Study design: A retrospective study.
Objective: The aim of this study is to introduce a novel regional predictor for sagittal balance in elderly populations and explore its effectiveness of evaluating sagittal balance.
Summary of background data: Sagittal balance is getting increasing recognition of importance due to its significant association of health-related quality of life. However, no regional parameters could well reflect and predict the whole sagittal balance.
Methods: Medical records of elderly patients in our outpatient clinic from January 2012 to January 2014 were reviewed with standing full-spine lateral radiograph. Radiological parameters were evaluated, including max thoracic kyphosis (maxTK), max lumbar lordosis (maxLL), LL minus TK(LL-TK), PI minus LL (PI-LL), sacrum slope (SS), pelvic tilt (PT), pelvic incidence (PI), and SVA (sagittal vertical axis). Correlation analysis between SVA, LL-TK, and other radiological spinopelvic parameters and was pursued. Patients were divided into two groups according to whether patients were well-aligned in sagittal plane: Group A (well-aligned, SVA ≤50 mm) and Group B (poorly aligned, SVA >50 mm), and demographic and sagittal parameters were compared. LL-TK ≥0° and PI-LL ≤13° were used as a threshold value to evaluate their effectiveness of prediction for sagittal balance.
Results: A total of 129 patients (M: 25 and F: 104) were included in this study. SVA was significantly correlated with NRS (numeric rating scales), age, maxLL, PT, LL-TK, and PI-LL (all, P < 0.05). Age, maxTK, maxLL, SS, PT, PI, SVA, and NRS were significantly correlated with LL-TK (all P < 0.05). Significant differences were found in age, maxLL, PT, LL-TK, PI-LL, SVA, and NRS between Group A (M: 15 and F: 72) and Group B (M: 10 and F: 32) (all P < 0.05). Furthermore, both LL-TK ≥0° and PI-LL ≤13° were observed in 75 patents, among which SVA ≤50 mm was found in 67 patients (89%). Among patients whose LL-TK and PI-LL were <0° and >13°, 34 patients were poorly aligned (34/39, 87%).
Conclusion: LL-TK was a good regional predictor for sagittal balance in elderly population, especially combined with PI-LL.
Level of evidence: 4.