In Vivo Biomechanical Testing of Nerve: A Procedure for Biomechanical Analysis of Brachial Plexus Nerve Injury in a Neonatal Pig Model

Brachial plexus is a network of nerves in the shoulder that carry signals from the spinal cord to the upper limbs. Traumatic conditions that stretch the nerves beyond their limit may cause rupture leading to a loss of muscular function.

To quantify the stretch bearing limit or failure strain of the brachial plexus, set up a load cell and clamp with a mobilizing device called an actuator. The actuator enables clamping of the target specimen with a specific force measured using the load cell. Connect this biomechanical assembly to a computer and data acquisition system.

Once the setup is ready, take an anesthetized neonatal pig in a supine position with exposed brachial plexus. Cut the nerve and anchor the incised end to the clamp. Now, mark various nerve segments to observe the marker's displacement during elongation. Place a reference ruler close to the clamped nerve to set the scale for imaging purposes.

Now set a stretch rate on the computer system and start the test. The clamp begins pulling the nerve longitudinally. Record the nerve elongation pattern to capture the nerve's breaking point. Use the data acquisition system to calculate the failure strain. Repeat the experiment to determine the biomechanical properties of individual nerve segments.