An experimental pain model to investigate the specificity of the neurodynamic test for the median nerve in the differential diagnosis of hand symptoms.

OBJECTIVE

To indirectly assess the specificity of the neurodynamic test for the median nerve using an experimental pain model.

DESIGN

Repeated-measures design.

SETTING

Laboratory setting.

PARTICIPANTS

Twenty asymptomatic participants in whom hand symptoms were induced by infusion of hypertonic saline into the thenar muscles.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain intensity of the induced hand symptoms and size of the painful area were evaluated in 8 different arm positions, which correspond with different stages of the neurodynamic test for the median nerve. These positions have a variable degree of median nerve provocation at the wrist.

RESULTS

Because the induced symptoms had a non-neural origin, changes in symptom provocation with the neurodynamic test would have indicated poor specificity. However, there were no statistically significant differences in pain perception (P> or =.22) and the recorded differences were negligible from a clinical perspective.

CONCLUSIONS

Taking into consideration the limitations of an experimental pain model, this study indirectly confirms the specificity of the neurodynamic test for the median nerve. The results of this study, together with previous studies that demonstrated a high sensitivity, support the use of the neurodynamic test for the median nerve to differentially diagnose neurogenic disorders, such as carpal tunnel syndrome, from other wrist and hand pathologies.