Spinal cord stimulation research in the restoration of motor, sensory and autonomic function for individuals living with spinal cord injuries: a scoping review

Objective: To describe the status of spinal cord stimulation (SCS) research for the improvement of motor, sensory and autonomic function for individuals living with a spinal cord injury (SCI).

Data Sources: This scoping review identified original research published prior to March 31, 2021, via literature searches using Medline, EMBASE, PubMed, Science Direct, CINAHL, Sport Discus, Web of Science, as well as a targeted search for well-known principal investigators. Search terms included permutations of “spinal cord stimulation”, “epidural spinal cord stimulation”, “transcutaneous spinal cord stimulation”, “magnetic spinal cord stimulation” and “neuromodulation”.

Study Selection: Studies were included if they: 1) were in English, 2) presented original research on humans living with a SCI, and 3) investigated at least one of the three forms of SCS.

Data Extraction: Extracted data included: authors, publication year, participant characteristics, purpose, study design, stimulation (device, location, parameters,) primary outcomes, and adverse events.

Data Synthesis: As a scoping review the extracted data was tabulated and presented descriptively. Themes and gaps in the literature were identified and reported. Of the 5,754 articles screened, 103 articles were included (55 epidural, 36 transcutaneous and 12 magnetic). The primary research design was a case study or series with only a single randomized clinical trial. Motor recovery was the most common primary outcome for epidural and transcutaneous SCS studies whereas bowel and bladder outcomes were most common for magnetic. Seventy percent of the studies included 10 or fewer participants, and 18 articles documented at least one adverse event. Incomplete stimulation parameter descriptions were noted across many studies. No articles mentioned direct engagement of consumers or advocacy groups.

Conclusion: This review identified a need for more robust study designs, larger sample sizes, comparative studies, improved reporting of stimulation parameters, adverse event data, and alignment of outcomes with the priorities of the SCI community.