Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P17. Regional and segmental changes of the spine from standing to sitting: a chain of compensation

• Published in: The spine journal Vol. 18; no. 8; p. S149
• Main Authors: Horn, Samantha R., Segreto, Frank A., Bortz, Cole, Vasquez-Montes, Dennis, Zhou, Peter L., Moon, John Y., Frangella, Nicholas J., Stekas, Nicholas, Steinmetz, Leah, Varlotta, Christopher, Ge, David H., Johnson, Bradley, Vira, Shaleen N., Diebo, Bassel G., Deflorimonte, Chloe, Moawad, Mohamed A., Lafage, Renaud, Lafage, Virginie, Schwab, Frank J., Gerling, Michael C., Fischer, Charla R., Protopsaltis, Themistocles S., Buckland, Aaron J., Errico, Thomas J., Passias, Peter G.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2018
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2018.06.555

Regional and segmental changes of the lumbar spine have previously been described as patients transition from standing to sitting, however alignment changes in the cervical and thoracic spine have yet to be investigated. The aim of this study was to assess cervical and thoracic regional and segmental changes in patients with normal spinal pathologies. Retrospective review of a single center database of full-body stereoradiographic imaging and clinical data. A total of 207 patients with nondegenerative, nondeformity spinal pathology. Global alignment parameters: sagittal vertical axis (SVA), PI-LL, PT, TK. Cervical alignment: cSVA, C2–C7 lordosis (CL), T1 slope minus CL (TS-CL). Segmental changes in alignment from C2 to T12 between standing and sitting radiographs. Patients age >18years old with nondegenerative, nondeformity spinal pathologies. Patients with lumbar degenerative conditions or thoracolumbar deformity were excluded. Sub-analysis was performed of patients with cervical and thoracic segmental measurements. A total of 207 patients were included (age 51±16years, BMI 26.7±6 kg/m2). As patients transitioned from standing to sitting, there was an increase in pelvic tilt of 12.2° (11.9°–24.2°), an increase in PI-LL by 22.8° (−7.1°–15.7°), and increase in SVA by 53.3 mm (−4.2 mm to 49.2 mm, all P<.001). In the cervical spine, there was an average 3.9° increase in C2–C7 cervical lordosis (6.2°–10.2°, P=.001) from standing to sitting, with a 5.9° increase in C2–T3 angle (2.9°–8.8°, P<.001) and 3.0mm increase in C2–T3 SVA (41.3 mm to 44.3 mm, P=.001). The thoracic spine experienced a decrease in thoracic kyphosis by 5.4° (−37.9° to −32.5°, all P<.001). Segmental changes were observed at C4–C5 (1.4°–2.3°, P=.023) and C5–C6 (1.8° to 2.5°, P=.026) to help maintain horizontal gaze when moving from standing to sitting position. There were no significant segmental changes in the cervicothoracic junction (C7–T1 change of 0.33°, P=.206) or upper thoracic spine (T1–T4). T4–T8 showed the most mobility from standing to sitting, primarily at T6–T7 (−3.1° to −2.7°, P=.003) and T7–T8 (−2.6° to −2.1°, P<.001). In this cohort of nondegenerative and nondeformity spine patients, the greatest amount of regional changes occur for cervical lordosis, C2–T3 angle, TK, SVA, and PI-LL as patients transition from standing to sitting position in order to maintain global spinal alignment, with C4–C5 and C5–C6 having the greatest mobility.