Implant for Walking After Incomplete SCI

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.