Prospective Observational Cohort Study of Health-related Quality of Life: Marked Adult Sagittal Deformity (ASD) in Comparison With Mild to Moderate ASD.

STUDY DESIGN: Retrospective analysis of prospective observational cohort OBJECTIVE.: This study assessed the difference in health-related quality of life (HRQOL) between participants with a mild to moderate adult sagittal deformity (ASD) (sagittal vertical axis [SVA] ≤9.5 cm) and those with a marked deformity (SVA >9.5 cm). We also evaluated predisposing factors for a marked deformity. SUMMARY OF BACKGROUND DATA: Sagittal imbalance is closely associated with HRQOL for the patient. However, how the effect changes depending on the degree of imbalance has not been fully evaluated. The understanding of the predisposing factor associated with marked deformity also lacks. METHODS: A total of 124 elderly persons with a stooping posture were enrolled. Questionnaires related to HRQOL were administered. Sagittal alignment parameters and pelvic parameters were measured with a whole spine x-ray. Lumbar spine magnetic resonance imaging was used to assess the presence of pathologic conditions, muscle quality and quantity. Multivariate logistic regression analysis was conducted to analyze potential risk factors. RESULTS: Marked ASD was associated with female sex, lower height and weight, and osteoporosis (P < 0.05). Back pain (assessed by a visual analogue scale) and the Oswestry Disability Index were significantly higher in the marked deformity group (P = 0.012, 0.002, respectively). Multivariate logistic regression analysis showed significant relationships between the following parameters and marked deformity: preexisting compression fracture (odds ratio [OR] = 7.793; 95% confidence interval [CI], 1.527-39.768), severe L5/S1 Pfirrmann disc degeneration grade (OR = 1.916; 95% CI, 1.086-3.382), and lower quantities of multifidus and psoas muscles (OR = 0.994, 0.997; 95% CI, 0.991-0.998, 0.994-0.999, respectively). CONCLUSION: Participants with a marked ASD showed different features from those with a mild to moderate ASD. This study also implies that anatomical factors, including the vertebrae, intervertebral discs, and paraspinal muscles, synergistically contribute to progression into marked deformity. LEVEL OF EVIDENCE: 3.

Pelvic Incidence Can Be Changed not only by Age and Sex, but also by Posture Used during Imaging.

OBJECTIVE: Computed tomography (CT), rather than conventional 2-dimensional radiography, was used to scan and measure pelvic parameters. The results were compared with measurements using X-ray. METHODS: Pelvic parameters were measured using both CT and X-ray in 254 patients who underwent both abdomino-pelvic CT and X-ray at the pelvic site. We assessed the similarity of the pelvic parameters between the 2 exams, as well as the correlations of pelvic parameters with sex and age. RESULTS: The mean values of the subjects' pelvic parameters measured on X-ray were: sacral slope (SS), 31.6°; pelvic tilt (PT), 18.6°; and pelvic incidence (PI), 50.2°. The mean values measured on CT were: SS, 35.1°; PT, 11.9°; and PI, 47.0°. PT was found to be 4.07° higher on X-ray and 2.98° higher on CT in women, with these differences being statistically significant (p<0.001, p<0.001). PI was 4.10° higher on X-ray and 2.78° higher on CT in women, with these differences also being statistically significant (p<0.001, p=0.009). We also observed a correlation between age and PI. For men, this correlation coefficient was 0.199 measured using X-ray and 0.184 measured using CT. For women, this correlation coefficient was 0.423 measured using X-ray and 0.372 measured using CT. CONCLUSION: When measured using CT compared to X-ray, SS increased by 3.5°, PT decreased by 6.7°, and PI decreased by 3.2°. There were also statistically significant differences in PT and PI between male and female subjects, while PI was found to increase with age.