A muscle synergy approach in evaluation of the gait recovery following surgical alignment

Abstract

Background: Adult Degenerative Scoliosis (ADS) is a common musculoskeletal problem that commonly affects the elderly. ADS patients often suffer from low back pain and consequently have reduced mobility. Surgical alignment is one of the possible treatments in ADS patients. Due to the highly variant nature of the ADS, tracking and comparing the improvements following surgery can be challenging. Muscle synergy theory suggests that the central nervous system may use a few groups of coactive muscles (i.e., synergies) to achieve a motor task. Methods: In this study, we propose to use muscle synergy approach to determine the recovery from the ADS following surgery. More specifically, two metrics are proposed: i) the number of the required muscle synergies for a motor task and ii) an entropy-inspired measure (EnIM). Entropy is a measure of uncertainty in the data and has been shown to be sensitive to detect functional mobility enhancement. We hypothesize that the number of muscle synergies required for walking increases following surgery. We also hypothesize that EnIM associated with the muscle synergies decreases following surgery. Results: The results showed that the patients required a significantly higher number of walking muscle synergies following a surgery. Also, EnIM decreased significantly in ADS patients following surgical procedures, showing a more deterministic control. Conclusions: A muscle synergy approach in tracking the improvements in motor skills could be advantageous as it considers all of the involved muscles together, bypassing the potential subject-dependent differences. Trial registration: Western Institutional Review Board, #20151780. Participants were recruited from the ClinicalTrials.gov (registration no.: NCT02761265)