Abstract
In scoliosis surgery, intraoperative somatosensory evoked potential (SSEP) monitoring has reduced the incidence of postoperative neurologic deficits. Many factors affect the amplitude and latency of SSEP waveforms during surgery. Somatosensory evoked potential amplitude decreases with ischemia and anoxia because of temporal dispersion of the afferent volley and conduction block in damaged axons. In conjunction with surgical manipulations, minor drops in blood pressure may result in substantial SSEP changes that reverse when perfusion pressure is increased. Irreversible anoxic injury to central nervous system white matter with loss of SSEP waveforms is dependent on calcium influx into the intracellular space. Somatosensory evoked potential monitoring may be less sensitive for detecting acute insults in the presence of preexisting white matter lesions. Increased extracellular potassium from acute barotrauma can block axonal conduction transiently even when there is no axonal disruption. Marked temperature-related drops in SSEP amplitude may occur after exposure of the spine but before instrumentation and deformity correction. Hypothermia may increase false-negative outcomes. Short-interval double-pulse stimulation may improve the sensitivity of the SSEP in detecting early ischemic changes. For neurosurgical procedures on the spinal cord the use of SSEP monitoring in improving postoperative outcome is less well established.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 409-415 |
| Number of pages | 7 |
| Journal | Journal of Clinical Neurophysiology |
| Volume | 19 |
| Issue number | 5 |
| State | Published - 2002 |
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Keywords
- Intraoperative monitoring
- Signal change mechanisms
- Somatosensory evoked potentials
ASJC Scopus subject areas
- Clinical Neurology
- Physiology
- Neuroscience(all)
Cite this
Mechanisms of signal change during intraoperative somatosensory evoked potential monitoring of the spinal cord. / Seyal, Masud; Mull, Brendan.
In: Journal of Clinical Neurophysiology, Vol. 19, No. 5, 2002, p. 409-415.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanisms of signal change during intraoperative somatosensory evoked potential monitoring of the spinal cord
AU - Seyal, Masud
AU - Mull, Brendan
PY - 2002
Y1 - 2002
N2 - In scoliosis surgery, intraoperative somatosensory evoked potential (SSEP) monitoring has reduced the incidence of postoperative neurologic deficits. Many factors affect the amplitude and latency of SSEP waveforms during surgery. Somatosensory evoked potential amplitude decreases with ischemia and anoxia because of temporal dispersion of the afferent volley and conduction block in damaged axons. In conjunction with surgical manipulations, minor drops in blood pressure may result in substantial SSEP changes that reverse when perfusion pressure is increased. Irreversible anoxic injury to central nervous system white matter with loss of SSEP waveforms is dependent on calcium influx into the intracellular space. Somatosensory evoked potential monitoring may be less sensitive for detecting acute insults in the presence of preexisting white matter lesions. Increased extracellular potassium from acute barotrauma can block axonal conduction transiently even when there is no axonal disruption. Marked temperature-related drops in SSEP amplitude may occur after exposure of the spine but before instrumentation and deformity correction. Hypothermia may increase false-negative outcomes. Short-interval double-pulse stimulation may improve the sensitivity of the SSEP in detecting early ischemic changes. For neurosurgical procedures on the spinal cord the use of SSEP monitoring in improving postoperative outcome is less well established.
AB - In scoliosis surgery, intraoperative somatosensory evoked potential (SSEP) monitoring has reduced the incidence of postoperative neurologic deficits. Many factors affect the amplitude and latency of SSEP waveforms during surgery. Somatosensory evoked potential amplitude decreases with ischemia and anoxia because of temporal dispersion of the afferent volley and conduction block in damaged axons. In conjunction with surgical manipulations, minor drops in blood pressure may result in substantial SSEP changes that reverse when perfusion pressure is increased. Irreversible anoxic injury to central nervous system white matter with loss of SSEP waveforms is dependent on calcium influx into the intracellular space. Somatosensory evoked potential monitoring may be less sensitive for detecting acute insults in the presence of preexisting white matter lesions. Increased extracellular potassium from acute barotrauma can block axonal conduction transiently even when there is no axonal disruption. Marked temperature-related drops in SSEP amplitude may occur after exposure of the spine but before instrumentation and deformity correction. Hypothermia may increase false-negative outcomes. Short-interval double-pulse stimulation may improve the sensitivity of the SSEP in detecting early ischemic changes. For neurosurgical procedures on the spinal cord the use of SSEP monitoring in improving postoperative outcome is less well established.
KW - Intraoperative monitoring
KW - Signal change mechanisms
KW - Somatosensory evoked potentials
UR - http://www.scopus.com/inward/record.url?scp=0036453979&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036453979&partnerID=8YFLogxK
M3 - Article
C2 - 12477986
AN - SCOPUS:0036453979
VL - 19
SP - 409
EP - 415
JO - Journal of Clinical Neurophysiology
JF - Journal of Clinical Neurophysiology
SN - 0736-0258
IS - 5
ER -