Lightning Podiums: Spinal Gumbo - 803A

Presented by: P. Passias

Author(s):

P. Passias(1), S. Horn(1), G. Poorman(1), S. Vira(1), D. Vasquez-Montes(1), C. Bortz(1), F. Segreto(1), N. Frangella(1), D. Ge(1), J. Moon(1), P. Zhou(1), B. Diebo(2), A. Sure(1), J. Tishelman(1), B. Beabrun(1), C. Jalai(1), C. Wang(1), T. Errico(1), T. Protopsaltis(1), A. Buckland(1), V. LaFage(3)

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

Abstract

Background: Full body stereographs allow for the assessment of lower limb compensation and global alignment in adult spinal deformity(ASD) patients, though little work has been done looking at how these recovery mechanisms change between early and late follow-up.

Objective: To evaluate the changes in lower limb compensation and global alignment for ASD patients from the early to late post-operative period.

Methods: Single-center retrospective review. ASD patients(SVA>5cm, PI-LL>10°, or PT>20°) with full body stereographic x-rays at baseline, 3 month(3M), 1 year(1Y) follow-up. Correction groups created to compare actual alignment with age-adjusted ideal values using established formulas for SVA, PI-LL, PT and TPA. Patients who matched("Match") within a 10-year range threshold for age-adjusted targets were compared to unmatched cases("Under"/"Over").

Results: 124 ASD patients(59yrs, 69%F) had an average of 8.2 levels fused and 9% had three-column osteotomy use. Mean baseline alignment parameters were: 65mm SVA, 25°PT, 17°PI-LL, and 26°TPA. At 3M, patients significantly improved in TPA, TK, KA, GSA, and PS(all p< 0.001). Patients that remained Undercorrected according to age-adjusted SVA ideals displayed significantly increased KA(8.3º), posterior pelvic shift(64.5mm), and GSA(8.8º) compared to Overcorrected patients(all p< 0.05). Of patients that Matched age-adjusted spino-pelvic ideals at Early follow-up, the rates of patients that subsequently degenerated to Undercorrected at Late follow-up were: SVA=22.6%; PT=35.5%; PI-LL=34.6%; TPA=20.0%. All spino-pelvic groups that went from Match-to-Undercorrected recruited an increasingly posterior pelvic shift(all p< 0.046) with the exception of SVA cases. ASD patients with BMI ≥ 30, and all spino-pelvic parameters displaying most severe alignment(++) were at significantly increased odds of degenerating from Match to Under between Early and Late follow-up.

Conclusions: When ASD patients were undercorrected for SVA, PT, or PI-LL, they recruited increasingly posterior PS and KA, reflected overall with a greater GSA, to maintain upright balance. At baseline, an increase BMI and moderate-severe spinal deformity significantly predicted those patients that degenerated from Match to Undercorrection between Early and Late follow-up.