Abstract
Introduction: Restoring sagittal and coronal parameters is a primary concern in adult scoliosis surgery, yet it remains challenging due to the matured bony structure. This study aims to analyze the relationship between clinical outcomes and the degree of correction achieved through posterior instrumentation surgery in adult scoliosis.
Materials and Methods: This study evaluated the clinical and radiological results of 27 adult scoliosis patients who underwent posterior instrumentation, decompression, and correction surgery. Preoperative and follow-up X-rays were performed to assess Cobb angle, sagittal balance, and coronal balance. Visual Analog Score (VAS) and Oswestry Disability Index (ODI) were evaluated preoperatively and at follow-up.
Results: The study comprised 27 patients (18 female, 9 male) with a mean age of 68.2 years. Preoperative Cobb angle averaged 42.4°, reducing to 5.9° at final follow-up. Sagittal balance decreased from 30.6 mm preoperatively to 9.7 mm at final follow-up. Coronal balance improved from 22.3 mm preoperatively to 10.5 mm at 2-year follow-up. Preoperative Cobb angle showed a strong correlation with preoperative ODI (p=0.028) and postoperative ODI (p=0.014). Preoperative sagittal balance also correlated strongly with pre and postoperative ODI. However, postoperative Cobb angle and sagittal balance did not correlate with postoperative ODI (p<0.05).
Conclusion: While restoring sagittal and coronal parameters is a primary concern in adult scoliosis surgery, the degree of correction achieved does not necessarily correlate with clinical outcomes. Surgeons should consider this when planning surgery, and patients should be informed accordingly.

Key words: Posterior instrumentation, deformity correction, clinical outcome, Cobb angle, Scoliosis