Clinical Characteristics and Neurophysiology of Lumbosacral Herniated Nucleus Pulposus (HNP)

Background: The most common causes of lower back pain (LBP) are lumbosacral herniated nucleus pulposus (HNP), especially at the L5-S1 disc. EMG is one of the choices to determine localization, distinguishing root irritation from root compression, and is an initial non-invasive examination with a relatively low cost. Information on the delivery of electrical impulses through the proximal segment of the spinal cord can only be known through examination of the F-response and H-reflex. The value of both examinations can be used to determine the presence of L5-S1 radiculopathy. Method: This is an analytical cross-sectional study, using consecutive sampling on patients with lumbosacral HNP. Examination of NCV, F-and H-reflex response were assessed and their values compared between lumbosacral HNP irritation lesions and compression lesions. Result: Among 50 samples with dominance of LBP, the mean of CMAP for latency, amplitude, NCV of tibial nerve 4,47±1,15msec;6,59±1,85mV;53,95±6,65m/sec and peroneal nerve 3,29±1,15msec;2,25±0,84mV;54,67±8,25m/sec. The mean of SMAP for latency, amplitude, NCV of sural nerve 4,17±0,67msec;6,73±2,98µV;59,06±9,12m/sec. Different results between the value of F-response and H-reflex examination according to compression lesions (p<0.05). But there is no difference between the value of examination F-response and H-reflex according to irritation lesions (p>0.05). Conclusion: Average value of patients with LBP of normal motor and sensory NCV, a significant difference in outcome between parameter value of F-response (minimum F wave latency, chronodispersion, and persistence) and parameter value of H-reflex (H/M ratio).