Clinical and stereoradiographic analysis of adult spinal deformity with and without rotatory subluxation

Abstract

Introduction: In degenerative adult spinal deformity (ASD), sagittal malalignment and rotatory sublux-ation (RS) correlate with clinical symptomatology. RS is defined as axial rotation with lateral listhesis.Stereoradiography, recently developed for medical applications, provides full-body standing radiographsand 3D reconstruction of the spine, with low radiation dose.Hypothesis: 3D stereoradiography improves analysis of RS and of its relations with transverse plane andspinopelvic parameters and clinical impact.Material and methods: One hundred and thirty adults with lumbar ASD and full-spine EOS®radiographs(EOS Imaging, Paris, France) were included. Spinopelvic sagittal parameters and lateral listhesis in thecoronal plane were measured. The transverse plane study parameters were: apical axial vertebral rotation(apex AVR), axial intervertebral rotation (AIR) and torsion index (TI). Two groups were compared: with RS(lateral listhesis > 5 mm) and without RS (without lateral listhesis exceeding 5 mm: non-RS). Correlationsbetween radiologic and clinical data were assessed.Results: RS patients were significantly older, with larger Cobb angle (37.4◦vs. 26.6◦, P = 0.0001), moresevere sagittal deformity, and greater apex AVR and TI (respectively: 22.9◦vs. 11.3◦, P < 0.001; and 41.0◦vs. 19.9◦, P < 0.001). Ten percent of patients had AIR > 10◦without visible RS on 2D radiographs. RS patientsreported significantly more frequent low back pain and radiculalgia.Discussion: In this EOS®study, ASD patients with RS had greater coronal curvature and sagittal and trans-verse deformity, as well as greater pain. Further transverse plane analysis could allow earlier diagnosisand prognosis to guide management.Level of evidence: 4, retrospective study.