Spinal Cord Implant Studies

Swiontek, Thomas; Sances, Anthony; Larson, Sanford J.; Ackmann, James J.; Cusick, Joseph F.; Meyer, Glenn A.; Millar, Edward A.

doi:10.1109/tbme.1976.324590

Cited by 34 publications

(13 citation statements)

References 7 publications

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“…While a distinct trail of degenerating myelin could be traced from small lesions produced by coagulation of blood vessels on the pos terior surface of each cerebellar hemisphere, there was no evidence of de generating myelin beneath the electrode. The arachnoid was thickened beneath the implant but not to an extent which would interfere with appli cation of current [16]. Sections counterstained for cells failed to demon strate any difference in the Purkinje cell population on the side to which currents had been applied as compared with the control side ( fig.…”

Section: Stimulate Upper Lim8mentioning

confidence: 94%

“…Of greater concern is the possibility of eventual loss of clinical improvement produced by cerebellar stimulation. This is not a major con sideration if currents are applied through the cerebellum from electrodes on the superior surface to those on the posterior surface, since changes at the electrode/tissue interface would not substantially affect clinical im provement associated with application of current [15,16]. Because the amount of current required for clinical improvement and for reduction in…”

mentioning

confidence: 99%

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Physiological and Histological Effects of Cerebellar Stimulation

Larson¹,

Sances²,

Hemmy³

et al. 1977

Stereotact Funct Neurosurg

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Cerebellar implants have been placed in 62 patients with postoperative follow-up of 4 months to 3 years. Initially currents were applied through electrodes of alternate polarity on the superior surface of the cerebellar hemispheres and subsequently through negative electrodes on the superior surface to positive electrodes on the posterior surface. The amount of current required for clinical improvement was approximately the same as that required to significantly reduce the amplitude of the somatosensory evoked potential. The clinical and electrophysiological effects were proportional to the intensity of current and to the number of electrodes through which the currents were applied. Currents applied through the cerebellum were more effective than those confined near the cerebellar surface. Histological examination of the cerebellum from the chimpanzees and from 1 patient who died of causes unrelated to stimulation failed to demonstrate any evidence of neuronal damage related to application of current.

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Section: Stimulate Upper Lim8mentioning

confidence: 94%

mentioning

confidence: 99%

Physiological and Histological Effects of Cerebellar Stimulation

Larson¹,

Sances²,

Hemmy³

et al. 1977

Stereotact Funct Neurosurg

Self Cite

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“…The current density flowing through the human spinal cord was measured in tissue extracted from cadavers and immersed in a glass tank filled with NaCl solution [43], but alternating current of a relatively high frequency (1000 Hz) was used in those experiments precluding the comparison of our data. Furthermore, post-mortem tissue changes and the large volume of the reservoir filled with electrically conductive NaCl would produce different current distributions compared to the in vivo context.…”

Section: Validation Of the Modelmentioning

confidence: 99%

Spinal cord direct current stimulation: finite element analysis of the electric field and current density

Hernández-Labrado

Polo

López-Dolado

et al. 2011

Med Biol Eng Comput

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Applied low-intensity direct current (DC) stimulates and directs axonal growth in models of spinal cord injury (SCI) and may have therapeutic value in humans. Using higher electric strengths will probably increase the beneficial effects, but this faces the risk of tissue damage by electricity or toxic reactions at the electrode-tissue interface. To inform the optimisation of DC-based therapeutics, we developed a finite element model (FEM) of the human cervical spine and calculated the electric fields (EFs) and current densities produced by electrodes of different size, geometry and location. The presence of SCI was also considered. Three disc electrodes placed outside the spine produced low-intensity, uneven EFs, whereas the EFs generated by the same electrodes located epidurally were about three times more intense. Changes in electrical conductivity after SCI had little effect on the EF magnitudes. Uniformly distributed EFs were obtained with five disc electrodes placed around the dura mater, but not with a paddle-type electrode placed in the dorsal epidural space. Replacing the five disc electrodes by a single, large band electrode yielded EFs > 5 mV/mm with relatively low current density (2.5 μA/mm(2)) applied. With further optimisation, epidural, single-band electrodes might enhance the effectiveness of spinal cord DC stimulation.

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“…11,14,17,19 To validate their 3D model, Coburn and Sin 17 modelled in-situ SCS experiments on monkeys 24 and compared calculated current densities and experimental data. However, the uncertainty regarding the exact experimental conditions prevented them from being conclusive.…”

Section: Computer Models Of Scsmentioning

confidence: 99%

Computer modelling of spinal cord stimulation and its contribution to therapeutic efficacy

1998

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An overview of computer models developed since the late seventies, which enable the simulation of the primary e ects of spinal cord stimulation (SCS) on nerve ®bres, is presented. These models consist of a 3-dimensional volume conductor model, representing anatomical structures and their electrical conductivities, and cable models representing the electrical behaviour of nerve ®bres. The characteristics of these models and their relation to anatomy and physiology, as well as the calculation of stimulation-induced electrical ®elds and their e ect on nerve ®bre models, are reviewed. It is shown that most characteristics of SCS as predicted by computer modelling correspond well with empirical data. Accordingly, a theoretical framework describing the relations between relevant parameters in SCS is presented. Finally, it is shown how theory and computer modeling are applied to improve the e cacy of SCS by the optimization of its technique, primarily by the design of new epidural electrodes.

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Spinal Cord Implant Studies

Cited by 34 publications

References 7 publications

Physiological and Histological Effects of Cerebellar Stimulation

Physiological and Histological Effects of Cerebellar Stimulation

Spinal cord direct current stimulation: finite element analysis of the electric field and current density

Computer modelling of spinal cord stimulation and its contribution to therapeutic efficacy

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