Spinal Cord Injuries

UC San Diego Health System has an multidisciplinary program for restoring function to people with spinal cord injuries (SCI). In the United States, approximately 12,000 new spinal cord injuries occur each year. There are around 300,000 people living with a spinal cord injury.


The degree of function following spinal cord injury corresponds to the American Spinal Injury Association (ASIA) impairment scale classification.

In a complete SCI, where no muscle function remains below the injury site, procedures such as nerve transfers and tendon transfers can bring control from above the injury level to muscles below that level. For example, a C5 complete SCI can recover grasp by using part of the nerve that helps flex the elbow. Recovering even partial arm and hand function can have an enormous impact on independence and quality of life because these individuals are dependent upon upper extremity function for mobility and activities of daily living.

In an incomplete SCI, limbs frequently have spasticity and reduced control. In an ASIA C, this is generally not enough for useful function. ASIA D patients are more functional, but often spastic with movements that are slow and difficult to execute. In both of these cases, surgeons at UC San Diego Health System can generally improve the patient's level of functioning. Surgical treatment techniques include reducing spasticity in particular muscles using peripheral neurotomies, as well as transferring the nerves with the best control to the most important muscle groups to improve function in that limb. Read more about these techniques below.

Tendon Transfers

Re-routing for Hand Function

Dr. Justin Brown, UC San Diego Health System neurosurgeon, recently quoted in Paraplegia News.

Currently, tendon transfers are the most common procedure for restoring hand function. The distal end of a working muscle (that is controlled by the part of the spinal cord above the injury) is cut and reattached to replace a nonworking muscle (which would otherwise be controlled by the spinal cord, but it isn't functioning because it is below the injury level). The tendon transfer sacrifices function at a lesser location in order to restore function at a more important location.

Tendon transfers offer functional gains for an estimated 70 percent of tetraplegic patients.

Nerve Transfers

Nerve transfers are a new option for patients with spinal cord injuries. Conceptually, this procedure is quite similar to tendon transfers. In this procedure, a healthy nerve serving one function is cut and reconnected to a nonfunctional nerve (below the injury level) serving a more important function. Nerve transfers provide options for patients who are not candidates for tendon transfers. A number of nerve transfer procedures have been developed for restoring function within the hand, but not every patient is a candidate for this procedure. Our physicians will determine which procedures are best for you.

Benefits of nerve transfers may provide advantages over tendon transfer for some patients. First, nerve transfers restore the original muscles function without changing the arm’s anatomy. Second, nerve transfers do not require casting and immobilization. Third, nerve transfers offer potential reconstructions when no tendon transfer options are available. Finally, sacrificing one simple function can potentially restore multiple functions. In some cases, there is actually no perceivable loss of function in any muscle groups. It should be noted that, unlike tendon transfers, nerve transfers can take as long as one year to provide the intended function.

UC San Diego Health System Expertise in Tendon and Nerve Transfers

Surgeons at UC San Diego Health System use both nerve and tendon transfer procedures to address spinal cord injury-related paralysis of the arms and hands. When a nerve transfer option is considered, neurophysiological testing is required. This is performed by Dr. Geoffrey Sheean. Dr. Justin Brown, who is a neurosurgeon and an expert in nerve transfers, works together with Dr. Reid Abrams, an orthopedic hand surgeon and expert in tendon transfers. Together, they develop effective strategies for recovering hand function in patients with hand impairments related to spinal cord injuries.

Talk to our peripheral nerve experts, call 858-246-0674.

ASIA Classification of Spinal Cord Injuries

A Complete – No sensory or motor function is preserved in the sacral segments S4 - S5.

B Incomplete –  Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4 - S5.

C Incomplete – Motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3.

D Incomplete –  Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade greater than or equal to 3.

E Normal – Sensory and motor functions are normal.

Muscle Grading

0 – total paralysis

1 – palpable or visible contraction

2 – active movement, full range of motion, gravity eliminated

3 – active movement, full range of motion against gravity

4 – active movement, full range of motion against gravity and provides some resistance

5 – active movement, full range of motion against gravity and provides normal resistance