Potential advantages of the h-reflex of the biceps femoris-long head in documenting s1 radiculopathy

PURPOSE: A novel H-reflex method using the biceps femoris-long head (BF-LH) was investigated to collect the normative data for this reflex arc and assess its clinical utility for S1 radiculopathy evaluation. Comparability with conventional tibial and Sol H-reflex findings was also determined. METHODS: BF-LH H-reflexes were recorded using surface electrodes to S1-root stimulation in 43 unilateral S1 radiculopathy patients (radiculopathy group) and 34 normal subjects (control group) from March 2009 to December 2011. H-M interval and peak-to-peak amplitudes were measured. The BF-LH H-reflex and the H-reflex from the soleus muscle (Sol H-reflex) to both tibial nerve stimulation (tibial H-reflex) and S1-root stimulation were used and compared for application in S1 radiculopathy evaluation. RESULTS: BF-LH H-reflexes were reliably recorded for all control group subjects. Abnormal BF-LH H-reflexes were recorded for 40 (93.0%) radiculopathy group patients in the involved extremity, and abnormal involved side tibial H-reflexes and Sol H-reflexes were recorded in 31 (72.1%) and 41 (95.3%) radiculopathy group patients, respectively. The BF-LH H-reflex exhibited significantly higher sensitivity for evaluation of S1 radiculopathy, accurate in 40 (93.0%) radiculopathy group patients, than that provided by the conventional tibial H-reflex of only 31 (72.1%) (P < 0.05). CONCLUSIONS: The BF-LH H-reflex is a highly sensitive and reliable clinical tool for evaluation of the S1 spinal reflex pathway in radiculopathy that is distinct from the Sol H-reflex and conventional tibial H-reflex arcs.