Mechanical properties of the human brachial plexus

Area of Science:

• Biomechanics
• Neuroscience
• Orthopedic Surgery

Background:

• Brachial plexus injuries often result from traction mechanisms.
• Understanding the biomechanical properties of the brachial plexus is crucial for injury prevention and treatment.

Purpose of the Study:

• To measure the force and elongation during experimental traction of the human brachial plexus.
• To identify the predominant lesion type and the initial site of mechanical failure.

Main Methods:

• Experimental traction was applied to fresh cadaveric human brachial plexus specimens.
• Simulated traction injury mechanisms were used.
• Force, elongation, stress, and strain at rupture were recorded.

Main Results:

• Direct lateral traction predominantly caused avulsion of the brachial plexus roots.
• Epineural mechanical failure initiated at the anterior margin of avulsed roots near the intervertebral foramen.
• The force causing rupture ranged from 217.7N to 546.3N.
• Stress values ranged from 1.3 N/mm² to 3.5 N/mm².
• Elongation at rupture was between 19.6% and 58.8% of the initial length.

Conclusions:

• Brachial plexus root avulsion is the primary injury under direct lateral traction.
• The biomechanical properties, including force and elongation at rupture, provide critical data for understanding traction injuries.
• Findings offer insights into the mechanisms of brachial plexus injury relevant to surgical repair and trauma management.