Outcomes of Circumferential Minimally Invasive Technique Versus Open Technique in Adult Spinal Deformity Surgery Patients Aged Older Than 80 years: A Propensity-Matched Analysis

BACKGROUND AND OBJECTIVES: Circumferential minimally invasive surgery (cMIS) techniques in adult spinal deformity (ASD) surgery may reduce physiological burden compared with open technique, but their utility in octogenarians has not been previously assessed. METHODS: Operative ASD patients aged 80 years or older with complete baseline (BL) and 2-year postoperative radiographic and health-related quality of life data were assessed and compared by surgical technique: open vs cMIS. Propensity score matching aligned groups by BL Charlson Comorbidity Index (CCI), C7-S1 sagittal vertical axis, pelvic incidence minus lumbar lordosis mismatch, and C7 plumb line. BL and peri/postoperative factors were assessed using analysis of variance and Bonferroni-adjusted analysis of covariance while controlling for BL CCI and posterior fusion length. RESULTS: Thirty-four octogenarian ASD patients met inclusion criteria, of whom 29.4% underwent cMIS and 70.6% underwent open correction. cMIS patients were less likely to require surgical intensive care unit (10% vs 75%, P < .001) and had shorter hospital stays (4.6 vs 10.1 days, P = .013). Open patients reported higher Scoliosis Research Society-22 Appearance and Mental domain scores (both P < .005) and more frequently reached minimal clinically important difference in both domains by 2 years (P = .025, .024). cMIS patients more often required reoperation for radiographic sagittal imbalance by 2 years when controlling for CCI and levels fused (20.0% vs 8.3%, P < .001). No deaths occurred in either group by 2 years. CONCLUSION: In octogenarians undergoing ASD surgery, cMIS reduced physiological burden but had higher reoperation rates, whereas open surgery showed greater durability.