Implant for Walking After Incomplete SCI

Enhancing Walking and Independence After Incomplete SCI With a Fully Implanted Neuroprosthesis

This is a device study that will evaluate the effect of an implanted stimulator on improving walking in people with incomplete spinal cord injury. There are two phases in the study: 1) Screening - this phase determines if the individual is a good candidate to receive an implanted system, 2) Implantation, controller development, and evaluation - this phase includes implanting the device and setting the individual up for system use, creating controllers for walking, and evaluating the effect of the device over a couple years.

The purpose of this study is to evaluate the effects of neural stimulation for improving walking after incomplete spinal cord injury. Participants will conduct pre-surgical gait training and then undergo surgery to implant a stimulator and electrodes to sense from and activate muscles used during walking. The device delivers electrical pulses to the nerves causing the muscles to contract to perform functional movements. The system coordinates assistance based on implanted sensors. After receiving the implanted device, participants undergo training to use the device to assist walking. Evaluations are completed prior to surgery as well after training and at later follow up sessions.

Inclusion Criteria:

• Between the ages of 18-75
• Non-ventilator dependent paralysis resulting from injuries such as: cervical/thoracic spinal cord injuries affecting the trunk and/or lower limbs
• Impairment classification of AIS B, C, or D (preservation of sensation and/or some motor function) with weakness in trunk and/or lower extremity muscles
• Unable to walk faster than 0.8m/s during a 10m walk test
• Gait deviation such as reduced peak hip, knee, and/or ankle range of motion during stance or swing phases due to motor impairment
• Time post injury greater than six months
• Innervated and excitable lower extremity and trunk musculature
• Adequate social support and stability
• Willingness to comply with follow-up procedures
• Appropriate body habitus (height and weight within acceptable limits as determined by study physician)
• Neurologically stable as determined by a physician

Exclusion Criteria:

• Significant fracture risk or history of spontaneous fractures
• History of heterotopic ossification at the hip, knee, or ankle
• Non-English speaking
• Insufficient upper extremity function to use an assistive device (e.g. walker or cane)
• Females who are pregnant
• Current pressure injury that would be exacerbated by study activities
• Uncontrolled spasticity that would interfere with study activities
• Significant range of motion limitations that would compromise study activities
• History of vestibular dysfunction, balance problems, or spontaneous falls
• Disorder or condition that require MRI monitoring
• Acute and/or untreated orthopedic issues that would prevent weight bearing or exercising implanted muscles such as a dislocation or fracture
• Acute and/or chronic medical problems left untreated or not controlled that would increase risk by using stimulation such as cardiac abnormalities, immunological/pulmonary/renal/circulatory compromise
• Uncontrolled diabetes or hypertension
• Presence of a demand pacemaker, cardiac defibrillator, or neuroprosthesis system with components in the legs
• Any other medical or psychological condition that would be a contraindication

Implant eligibility criteria

• In addition to all of the above, the participant must be able to fully support their body weight in standing with an assistive device prior to implantation.