International Journal of Psychophysiology 25 1997 221᎐226
Dermatomal SEPs ᎏ a complementary study in evaluating
patients with lumbosacral disc prolapse
, F. Fotiou
, I. Tsiptsios
, C. Tsonidis
, K. Fountoulakis
, P. Tsitsopoulos
Department of Clinical Neurophysiology, Psychiatric Hospital of Thessaloniki, Thessaloniki, Greece
Neurosurgical Department, Ippokration General Hospital, Aristotle Uni®ersity, Thessaloniki, Greece
Bristol Eye Hospital, Bristol, England
Received 24 April 1996; revised 5 November 1996; accepted 7 November 1996
We investigated the value of Dermatomal Somatosensory Evoked Potentials in 24 patients with unilateral
radiculopathy due to lumbosacral disk prolapse. All patients had clinical signs and symptoms of disk prolapse and
positive ﬁndings on neuroradiologic testing. We assessed the latency and the amplitude of the ﬁrst positive waveform
of Dermatomal SEPs, as well as conducting peripheral nerve conduction studies and electromyography. Our studies
showed a clear correlation of Dermatomal SEP abnormalities and radiculopathy in up to 83.3% of subjects studied.
Use of electromyography testing provided this correlation in about 62.5% of the same subjects. On the basis of these
results, we propose that Dermatomal SEPs have value in complementing the routine electrophysiological testing of
the patients with radiculopathy and provide a sensitive non-invasive technique for deﬁning the level of disk prolapse.
ᮊ 1997 Elsevier Science B.V.
Keywords: Dermatomal SEPs; EMG; Lumbosacral disk prolapse
Electrophysiological abnormalities have been
reported in patients with clinical diagnosis of
lumbosacral root disease Eisen et al., 1977; Fisher
et al., 1978; Tonzola et al., 1981; Aminoff et al.,
1985b . However, the diagnostic yield of these
Corresponding author. Tel.: q30 31 200802; fax: q30 31
methods remains limited because they cannot
provide direct proof of impaired nerve conduction
in the very proximal segment of peripheral nerves;
the routine EMG and nerve conduction studies
are only occasionally helpful because they give
information only about the motor roots.
Somatosensory evoked potential studies SEPs
permit assessment of the sensory function of
proximal portions of the peripheral nerves and
their constituent roots in a non-invasive manner.
They have been used to investigate lumbar root
0167-8760r97r$17.00 ᮊ 1997 Elsevier Science B.V. All rights reserved.
PII S0167-8760 96 00735-0