Introduction/Statement of the problem: Objective validation of the spine pain complaint is a major problem in the assessment and treatment of chronic spine pain. The sensitivity and specificity of the physical examination, imaging studies and needle EMG studies is high. As such, scheduled medications use and adjudications for compensation benefits, are driven to a great extent solely by subjective symptoms. There is a need for an objective marker of pain. Material and Methods: In this study we studied sensory nerve action potentials of A-delta fibers. These were evaluated by stimulating the A delta fibers in the peripheral dermatomes from 0 – 10 mA and 0 – 50 volts at 250 Hz using a Neural Scan device. An objective response to this peripheral stimulus was measured by a potentiometer placed at the level of spinal C6. The apparatus used for this was a Myovision dynamic surface EMG electrode. This measured the action potentials of the A-delta fibers. Results do not depend on patient cooperation. In a previous study we had reported that the amplitudes of the action potentials were significantly lower in chronic spine patients. We have found that in chronic spine patients there is chronic hyperstimulation of A delta fibers and measuring this appears to be useful as an objective marker of severe spine pain.

Results: In this study, with IRB approval, we looked at a group of 20 spine patients describing the morphologies and amplitudes in both acute and chronic pain. We have found that there a specific morpologic marker for acute spine pain. The morphologies of the A-delta nerve action potential in chronic spine patients show some variability depending on chronicity.

Conclusions: There is a great need for further research in this area. This testing is inexpensive, has no morbidity, and holds promise as an objective marker of pain.