Association of upper-limb neurological recovery with functional outcomes in high cervical spinal cord injury
Authors: Javeed Saad , Greenberg Jacob K. , Zhang Justin K. , Plog Benjamin , Dibble Christopher F. , Benedict Braeden , Botterbush Kathleen , Khalifeh Jawad M. , Wen Huacong , Chen Yuying , Park Yikyung , Belzberg Allan J. , Tuffaha Sami , Burks Stephen S. , Levi Allan D. , Zager Eric L. , Faraji Amir H. , Mahan Mark A. , Midha Rajiv , Wilson Thomas J. , Juknis Neringa , Ray Wilson Z. 
Published: May 2023

OBJECTIVE
High cervical spinal cord injury (SCI) results in complete loss of upper-limb function, resulting in debilitating tetraplegia and permanent disability. Spontaneous motor recovery occurs to varying degrees in some patients, particularly in the 1st year postinjury. However, the impact of this upper-limb motor recovery on long-term functional outcomes remains unknown. The objective of this study was to characterize the impact of upper-limb motor recovery on the degree of long-term functional outcomes in order to inform priorities for research interventions that restore upper-limb function in patients with high cervical SCI.

METHODS
A prospective cohort of high cervical SCI (C1–4) patients with American Spinal Injury Association Impairment Scale (AIS) grade A–D injury and enrolled in the Spinal Cord Injury Model Systems Database was included. Baseline neurological examinations and functional independence measures (FIMs) in feeding, bladder management, and transfers (bed/wheelchair/chair) were evaluated. Independence was defined as score ≥ 4 in each of the FIM domains at 1-year follow-up. At 1-year follow-up, functional independence was compared among patients who gained recovery (motor grade ≥ 3) in elbow flexors (C5), wrist extensors (C6), elbow extensors (C7), and finger flexors (C8). Multivariable logistic regression evaluated the impact of motor recovery on functional independence in feeding, bladder management, and transfers.

RESULTS
Between 1992 and 2016, 405 high cervical SCI patients were included. At baseline, 97% of patients had impaired upper-limb function with total dependence in eating, bladder management, and transfers. At 1 year of follow-up, the largest proportion of patients who gained independence in eating, bladder management, and transfers had recovery in finger flexion (C8) and wrist extension (C6). Elbow flexion (C5) recovery had the lowest translation to functional independence. Patients who achieved elbow extension (C7) were able to transfer independently. On multivariable analysis, patients who gained elbow extension (C7) and finger flexion (C8) were 11 times more likely to gain functional independence (OR 11, 95% CI 2.8–47, p < 0.001) and patients who gained wrist extension (C6) were 7 times more likely to gain functional independence (OR 7.1, 95% CI 1.2–56, p = 0.04). Older age (≥ 60 years) and motor complete SCI (AIS grade A–B) reduced the likelihood of gaining independence.

CONCLUSIONS
After high cervical SCI, patients who gained elbow extension (C7) and finger flexion (C8) had significantly greater independence in feeding, bladder management, and transfers than those with recovery in elbow flexion (C5) and wrist extension (C6). Recovery of elbow extension (C7) also increased the capability for independent transfers. This information can be used to set patient expectations and prioritize interventions that restore these upper-limb functions in patients with high cervical SCI.