Spinal evoked response in the cat

1975 ◽  
Vol 43 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Robert J. Sarnowski ◽  
Roger Q. Cracco ◽  
Harold B. Vogel ◽  
Fred Mount
Keyword(s):  
Spinal Cord ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Stimulation ◽  
Nerve Fibers ◽  
Evoked Responses ◽  
Afferent Pathways ◽  
Content Type ◽  
Sciatic Nerve Stimulation ◽  
Fine Print

✓ Summated evoked potentials to sciatic nerve stimulation were recorded from surface electrodes placed over the spine of cats. The response progressively increased in latency rostrally. It was largest and most complex in configuration in leads placed over the caudal spinal cord where sciatic nerve roots enter and begin to ascend the cord. The conduction velocity of the response was about 90 m/sec from rostral sacral to cervical regions. A comparison of surface-recorded evoked responses to stimulation of the sural nerve, the nerve to the medial head of the gastrocnemius muscle and the sciatic nerve suggest that the peripheral nerve fibers that mediate the response to sciatic nerve stimulation are primarily muscle nerve afferents. In surface, lamina, and durai recordings made over similar segmental levels, the response to sciatic nerve stimulation progressively increased in amplitude, duration, and wave form complexity from surface to depth. Failure of transmission across complete cord transections was demonstrated. Results in preparations with partial cord sections suggest that the surface-recorded response is mediated by multiple spinal cord afferent pathways which are situated primarily ipsilateral to the stimulated peripheral nerve. The data indicate that summated evoked responses arising in spinal cord afferent pathways can be recorded from surface-recording electrodes in cats. They suggest that this animal model may prove useful in the study of certain aspects of spinal cord pathology.

Peripheral nerve grafts promoting central nervous system regeneration after spinal cord injury in the primate

2002 ◽  
Vol 96 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Allan D. O. Levi ◽  
Hector Dancausse ◽  
Xiuming Li ◽  
Suzanne Duncan ◽  
Laura Horkey ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Spinal Cord Injury ◽  
Nervous System ◽  
Peripheral Nerve ◽  
Content Type ◽  
Nerve Grafts ◽  
Cord Injury ◽  
Peripheral Nerve Grafts ◽  
Fine Print

Object. Partial restoration of hindlimb function in adult rats following spinal cord injury (SCI) has been demonstrated using a variety of transplantation techniques. The purpose of the present study was twofold: 1) to determine whether strategies designed to promote regeneration in the rat can yield similar results in the primate; and 2) to establish whether central nervous system (CNS) regeneration will influence voluntary grasping and locomotor function in the nonhuman primate. Methods. Ten cynomologus monkeys underwent T-11 laminectomy and resection of a 1-cm length of hemispinal cord. Five monkeys received six intercostal nerve autografts and fibrin glue containing acidic fibroblast growth factor (2.1 µg/ml) whereas controls underwent the identical laminectomy procedure but did not receive the nerve grafts. At 4 months postgrafting, the spinal cord—graft site was sectioned and immunostained for peripheral myelin proteins, biotinylated dextran amine, and tyrosine hydroxylase, whereas the midpoint of the graft was analyzed histologically for the total number of myelinated axons within and around the grafts. The animals underwent pre- and postoperative testing for changes in voluntary hindlimb grasping and gait. Conclusions. 1) A reproducible model of SCI in the primate was developed. 2) Spontaneous recovery of the ipsilateral hindlimb function occurred in both graft- and nongraft—treated monkeys over time without evidence of recovering the ability for voluntary tasks. 3) Regeneration of the CNS from proximal spinal axons into the peripheral nerve grafts was observed; however, the grafts did not promote regeneration beyond the lesion site. 4) The grafts significantly enhanced (p < 0.0001) the regeneration of myelinated axons into the region of the hemisected spinal cord compared with the nongrafted animals.

Peripheral nerve stimulation for pain relief using a multicontact electrode system

1979 ◽  
Vol 51 (6) ◽  
pp. 872-873 ◽  
Author(s):  
Blaine S. Nashold ◽  
John B. Mullen ◽  
Roger Avery
Keyword(s):  
Pain Relief ◽  
Peripheral Nerve ◽  
Nerve Stimulation ◽  
Electrode System ◽  
Peripheral Nerve Stimulation ◽  
Content Type ◽  
Cuff Electrodes ◽  
Fine Print

✓ A new electrode system for peripheral nerve stimulation is described. The electrodes are directly sutured to the nerve, eliminating rotational and compressive effects associated with cuff electrodes.

