TY - JOUR
T1 - Thoracolumbar Realignment Surgery Results in Simultaneous Reciprocal Changes in Lower Extremities and Cervical Spine
AU - Day, Louis M.
AU - Ramchandran, Subaraman
AU - Jalai, Cyrus M.
AU - Diebo, Bassel G.
AU - Liabaud, Barthelemy
AU - Lafage, Renaud
AU - Protopsaltis, Themistocles
AU - Passias, Peter G.
AU - Schwab, Frank J.
AU - Bess, Shay
AU - Errico, Thomas J.
AU - Lafage, Virginie
AU - Buckland, Aaron J.
N1 - Publisher Copyright:
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
PY - 2017/6/1
Y1 - 2017/6/1
N2 - Study Design. A retrospective, clinical, and radiographic single-center study. Objective. The aim of this study was to assess simultaneous cervical spine and lower extremity compensatory changes with changes in thoracolumbar spinal alignment. Summary of Background Data. Full-body stereoradiographic imaging allows better understanding of reciprocal changes in cervical and lower extremity alignment in the setting of thoracolumbar malalignment. Few studies describe the simultaneous effect of alignment correction on these mechanisms. Methods. Patients aged ≥18 years undergoing instrumented thoracolumbar fusion without previous cervical spine fusion, hip, knee, or ankle arthroplasty were included. Spinopelvic, lower extremity, and cervical alignment were assessed from full-body standing stereoradiographs using validated software. Patients were matched for pelvic incidence and stratified on the basis of baseline T1-pelvic angle (TPA) as: TPA-Low <14°, TPA-Moderate = 14° to 22°, and TPA-High >22°. Perioperative changes between baseline and first postoperative visit <6 months in lower extremity alignment (pelvic shift: P Shift, sacrofemoral angle: SFA, knee angle: KA, ankle angle: AA, global sagittal axis: GSA) and cervical alignment (C0-C2 angle, C2-slope, C2-C7 lordosis and C2-C7 SVA:cSVA) were correlated with change in magnitude of TPA and sagittal vertical axis (SVA) correction. Results. After matching, 87 patients were assessed. Increasing baseline TPA severity was associated with a progressive increase in all regional spinopelvic parameters except thoracic kyphosis, in addition to increased SFA, P Shift, KA, GSA, and C2-C7 lordosis. As TPA correction increased, there was a reciprocal reduction in SFA, KA, P Shift, GSA, and C2-C7 lordosis. Change in SVA correlated most with change in GSA (r = 0.886), P Shift (r = 0.601), KA (r = 0.534), and C2-C7 lordosis (r = 0.467). Change in TPA correlated with change in SFA (r = 0.372), while SVA did not. Conclusion. Patients with thoracolumbar malalignment exhibit compensatory changes in cervical spine and lower extremity simultaneously in the form of cervical hyperlordosis, pelvic shift, knee flexion, and pelvic retroversion. These compensatory mechanisms resolve reciprocally in a linear fashion following optimal surgical correction.
AB - Study Design. A retrospective, clinical, and radiographic single-center study. Objective. The aim of this study was to assess simultaneous cervical spine and lower extremity compensatory changes with changes in thoracolumbar spinal alignment. Summary of Background Data. Full-body stereoradiographic imaging allows better understanding of reciprocal changes in cervical and lower extremity alignment in the setting of thoracolumbar malalignment. Few studies describe the simultaneous effect of alignment correction on these mechanisms. Methods. Patients aged ≥18 years undergoing instrumented thoracolumbar fusion without previous cervical spine fusion, hip, knee, or ankle arthroplasty were included. Spinopelvic, lower extremity, and cervical alignment were assessed from full-body standing stereoradiographs using validated software. Patients were matched for pelvic incidence and stratified on the basis of baseline T1-pelvic angle (TPA) as: TPA-Low <14°, TPA-Moderate = 14° to 22°, and TPA-High >22°. Perioperative changes between baseline and first postoperative visit <6 months in lower extremity alignment (pelvic shift: P Shift, sacrofemoral angle: SFA, knee angle: KA, ankle angle: AA, global sagittal axis: GSA) and cervical alignment (C0-C2 angle, C2-slope, C2-C7 lordosis and C2-C7 SVA:cSVA) were correlated with change in magnitude of TPA and sagittal vertical axis (SVA) correction. Results. After matching, 87 patients were assessed. Increasing baseline TPA severity was associated with a progressive increase in all regional spinopelvic parameters except thoracic kyphosis, in addition to increased SFA, P Shift, KA, GSA, and C2-C7 lordosis. As TPA correction increased, there was a reciprocal reduction in SFA, KA, P Shift, GSA, and C2-C7 lordosis. Change in SVA correlated most with change in GSA (r = 0.886), P Shift (r = 0.601), KA (r = 0.534), and C2-C7 lordosis (r = 0.467). Change in TPA correlated with change in SFA (r = 0.372), while SVA did not. Conclusion. Patients with thoracolumbar malalignment exhibit compensatory changes in cervical spine and lower extremity simultaneously in the form of cervical hyperlordosis, pelvic shift, knee flexion, and pelvic retroversion. These compensatory mechanisms resolve reciprocally in a linear fashion following optimal surgical correction.
KW - adult spinal deformity
KW - alignment correction
KW - cervical spine
KW - compensatory mechanisms
KW - lower extremity
KW - sagittal spinal deformity
KW - sagittal vertical axis
KW - scoliosis
KW - T1 pelvic angle
KW - thoracolumbar surgery
UR - http://www.scopus.com/inward/record.url?scp=84991444256&partnerID=8YFLogxK
U2 - 10.1097/BRS.0000000000001928
DO - 10.1097/BRS.0000000000001928
M3 - Article
C2 - 27755494
AN - SCOPUS:84991444256
SN - 0362-2436
VL - 42
SP - 799
EP - 807
JO - Spine
JF - Spine
IS - 11
ER -