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Page 2 of 12 Lin et al. Plast Aesthet Res 2024;11:8 https://dx.doi.org/10.20517/2347-9264.2023.57

INTRODUCTION
Over a quarter million individuals are living with spinal cord injury (SCI) and approximately 18,000 new
[1,2]
SCI cases occur in the United States alone each year . Over half of these are at the cervical level and
profoundly affect the individual’s upper extremity (UE) movement and function . Restoring UE function is
[3]
essential to performing basic activities of daily living (ADLs) and can improve independence in this
[4,5]
setting .
Spontaneous recovery with standard rehabilitation and UE surgery can both lead to gains in UE movement;
[5-7]
devices such as neuroprostheses may be useful but are not currently commercially available . Both
traditional tendon transfer (TT) [8-10] and newer nerve transfer (NT) [11-19] surgeries can restore key movements
such as elbow and wrist extension and hand opening and closing. Reports of TT surgeries in the setting of
cervical SCI appeared in the literature in the 1940s and 50s . The first reports of NT surgery in this setting
[10]
were in the 1960s and 80s [20,21] , but these predated the extensive use of NT techniques in peripheral nerve
and brachial plexus injury, which has added immensely to surgeons’ understanding of the detailed intra-
neural anatomy that allows for successful surgery. Thus, it is only in the last decade that NT surgery has
been more widely used in people with cervical SCI.

Historically, outcome measures used in studies of TT surgery have been comprised of manual muscle
strength testing, myometry (pinch and grip), and measures of range of motion. In 2007, Mulcahey and
Kozin described some of tools for evaluation of the UE in cervical SCI, and made recommendations for
continued attention to developing, validating, and using better tools to measure outcomes in this setting .
[22]
Reports on NT surgery have used a variety of outcomes measures that have differed from those reported in
the TT surgery literature. For example, a prospective study of NT in SCI reported changes in manual muscle
testing and results for the following: (1) the action research arm test (ARAT); (2) the grasp and release test
(GRT); and (3) the spinal cord independence measure (SCIM) .
[23]

The purpose of this study was to provide a broad overview of the assessment measures and outcomes tools
reported in the NT surgery in cervical SCI literature. We hypothesize that the measures are heterogeneous
across studies and limit our understanding of the effect of NT surgery on UE function in cervical SCI.

METHODS
We performed a comprehensive review of assessment measures and outcomes tools used in articles
reporting clinical results after NT surgery in people with cervical SCI. The preferred reporting items for
systematic reviews and meta-analysis (PRISMA) statement guidelines were followed as the subject matter
and content of articles permitted.

Eligibility, information sources, and search strategy
First, the senior author shared a working list of pertinent articles with the co-author and a health sciences
librarian. Articles were reviewed for relevance and key words. Using this information, the literature search
strategies were designed by the health sciences librarian for the concepts of NT surgery and spinal cord
injury or quadriplegia, with related synonyms. The strategies were created using a combination of
controlled vocabulary terms and keywords including NT, nerve transplant, nerve crossover, SCI, spinal cord
trauma, quadriplegia, and tetraplegia. The search strategy was executed in Embase.com, Ovid-Medline All,
and Scopus. A filter for human studieswas utilized to exclude animal studies. All database searches were
completed on April 27, 2023. See [Figure 1] for the detailed search strategy information. Finally, after the
search strategy was completed, the results were cross-referenced back to the senior author’s list of pertinent
articles.