MOTOR EVOKED-POTENTIAL AS A RELIABLE METHOD TO VERIFY THE CONDUCTIVITY OF ANTERIOR SPINAL ROOTS IN BRACHIAL-PLEXUS SURGERY - AN EXPERIMENTAL-STUDY ON GOATS

The goal of this experimental study was to confirm the reliability of motor evoked potential (MEP) in testing the function of anterior motor roots in brachial plexus surgery. On central stimulation, nerve compo und action potentials (NCAPs) are registered from the exposed spinal n erves. if NCAPs can be recorded, the anterior root is considered to be intact. Two factors might cause positive recordings even in the prese nce of an avulsed anterior motor root: Volume conduction, and impulse transmission through an intact posterior root. In five Nubian goats, s pinal nerves C6, C7, and their corresponding spinal roots were dissect ed. On central stimulation, NCAPs were repeatedly recorded from the su rface of ail ten spinal nerves. Then, the anterior motor roots were tr anssected and central stimulation repeated. NCAPs disappeared irrevers ibly in all ten tested spinal nerves, The experiment showed that, on c entral stimulation, NCAPs cannot be recorded from spinal nerves unless the anterior root is intact.