Value of the H reflex elicited by magnetic stimulation and the F wave in the diagnosis of S1 radiculopathy / 中华物理医学与康复杂志

ABSTRACT

Objective To explore a new electrodiagnostic approach using the H reflex elicited by magnetic stimulation of the S1 nerve root and F waves to evaluate sensory nerve root function in patients with S1 radiculopathy.Methods Thirty normal subjects and 30 patients with unilateral S1 radiculopathy were recruited in this study.H reflex and M response were recorded from the bilateral soleus of all the subjects by magnetic stimulation of S1 nerve roots.F and M wave responses elicited by electrical stimulation of bilateral tibial nerves at the popliteal fossa were also recorded.The sensory root conduction time (SRCT) was calculated.Correlations of age and body height with SRCT in the healthy subjects,and between SRCT and pain in the patients with S1 radiculopathy were analyzed.Results The mean values of normal subjects were 3.10 ± 0.44 ms for SRCT,and 0.13 ± 0.19 ms for inter-side SRCT differences.In the 30 patients with S1 radiculopathy,H reflex could not be elicited from 4 patients.Among the remaining patients,the SRCT of the affected side was prolonged significantly (3.90 ±0.65 ms),and the mean value of the inter-side difference increased significantly (0.90 ±0.50 ms).A regression equation correlating SRCT with height was developed,but no significant correlation between SRCT and age in the normal subjects was revealed.There was positive correlation between SRCT and the severity of pain among the patients.Conclusion SRCT can be used as a new electrodiagnostic index in estimating sensory nerve root function in patients with S1 radiculopathy.