Diagnostic value of different neurophysiological methods in the assessment of lumbar nerve root lesions.

OBJECTIVE

To investigate the sensitivity of a combination of different neurophysiological testing methods in patients with lumbar nerve root lesions.

DESIGN AND SETTING

A prospective study was carried out in an electrodiagnosis laboratory on 57 patients with clinically proven lumbar radiculopathies.

PATIENTS AND INTERVENTIONS

On 9 patients with L4 nerve root lesions, 31 patients with L5 nerve root lesions, and 17 patients with S1 nerve root lesions, extensive electromyography (EMG), nerve conduction studies, F-wave-deviations, and somatosensory evoked potentials (SEPs) were performed.

RESULTS

In 93% of all patients, a pathological neurophysiological result was found. In L4 nerve root lesions, EMG was abnormal in 89%, dermatome SEPs were abnormal in 67%, and F-wave latencies were abnormal in 44%. In L5 nerve root lesions, a pathological result was found on EMG in 87%, in peroneus SEPs in 67%, and in F-wave latencies in 66%. In S1 nerve root lesions, the most sensitive results were from dermatome SEPs in 64%, followed by EMG in 53% and F-wave latencies in 24%. Nerve conduction study results were always normal.

CONCLUSION

There are segment-specific neurophysiological results. It is possible to enhance testing sensitivity by a combination of different neurophysiologic testing methods. On these grounds, we recommend a segment-specific neurophysiological "diagnosis scheme" to corroborate the clinical diagnosis in lumbar nerve root lesions.