Reversible spinal cord trauma: a model for electrical monitoring of spinal cord function

1972 ◽  
Vol 36 (4) ◽  
pp. 402-406 ◽  
Author(s):  
Thomas J. Croft ◽  
Jerald S. Brodkey ◽  
Frank E. Nulsen
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Sensitive Indicator ◽  
Spinal Cord Trauma ◽  
Content Type ◽  
Cortical Evoked Potentials ◽  
Spinal Cord Damage ◽  
Sensory Transmission ◽  
Spinal Cord Function ◽  
Fine Print

✓ Cortical evoked potentials in anesthetized cats were recorded by a noninvasive averaging technique as a means of estimating spinal cord damage. Graded pressure on the spinal cord produced reversible blocking of these potentials. With this type of trauma, block of motor transmission through the cord paralleled the block of sensory transmission, and each seemed to be a sensitive indicator of spinal cord function. The possible use of such monitoring in anesthetized patients undergoing spinal operations is discussed.

Electrospinogram and spinal and cortical evoked potentials in experimental spinal cord trauma

1975 ◽  
Vol 43 (6) ◽  
pp. 737-741 ◽  
Author(s):  
Glenn Morrison ◽  
Ronald J. Lorig ◽  
Jerald S. Brodkey ◽  
Frank E. Nulsen
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Spinal Cord Compression ◽  
Evoked Potential ◽  
Cord Compression ◽  
Spinal Cord Trauma ◽  
Content Type ◽  
Cortical Evoked Potentials ◽  
Acute Changes ◽  
Fine Print

✓ Studies in 28 traumatized cats showed the following acute changes after spinal cord compression in the cord segment below the trauma: 1) increase in size of the spinal cord evoked potential; 2) increase in size of the electrospinogram; and 3) increase in frequency of the electrospinogram.

Percutaneous flexible bipolar epidural neuroelectrode for spinal cord stimulation

1984 ◽  
Vol 60 (6) ◽  
pp. 1317-1319 ◽  
Author(s):  
Alfred G. Kaschner ◽  
Wilhelm Sandmann ◽  
Heinz Larkamp
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Epidural Space ◽  
Somatosensory Evoked Potentials ◽  
Spinal Cord Stimulation ◽  
Spinal Cord Ischemia ◽  
Aortic Occlusion ◽  
Content Type ◽  
Fine Print

✓ This article describes a new flexible bipolar neuroelectrode which is inserted percutaneously into the epidural space for segmental spinal cord stimulation. This electrode was used in experiments with dogs and monkeys for recording cortical somatosensory evoked potentials in order to identify intraoperative spinal cord ischemia during periods of aortic occlusion.

Neurophysiological effects of dorsal column stimulation in man and monkey

1974 ◽  
Vol 41 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Sanford J. Larson ◽  
Anthony Sances ◽  
Donald H. Riegel ◽  
Glenn A. Meyer ◽  
Donald E. Dallmann ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Intractable Pain ◽  
Current Application ◽  
Content Type ◽  
Bipolar Recording ◽  
Stimulating Electrodes ◽  
Recording Electrodes ◽  
Fine Print

✓ In 18 patients with cancer and intractable pain, capacitatively coupled pulses of 0.25 msec duration were delivered transcutaneously at 100 Hz to sets of five in-line electrodes implanted subdurally over the dorsal columns. Averaged somatosensory-evoked potentials were recorded from scalp electrodes before, during, and after application of current. All but one patient experienced relief of pain during stimulation, persisting for as long as several hours afterward. Eleven patients developed hyperactive deep reflexes, pathological reflexes, and decreased perception of joint rotation, pain, and touch below the level of current application. Somatosensory-evoked potential amplitudes were markedly reduced. All neurological findings returned to control values within 1 hour after each of repeated applications of current. Histological examination of spinal cord sections from four cancer patients showed no changes secondary to long-term current application. Similar currents were applied to the spinal cord of 15 monkeys with chronically implanted bipolar recording or stimulating electrodes over the lower, middle, and upper thoracic cord, in nucleus ventralis posterior lateralis (VPL), and over the sensory motor cortex (SMC). With application of current, the responses in VPL and SMC to peripheral stimulation were abolished. Evoked potential responses were abolished between bipolar stimulating electrodes and bipolar recording electrodes separated by the five in-line electrodes used to supply the 100 Hz current. However, when both stimulating and recording electrodes were either above or below the five in-line electrode set, evoked responses were unaffected. The findings indicate that applied currents blocked neuronal transmission by producing local changes in the cord. The prolonged alteration of cerebral evoked potentials and relief of pain, however, could also be related to involvement of supraspinal neurons.

