Lightning Podiums: Adult Spinal Deformity - Room 801A

Presented by: V. Lafage

Author(s):

N. Plais(1), H. Bao(2), H.J. Kim(1), M. Gupta(3), V. Lafage(1), J. Smith(4), G. Mundis(5), R. Hostin(6), D. Burton(7), C. Ames(8), E. Klineberg(9), S. Bess((1)0), F. Schwab(1), R. Lafage(1), International Spine Study Group (ISSG)

(1) Hospital for Special Surgery, New York, NY, United States
(2) Nanjing Drum Tower Hospital, Nanjing, China
(3) Washington University, Saint Louis, MO, United States
(4) University of Virginia, Charlottesville, VA, United States
(5) San Diego Center for Spinal Disorders, La Jolla, CA, United States
(6) Baylor Scoliosis Center, Plano, TX, United States
(7) University of Kansas Medical Center, Kansas City, KS, United States
(8) University of California, San Francisco, San Francisco, CA, United States
(9) University of California, Davis, Sacramento, CA, United States
((1) 0) Denver International Spine Center, Denver, CO, United States

Abstract

Introduction: The clinical impact of global coronal malalignment (GCM) in patients with Adult Spinal Deformity (ASD) remains controversial. A recent Chinese publication demonstrated that the laterality of the coronal offset is a key parameter that directly impacts postoperative outcomes. To investigate if findings of hold true pre-operatively and to analyze the impact of specific patterns of curves in the coronal plane with functional outcomes

Purpose: To analyze the laterality of the coronal offset pre-operatively and to determine the impact of specific patterns of curves on postoperative outcomes.

Methods: Patients were drawn from a multi-center database of ASD patients. Primary cases were retained for analysis and categorized with the Qiu classification: Type A = GCM < 3cm, Type B = GCM >3cm toward the concave side of the curve, and Type C= GCM >3cm toward the convex side. In addition to the classic radiographic parameter, the coronal truncal inclination was investigated in regard to the pelvic obliquity. Clinical outcomes, radiographic parameters and demographics were compared across the 3 types using an ANOVA test. The analysis was then repeated following propensity matching of the 3 types by age and sagittal alignment (PI-LL mismatch, Pelvic Tilt and SVA).

Results: 576 ASD patients (mean age 58.8yo) were included. Type A was the most prevalent group (57.1%), followed by Type C and B (28% and 14.9% respectively). Prior to matching for age and sagittal alignment, Type B patients had significantly worse HRQOL scores (ODI, SF-36 PCS, and SRS-22) and a more severe coronal deformity in terms of maximum Cobb angle, global coronal deformity angle, and coronal malalignment (GCM offset); they were also older (65.4yo vs 58.8, p=0.004), and more severe sagittal malalignment: PI-LL (Type B=23.45°, vs 9.62° and 10.72° for Types A and C; p< 0.001), SVA (Type B=100.7mm vs. 36mm and 30mm for Types A and C). After propensity matching, 64 patients were retained in each type. Type B patients remained more disabled (ODI, SRS-Total, SRS-Activity, and SRS-Pain; all p< 0.038) and still presented a more severe coronal deformity than the other types: GCM: 75mm (Type B) vs 13mm (type A) and 51mm (Type C), p < 0.001; GCDA 10.6° Type B vs 2.3° (Type A) and 3.3° (Type C) ; p < 0.001; Maximum Cobb angle: 49.5 ±19.7 (Type B) vs 41.7 ± 16.2 (type A) and 43.6 ± 14.4 (Type C).

Conclusion: This study is the first to establish an association between functional outcomes and the severity of the coronal plane deformity in the setting of a specific coronal curve pattern. Coronal malalignment affects significantly the health status of patients when the offset is greater than 3cm in the direction of the curve concavity. These patients also present larger deformity in the coronal plane when compared to the other types. The Qiu classification has proven to be a useful tool to identify patients with coronal malalignment in a US population.