Introduction: Pain and disability in adult spinal deformity (ASD) are correlated to radiographic parameters. A main goal of surgery for ASD is to restore a harmonious spino-pelvic (SP) alignment. This study aims to evaluate the effectiveness of surgical treatment in restoring SP alignment.
Methods: Prospective analysis of consecutive ASD patients. Inclusion criteria: operative patients, age>18, baseline (BL) and 1-year full-length X-rays. Thoracic (T) and Thoraco-lumbar (TL) Cobb angle, Coronal Imbalance (CI), Sagittal Vertical Alignment (SVA), pelvic incidence/lumbar lordosis mismatch (PI-LL) and Pelvic Tilt (PT) were calculated. Each parameter, at BL and 1yr, was categorized as pathologic or normal. Pathologic limits were: Cobb>30°, CI>50mm, SVA>50mm, PI-LL>10° and PT>25°. According to thresholds, corrected or worsened patients were identified. Distinction between curve type (Coronal [T, TL, Double (D)], Sagittal [T, TL, D] and Sagittal only) was also analyzed.
Results: 161 patients (age=55±15) were included. At BL, 82% of patients had Cobb angle>30°, 15% had CI and 39%-44% had a pathological sagittal parameter (PI-LL, SVA or PT). For patients with pathological Cobb angle, the coronal correction was better for patients without sagittal deformity (81%) than for patients with sagittal deformity (59%). Post-operative CI was most frequent in the setting of coronal TL deformity (TL (22%), Sagittal TL (31%)). Independently of curve type, sagittal deformity was corrected in ~50% of the cases for patients with pathological SVA or PI-LL, while PT was most commonly worsened (27%) and least often corrected (33%). The Sagittal only patients were the least corrected (SVA: 32% and PI-LL: 33%).
Conclusions: The frequency of inadequate SP correction is high and PT is least likely to be corrected. Preoperative analysis is not enough to achieve adequate spinal realignment. The high rate of alignment failure points to the need for better preoperative planning, intra-operative imaging, and need for increased sagittal plane angular correction.
Patient Care: This research improves patient care by assessing adults surgically treated for spinal deformity who have achieved less than ideal radiographic outcomes, with the goal of improving pre-operative planning and outcomes for future patients.
Learning Objectives: By the conclusion of this presentation, participants should: (1) appreciate that with surgery for adult spinal deformity (ASD), the frequency of inadequate sagittal plane correction is high (50%) and that pelvic tilt is least likely to be well corrected, (2) appreciate that the high rate of alignment failure following ASD surgery indicates a need for better preoperative planning, intra-operative imaging, and perhaps the need for increased angular correction in the sagittal plane.