TENDON TRANSFERS AND FUNCTIONAL ELECTRICAL-STIMULATION FOR RESTORATION OF HAND FUNCTION IN SPINAL-CORD INJURY

Spinal cord injury at the C5 and C6 level results in loss of hand func tion. Electrical stimulation of paralyzed muscles is one approach that has demonstrated significant capacity for restoring grasp and release function. One potential limitation of this approach is that key muscl es for stimulation may have lower motor neuron damage, rendering the m uscles unexcitable. We have used surgical modification of the biomecha nics of the hand to overcome this limitation. Tendon transfer of paral yzed but lower motor neuron intact muscles can compensate for potentia l function lost owing to muscles with lower motor neuron damage. Such procedures have been performed to provide finger extension, thumb exte nsion, finger flexion, and wrist extension. Additional surgical proced ures have been performed to enhance the function provided with electri cal stimulation. These are side-to-side synchronization of the finger flexor and extensor tendons, the flexor digitorium superficialis Zanco lli-lasso procedure, and thumb interphalangeal joint arthrodesis. Thes e procedures have been performed in 11 patients with C5 and C6 level s pinal injuries and functional electrical stimulation neuroprostheses. In these patients, 41 different functional electrical stimulation-rela ted procedures were performed and 38 gave the desired result after sur gery. One procedure resulted in no increase or decrease in function or muscle output, and two procedures resulted in a decrease in muscle fo rce or joint range of motion. The issues that must be considered in pe rforming functional electrical stimulation-related tendon transfers ar e discussed.