Sagittal realignment: surgical restoration of the global alignment and proportion score parameters: a subgroup analysis. What are the consequences of failing to realign?

• Published in: European spine journal 2023-06, Vol.32 (6), p.2238-2247
• Main Authors: Raganato, Riccardo, Pizones, Javier, Yilgor, Caglar, Moreno-Manzanaro, Lucía, Vila-Casademunt, Alba, Sánchez-Márquez, José Miguel, Fernández-Baíllo, Nicomedes, Sánchez Pérez-Grueso, Francisco Javier, Kleinstück, Frank, Alanay, Ahmet, Obeid, Ibrahim, Pellisé, Ferran
• Format: Article
• Language: English
• Subjects: Adult; Back surgery; Bone surgery; Clinical outcomes; Humans; Lordosis - surgery; Mechanical properties; Medicine; Medicine & Public Health; Neurosurgery; Original Article; Orthopedics; Patients; Pelvis; Postoperative Complications - epidemiology; Postoperative Complications - etiology; Prospective Studies; Quality of Life; Regression analysis; Retrospective Studies; Risk factors; Software; Surgical Orthopedics; Treatment Outcome; Vertebrae
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-023-07649-w

Introduction The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version–RPV, relative lumbar lordosis—RLL, lumbar distribution index—LDI) and one indirectly restored (relative spinopelvic alignment—RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs. Materials and methods From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed. Results The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the “Severe hypolordosis” and “Hyperlordosis” subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w ( p  = 0.025) and RSA-6w ( p  = 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion ( p  = 0.026) and severe positive malalignment ( p  = 0.007) were risk factors for mechanical complications. RSA-6w “Severe positive malalignment” was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2; p  = 0.011), ∆SRS-22 total (0.54 vs 0.87; p  = 0.007), and ∆SF-36PCS (3.47 vs 7.76; p  = 0.04); MCID for ODI (37.0 vs 55.5%; p  = 0.023), and SRS-22 (40.8 vs 60.1%; p  = 0.015); and PASS for ODI (17.6 vs 31.7%; p  = 0.047). Conclusions RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.