Search Results

You are looking at 1 - 10 of 1,216 items for :

  • "somatosensory evoked potentials" x
Clear All
Restricted access

Conducted somatosensory evoked potentials during spinal surgery

Part 1: Control conduction velocity measurements

James B. Macon and Charles E. Poletti

C ortical somatosensory evoked potentials (CSEP's) have been proposed as a means of monitoring spinal cord function intraoperatively. 10, 12 Measuring CSEP's, especially in response to peroneal stimulation, is limited by a number of factors, including: 1) marked variability of both latency and amplitude with changing levels of general anesthesia; 2) insensitivity to incomplete spinal cord lesions because of supraspinal polysynaptic components; 3) excessively long conduction distance masking the effects of spinal lesions; and 4) unreliability of responses from

Restricted access

Dudley S. Dinner, Hans Lüders, Ronald P. Lesser, Harold H. Morris, Gene Barnett and G. Klem

M onitoring of somatosensory evoked potentials (SEP's) to peripheral nerve stimulation (posterior tibial, peroneal, or median nerves) during spinal column or spinal cord surgery is commonplace. The detection of significant changes in the monitored potentials may indicate early spinal cord dysfunction and allow appropriate measures to be carried out to prevent irreversible spinal cord damage. The two basic types of spinal cord monitoring currently used employ noninvasive or invasive techniques. The noninvasive techniques 1, 2, 11, 27, 29, 31, 32, 34, 38, 39

Restricted access

James B. Macon, Charles E. Poletti, William H. Sweet, Robert G. Ojemann and Nicholas T. Zervas

I n the preceding paper, 4 we have described a technique for recording spinal somatosensory evoked potentials (SEP's) during spinal operations using bipolar epidural electrodes. Measurement of spinal conduction velocity (CV) across the operative field was proposed as a potentially safe, reliable, and sensitive means of intraoperatively monitoring spinal cord function. This paper addresses the question of whether permanent postoperative changes in neurological function, especially deterioration, can be predicted by intraoperative changes in spinal cord CV

Restricted access

Stephen K. Powers, Catherine A. Bolger and Michael S. B. Edwards

D espite a great deal of experimental and clinical research, a controversy exists concerning which spinal pathways mediate cortical somatosensory evoked potentials (SEP's). Several investigators 4, 8, 10, 17, 24, 36, 38 have concluded that the dorsal and dorsolateral columns contain the pathways that mediate the cortical SEP's. Early clinical investigations into SEP's in patients with dissociated sensory loss have shown that the integrity of the dorsal columns must be maintained for transmission of the cortical SEP's after stimulation of peripheral nerves. 25

Restricted access

Howard H. Ginsburg, Andrew G. Shetter and Peter A. Raudzens

I ntraoperative somatosensory evoked potentials (SSEP's) have been used increasingly in recent years to monitor neurological function during scoliosis surgery and other high-risk spinal operations. 1, 2, 7, 14 Numerous cases have been reported in which early recognition of SSEP latency and amplitude changes appeared to have prevented permanent neurological deficits by alerting the surgeon to the need for appropriate corrective action. 3–5, 8, 13, 15, 18, 19 We report a case of postoperative paraplegia that occurred despite preserved intraoperative SSEP

Restricted access

Alex Berenstein, Wise Young, Joseph Ransohoff, Vallo Benjamin and Henry Merkin

followed multilevel injections of angiographic contrast material. Responses were deemed significantly altered if the peak-to-peak amplitude or latency of early components during the first 50 msec deviated by more than one standard deviation from the controls. Many of the patients received long-term follow-up SEP tests several weeks, months, and sometimes years after the procedures. Fig. 1. Baseline somatosensory evoked potentials recorded prior to angiography (upper) and after each level of injection (INJ, lower ). There is no change in amplitude or latency

Restricted access

Kathleen L. Meyer, Robert J. Dempsey, Mark W. Roy and David L. Donaldson

E xperimental cerebral ischemia alters central nervous system (CNS) function and leads to infarction. While most studies of ischemia rely on evaluation of the size and distribution of the resulting infarct, in this study we evaluated somatosensory evoked potentials (SEP's) as a means of measuring neurophysiological function in the remaining viable brain during ischemia. The SEP peaks in man and animals are presumed to be generated by specific CNS structures. 1, 3, 7, 11 Evoked potential components that are consistently identifiable, and their presumed

Restricted access

Akifumi Suzuki and Nobuyuki Yasui

P revious reports have described the usefulness of cortical surface recording of somatosensory evoked potentials (SEP's) for the functional localization of the human cortex during surgery. 1–5, 7, 8 Since 1985, we have recorded SEP's from the exposed cortical surface to localize the central sulcus in surgery. We have recently treated a patient who showed perplexing findings for determining the central sulcus. We report this case and describe a potential pitfall in the clinical application of cortical SEP's for functional localization of the sensorimotor

Restricted access

Ian R. Whittle, Ian H. Johnston and Michael Besser

T echniques for the intraoperative monitoring of spinal cord function, particularly in kyphoscoliosis, have been developed in recent years. 1, 2, 5–10 Although various techniques of eliciting and recording the somatosensory evoked potentials (SEP's) have been employed, most authors agree that changes occurring in the waveform during surgical procedures may indicate significant spinal cord dysfunction, whether due to hypotension, hypoxia, or cord manipulation. Any technique that monitors spinal cord function using SEP's should be safe, be simple in execution

Restricted access

Ian R. Whittle, Ian H. Johnston and Michael Besser

A s experience with intraoperative recording of cortical somatosensory evoked potentials to monitor spinal cord function during surgery has increased, many problems and limitations with this mode of monitoring have become apparent. 3, 4, 7 Experimental data have suggested that the spinal somatosensory evoked potential (SSEP) is a more specific index of spinal cord function and that acquisition and interpretation of this signal is considerably simpler than its cortical equivalent. 2, 18, 19 New methods of intraoperative recording of SSEP's have recently been