Nerve Transfers for Upper Extremity Reanimation in Tetraplegia: Part I—Background and Operative Considerations

Traumatic spinal cord injury (SCI) leads to chronic impairment and disability. In the United States, the annual incidence of SCI is estimated as 54 cases per 1 million population, with a prevalence of greater than 250,000 persons currently living with the condition. Greater than 50% of SCIs occur in the cervical segments of the spinal cord, which can result in tetraplegia. Depending on the severity and level of injury, SCI may lead to varying degrees of motor and sensory loss in the neck, trunk, and upper and lower extremities. As recovery from a complete SCI is exceedingly rare, affected patients are left with permanent disability requiring lifelong medical care and rehabilitation. Patients with tetraplegia experience significant limitations in their mobility, ability to self-care, and participation restrictions in their education, employment, social relationships, and community engagement. They are often dependent on residual motor function and the assistance of caregivers to complete their activities of daily living. A survey of patients with tetraplegia indicated that regaining arm and hand function is rated as the highest priority, above autonomic functions of the bowel and bladder, walking ability, sexual function, and pain control. Therefore, therapeutic interventions that target functional recovery of the upper extremity have a significant impact on independence and quality of life. Operative reconstruction of the upper extremity in tetraplegia involves stand-alone or combined approaches using nerve transfers, tendon transfers, tenodeses, and/or joint stabilizations. The goal of surgery is improved strength and usability of the arm and hand, and occasionally reduction of muscle instability, pain with spasticity, or joint contractures. Tendon transfers have an established role as the mainstay approach to restore critical hand movements in