| Abstrakt | | Somatosensory evoked potentials are responses of the spinal cord to a stimulation of peripheral nerves. Our aim was to evaluate the role of the long sensory tracts, especially that of the fasciculus cuneatus, in the cervical somatosensory evoked potentials of the spinal cord (SEPS). Our assumption was that the high frequency waves seen on the cervical SEPSs registered in the segments of afferent volleys originate in long sensory tracts, most probably in the fasciculus cuneatus. Cervical SEPSs were registered during the intraoperative neuromonitoring with SEPSs, which is used routinely on The Clinic for Neurosurgery in Ljubljana during surgical intervention on a spinal cord. The subpial tehnique was used to register SEPSs. Square pulse electrical current was used in the stimulation of the median nerve at wrist and in some cases also cutaneous nerves of the thumb, the middle finger or of the little finger were stimulated. In order to clearly demonstrate the high frequency waves of SEPSs low frequency high amplitude waves were removed from the original recordings. The obtained responses showed characteristics similar to those of conducted SEPSs, registered higher above the segments of the afferent volleys. Normal SEPSs were registered in three patients with the chronic pain syndromes of the upper extremity in whom the somatosensory system of the spinal cord was intact. These SEPSs were used for comparison to the cervical SEPSs registered in seven patients with the spinal cord lesions. (Abstract truncated at 2000 characters)
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