print this pageSetting Hands Free
New Surgical Technique can restore hand function to people with SCI
By Scott Huelskamp
When James Brown plunged headfirst into a pool 15 years ago and with the cement bottom, he surrendered capabilities he thought were lost forever.
For Brown, who has C5-6 quadriplegia, the days of hand function and grip strength became fading memories, slowly evaporating like early morning fog. What would it feel like, he wondered, to tip a cup to his lips and sip water again, or pick up a stray piece of paper?
Last year, he found out. After undergoing a revolutionary procedure to restore hand function, Brown now writes, eats and brushes his teeth without using any adaptive equipment. With his newly discovered freedom, he spends his spare time woodworking, deftly handling electric drills, guiding a power saw through a fresh piece of lumber and hammering nails into place.
Brown is a living advertisement for the potential of a new surgical technique in which implanted electrodes restore hand function to people with C5-6 spinal cord injury.
The capabilities of this technology, "stunned me," says Brown, 37, a manager of an apartment complex in La Grange, Ky. "It opened doors to things that I didn't think the ... system would allow me to do. The more you use it, the more things you find out ... and the more things you are able to do with it."
Approved by the Federal Drug Administration in 1997, the surgical implant blends neuroprostheses with conventional, tendon transfer hand surgery. A surgeon attaches electrodes to muscles in the hand and forearm and implants an electrical device, similar to a pacemaker, into the patient's chest. Small, almost unnoticeable shoulder movements from the opposite shoulder send impulses to the pacemakerlike device, which stimulates the electrodes and makes the arm move. Freehand surgery takes tendon transfer surgery; a common procedure that's been in practice for almost 20 years, one step further. Used together, the two procedures provide elbow extension, wrist extension, hand grasp and key pinch.
A shoulder position sensor mounted on the chest and shoulder translates small shoulder movements into a control signal. An external controller-the power source or "brain"receives the signal, processes it and sends it back through a transmitting coil. The signal continues through the coil to the implanted stimulator in the chest, in turn sending electrical impulses surging through wires to the electrodes attached to hand and forearm muscles.
Explaining the procedure, John Shaw, MD, says surgeons "will implant muscles to activate the wrist, extend the thumb and fingers, to flex fingers and ... control thumb opposition, adduction and flexion to provide a choice of both a palmar pinch and a key pinch." Dr. Shaw is medical director of Southern Indiana Rehab Hospital, New Albany, Ind., and on staff at Clark Memorial Hospital, Jeffersonville, one of 23 facilities in the nation offering the surgery.
The palmar pinch allows patients to cup the hand and pick up larger objects while the key pinch allows them to press the thumb against the index finger for activities such as brushing teeth and writing.
Surgeons can implant a maximum of eight electrodes on muscles during the 12 to 15 hour procedure - the average is six electrodes, says Brock Bowman, MD, a physiatrist at the Shepherd Center in Atlanta.
After the surgery, patients can go from having virtually no ability to grasp or hold objects to being able to pick up the telephone receiver, handle money, write a check and pour a cup of coffee. Eventually, they can progress to more advanced manipulation tasks, such as cooking and playing with children.
If the procedure is going to be effective, however, patients must have a strong relationship with the rehabilitation team; preand post-surgical therapy are key components of the program.
That relationship extends into the operating room. Beth Garcia, OTR, CHT, a hand therapist at the Southern Indiana Rehab Hospital, is part of the surgical team and provides input during the electrode placement portion of surgery. Since she's followed most patients through therapy to condition forearm and shoulder muscles before surgery, she has more detailed knowledge of the strength and capabilities of certain muscles. That insight allows the surgeon to affix electrodes to the most efficient muscle area.
"When we stimulate a muscle in surgery, we may get spillover to an adjacent muscle or peripheral nerve," she says. "Some of those spillovers are good and conducive to functional grasp, and some aren't. Once all the electrodes are placed, we look at the combination, how they work together and make sure the grasp patterns will work for a patient in the real world."
To qualify for the procedure, candidates must meet various criteria. For starters, they must be injured at the C5-6 level and have at least minimal use of shoulder and biceps muscles, with weak or no wrist control.
They also must be at least one year postinjury. Before introducing the idea of this surgery, clinicians like to wait at least 12 months to see if patients regain any upper extremity use on their own, says Marci Floersheim, OT, a staff therapist at the Shepherd Center.
Even people 20 years post-injury can be eligible, as long as they have the muscle potential. However, these cases present different challenges. Over time, patients who have been away from rehab may have developed contractures, spasticity or grown accustomed to certain coping techniques.
"They need a lot of work prepping," Dr. Shaw says. "We want fingers and hands that are supple and pliable." The dominant hand is the extremity of choice.
During an evaluation, Garcia assesses active range of motion in the shoulder and elbow and passive ROM of the hand. "We're mapping each of the muscles that would be potentially implanted with an electrode. Do they stimulate and what is the strength?" she says.
article from Advance for Directors in Rehabilitation
February 2000