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Hiroshi Yamada - One of the best experts on this subject based on the ideXlab platform.
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Differences in sensitivity between magnetic motor-Evoked Potentials and somatosensory-Evoked Potentials in experimental spinal cord lesions.
Spine, 1996Co-Authors: Yutaka Hiraizumi, Ensor E. Transfeldt, Norio Kawahara, Hiroshi YamadaAbstract:Study Design. Graded posterior spinal cord compression and partial sectioning of the spinal cord were performed, and magnetically induced descending spinal cord Potentials were recorded. Objectives. To compare the sensitivity of transcranial magnetic motor-Evoked Potentials in the spinal cord and other spinal cord Evoked Potentials to spinal cord lesions. Summary of Background Data. Somatosensory-Evoked Potentials have been the standard technique for monitoring spinal cord function during spinal surgery. These Potentials, however, do not necessarily reflect descending motor tract function. Transcranial electric or magnetic stimulation for motor-Evoked Potentials is a more direct measure of motor tract function. However, more research on magnetic motor-Evoked Potentials is needed. Methods. Fifteen adult cats were used. Graded posterior spinal cord compression was performed at L2 in 10 cats, and partial sectioning of the spinal cord was performed at L2 in five cats. The location sequence of lesioning was dorsal column section, dorsal 1/2 section, dorsal 2/3 section, and total spinal cord section. Magnetic motor-Evoked Potentials were recorded by epidural catheter electrodes placed above, at, and below the lesion. Electric motor-Evoked Potentials and spinal and cortical somatosensory-Evoked Potentials were recorded serially for a comparison of their sensitivity to spinal cord dysfunction. Results. In posterior spinal cord compression, N1 amplitude of magnetic motor-Evoked Potentials at and below the lesion decreased after 1 minute of compression with a 70 g weight, and N1 and N2 amplitude disappeared after 1 minute of compression with a 100-to 120-g weight. Electric motor-Evoked Potentials changed at amplitudes comparable with those shown by magnetic motor-Evoked Potentials. Spinal somatosensory-Evoked Potentials showed the most sensitive changes to spinal cord posterior compression and disappeared after 1 minute of compression with 80 g. Cortical somatosensory-Evoked Potentials in five cats were not sensitive enough for spinal cord posterior compression injury and did not disappear even after 1 minute of compression with 120 g. In magnetic motor-Evoked Potentials, after dorsal hemisectioning of the spinal cord only N3 disappeared; N1 and N2 disappeared after ventral spinal cord sectioning. In spinal somatosensory-Evoked Potentials, amplitudes decreased after dorsal column sectioning, and all negative peaks disappeared after dorsal hemisectioning of the spinal cord. Conclusions. Posterior compression injuries are diagnosed more easily with spinal somatosensory-Evoked Potentials. Motor-Evoked Potentials were slightly less sensitive, but they were significantly more useful in diagnosing posterior compression injuries than were cortical somatosensory-Evoked Potentials.
Dennis P. Grogan - One of the best experts on this subject based on the ideXlab platform.
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Effect of intrathecal opioids on somatosensory-Evoked Potentials during spinal fusion in children
Spine, 1996Co-Authors: Mashallah Goodarzi, Nicte-ha Shier, Dennis P. GroganAbstract:STUDY DESIGN: Intraoperative recording of somatosensory-Evoked Potentials is useful for monitoring spinal cord tolerance during spinal fusion with instrumentation. Volatile anesthetic agents are known to have prominent suppressive effects on somatosensory-Evoked Potentials. This study evaluates the effect of intrathecal administration of opioid, consisting of morphine sulfate and sufentanil, on somatosensory-Evoked potential monitoring. OBJECTIVES: To study the effect of different anesthesia techniques on somatosensory-Evoked Potentials during spinal fusion. SUMMARY OF BACKGROUND DATA: The effect of intravenous narcotic administration on somatosensory-Evoked Potentials has been well studied and reported. This study shows the effect of intrathecal opioids on somatosensory-Evoked Potentials. METHODS: Ten patients scheduled for spinal fusion with Cotrel-Dubousset instrumentation were induced with thiopental and maintained with intrathecal morphine sulfate (20 micrograms/kg) and sufentanil 50 micrograms, supplemented with isoflurane 0.5% air and oxygen. Routine monitoring was done, including arterial line and continuous somatosensory-Evoked Potentials. Anesthesia was maintained constant, with a mean blood pressure of 55 mm Hg. Normocarbia and normothermia were maintained. Baseline somatosensory-Evoked Potentials were recorded using bilateral posterior tibial nerve stimulation, with constant somatosensory-Evoked potential monitoring after the induction of anesthesia. RESULTS: There were no significant changes in either latencies or amplitudes in cortical somatosensory-Evoked Potentials after opioid injection at any time during the surgical procedures. CONCLUSIONS: Somatosensory-Evoked potential monitoring was possible in all patients undergoing extensive spinal surgery. Intrathecal opioid anesthesia with low concentrations of isoflurane in air and oxygen seems to have no effects on somatosensory-Evoked Potentials.
