Functional Mobility Tests for Evaluation of Functionalities in Patients with Adult Spinal Deformity

Abstract Study Design: Retrospective cohort study. Background: Current evaluation of patients with adult spinal deformity (ASD) is mainly based on radiographic parameters derived from X-rays. However, due to their static nature, X-rays fall short of assessing the dynamic functionalities including balance, gait, and the risk of falling. This study aimed to determine the functionalities of ASD patients by measuring functional mobility tests (FMTs) and compared relationships between patient-reported outcomes (PROs) with FMTs and radiographic parameters to prove whether FMTs are useful evaluation tools for evaluation of patients with ASD. Methods: This age- and sex-matched case-control study included 66 patients with ASD and 66 patients with LSS, all of whom were scheduled to undergo spinal surgery. All patients were evaluated with four FMTs including alternate step test (AST), six-meter walk test (SMT), sit-to-stand test (STS), and timed up and go test (TUGT). Correlations of the PROs with FMTs and static radiographic parameters were analyzed. Results: The baseline characteristics were not significantly different between the two groups. However, compared with patients with LSS, those with ASD showed significantly poorer performance on all four FMTs, spending significantly more time performing the SMT, STS, and TUGT (P = 0.046, 0.045, and 0.015, respectively). The results of the four FMTs were significantly correlated with the ODI (Oswestry Disability Index) scores only in the ASD group and not in the LSS group. Conclusions: FMTs were appropriate tools for assessing the dynamic functionalities of patients with ASD. FMTs might play a bridging role between static radiographic parameters and subjective PROs when treating patinets with ASD.