Ab0867 Analysis of Spinal Movement Using 3d Motion Capture: New Insights to Improve Patient-Specific Spinal Mobility Assessment in Axial Spondyloarthritis

Background: Within axial spondyloarthritis (axSpA), the Bath Ankylosing Spondylitis Metrology Index (BASMI) is widely used to assess spinal mobility. However, this measure does not correlate well with radiographic disease progression 1, can produce inconsistent results between clinicians and only assesses lumbar and cervical mobility. Thus, restricted mobility at other areas are ignored, despite axSpA patients presenting with highly variable locations of disease activity, limiting the potential to develop patient-specific interventions to maintain lifetime mobility. Objectives: Compare forward flexion, lateral bending and cervical rotation BASMI measures to range of motion (RoM) of a 3D multi-segment spine, and examine how lumbar, thoracic, and cervical spine mobility differs between patients. Methods: Thirty-one (21M, 10F, 50 ± 8 years, 82 ± 18 kg, 173 ± 8.5 cm) radiographic axSpA patients were assessed using the BASMI, and then performed standing spine forward flexion, lateral bending and axial rotation, while recorded with 3D marker-based motion capture. Motion capture used markers placed on five body segments (head/neck, upper thoracic, lower thoracic, lumbar and pelvis), to examine segment-segment RoM using inverse kinematics in OpenSim 2. Three maximal RoM values were recorded for each patient and then averaged, with whole spine RoM calculated as the sum of all segments, excluding the pelvis. Pearson r correlations were calculated between composite BASMI measures (lumbar forward flexion, lumbar lateral bending and cervical rotation) and full spine RoM or individual segment-segment RoM obtained from 3D motion capture. Results: Despite assessing lumbar and cervical RoM, composite BASMI measures correlated better with whole spine RoM obtained from 3D motion capture (Table 1). This result is consistent with BASMI lateral lumbar bending, a measures which records the distance between the fingers and the ground, capturing whole spine lateral bending. In general, composite BASMI measures were not very strongly correlated (r = Conclusion: To improve monitoring of spinal mobility and disease progression in axSpA, focussing on regional differences within each patient's spine, as well as across different spinal movements, will be vital. A more in-depth and targeted assessment, harnessing future markerless motion capture methods 3, could potentially enable patient-specific interventions to maximise their mobility, and could also have improved correlation with radiographic disease progression. REFERENCES: 1 Rezvani A et al. Spine, 37(19). 2012 2 Bruno A et al. J Biomech Eng, 137(8). 2015 3 Wade, L et al. Peer J, 10. 2022 REFERENCES: NIL. Acknowledgements: This research was funded by the UKRI Centre for Analysis of Motion, Entertainment Research and Applications (EP/M023281/1 and EP/T014865). Disclosure of Interests: None declared.