Browsing by Author "Plais, Nicolas"

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    Fractional Curve in Adult Spinal Deformity: Is it a Driver of or a Compensation for Coronal Malalignment?
    (Clinical Spine Surgery, 2021-06-01) Plais, Nicolas; Bao, Hongda; Lafage, Renaud; Kim, Han Jo; Gupta, Munish; Smith, Justin S; Shaffrey, Christopher; Mundis, Gregory; Burton, Douglas; Ames, Christopher; Klineberg, Eric; Bess, Shay; Hostin, Richard A; Schwab, Frank; Lafage, Virginie; International Spine Study Group, Littleton, CO
    Study Design: This was a retrospective review of the multicenter adult spine deformity database. Objective: The objective of this study was to investigate the role of the fractional curve (FC) on global coronal malalignment. Summary of Background Data: Despite being very common, the role of the coronal FC as either a driver or compensation for global coronal malalignment is not well documented Materials and Methods: Patients with the following characteristics were extracted from a prospective multicenter database: lumbar/thoracolumbar (TL) major coronal curve >15 degrees, apex at T11-L3, lower end vertebra at L3 or L4, above 45 years old, and FC >5 degrees. In addition to the classic radiographic parameters, baseline analysis included Cobb angle, pelvic obliquity (PO), fractional ratio (fractional Cobb/main Cobb), the sum of PO and FC, as well as the coronal Qiu classification. Curves distribution (TL vs. FC) were compared across the 3 Qui types, and the role of the FC was investigated. Results: A total of 404 patients (63 y old, 83.3% female) were included: 43 patients were classified as type B, 120 as type C, and 241 were coronally balanced (type A). Compared with the balanced patients, type C patients had similar major TL Cobb angles but significantly larger fractional Cobb angles (17.5 vs. 22.3 degrees, P<0.001). By opposition, type B patients had significantly larger major TL Cobb angles (49 vs. 41 degrees, P=0.001) but smaller fractional Cobb angles (P<0.001). PO>5 degrees in the same direction as FC was more common in type B patients (20%) than in type C patients (7.5%), which suggests the preferential role of pelvic compensation. Conclusions: Our findings challenge the idea that FC is only a compensatory curve below a main lumbar or TL curve. In type B patients, FC acts as a compensation mechanism but fails to maintain coronal alignment despite the presence of PO. In type C patients, however, the lumbosacral FC acts as a primary driver of coronal malalignment. Level of Evidence: Level III.
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    The clinical impact of global coronal malalignment is underestimated in adult patients with thoracolumbar scoliosis.
    (Spine deformity, 2020-02) Plais, Nicolas; Bao, Hongda; Lafage, Renaud; Gupta, Munish; Smith, Justin S; Shaffrey, Christopher; Mundis, Gregory; Burton, Douglas; Ames, Christopher; Klineberg, Eric; Bess, Shay; Schwab, Frank; Lafage, Virginie; International Spine Study Group
    STUDY DESIGN:Retrospective review of multicenter adult spine deformity (ASD) database. OBJECTIVES:A recent publication demonstrated that the laterality of the coronal offset is a key parameter that directly impacts postoperative outcomes. The objective of this study is to analyze the relationship between global coronal malalignment (GCM) and functional outcomes in a North American population of ASD patients with no history of previous surgery. The clinical impact of GCM in patients with ASD remains controversial. METHODS:Primary patients were drawn from a multicenter database of ASD patients and categorized with the Qiu classification: Type A = GCM < 3 cm; Type B = GCM > 3 cm toward the concave side of the curve; and Type C = GCM > 3 cm 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 three Qiu Types using analysis of variance. The analysis was repeated after propensity matching of the three types by age and sagittal alignment (PI-LL mismatch, pelvic tilt, and sagittal vertical axis). RESULTS:576 ASD patients (mean age 58.8 years) were included. Type B patients had significantly worse functional scores (Oswestry Disability Index, 36-item Short Form Survey physical component summary, and Scoliosis Research Society-22) and a more severe coronal deformity in terms of maximum Cobb angle, global coronal deformity angle, and coronal malalignment; they were also older (65.4 vs. 58.8 years, p = 0.004) and displayed more severe sagittal malalignment. Similar findings were observed after propensity matching. CONCLUSIONS: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 in patients without previous surgery. Coronal malalignment significantly affects the health status of patients when the offset is greater than 3 cm in the direction of curve concavity. LEVEL OF EVIDENCE:III.