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.

Tethered cervical spinal cord

1987 ◽  
Vol 67 (4) ◽  
pp. 600-602 ◽  
Author(s):  
Theodore W. Eller ◽  
Lawrence P. Bernstein ◽  
Richard S. Rosenberg ◽  
David G. McLone
Keyword(s):  
Spinal Cord ◽  
Young Adult ◽  
Evoked Potentials ◽  
Clinical Improvement ◽  
Somatosensory Evoked Potentials ◽  
Imaging Technique ◽  
Cervical Spinal Cord ◽  
Tethered Spinal Cord ◽  
Content Type ◽  
Fine Print

✓ A case of congenital tethered cervical spinal cord is presented in a young adult. Metrizamide computerized tomography was the most useful imaging technique for identifying the tethered spinal cord. Intraoperative somatosensory evoked potentials correlated well with clinical improvement following surgery.

Spinal cord pathways mediating somatosensory evoked potentials

1982 ◽  
Vol 57 (4) ◽  
pp. 472-482 ◽  
Author(s):  
Stephen K. Powers ◽  
Catherine A. Bolger ◽  
Michael S. B. Edwards
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
High Intensity ◽  
Dorsal Column ◽  
Motor Threshold ◽  
Spinal Cord Lesions ◽  
Content Type ◽  
Spinocerebellar Tract ◽  
Fine Print

✓ Using a CO2 laser, discrete thoracic spinal cord lesions were made in cats anesthetized with ketamine and xylazine (Rompun). Differences in cortical somatosensory evoked potentials (SEP's) produced with high-intensity stimulation (20 times the motor threshold) of each posterior tibial nerve were determined for nine different combinations of unilateral spinal cord lesions. The results of these studies show that nerve fibers in the ipsilateral dorsal column, the ipsilateral dorsal spinocerebellar tract, and the contralateral ventrolateral tracts with respect to the side of leg stimulation, contribute to cortical SEP's. A lesion of the dorsal spinocerebellar tract affected only the early waves (< 30 msec) of the SEP from leg stimulation ipsilateral to the side of the lesion, whereas a solitary lesion of the ventrolateral tract caused changes primarily in the amplitude of later waves (> 30 msec) of the SEP produced by contralateral leg stimulation. Lesions involving one-half of the dorsal column caused changes in the amplitude of both the early and late waves produced by stimulation ipsilateral to the side of the lesion. The effects of various combinations of lesions on the cortical SEP's were not additive, which indicates significant interaction between afferent pathways. These findings suggest that high-intensity peripheral nerve stimulation, which activates both C and A fibers, could be used intraoperatively to assess spinal cord function with more accuracy than the current practice of using a stimulus strength of twice the motor threshold. The importance of using anesthetic agents that do not depress cortical activity (which may affect the later components of the SEP) is also emphasized.

Effect of naloxone on posttraumatic ischemia in experimental spinal contusion

1981 ◽  
Vol 55 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Wise Young ◽  
Eugene S. Flamm ◽  
Harry B. Demopoulos ◽  
John J. Tomasula ◽  
Vincent DeCrescito
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Sensory Function ◽  
Thoracic Spinal Cord ◽  
Flow Rates ◽  
Content Type ◽  
Cord Injury ◽  
Fine Print

✓ The effect of naloxone on blood flow and somatosensory evoked potentials was studied in cats subjected to 400 gm-cm contusion injuries of the thoracic spinal cord. Eight cats were treated with 10 mg/kg naloxone 45 to 60 minutes after injury, 11 cats were given 10 ml of saline instead of naloxone, and six cats were neither injured nor treated. Hydrogen clearance was used to measure blood flow in the lateral white columns at the contusion site. Naloxone, given intravenously, significantly improved the blood flow rates in the lateral column white matter. At 2 hours after injury, the mean blood flow in the saline-treated cats fell to 50% (p < 0.01) of preinjury flow rates, whereas it increased 6% (p > 0.50) in naloxone-treated cats, and 12% (p > 0.50) in uninjured cats. At the 3rd hour after injury, the respective flows fell 47% (p < 0.01), and 6% (p > 0.50), and increased 15% (p > 0.50) of the preinjury flow rates. The naloxone-treated cats had striking preservation of sensory function and somatosensory evoked potentials at 24 hours after injury. At 24 hours, responses had returned in all the naloxone-treated cats and in only 11% of the saline-treated cats. The probability of this combination of events occurring by chance is 0.0030. The authors conclude that naloxone may be useful for the treatment of spinal cord injury. The mechanism of the effect is unknown.

Immediate effects of spinal cord stimulation in spinal spasticity

1985 ◽  
Vol 62 (4) ◽  
pp. 558-562 ◽  
Author(s):  
Giancarlo Barolat-Romana ◽  
Joel B. Myklebust ◽  
David C. Hemmy ◽  
Barbara Myklebust ◽  
William Wenninger
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Cord Stimulation ◽  
Content Type ◽  
Clinical Observations ◽  
Cord Injury ◽  
Epidural Spinal Cord Stimulation ◽  
Stimulation System ◽  
Fine Print

✓ Six patients with intractable spasms after spinal cord injury underwent implantation of an epidural spinal cord stimulation system. All the patients experienced good relief postoperatively. In three patients spinal cord stimulation consistently produced immediate inhibition of the spasms. This was evident within less than 1 minute of stimulation. Conversely, the spasms reappeared within less than 1 minute after cessation of the stimulation. The clinical observations were confirmed by polygraphic electromyographic recordings.

Effects of aortic occlusion on regional spinal cord blood flow and somatosensory evoked potentials in sheep

Neurosurgery ◽  
1987 ◽  
Vol 21 (5) ◽  
pp. 668???75
Author(s):  
B J Kaplan ◽  
W A Friedman ◽  
N Gravenstein ◽  
R Richards ◽  
R F Davis
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Evoked Potentials ◽  
Cord Blood ◽  
Somatosensory Evoked Potentials ◽  
Aortic Occlusion ◽  
Spinal Cord Blood Flow

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.

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