Introduction: The purpose of this study was to systematically review the literature that has examined balance control in adult spinal deformity (ASD) patients (e.g. scoliosis >20°, sagittal vertical axis >5cm, pelvic tilt >25° and/or thoracic kyphosis >60°). We aimed to ascertain whether patients with ASD demonstrate balance deficits; and if so, which domains of balance are impaired in those with ASD.
Methods: Five databases were used for the literature search: Pubmed, Medline, Scopus, Embase, and CINAHL. Assessment of bias in study design, conduct, and analysis for the located articles was assessed using the Joanna Briggs Institute critical appraisal tools, and a posturography methodological quality assessment scale was used to rate the internal, statistical, and external validity of studies incorporating force plate assessment of standing balance. Inclusion criteria consisted of any balance assessment method used on the population of adults (18+) who had X-ray-diagnosed ASD. We followed PRISMA guidelines and registered this review in PROSPERO.
Results: 19 articles were included from 486 articles located in the 5 databases. Study quality was determined to be generally high. Six different types of balance assessments have been utilized. Of 12 studies assessing ASD vs. control participants, the balance evaluation systems test (BESTest), cone of economy (COE), sensory organization test (SOT) and force plate-derived center-of-pressure (COP) metrics showed statistically different (worse) scores for ASD participants.
Discussion: There is preliminary evidence that ASD patients have lower BESTest scores, increased sway within the COE, lower equilibrium scores on SOT conditions 5 and 6, as well as greater magnitudes of several force plate-derived COP metrics (e.g. displacement, velocity, area, shear force, left-to-right ground reaction force percentage difference) versus age-matched control participants. Despite the lack of comparability between studies, the preliminary evidence suggests ASD patients display impairments of postural control. Conclusive parameter-specific findings, however, cannot be made due to heterogeneous trial conditions across studies. Future studies are needed and should implement standardized balance testing parameters.