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.

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.

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.

Minimally invasive implantation of epidural spinal cord neurostimulator electrodes by using a tubular retractor system

2004 ◽  
Vol 100 (6) ◽  
pp. 1119-1121 ◽  
Author(s):  
Matthew R. Johnson ◽  
Daniel J. Tomes ◽  
John S. Treves ◽  
Lyal G. Leibrock
Keyword(s):  
Spinal Cord ◽  
Postoperative Pain ◽  
Minimally Invasive ◽  
Intractable Pain ◽  
Tubular Retractor ◽  
Content Type ◽  
Novel Technique ◽  
Pain Syndromes ◽  
Hospital Stays ◽  
Fine Print

✓ The authors describe a novel technique for the implantation of multipolar epidural spinal cord neurostimulator electrodes with the aid of a tubular retractor system. Spinal cord neurostimulation is used as a neuroaugmentive tool for treating chronic intractable pain syndromes. Minimally invasive placement of the multipolar neurostimulator electrodes may allow for shorter hospital stays and less postoperative pain associated with the incision.

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.

Percutaneous cervical cordotomy: a review of 181 operations on 146 patients with a study on the location of “pain fibers” in the C-2 spinal cord segment of 29 cases

1994 ◽  
Vol 80 (6) ◽  
pp. 975-985 ◽  
Author(s):  
Juan Lahuerta ◽  
David Bowsher ◽  
Simpson Lipton ◽  
Peter H. Buxton
Keyword(s):  
Spinal Cord ◽  
Tissue Damage ◽  
Intractable Pain ◽  
Pain Sensation ◽  
Content Type ◽  
Somatotopic Organization ◽  
Current Series ◽  
Spinal Cord Segment ◽  
Pathological Pain ◽  
Fine Print

✓ The authors present a review of 146 patients who underwent 181 percutaneous cervical cordotomies for intractable pain. In addition, an anatomical-clinical correlation was carried out for 29 of these patients. It was found that the fibers subserving pain sensation in the C-2 segment lie in the anterolateral funiculus between the level of the denticulate ligament and a line drawn perpendicularly from the medial angle of the ventral gray-matter horn to the surface of the cord. The best analgesic results have been obtained by creating lesions that extend 5.0 mm deep to the surface of the cord and destroy about 20% of the hemicord. There is a somatotopic organization with sacral fibers running ventromedially and cervical fibers running dorsolaterally. The authors believe that the ascending fibers subserving the distinct sensations of pain induced by tissue damage and pinprick, although mixed (overlapping) in the anterolateral funiculus of the spinal cord, are physiologically distinct from one another. Whereas some cordotomies, both in the current series and as reported in the literature, may affect these functions differentially, optimum pain relief seems to be obtained only when pinprick sensation is also abolished in the affected segments. Evoked pain sensation is not abolished by cordotomy, but its threshold is greatly raised. When pathological pain is completely abolished, so is pinprick sensation. However, in a number of cases where pathological pain was only partially alleviated, pinprick sensation remained intact. The significance of these and other cases reported in the literature is discussed. The importance of clinically distinguishing between pain caused by tissue damage and pinprick sensation is emphasized, as well as that between return of pre-existing or new tissue-damage pain and painful dysesthesia.

Noninvasive localization of brain-stem lesions in the cat with multimodality evoked potentials

1981 ◽  
Vol 54 (6) ◽  
pp. 740-750 ◽  
Author(s):  
Richard P. Greenberg ◽  
Donald M. Stablein ◽  
Donald P. Becker
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Evoked Potential ◽  
Animal Experiments ◽  
Content Type ◽  
Central Nervous System Dysfunction ◽  
Multimodality Evoked Potentials ◽  
Stem Lesions ◽  
The Brain ◽  
Fine Print

