Neurophysiological and radiological assessment of spinal cord lesions

ABSTRACT

Several electrophysiological techniques have been used to evaluate the functional neurologic condition of patients with spinal cord lesions. Somatosensory evoked potentials [SEPs] and motor evoked potentials [MEPs] are safe, noninvasive and commonly used techniques to evaluate the integrity of central sensory and motor pathways. Twenty patients [10 males and 10 females] with mean age of 39.7 +/- 15.8 years were included in the study. All patients had focal spinal paraplegia with dorsal sensory level. They underwent the posterior tibial nerve somatosensory evoked potentials [PT-SEPs] studied on both lower limbs and tibialis anterior motor evoked potentials [TA-MEP] studied on both upper and lower limbs by means of transcranial magnetic stimulation. Subjects with evidence of medical disorders, peripheral neuropathy or evidence of cervical lesions were excluded from the study. Moreover, the patients were subjected to nerve conduction studies of both lower limbs and MRI with contrast on dorsal spine. From the results obtained, it was concluded that clinically complete lesions are not necessarily neurophysiologically silent. Recordable SEPs and MEPs may be obtained in spite of clinically complete lesions and vise versa. MRI is the procedure of choice for detecting most of the spinal cord lesions. Despite the accuracy of the MR study in detection of anatomic changes of the spinal cord, they may fail to correlate such changes with the functional state of the cord. Sensory and motor evoked potential can play an important role in following up and monitoring the patients with dorsal cord lesions