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.

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.

Microangioarchitecture of the feline spinal cord

1987 ◽  
Vol 66 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Yutaka Naka ◽  
Toru Itakura ◽  
Kunio Nakai ◽  
Kazuo Nakakita ◽  
Harumichi Imai ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Anterior Spinal Artery ◽  
Corrosion Casts ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Fine Print ◽  
Anterior Median

✓ The microangioarchitecture of corrosion casts of the cat spinal cord was studied by scanning electron microscopy. On the ventral surface of the spinal cord, the anterior spinal artery and the anterior spinal vein ran parallel along the anterior median fissure. Many central arteries branching from the anterior spinal artery coursed in a wavelike manner in the anterior median fissure. The number of central arteries was lowest in the thoracic spinal cord. Central arteries at some spinal cord levels revealed well-developed anastomoses with other central arteries in the anterior median fissure. These well-developed anastomotic central arteries were frequently observed in the thoracic spinal cord, in which the number of central arteries was lowest. On the dorsal surface of the spinal cord, the posterior spinal vein ran longitudinally at the midline and was drained by circumferential veins and posterior central veins. This vein formed a characteristic anastomotic plexus. Small arterioles (20 µm in diameter) in the spinal parenchyma revealed a ring-like compression at the branching site.

Effects of epidural hypothermic saline infusion on locomotor outcome and tissue preservation after moderate thoracic spinal cord contusion in rats

2005 ◽  
Vol 2 (3) ◽  
pp. 308-318 ◽  
Author(s):  
Carlos E. Casas ◽  
Loren P. Herrera ◽  
Chad Prusmack ◽  
Gladys Ruenes ◽  
Alexander Marcillo ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Gray Matter ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Treatment Groups ◽  
Thoracic Spinal ◽  
Cord Injury ◽  
Spinal Cord Contusion ◽  
Tissue Sparing ◽  
Fine Print

Object. Regionally delivered hypothermia has advantages over systemic hypothermia for clinical application following spinal cord injury (SCI). The effects of local hypothermia on tissue sparing, neuronal preservation, and locomotor outcome were studied in a moderate thoracic spinal cord contusion model. Methods. Rats were randomized to four treatment groups and data were collected and analyzed in a blinded fashion. Chilled saline was perfused into the epidural space 30 minutes postcontusion to achieve the following epidural temperatures: 24 ± 2.3°C (16 rats), 30 ± 2.4°C (13 rats), and 35 ± 0.9°C (13 rats). Hypothermia was continued for 3 hours when a 45-minute period of rewarming was instituted. In a fourth group a moderate contusion only was induced in 14 animals. Rectal (core) and T9–10 (epidural) temperatures were measured continuously. Locomotor testing, using the Basso-Beattie-Bresnahan (Ba-Be-Br) scale, was performed for 6 weeks, and rats were videotaped for subsequent analysis. The lesion/preserved tissue ratio was calculated throughout the entire lesion cavity and the total lesion, spinal cord, and spared tissue volumes were determined. The rostral and caudal extent of gray matter loss was also measured. At 6 weeks locomotor recovery was similar in all groups (mean Ba-Be-Br Scale scores 14.88 ± 3.71, 14.83 ± 2.81, 14.50 ± 2.24, and 14.07 ± 2.39 [p = 0.77] for all four groups, respectively). No significant differences in spared tissue volumes were found when control and treatment groups were compared, but gray matter preservation was reduced in the infusion-treated groups. Conclusions. Regional cooling applied 30 minutes after a moderate contusive SCI was not beneficial in terms of tissue sparing, neuronal preservation, or locomotor outcome. This method of cooling may reduce blood flow in the injured spinal cord and exacerbate secondary injury.

Thoracic spinal cord ependymoma presenting with ejaculatory failure

1982 ◽  
Vol 56 (1) ◽  
pp. 143-144
Author(s):  
Jose Berciano ◽  
Jaime Gutierrez ◽  
Mariano Rebollo ◽  
Guillermo Dierssen
Keyword(s):  
Spinal Cord ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Spinal Cord Ependymoma ◽  
Fine Print

✓ A case of thoracic spinal cord ependymoma presenting with ejaculatory failure is described. This mode of onset has not previously been reported in patients with thoracic intraspinal tumors.

Effects of local hypothermia and tissue oxygen studies in experimental paraplegia

1970 ◽  
Vol 33 (5) ◽  
pp. 554-563 ◽  
Author(s):  
David L. Kelly ◽  
Kenneth R. L. Lassiter ◽  
John A. Calogero ◽  
Eben Alexander
Keyword(s):  
Spinal Cord ◽  
Untreated Group ◽  
Severe Hypoxia ◽  
Tissue Oxygen ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Clinical Recovery ◽  
Thoracic Spinal ◽  
Local Hypothermia ◽  
Fine Print

✓ A controlled series of adult mongrel dogs were rendered paraplegic by traumatizing the thoracic spinal cord. Those animals treated with local hypothermia, whether immediately or after a delay, recovered to a significantly greater degree than the untreated group. Spinal cord pO2 studies revealed a marked fall in the pO2 at the area of maximal injury over a 30-min period. The severe hypoxia lasted at least 7 hours. Pathological studies showed the varying degrees of injury produced. It is postulated that local hypothermia may be effective in altering the clinical recovery by decreasing the tissue metabolism at the site of injury.