✓ Multimodality evoked potential (MEP) data from over 300 comatose head-injured patients suggest that central nervous system dysfunction of the brain stem and/or hemispheres can be localized with this noninvasive neuroelectric technique. Based on this work, decerebrate motor posturing and prolonged coma are not associated with brain-stem dysfunction but rather with dysfunction of the hemispheres, while absent pupillary and oculocephalic responses are correlated with brain-stem dysfunction alone. However, the accuracy with which MEP data localized human brain-stem or hemispheric dysfunction could not be confirmed by pathological correlation because of low mortality and the small number of autopsies obtained in the patients who died. Therefore, this study was undertaken in an animal model of brain-stem lesion. Complete brain-stem transections were made at the cervicomedullary junction, the medulla just caudal to the eighth nerve, and at the intercollicular region. All cortical visual evoked potential (VEP) peaks were reduced in amplitude and delayed by each of the brain-stem transections, but none of the peaks was abolished. In spite of brain-stem transection, VEP's can be used to gain information about hemispheric function. Somatosensory (SEP) and auditory cortically generated evoked potentials (AEP) were abolished by these brain-stem transections, but early-latency brain-stem SEP and AEP data could accurately localize specific areas of brain-stem dysfunction caused by the lesions. Observations made on human MEP data seem to be confirmed by these animal experiments. Correlations between human and cat MEP data are discussed.

Spinal evoked potentials from the motor tracts

1983 ◽  
Vol 58 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Walter J. Levy
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor System ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Dorsal Column ◽  
Content Type ◽  
Dorsal Columns ◽  
Evoked Potential Monitoring ◽  
Potential Monitoring

✓ There is a need to monitor the motor system, but it has a different blood supply and a different location in the spinal cord from those measured by traditional somatosensory evoked potential monitoring. This paper reports a motor evoked potential monitoring system that uses direct spinal cord stimulation overlying the areas of the motor tract in the cord. In nine cats, evoked potentials were recorded from the dura, which gave a much faster main signal component than the traditional dorsal column evoked potentials, which were also recorded. This 100-m/sec signal was not affected by sectioning of the dorsal columns, which was verified histologically. This mode of monitoring the motor system can be used during surgery. It may also provide a better evaluation of patients after spinal cord trauma.

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.

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.

The long-latency component of cerebral evoked potentials in anesthetized cats

1986 ◽  
Vol 65 (3) ◽  
pp. 392-397 ◽  
Author(s):  
Kyu Ho Lee ◽  
Jun Kim ◽  
Jin Mo Chung
Keyword(s):  
Evoked Potentials ◽  
Sural Nerve ◽  
Evoked Potential ◽  
Afferent Input ◽  
Late Component ◽  
Content Type ◽  
C Fibers ◽  
Long Latency ◽  
Fine Print ◽  
Stimulation Of

✓ A late component of the cortical evoked potential elicited by somatosensory afferent input was studied in cats anesthetized with α-chloralose. Cortical evoked potentials were recorded from the somatosensory-motor cortex during stimulation of the sural nerve with graded intensities. The stimulus intensity was adjusted to activate Aαβ fibers only, then both Aαβ and Aδ fibers, and both A and C fibers, as judged by afferent volleys monitored from the sural nerve proximal to the stimulating site. In addition to early components reported previously, a very late component was identified at a latency of 400 to 600 msec following stimulation of the sural nerve with intensities above threshold for Aδ fibers. A further increase in stimulation intensity to include activation of C fibers did not reveal any more components. This late component was depressed by a systemic intravenous injection of morphine (2 mg/kg), and intravenous naloxone (0.1 mg/kg) reversed the effect of morphine. The late component of the evoked potential could also be recorded from subcortical tissue after decortication of the sensorimotor cortex. From these results, it appears that a very late component of the cortical evoked potential can be recorded from cats anesthetized with α-chloralose. The late component is evoked by activation of peripheral Aδ fibers. Furthermore, its morphine sensitivity suggests that this component may be elicited by nociceptive afferent fibers. If further investigations prove this, the late component, which is analogous to human long-latency potentials, could be used in an experimental model for pain research.

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