were noted during sit-up maneuvers.

Conclusions:

• NIH application is biomechanically less disruptive to cervical spine motion than CH.
• CH demonstrates superior immobilization for specific instability types and maneuvers.
• Both devices achieve similar immobilization during the sit-up maneuver.