THU0380 LUMBOPELVIC RHYTHM IN PATIENTSWITH AXIAL SPONDYLOARTHRITIS COMPARED WITH LOW BACK PAIN AND HEALTHY SUBJECTS
Authors: Juan L. Garrido-Castro, Inmaculada Concepcion Aranda-Valera, Sandra Alcaraz-Clariana, Lourdes García-Luque, Daiana Rodriguez-de-Souza, Cristina Gonzalez-Navas, Francisco Alburquerque-Sendin, Philip Gardiner, Eduardo Collantes Estevez
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Lumbar back pain reduces spinal mobility in patients. Although there are some symptoms that characterise 'inflammatory back pain', these are non-specific and the diagnosis is often delayed. It is not clear if there are kinematic differences between axial Spondyloarthritis (axSpA) and other types of back pain. Inertial motion sensors are now available that can accurately and reliably measure spinal mobility. The ViMove system uses two inertial sensors located at L1 and S1 allowing spinal flexion to be separated into its lumbar and pelvic components. The relation between different parts of the spine during a full flexion movement is known as lumbopelvic rhythm. The trunk sensor measures the total flexion, whilst the contribution of hip is measured by the pelvis sensor leaving lumbar flexion as the difference between the two angles. <h3>Objectives</h3> To analyse relation of lumbopelvic angles in axSpA patients, LBP patients and healthy controls. <h3>Methods</h3> 92 subjects were included in our study: 56 axSpA (from the COSPAR cohort of the Reina Sofia University Hospital), 14 LBP and 22 healthy controls. Inertial based system, the ViMove, was used to measure mobility. axSpA patients were stratified in three groups according their overall mobility using the BASMI: axSpA Low (&lt; 2), Med (2-4) and High (&gt;4) <h3>Results</h3> Table shows the results of spinal mobility tests in each group. The trunk, pelvis and lumbar angles are expressed in degrees (Mean and SD). cPelvis is the contribution of pelvis to the overall movement as percentage. Three of the five measurements in BASMI are outside the lower back so unlikely to be affected in LBP patients. There were significantly differences in the trunk, lumbar and pelvis angles between control and axSpA groups (p&lt;0.01). The only significant difference between LBP and axSpA was in the lumbar angles (p&lt;0.05). The left part of the figure shows a reconstruction of the mean flexion angles for each group: these are also represented in the bar graph on the right. The trunk angle is higher in the healthy control group, is similar to the less affected axSpA patients (No significant differences between two groups). The most severely affected axSpA patients show reduced lumbar movement, and the pelvic contribution of the pelvis is also higher than the other two axSpA groups (p&lt;0.001) controls (p&lt;0.001) and LBP (p&lt;0.01). <h3>Conclusion</h3> A reduction in spinal flexion was found in all patient groups, but there are interesting differences in the pattern of movement. LBP patients were characterised by a greater reduction in pelvis movement compared to the axSpA patients, although the final trunk flexion angle is actually lower in axSpA. When we compared more and less affected axSpA patients (according to BASMI), the most severely affected had severe restriction in lumbar movement whilst pelvic movement was increased. Lumbo-pelvic rhythm can also be analysed throughout early, middle and the end of the movement. Investigating spinal kinematics could help us to understand better axSpA and how it affects spinal mobility. <h3>Acknowledgement</h3> This study was funded by FOREUM (www.foreum.org), Junta de Andalucia (PIN-0079-2016) and XXI Research Promotion Program of the University of Córdoba (Spain). <h3>Disclosure of Interests</h3> None declared