Wireless control of intraspinal microstimulation in a rodent model of paralysis

Peter J. Grahn, Kendall H Lee, Aimen Kasasbeh, Grant W. Mallory, Jan T. Hachmann, John R. Dube, Christopher J. Kimble, Darlene A. Lobel, Allan Bieber, Ju H o Jeong, Kevin E. Bennet, Jose Lujan

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

OBJECT: Despite a promising outlook, existing intraspinal microstimulation (ISMS) techniques for restoring functional motor control after spinal cord injury are not yet suitable for use outside a controlled laboratory environment. Thus, successful application of ISMS therapy in humans will require the use of versatile chronic neurostimulation systems. The objective of this study was to establish proof of principle for wireless control of ISMS to evoke controlled motor function in a rodent model of complete spinal cord injury.

METHODS: The lumbar spinal cord in each of 17 fully anesthetized Sprague-Dawley rats was stimulated via ISMS electrodes to evoke hindlimb function. Nine subjects underwent complete surgical transection of the spinal cord at the T-4 level 7 days before stimulation. Targeting for both groups (spinalized and control) was performed under visual inspection via dorsal spinal cord landmarks such as the dorsal root entry zone and the dorsal median fissure. Teflon-insulated stimulating platinum-iridium microwire electrodes (50 μm in diameter, with a 30- to 60-μm exposed tip) were implanted within the ventral gray matter to an approximate depth of 1.8 mm. Electrode implantation was performed using a free-hand delivery technique (n = 12) or a Kopf spinal frame system (n = 5) to compare the efficacy of these 2 commonly used targeting techniques. Stimulation was controlled remotely using a wireless neurostimulation control system. Hindlimb movements evoked by stimulation were tracked via kinematic markers placed on the hips, knees, ankles, and paws. Postmortem fixation and staining of the spinal cord tissue were conducted to determine the final positions of the stimulating electrodes within the spinal cord tissue.

RESULTS: The results show that wireless ISMS was capable of evoking controlled and sustained activation of ankle, knee, and hip muscles in 90% of the spinalized rats (n = 9) and 100% of the healthy control rats (n = 8). No functional differences between movements evoked by either of the 2 targeting techniques were revealed. However, frame-based targeting required fewer electrode penetrations to evoke target movements.

CONCLUSIONS: Clinical restoration of functional movement via ISMS remains a distant goal. However, the technology presented herein represents the first step toward restoring functional independence for individuals with chronic spinal cord injury.

Original languageEnglish (US)
Pages (from-to)232-242
Number of pages11
JournalJournal of Neurosurgery
Volume123
Issue number1
DOIs
StatePublished - Jul 1 2015

Fingerprint

Paralysis
Rodentia
Spinal Cord
Electrodes
Spinal Cord Injuries
Hindlimb
Ankle
Hip
Knee
Controlled Environment
Iridium
Spinal Nerve Roots
Polytetrafluoroethylene
Platinum
Biomechanical Phenomena
Sprague Dawley Rats
Hand
Staining and Labeling
Technology
Muscles

Keywords

  • diagnostic and operative techniques
  • EMG = electromyographic
  • functional electrical stimulation
  • intraspinal microstimulation
  • ISMS = intraspinal microstimulation
  • MINCS = Mayo investigational neuromodulation control system
  • SCI = spinal cord injury
  • spinal cord injury

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Wireless control of intraspinal microstimulation in a rodent model of paralysis. / Grahn, Peter J.; Lee, Kendall H; Kasasbeh, Aimen; Mallory, Grant W.; Hachmann, Jan T.; Dube, John R.; Kimble, Christopher J.; Lobel, Darlene A.; Bieber, Allan; Jeong, Ju H o; Bennet, Kevin E.; Lujan, Jose.

In: Journal of Neurosurgery, Vol. 123, No. 1, 01.07.2015, p. 232-242.

Research output: Contribution to journalArticle

Grahn, PJ, Lee, KH, Kasasbeh, A, Mallory, GW, Hachmann, JT, Dube, JR, Kimble, CJ, Lobel, DA, Bieber, A, Jeong, JHO, Bennet, KE & Lujan, J 2015, 'Wireless control of intraspinal microstimulation in a rodent model of paralysis', Journal of Neurosurgery, vol. 123, no. 1, pp. 232-242. https://doi.org/10.3171/2014.10.JNS132370
Grahn, Peter J. ; Lee, Kendall H ; Kasasbeh, Aimen ; Mallory, Grant W. ; Hachmann, Jan T. ; Dube, John R. ; Kimble, Christopher J. ; Lobel, Darlene A. ; Bieber, Allan ; Jeong, Ju H o ; Bennet, Kevin E. ; Lujan, Jose. / Wireless control of intraspinal microstimulation in a rodent model of paralysis. In: Journal of Neurosurgery. 2015 ; Vol. 123, No. 1. pp. 232-242.
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AU - Hachmann, Jan T.

AU - Dube, John R.

AU - Kimble, Christopher J.

AU - Lobel, Darlene A.

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AU - Jeong, Ju H o

AU - Bennet, Kevin E.

AU - Lujan, Jose

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N2 - OBJECT: Despite a promising outlook, existing intraspinal microstimulation (ISMS) techniques for restoring functional motor control after spinal cord injury are not yet suitable for use outside a controlled laboratory environment. Thus, successful application of ISMS therapy in humans will require the use of versatile chronic neurostimulation systems. The objective of this study was to establish proof of principle for wireless control of ISMS to evoke controlled motor function in a rodent model of complete spinal cord injury.METHODS: The lumbar spinal cord in each of 17 fully anesthetized Sprague-Dawley rats was stimulated via ISMS electrodes to evoke hindlimb function. Nine subjects underwent complete surgical transection of the spinal cord at the T-4 level 7 days before stimulation. Targeting for both groups (spinalized and control) was performed under visual inspection via dorsal spinal cord landmarks such as the dorsal root entry zone and the dorsal median fissure. Teflon-insulated stimulating platinum-iridium microwire electrodes (50 μm in diameter, with a 30- to 60-μm exposed tip) were implanted within the ventral gray matter to an approximate depth of 1.8 mm. Electrode implantation was performed using a free-hand delivery technique (n = 12) or a Kopf spinal frame system (n = 5) to compare the efficacy of these 2 commonly used targeting techniques. Stimulation was controlled remotely using a wireless neurostimulation control system. Hindlimb movements evoked by stimulation were tracked via kinematic markers placed on the hips, knees, ankles, and paws. Postmortem fixation and staining of the spinal cord tissue were conducted to determine the final positions of the stimulating electrodes within the spinal cord tissue.RESULTS: The results show that wireless ISMS was capable of evoking controlled and sustained activation of ankle, knee, and hip muscles in 90% of the spinalized rats (n = 9) and 100% of the healthy control rats (n = 8). No functional differences between movements evoked by either of the 2 targeting techniques were revealed. However, frame-based targeting required fewer electrode penetrations to evoke target movements.CONCLUSIONS: Clinical restoration of functional movement via ISMS remains a distant goal. However, the technology presented herein represents the first step toward restoring functional independence for individuals with chronic spinal cord injury.

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KW - MINCS = Mayo investigational neuromodulation control system

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