Effect of vasodilators and myelotomy on recovery after acute spinal cord injury in rats

1979 ◽  
Vol 50 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Alex S. Rivlin ◽  
Charles H. Tator
Keyword(s):  
Spinal Cord ◽  
Quantitative Method ◽  
Cord Compression ◽  
Central Canal ◽  
Compression Injury ◽  
Dorsal Midline ◽  
Content Type ◽  
Cord Injury ◽  
Spinal Cord Function ◽  
Fine Print

✓ The effect of papaverine, nitroprusside, or myelotomy on the recovery of spinal cord function was studied in rats after acute cord-compression injury. Spinal cord recovery was measured by a quantitative method of clinical assessment previously developed in our laboratory. Neither papaverine nor nitroprusside improved recovery of cord function. Dorsal midline myelotomy extending anteriorly as far as the central canal did not produce significant improvement (p > 0.05). However, when the myelotomy extended completely through the cord in the anteroposterior plane significant improvement (p < 0.01) was obtained.

Pathological findings in acute experimental spinal cord trauma

1971 ◽  
Vol 35 (6) ◽  
pp. 700-708 ◽  
Author(s):  
Thomas B. Ducker ◽  
Glenn W. Kindt ◽  
Ludwig G. Kempe
Keyword(s):  
Spinal Cord ◽  
White Matter ◽  
Clinical Improvement ◽  
Spinal Cord Trauma ◽  
Pathological Findings ◽  
Pathological Changes ◽  
Content Type ◽  
Acute Trauma ◽  
Central Gray ◽  
Fine Print

✓ This study shows that spinal cord pathology secondary to acute trauma in monkeys evolves with stepwise sequential changes. The acute damage is more central than peripheral. Depending on the amount of trauma, the subacute damage may be limited to central gray necrosis or may progress or evolve to include the neighboring white matter. These pathological changes may be taking place even in the presence of clinical improvement.

Norepinephrine levels in experimental spinal cord trauma

1977 ◽  
Vol 46 (3) ◽  
pp. 342-349 ◽  
Author(s):  
Stephen E. Rawe ◽  
Robert H. Roth ◽  
Margaret Boadle-Biber ◽  
William F. Collins
Keyword(s):  
Spinal Cord ◽  
Tyrosine Hydroxylase ◽  
Concentration Gradient ◽  
Neurological Function ◽  
Spinal Cord Tissue ◽  
Spinal Cord Trauma ◽  
Content Type ◽  
Spinal Cord Segment ◽  
Fine Print

✓ Levels of norepinephrine (NE) in the spinal cord tissue of nontraumatized cats are highest in the cervical and lumbar enlargements. A rather uniform but slightly increasing concentration gradient from cephalad to caudad is observed in the thoracic segments. A 500 gm-cm trauma at the T-5 or C-7 spinal cord segment did not demonstrate any significant increase in NE levels measured sequentially over a 4-hour period after trauma. Dopamine levels could not be detected in the nontraumatized or traumatized cat spinal cords. Four traumatized cats treated with alpha methyl tyrosine, a tyrosine hydroxylase inhibitor, and followed clinically for 5 months showed no improvement in neurological function when compared to untreated traumatized cats. This study does not support the norepinephrine hypothesis of experimental spinal cord trauma.

Evoked potentials from direct cerebellar stimulation for monitoring of the rodent spinal cord

1992 ◽  
Vol 76 (2) ◽  
pp. 280-291 ◽  
Author(s):  
R. John Hurlbert ◽  
Charles H. Tator ◽  
Michael G. Fehlings ◽  
Greg Niznik ◽  
R. Dean Linden
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Posterior Fossa ◽  
Evoked Potential ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Ventral Funiculus ◽  
Fine Print ◽  
Cerebellar Stimulation

✓ Although the assessment of spinal cord function by electrophysiological techniques has become important in both clinical and research environments, current monitoring methods do not completely evaluate all tracts in the spinal cord. Somatosensory and motor evoked potentials primarily reflect dorsal column and pyramidal tract integrity, respectively, but do not directly assess the status of the ventral funiculus. The present study was undertaken to evaluate the use of evoked potentials, elicited by direct cerebellar stimulation, in monitoring the ventral component of the rodent spinal cord. Twenty-nine rats underwent epidural anodal stimulation directly over the cerebellar cortex, with recording of evoked responses from the lower thoracic spinal cord, both sciatic nerves, and/or both gastrocnemius muscles. Stimulation parameters were varied to establish normative characteristics. The pathways conducting these “posterior fossa evoked potentials” were determined after creation of various lesions of the cervical spinal cord. The evoked potential recorded from the thoracic spinal cord consisted of five positive (P1 to P5) and five negative (N1 to N5) peaks. The average conduction velocity (± standard deviation) of the earliest wave (P1) was 53 ± 4 m/sec, with a latency of 1.24 ± 0.10 msec. The other components followed within 4 msec from stimulus onset. Unilateral cerebellar stimulation resulted in bilateral sciatic nerve and gastrocnemius muscle responses; there were no significant differences (p > 0.05) in the thresholds, amplitudes, or latencies of these responses elicited by right- versus left-sided stimulation. Recordings performed following creation of selective lesions of the cervical cord indicated that the thoracic response was carried primarily in the ventral funiculus while the sciatic and gastrocnemius responses were mediated through the dorsal half of the spinal cord. It is concluded that the posterior fossa evoked potential has research value as a method of monitoring pathways within the ventral spinal cord of the rat, and should be useful in the study of spinal cord injury.