Experimental investigation on the spinal cord evoked injury potential

1983 ◽  
Vol 59 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Johannes Schramm ◽  
Rolf Krause ◽  
Taku Shigeno ◽  
Mario Brock
Keyword(s):  
Spinal Cord ◽  
Diagnostic Value ◽  
Spinal Cord Monitoring ◽  
Content Type ◽  
Recording Technique ◽  
Common Reference ◽  
Cord Injury ◽  
Sciatic Nerve Stimulation ◽  
Fine Print ◽  
Injury Potential

✓ Averaged somatosensory evoked potentials from the epidural space in response to sciatic nerve stimulation were recorded in bipolar and common reference mode in cats following various types of injury. An investigation was conducted on the development and properties of the spinal evoked response recorded from the center of the injury site, designated here as the “spinal cord evoked injury potential.” Typically it is a two-peak monophasic positive potential, approximately 40 msec in duration, with a slight negative afterwave. With increasing distance from the site of injury, its amplitude rapidly decreases, whereas latency remains constant. The common reference recording technique resulted in an earlier and better demonstration of the evoked injury potential, especially when it was transitory or incomplete. When impairment of conduction developed gradually, the evoked injury potential developed gradually too. In serial recordings along the spinal cord axis, the transition from a normal triphasic to a monophasic evoked injury potential allowed a precise localization of the lesion. These data suggest that the diagnostic value of intraoperative spinal cord monitoring may be increased by adopting a technique that incorporates several epidural recordings with a common reference recording technique. The spinal cord evoked injury potential seems to be a more sensitive indicator of spinal cord injury than the cortical evoked potential. The findings are discussed in the light of the presently developing spinal cord monitoring techniques.

Peripheral nerve regeneration by transplantation of bone marrow stromal cell—derived Schwann cells in adult rats

2004 ◽  
Vol 101 (5) ◽  
pp. 806-812 ◽  
Author(s):  
Toshiro Mimura ◽  
Mari Dezawa ◽  
Hiroshi Kanno ◽  
Hajime Sawada ◽  
Isao Yamamoto
Keyword(s):  
Bone Marrow ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Schwann Cells ◽  
Peripheral Nerve Regeneration ◽  
Adult Rats ◽  
Content Type ◽  
Alternative Method ◽  
Fine Print

Object. Bone marrow stromal cells (BMSCs) can be induced to form Schwann cells by sequentially treating the cells with β-mercaptoethanol and retinoic acid, followed by forskolin and neurotrophic factors including heregulin. In this study the authors made artificial grafts filled with BMSC-derived Schwann cells (BMSC-DSCs) and transplanted them into the transected sciatic nerve in adult rats to evaluate the potential of BMSCs as a novel alternative method of peripheral nerve regeneration. Methods. The BMSC-DSCs were suspended in Matrigel and transferred into hollow fibers (12 mm in length), which were transplanted into the transected sciatic nerve in adult Wistar rats. Six months after cell transplantation, electrophysiological evaluation and walking track analysis were performed. Results of these studies showed significant improvement in motor nerve conduction velocity and sciatic nerve functional index in the BMSC-DSC—transplanted group compared with the control group (Matrigel graft only). Immunohistochemical study data demonstrated that transplanted BMSCs labeled with retrovirus green fluorescent protein were positive for P0 and myelin-associated glycoprotein and had reconstructed nodes of Ranvier and remyelinated regenerated nerve axons. The number of regenerated axons in the axial section of the central portion of the graft was significantly greater in the transplanted group. Although BMSCs can differentiate into several types of cells, tumor formation did not occur 6 months after engraftment. Conclusions. Results in this study indicate that BMSC-DSCs have great potential to promote regeneration of peripheral nerves. The artificial graft made with BMSC-DSCs represents an alternative method for the difficult reconstruction of a long distance gap in a peripheral nerve.

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