Lightning Podiums: Spinal Gumbo - 803A

Presented by: S. Horn

Author(s):

S. Horn(1), D. Vasquez-Montes(1), A. Sure(1), M. Siow(1), G. Poorman(1), B. Diebo(2), C. Bortz(1), F. Segreto(1), C. Varlotta(1), N. Stekas(1), P. Zhou(1), J. Moon(1), J. Tishelman(1), B. Beaubrun(1), C. Wang(1), S. Vira(1), M. Gerling(1), T. Protopsaltis(1), T. Errico(1), A. Buckland(1), P. Passias(1)

(1) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(2) SUNY Downstate Medical Center, Department of Orthopaedic Surgery, Brooklyn, NY, United States

Abstract

Introduction: Previous studies have shown that thoracolumbar deformity (TLD) often correlates with lower extremity compensation as well as changes in cervical spine alignment. Likewise, correction of thoracolumbar deformity leads to better alignment of the cervical spine and decreased lower extremity compensation. However, current literature is devoid of evidence regarding whether surgical correction of cervical deformity (CD) leads to changes in the remaining spine or on lower extremity alignment. The aim of this study was to compare the impact of CD correction on thoracolumbar alignment and lower extremity compensation in patients with and without concurrent TLD.

Methods: Retrospective cohort study at a single center. Inclusion criteria: Surgical patients >18 years who meet cervical deformity criteria (cSVA>4cm, TS-CL>20°, or CL>10°) with the upper instrumented vertebra within the cervical spine and with standing stereoradiographs pre-operatively and at minimum of 6 weeks post-operatively. All CD patients were evaluated for pre- and post-operative global sagittal alignment and lower limb compensation. Patients were then divided on the basis of concomitant TLD, defined as SVA>4cm, PI-LL>10°, or PT>20°. Spinal Alignment Parameters: C0-C2, cervical lordosis (C2-C7), C2-T3, cervical thoracic pelvic angle (CTPA), Cervical Sagittal Vertical Angle (cSVA) thoracic kyphosis (TK), T1 pelvic angle (TPA), T1 slope (T1S), Sagittal Vertical Angle (SVA), lumbar lordosis (LL), pelvic incidence (PI) Spino-Pelvic mismatch (PI-LL), and pelvic tilt (PT). Lower Extremity Parameters: Sacrofemoral angle (SFA), knee flexion (KA), ankle flexion (AA), pelvic shift (PS), global sagittal angle (GSA). Health Related Quality of Life Scores: Neck disability index (NDI) and Oswestry disability index (ODI). Alignment changes from pre- to post-op were compared between the CD-only group and the group with concurrent TLD with paired t-tests and ANOVA.

Results: 76 cervical deformity patients (40 CD-only, 36 with concomitant TLD) were included (mean age 57.3 years, 46% female, BMI 28.3). The average pre-operative alignment parameters were: cSVA 29.4mm, C2-T3 SVA 56.7mm, SVA 29.4°, TK 43.2°, LL 52.2°, KA 3.5°, AA 6.5°, and GSA 1.9°. In the overall CD cohort, there were no significant changes pre- to post-operative in either global alignment or lower limb compensatory mechanisms (all p>0.05). In the CD-only group, there were significant post-operative changes in C2-T3 SVA (50.8mm to 55.1mm, p=0.036), SVA (-9.4mm to 3.9mm, p=0.004), and AA (5.4° to 4.3°, p=0.001). CD patients with concurrent TLD did not experience any significant changes in spinal alignment parameters from pre- to post-op. When comparing the two cohorts, NDI was significantly lower for patients with CD and TLD both pre- and post-operatively (p=0.02); ODI was not significantly different (p=0.13).

Conclusions: Correction of cervical deformity improves alignment of the cervicothoracic spine and lower extremities in patients without thoracolumbar deformity. However, patients with concurrent thoracolumbar deformities do not experience similar improvements in lower extremity compensation, suggesting that we must align expectations appropriately for these patients prior to surgery for cervical deformity.