Video Clips

Human Spinal Cord - M. A. Howard III et. al., U. Iowa

Exposed via durotomy during a standard surgical procedure, the vascularized surface of the patient's spinal cord can be seen. Note the small, periodic pulsations of it that are driven by the cardiac cycle

Run-time: 0 m 37 s. (

Ovine Spinal Cord - H. Oya et al., U.Iowa

Testing of the HSCMS is carried out in sheep, which have a spinal cord similar in many respects to that of man. The ovine spinal cord is shown here, emphasizing one of the dentate ligaments that suspends it inside of the dura mater.

Run-time: 0 m 5 s. (

Ovine Spinal Dynamics - S. Safayi and N. D. Jeffery, ISU

The sheep’s neck and spine are supple enough to allow rotation of the head through 360 degree arcs, as measured and shown here via video-based motion analysis. HSCMS devices implanted in them will thus be tested under extreme conditions of performance.

Run-time: 1 m 5 s. (

Action Potentials vs. Stimulation Frequency - M. Utz, U.Southampton

A FitzHugh-Nagumo model of axonal signal transmission shows that low frequency stimuli will generate travelling action potentials. However, high frequency stimulation suppresses action potential generation and blocks transmissions on the axon.

Run-time: 2 m 0 s. (

Device Implantation - S. Viljoen et al., U.Iowa

The first HSCMS implantation in an ovine model was done on August 3, 2011. Shown here is the placement of the implant on the spinal cord’s surface using a custom-designed applier tool. This version of the implant has been superseded by improved ones.

Run-time: 1 m 48 s. (

Device Leads - M. S. Oliynyk and G. T. Gillies, U.Virginia

The small wires connecting the electrodes on the implant to the pulse generator are shaped in loops. As shown here, this configuration produces a mild spring-like action that helps to seat the prototype device onto the surface of a life-size surrogate spinal cord.

Run-time: 0 m 8 s. (

Device in Fluid - M. S. Oliynyk and G. T. Gillies, U.Virginia

To simulate HSCMS performance within the cerebrospinal fluid inside the dura mater, a prototype device and surrogate spinal cord are submerged in water. The surface of the device remains stably in place without slippage during lead loop compression.

Run-time: 0 m 9 s. (

Continuity Tests - J. K. Kanwal and G. T. Gillies, U.Virginia

The electrical continuity of the HSCMS electrodes and leads was evaluated during compression of the lead loops. This was done by lowering the device onto exposed wires on the surface of the surrogate spinal cord, and monitoring continuity across lead-loop pairs.

Run-time: 0 m 21 s. (

Accommodating Movement - R. Shurig et al., Evergreen Medical Technologies, Inc.

The spinal cord moves inside the spinal canal during bending of the back. Therefore, the lead loops of the HSCMS are made of a diameter that is large enough to accommodate these motions. Large relative motions of the top vs. bottom of the device are shown here.

Run-time: 0 m 20 s. (

Mechanical Stability Testing - R. Shurig et al., Evergreen Medical Technologies, Inc.

A test rig was designed and built for the purpose of carrying out long-duration studies on the mechanical stability of the HSCMS while it was in place on a moving spinal cord surrogate. Shown here is lead loop response to simulated axial movement of the cord.

Run-time: 0 m 19 s. (

Accelerated Stress Testing - R. Shurig et al., Evergreen Medical Technologies, Inc.

By operating the stability test rig at high speeds, eg., 2 movement cycles per second, one can evaluate lifetime performance of the HSCMS (roughly ten million cycles) within a short period of time. A HSCMS with lateral stiffening arms is shown under test here.

Run-time: 0 m 16 s. (

Ovine Treadmill Full View - S. Safayi and N. D. Jeffery, ISU

Video-based gait analysis provides a sensitive means of evaluating neurological responses of walking animals. Shown here in full view is an adult sheep trained to walk at normal speed on a treadmill, prior to implantation of a HSCMS device on the spinal cord.

Run-time: 0 m 10 s. (

Ovine Treadmill Close-Up - S. Safayi and N. D. Jeffery, ISU

There is a wealth of neuro-mechanical information encoded in the lower-limb motions of walking quadrupeds, such as the one shown here. We will test the effectiveness of HSCMS stimulation in restoring normal gait in animals with various neurological problems.

Run-time: 0 m 10 s. (

Ovine Treadmill Post-Op - S. Safayi and N. D. Jeffery, ISU

Gait analysis testing of an adult sheep was carried out following HSCMS implantation and post-op recovery. That animal is shown here in treadmill exercises in preparation for the spinal cord stimulation studies.

Run-time: 0 m 11 s. (

Ovine Treadmill Nerve Ligation - S. Safayi, ISU and C. Reddy, U.Iowa

The post-op treadmill performance of an ovine model of peroneal nerve ligation is shown. Following HSCMS implantation, treadmill exercise with video gait analysis will be used to evaluate the possible efficacy of spinal cord stimulation in modifying leg movements.

Run-time: 1 m 5 s. (

Ovine Treadmill SCI 12 Weeks - S. Safayi, ISU and S. Wilson, U.Iowa

An ovine model of mild spinal cord injury is shown in treadmill exercise 12 weeks post-op. A hind-limb gait deficit can be seen, which results from neuromuscular spasticity. This is a common outcome in such cases.

Run-time: 0 m 4 s. (

Ovine Treadmill SCI 14 Weeks - S. Safayi, ISU and S. Wilson, U.Iowa

Non-invasive Velcro markers have been attached to the animal at 14 weeks post-op, to enable video tracking for gait analysis. The goal of the study will be to see if spinal cord stimulation via an implanted HSCMS can moderate hind limb spasticity.

Run-time: 0 m 11 s. (