Implanted Myoelectric Control for Restoration of Hand Function in Spinal Cord Injury

The design of this study is to determine the efficacy of improving upper extremity function in tetraplegic subjects after receiving an implantable device for neuromuscular control. Evaluations will be made so as to document changes in performance of manipulative tasks when using the stimulation system.

Subjects who consent to participate in this project will have an implantable stimulator surgically placed in the upper extremity for control of the upper extremity. A series of tests will be performed before implantation, and repeated at intervals after implantation to assess changes in each subject's performance.

This study is a non-randomized feasibility study with concurrent (neuroprosthesis on and off) and longitudinal (pre- and post-implantation/training) self-controls.

Subjects participating in the study can expect to be actively involved in the study for two years after implantation and followed for life thereafter. The screening procedures take up to two days, depending on the specific evaluations necessary to determine candidacy. Pre-surgical exercise is conducted for at least two weeks. The implantation surgery itself lasts one day, with three to seven days of post-surgical hospitalization. Following an eight-week exercise program and a twelve-week training program, subjects are discharged from the active rehabilitation phase. They are followed quarterly for one year, and then annually thereafter.

The device is referred to as the Implanted Stimulator-Telemeter (IST) -12. The device uses functional electrical stimulation (FES) to activate paralyzed muscles.

Inclusion criteria

• C5-C8 spinal cord injury
• Minimum of one-year post injury with no additional function prior to implantation surgery
• Male or female
• 18-60 years of age
• intact vision
• pharmacologically controlled spasticity, when applicable
• Functional in wheelchair with adequate trunk support to allow bimanual manipulation
• Positive attitude and motivation with supportive home environment
• Willingness to return to laboratory for periodic evaluation and testing
• Free of contractures known to diminish performance of the system (e.g., supination contracture of the wrist).
• Integrity of the lower motor neuron (peripheral nerve) to the muscles to be activated
• Adequate range of motion of joints of the shoulder, wrist, and hand (upper extremity).
• If an acute infection is present, the subject will not be considered for surgery until it clears.

Exclusion criteria

• Prior history of a major chronic systemic infection or other illness that would increase the risk of surgery.
• Contraindications include immunologic diseases, cardiac arrhythmias, undiagnosed or high-risk breast masses, dermatologic conditions, and any major system failure.
• Acute infection currently present that has not cleared.
• Hypersensitivity that inhibits their ability to sustain pressure over their digits.
• Blind
• Uncontrolled disorders, i.e., seizures