Hanspeter Richter - One of the best experts on this subject based on the ideXlab platform.
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evaluation of traumatic cervical nerve root injuries by intraoperative Evoked Potentials
Neurosurgery, 2002Co-Authors: Joachim Oberle, Gregor Antoniadis, Erich Kast, Hanspeter RichterAbstract:OBJECTIVE: To evaluate intraoperative Evoked Potentials as a diagnostic tool in traumatic brachial plexus injuries. METHODS: Thirteen patients with traumatic brachial plexus injuries were investigated by intradural nerve root inspection (n = 28 roots) via cervical hemilaminectomy to assess or rule out nerve root avulsion from the spinal cord. Two to 8 weeks later, Evoked Potentials from neck and scalp were recorded after direct electrical nerve root stimulation close to the vertebral foramen during operative brachial plexus repair via an anterior (supraclavicular and infraclavicular) approach. Recordings were performed without and after full muscle relaxation. RESULTS: There was a clear relationship between the state of the root as documented by intradural root inspection and the result of intraoperative recording of Evoked Potentials: the absence of Evoked muscle action Potentials from neck muscles demonstrated a 100% sensitivity for anterior root lesions, whereas sensory Evoked Potentials from the scalp demonstrated a 100% sensitivity for posterior root lesions. Moreover, roots could be identified with preserved continuity that did not conduct, suggesting a nerve lesion in continuity. CONCLUSION: Intraoperative Evoked muscle action Potentials and sensory Evoked Potentials after electrical nerve root stimulation allow selective functional evaluation of anterior and posterior nerve roots in patients with traumatic brachial plexus injuries. The high sensitivity and reliability of this test obviate the need for additional diagnostic surgery.
Johannes Schramm - One of the best experts on this subject based on the ideXlab platform.
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monitoring of motor Evoked Potentials compared with somatosensory Evoked Potentials and microvascular doppler ultrasonography in cerebral aneurysm surgery
Journal of Neurosurgery, 2004Co-Authors: Georg Neuloh, Johannes SchrammAbstract:Object. The aims of this study were to compare the efficiency of motor Evoked Potentials (MEPs), somatosensory Evoked Potentials (SSEPs), and microvascular Doppler ultrasonography (MDU) in the detection of impending motor impairment from subcortical ischemia in aneurysm surgery; to determine their sensitivity for specific intraoperative events; and to compare their impact on the surgical strategy used. Methods. Motor Evoked Potentials, SSEPs, and MDU were monitored during 100 operations for 129 aneurysms in 95 patients. Intraoperative events, monitoring results, and clinical outcome were correlated in a prospective observational design. Motor Evoked Potentials indicated inadequate temporary clipping, inadvertent occlusion, inadequate retraction, vasospasm, or compromise to perforating vessels in 21 of 33 instances and deteriorated despite stable SSEPs in 18 cases. Microvascular Doppler ultrasonography revealed inadvertent vessel occlusion in eight of 10 cases and insufficient clipping in four of four case...
B. A. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Somatosensory Evoked Potentials
Journal of Bone and Joint Surgery American Volume, 2000Co-Authors: M. H. H. Noordeen, B. A. TaylorAbstract:To The Editor: We are surprised by the claim made in the article "Dysfunction of the Spinal Cord During Spinal Arthrodesis for Scoliosis: Recommendations for Early Detection and Treatment. A Case Report" (80-A: 1679-1683, Nov. 1998), by Potenza et al., who state that "this is the first case to be reported in the English-language literature in which changes in the somatosensory Evoked Potentials and in the function of the spinal cord were reversed when appropriate treatment was given at the optimum time." We refer to our article1, which was cited by Potenza et al. We described the case of a patient who had precisely the same condition (a scoliosis with syrinx treated by intstrumented arthrodesis). Abnormalities in somatosensory Evoked Potentials were observed when distraction was applied. In our study, the distraction that was applied correlated with the …