Chemotherapy as the initial treatment of spinal cord compression due to disseminated neuroblastoma

1989 ◽  
Vol 70 (5) ◽  
pp. 688-690 ◽  
Author(s):  
I. R. Sanderson ◽  
Jon Pritchard ◽  
Henry T. Marsh
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Compression ◽  
Initial Treatment ◽  
Cord Compression ◽  
Response To Treatment ◽  
Trial Period ◽  
Content Type ◽  
Sick Children ◽  
Spinal Cord Function ◽  
Fine Print

✓ During a 12-month trial period, all children attending the Hospitals for Sick Children, London, England, for management of spinal cord compression due to disseminated neuroblastoma were given chemotherapy as initial treatment rather than radiotherapy or laminectomy. Response to treatment was evaluated by a neurosurgeon as well as by oncologists. Four children were treated in this way and all made a full recovery of spinal cord function.

Somatosensory evoked potential monitoring in anterior thoracic vertebrectomy

2000 ◽  
Vol 92 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Harel Deutsch ◽  
Marc Arginteanu ◽  
Karen Manhart ◽  
Noel Perin ◽  
Martin Camins ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Vertebral Body ◽  
Evoked Potential ◽  
False Negative ◽  
False Negative Rate ◽  
Neurological Deterioration ◽  
Somatosensory Evoked Potential ◽  
Content Type ◽  
Spinal Cord Function ◽  
Fine Print

Object. Spine surgeons have used intraoperative cortical and subcortical somatosensory evoked potential (SSEP) monitoring to detect changes in spinal cord function when intraoperative procedures can be performed to prevent neurological deterioration. However, the reliability of SSEP monitoring as applied to anterior thoracic vertebral body resections has not been rigorously assessed. Methods. The authors retrospectively reviewed hospital charts and operating room records obtained between August 1993 and December 1998 and found that SSEP monitoring was used in 44 surgical procedures involving an anterior approach for thoracic vertebral body resections. There were no patients in whom SSEP changes did not return to baseline during the surgical procedure. Patients in four cases, despite their stable SSEP recordings throughout the procedure, were noted immediately postoperatively to have experienced significant neurological deterioration. The false-negative rate in SSEP monitoring was 9%. Sensitivity was determined to be 0%. Conclusions. It is important to recognize high false-negative rates and low sensitivity of SSEP monitoring when it is used to record spinal cord function during anterior approaches for thoracic vertebrectomies. The insensitivity of SSEPs for motor deterioration during anterior thoracic vertebrectomies is likely due to the limitation of SSEPs, which monitor only posterior column function whereas motor paths are conveyed in the anterior and anterolateral spinal cord. The authors believe that SSEPs can not be relied on to detect reversible spinal damage during anterior thoracic vertebrectomies.

Studies in experimental spinal cord trauma

1974 ◽  
Vol 40 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Lynn S. Hedeman ◽  
M. Kent Shellenberger ◽  
J. H. Gordon
Keyword(s):  
Spinal Cord ◽  
Pilot Study ◽  
Spinal Cord Trauma ◽  
Significant Elevation ◽  
Small Pilot Study ◽  
Content Type ◽  
Essentially Normal ◽  
Before And After ◽  
Fine Print

✓ The authors report a study of levels of norepinephrine (NE), dopamine (DA), and 5-hydroxytryptamine (5-HT) in the traumatized spinal cords of dogs, and with alpha-mehtyltyrosine before and after injury. There was a significant elevation of DA 15 to 45 minutes after injury. NE was significantly reduced. Twenty-four hours of pretreatment with alpha-methyltyrosine depleted cord catecholamines and prevented trauma-induced DA elevation. Alpha-methyltyrosine given 15 minutes after the trauma did not prevent this trauma-related DA elevation. In a small pilot study in cats, DA was elevated and NE remained essentially normal.

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