395 - Reciprocal Changes in Lower Extremities and Cervical Alignment with Th...

Oral Posters: Cervical

Presented by: A.J. Buckland - View Audio/Video Presentation (Members Only)


A.J. Buckland(1), L.M. Day(2), S. Ramchandran(1), T.S. Protopsaltis(1), P.G. Passias(1), T.J. Errico(1), B. Liabaud(3), B. Diebo(3), R. Lafage(4), J. Henry(5), D.L. Cruz(6), C.M. Jalai(7), G.W. Poorman(1), F.J. Schwab(8), V. Lafage(4)

(1) Hospital for Joint Diseases at NYU Langone Medical Center, Department of Orthopaedic Surgery, New York, NY, United States
(2) SUNY Downstate College of Medicine, Brooklyn, NY, United States
(3) SUNY Downstate Medical Center, Brooklyn, NY, United States
(4) Hospital for Special Surgery, Spine Research, New York, NY, United States
(5) NYU School of Medicine, New York, NY, United States
(6) Temple University Hospital, Philadelphia, PA, United States
(7) University of Vermont College of Medicine, Burlington, VT, United States
(8) Hospital for Special Surgery, Spine Service, New York, NY, United States


Summary: The advent of full-body stereoradiographic assessment has enabled better understanding of the role of the lower extremities and cervical spine in compensating for thoracolumbar deformity. Thoracolumbar realignment surgery results in reciprocal changes in both lower extremity and cervical alignment. Larger thoracolumbar corrections are associated with larger changes in lower extremity alignment parameters, and changes in C2-C7 angle. Statistically significant, but minor change in C2-C7 SVA was also observed. No perioperative change was noted in C2 slope, C0-C2 angle.

Hypothesis: Cervical alignment and lower extremity compensatory mechanisms change simultaneously with correction of thoracolumbar deformity. Design: Retrospective clinical and radiographic database.

Introduction: Full-body stereoradiographic imaging allows better understanding of the reciprocal changes in cervical and lower extremity compensatory mechanisms in the setting of thoracolumbar deformity. The effect of thoracolumbar deformity correction on these mechanisms has not previously been described.

Methods: Patients undergoing lumbar or thoracic spinal surgery with no previous fusion of the cervical spine, hip, knee or ankle were included. Spinopelvic, lower extremity and cervical alignment were assessed from standardized fullbody standing stereoradiographs using validated software. Patients were stratified by degree of thoracolumbar deformity (T1-Pelvic Angle - TPA) and propensity matched for pelvic incidence preoperatively. Perioperative changes in lower extremity alignment (pelvic shift - P.Shift, sacrofemoral angle-SFA, Knee Angle - KA, Ankle Angle - AA) and cervical alignment (C0-C2 lordosis, C2-slope, C2-C7 lordosis and C2-C7 SVA) were compared with changes in TPA at baseline and first postop x-ray < 6 months.

Results: 218 patients met inclusion criteria. Both pre- and post-operatively, increasing TPA severity was associated with a stepwise increase in all regional spinopelvic alignment parameters except thoracic kyphosis and thoracolumbar kyphosis (T10-L2). Increased TPA at baseline and postoperatively was associated with increased hip extension (SFA), P Shift, KA and C2-C7 lordosis and C2-C7 SVA (but < 7mm). As magnitude of TPA correction increased, this was reflected by reciprocally reduced, KA, P Shift, and C2-C7 lordosis. No association was found between TPA severity and C0-C2 angle, or ankle angle.

Conclusion: Perioperative changes in thoracolumbar alignment result in reciprocal lower extremity alignment changes, and change in C2-C7 angle. No resultant change in C0-C2 angle, C2-C7 SVA or CBVA was noted.

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