Combined medical and surgical treatment after acute spinal cord injury: results of a prospective pilot study to assess the merits of aggressive medical resuscitation and blood pressure management

1997 ◽  
Vol 87 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Fernando L. Vale ◽  
Jennifer Burns ◽  
Amie B. Jackson ◽  
Mark N. Hadley
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injuries ◽  
Bladder Function ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Arterial Blood ◽  
Thoracic Spinal ◽  
Cord Injury ◽  
Fine Print

✓ The optimal management of acute spinal cord injuries remains to be defined. The authors prospectively applied resuscitation principles of volume expansion and blood pressure maintenance to 77 patients who presented with acute neurological deficits as a result of spinal cord injuries occurring from C-1 through T-12 in an effort to maintain spinal cord blood flow and prevent secondary injury. According to the Intensive Care Unit protocol, all patients were managed by using Swan—Ganz and arterial blood pressure catheters and were treated with immobilization and fracture reduction as indicated. Intravenous fluids, colloid, and vasopressors were administered as necessary to maintain mean arterial blood pressure above 85 mm Hg. Surgery was performed for decompression and stabilization, and fusion in selected cases. Sixty-four patients have been followed at least 12 months postinjury by means of detailed neurological assessments and functional ability evaluations. Sixty percent of patients with complete cervical spinal cord injuries improved at least one Frankel or American Spinal Injury Association (ASIA) grade at the last follow-up review. Thirty percent regained the ability to walk and 20% had return of bladder function 1 year postinjury. Thirty-three percent of the patients with complete thoracic spinal cord injuries improved at least one Frankel or ASIA grade. Approximately 10% of the patients regained the ability to walk and had return of bladder function. As of the 12-month follow-up review, 92% of patients demonstrated clinical improvement after sustaining incomplete cervical spinal cord injuries compared to their initial neurological status. Ninety-two percent regained the ability to walk and 88% regained bladder function. Eighty-eight percent of patients with incomplete thoracic spinal cord injuries demonstrated significant improvements in neurological function 1 year postinjury. Eighty-eight percent were able to walk and 63% had return of bladder function. The authors conclude that the enhanced neurological outcome that was observed in patients after spinal cord injury in this study was in addition to, and/or distinct from, any potential benefit provided by surgery. Early and aggressive medical management (volume resuscitation and blood pressure augmentation) of patients with acute spinal cord injuries optimizes the potential for neurological recovery after sustaining trauma.

Spinal cord compression by extradural fat after prolonged corticosteroid therapy

1982 ◽  
Vol 56 (2) ◽  
pp. 267-269 ◽  
Author(s):  
Yvon Guegan ◽  
Raeph Fardoun ◽  
Bernard Launois ◽  
Jean Pecker
Keyword(s):  
Spinal Cord ◽  
Renal Transplant ◽  
Clinical Improvement ◽  
Corticosteroid Therapy ◽  
Spinal Cord Compression ◽  
Cord Compression ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Fine Print

✓ This young man was operated on twice for thoracic spinal cord compression. He had been on corticosteroid therapy for the last 2 years subsequent to a renal transplant. The only anomaly discovered during the operation was a large quantity of extradural fat that did not present the characteristics of lipoma. The remarkable postoperative clinical improvement suggested that the fat deposit was responsible for the spinal cord compression.

Effects of vertebral column distraction in the monkey

1982 ◽  
Vol 57 (5) ◽  
pp. 651-659 ◽  
Author(s):  
Joseph F. Cusick ◽  
Joel Myklebust ◽  
Mark Zyvoloski ◽  
Anthony Sances ◽  
Chris Houterman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Vertebral Column ◽  
Evoked Potential ◽  
Late Onset ◽  
Spinal Cord Ischemia ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Fiber Tracts ◽  
Thoracic Spinal

✓ Experiments were performed to assess the effects of vertebral column distraction on evoked potential responses from multiple recording sites along the conducting pathway in the monkey, and on concurrent blood flows, measured with the radioactive microsphere technique, along the axis of the central nervous system. Linear distractive loads were applied until the amplitude of the evoked response was significantly reduced. In four monkeys, the loads (100 to 150 lb) were sustained, whereas in two monkeys the forces (80 to 110 lb) were relaxed. The earliest response changes were most marked in recordings dependent upon the integrity of the upper cervical dorsal columns or brain stem-lemniscal pathway. The responses returned to control levels with load relaxation, but maintenance of the tractive load produced generalized and progressive response attenuation. At selected periods of significant changes in the evoked potential response, blood flow remained stable except for the late onset of regional ischemia in the middle cervical through upper thoracic spinal cord levels in the animals undergoing sustained loads. These findings indicate that brain-stem or spinal cord dysfunction occurring with both acute and gradual elongation of the spinal canal are the result of excess tensile stress acting on fiber tracts, and the delayed onset of spinal cord ischemia is the probable result of a similar mechanical process acting upon intrinsic spinal cord blood vessels.

Intradural lipomas of the spinal cord

1976 ◽  
Vol 44 (3) ◽  
pp. 331-336 ◽  
Author(s):  
Bruce J. Ammerman ◽  
James M. Henry ◽  
Umberto De Girolami ◽  
Kenneth M. Earle
Keyword(s):  
Spinal Cord ◽  
Operative Procedure ◽  
Subtotal Resection ◽  
Diagnostic Study ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Fourth Decade ◽  
Sensory Changes ◽  
Fine Print

✓ Nine original cases of intradural spinal cord lipomas have been examined from a clinical and pathological standpoint. These tumors occur more commonly in men in the second to fourth decade and are found most frequently in the thoracic spinal cord. Paraparesis, sensory changes, urinary incontinence, and pain are frequent presenting complaints. Myelography is the diagnostic study of choice. All lipomas in this series were located primarily within the cord; four of these also presented an extramedullary extension. Admixed nerve bundles were present in five cases with associated hypertrophic onion-bulb formations in three. Decompression with biopsy or subtotal resection is the operative procedure of choice.

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.

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