Role of EMG to evaluate radiculopathy
What is the role of electromyography (EMG) in the evaluation of radiculopathy?
Electromyography provides neurophysiologic confirmation of the radiographic lesion.
Electromyography evidence of altered innervation suggests significant nerve root compromise.
The most widely accepted electromyography evidence of radiculopathy is the presence of positive sharp waves and fibrillation potentials.
Electromyography changes are first seen in the muscles closest to the site of nerve injury, underscoring the importance of examination of the paraspinous muscles.
A disadvantage of electromyography is the delay in the appearance of reliable abnormalities until 7 to 10 days after a root injury.
The sequence of electromyography changes begins with positive sharp waves in paraspinal muscles between days 7 and 10, followed by paraspinous fibrillation potentials and positive sharp waves in limb muscles between days 17 and 21.