title: Comparison of evoked spinal potentials by stimulation of the sciatic nerve and the spinal cord.
abstract: Spinal cord monitoring during surgery using evoked spinal potentials (ESP) is now popular. In cats, ESPs due to both sciatic nerve (SN-ESP) and spinal cord stimulation (SC-AESP and SC-DESP) were recorded from the epidural space. Both SN-ESP and SC-AESP were compared by parameter studies. Stimulus frequencies up to 100 Hz did not significantly alter the SC-AESP, whereas the later components of the SN-ESP decreased greatly in amplitude. The SN-ESP was more sensitive to asphyxia than the SC-AESP. Augmentation of the ESP occurred approximately 5 minutes after the asphyxia was introduced, which was interpreted as an impending sign of anoxia of the spinal cord. The SN-ESP had more potentials arising from synaptic and postsynaptic activities, while the SC-AESP was mainly derived from the spinal tracts. To monitor the function of the spinal cord, both methods should be used.
mesh_terms: D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D004824:Epidural Space; D005071:Evoked Potentials; D007430:Intraoperative Care; D008991:Monitoring, Physiologic / Q000379:methods*; D012584:Sciatic Nerve / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*