Spinal Cord Injury Epidural Stimulation

A Feasibility Study: Epidural Stimulation to Enable Volitional Movement After Chronic Complete Paralysis in Humans.

This is a feasibility study to test the use of epidural stimulation to restore volitional function previously lost due to spinal cord injury.

Previous studies conducted in animal models, performed elsewhere and here at Mayo Clinic, have shown that direct electrical stimulation of the spinal cord increases the excitability of spared neuronal connections within the site of injury, thereby enhancing signal transmission and allowing recovery of previously lost volitional function. Recently, epidural electrical stimulation of the lumbosacral spinal cord in four individuals with spinal cord injury (SCI) has restored motor and autonomic function below the level of injury. Despite positive results, further translational research is needed to validate these findings. The goal of this proposal is to perform epidural stimulation to restore volitional function in patients with SCI. In two patients, we will implant an epidural stimulator onto the dorsal aspect of the lumbosacral spinal cord dura mater. Patients will undergo a structured program of daily physical rehabilitation, treadmill step training, and epidural stimulation to recover motor, sensory, and autonomic function.

Inclusion Criteria:

• Stable medical condition without *cardiopulmonary disease or *dysautonomia that would contraindicate standing or stepping with body weight support training
• No current anti-spasticity medication regimen
• Non-progressive spinal cord injury between the vertebral levels of C7 & T10
• American Spinal Injury Association grading scale of A or B
• Sensory evoked potentials are either not present or have a bilateral delay
• Segmental reflexes remain functional below the lesion
• At least 2-years post-injury.

Exclusion Criteria:

• Pregnancy at time of enrollment
• Failure to obtain consent
• Prisoners
• Children (age less than 21)
• Any patient identified as unsuitable for this protocol by the Mayo study team
• Skeletal fracture
• Osteoporosis with Dual-energy X-ray absorptiometry (DEXA) t score ≤-3.5
• Uncontrolled urinary tract infections
• Presence or history of frequent decubitus ulcers
• Clinical depression
• Drug abuse
• Painful musculoskeletal dysfunction, unhealed fracture, contracture, pressure sore, or urinary tract infection that might interfere with stand or step training
• Current anti-spasticity medication regimen
• Voluntary motor response present in leg muscles
• Volitional control during voluntary movement attempts in leg muscles as measured by electromyography (EMG) activity
• Brain influence on spinal reflexes as measured by EMG activity
• Recordable motor evoked potential in the lower limbs with transcranial magnetic stimulation
• Implanted cardiac pacemaker
• Implanted defibrillator
• Other implanted metallic or active body worn medical electronic device such as an insulin pump
• *Cardiopulmonary disease that would result in exclusion from the study will be defined as clinically diagnosed chronic obstructive pulmonary disease, cardiac failure, and heart arrhythmia that would contraindicate sudden changes in body position such as sit-to-stand and stepping
• *Excessive and uncontrolled autonomic dysreflexia characterized by symptomatic hypotension, light headedness and hypertension, flushing and bradycardia. Additionally blood pressure monitoring will be available at all times during rehabilitation and assessment times.