[Neurophysiological evaluation of patients with degenerative diseases of the cervical spine]

Abstract

Background/aim: Diagnostic protocol for patients with degenerative diseases of the cervical spine demands, in parallel with neuroimaging methods, functional evaluation through neurophysiological methods (somatosensitive and motor evoked potentials and electromyoneurography) aiming to evaluate possible subclinical affection of spinal medula resulting in neurological signs of long tract abnormalities. Considering diversities of clinical outcomes for these patients, complex diagnostic evaluation provides a prognosis of the disease progression. METHODS. The study included 21 patients (48.24 +/- 11.01 years of age) with clinical presentation of cervical spondylarthropathy, without neuroradiological signs of myelopathy. For each patient, in addition to conventional neurophysiological tests (somatisensory evoked potentials--SSEP, motor evoked potentials--MEP, electromyoneurography--EMG, nerve conduction studies), we calculated central motor conduction time (CMCT(F)), as well the same parameter in relation to a different position of the head (maximal anteflexion and retroflexion), so-called dynamic tests.

Results: Abnormalities of the peripheral motor neurone by conventional EMNeG was established in 2/3 of the patients, correponding to the findings of root condution time. Prolonged conventional CVMP(F) were found in 29% of the patients, comparing to 43% CVMP(F) abnormalities found with the dynamic tests. In addition, the SSEP findings were abnormal in 38% of the patients with degenerative diseases of the cervical spine.

Conclusion: An extended neurophysiological protocol of testing corticospinal functions, including dynamic tests of central and periheral motor neurons are relevant for detection of subclinical forms of cervical spondylothic myelopathy, even at early stages. In addition to the conventional neurophysiological tests, we found useful to include the dynamic motor tests and root conduction time measurement in diagnostic evaluation.