Natural History of Adult Spinal Deformity: How Do Patients with Less Than Optimal Surgical Outcomes Fare Relative to Non-Operative Counterparts?

Abstract

Introduction Management of adult spinal deformity (ASD) increasingly favors operative intervention, however complication rates remain high. This study compares health-related-quality-of-life (HRQL) metrics of patients with suboptimal surgical outcomes to non-operative management, which approximates the natural history of ASD. Methods This is a retrospective analsis of operative and non-operative patients(≥18yo) from a single-center ASD database. Patients with baseline and 2-year follow-up were included. For non-operative patients, decision to forego surgery was made by the patient. Operative patients were selected for “suboptimal outcomes,” defined as any reoperation, major complication, or ≥2 severe SRS-Schwab modifiers at 2-years. Suboptimal operative(SOp) vs. natural history (NH) groups were propensity score matched (PSM) by age, deformity, Oswestry-Disability-Index (ODI), and comorbidities. Means comparison tests assess differences in improvement and rates of achieving minimal clinically important difference (MCID) in ODI and Scoliosis- Research-Society-22 (SRS-22). Results After PSM, 74 patients were included(37-SOp; 37-NH). SOp and NH groups were not significantly different in baseline demographics, HRQLs, or radiographic deformity(Table 1). At 2Y, SOp patients had greater improvement in ODI and higher rates of reaching MCID, both p-values<.001. SOp patients had significantly better SRS-22-Total, SRS-22-Pain and SRS-22-Satisfaction scores at 2Y, all p-values<.001. Finally, significantly more SOp patients gained ≥1 MCID in SRS-Activity and SRS-Pain, both p-values<.002. Conclusion Compared to the natural history of ASD, operative patients with suboptimal outcomes still experience significantly greater improvement in HRQLs. Such divergent outcomes at 2Y, highlight the stagnation and deterioration associated with the disease process. Spine surgeons should consider the outcomes associated with the natural history of ASD when weighing risks and benefits of operative intervention.