The electrodiagnostic evaluation of spinal root lesions

Area of Science:

• Neurology
• Neurophysiology

Background:

• Root lesions can be challenging to diagnose using traditional methods.
• Early identification of root lesions is crucial for effective treatment and patient outcomes.

Purpose of the Study:

• To survey available electrophysiologic techniques for identifying root lesions.
• To highlight the complementary role of electrophysiology in diagnosing neurological conditions.

Main Methods:

• Review of electrophysiologic techniques including fibrillation potentials, positive sharp waves, F-wave analysis, H-reflex, and somatosensory evoked potentials (SEPs).
• Comparison of electrophysiologic findings with clinical and myelographic data.

Main Results:

• Fibrillation or positive sharp waves in paraspinal muscles indicate root lesions earlier than other muscle groups.
• F-wave abnormalities reflect proximal motor axonal dysfunction.
• H-reflex assesses S1 sensory root integrity, and SEPs are valuable for sensory-predominant conditions.
• A 70-80% correlation exists between clinical, myelographic, and electrophysiologic findings, with potential for discordance.

Conclusions:

• Electrophysiology provides valuable, often complementary, information for diagnosing root lesions.
• Electrophysiologic findings can indicate lesions proximal to the root and assess sensory and motor axonal integrity.
• Electrophysiology has limited utility in postlaminectomy assessment.