Lordosis Distribution Index in an Asymptomatic Elderly Population : The Role of Lower and Upper Lumbar Lordosis According to Individual Pelvic Incidence and Roussouly Type
- Author:
Seung-Jae HYUN
1
;
Sanghyun HAN
;
Youngbae B. KIM
Author Information
- Publication Type:Clinical Article
- From:Journal of Korean Neurosurgical Society 2026;69(1):92-99
- CountryRepublic of Korea
- Language:English
-
Abstract:
Objective:: This study aimed to elucidate the normative upper lumbar lordosis (ULL) and lower LL (LLL) based on individual pelvic and spinal morphology within an asymptomatic elderly population.
Methods:: Whole spine standing radiographs were obtained from asymptomatic elderly populations who had not undergone previous spinal surgery. The LL, LLL and ULL were measured. Pelvic incidence (PI), upper lumbar distribution index (ULDI), and lower LDI were calculated. Pearson correlation and linear regression analyses were performed, and the mean value for each parameter was obtained according to PI subgroup (PI <40°, 40°≤ PI <50°, 50°≤ PI <60°, and 60°≤ PI) and “theoretical” Roussouly type.
Results:: Overall, data from 150 male were retrospectively collected in the study, with an average age of 64.1±6.4 years. The mean height was 167.0±5.5 cm, weight was 67.3±9.8 kg, and body mass index was 24.1±3.1 kg/m2. The average LL was -57.5°±9.0°, LLL was -39.7°±6.8°, and PI was 48.6°±8.6°. Pelvic tilt (PT) tended to increase with ULL, PI-LL, PI-ULL, PI-LLL, and ULDI and decrease with LLL and LDI. However, PT was not significantly related to LL. The mean ULDI and LDI were 30.4%±11.7% and 69.7%±11.7%, respectively. The differences between PI and LL (PI-LL) and between PI and LLL (PI-LLL) were -8.9°±8.0° and 9.0°±9.3°, respectively. As PI increased from low (<40°) to high (≥60°), ULDI increased significantly from 25.9% to 38.9%, while LDI decreased from 74.1% to 61.1%. Additionally, LDI varied by Roussouly type, ranging from 62.6% to 81.0%. The LDIs of Roussouly types 1 and 4 were significantly higher and lower, respectively, than those of types 2 and 3 (p<0.001).
Conclusion:: As PI and Roussouly type increase, the contribution of ULL to overall LL rises, reaching up to 38.9%. Conversely, LLL substantially impacts LL in patients with a low PI and those classified as Roussouly type 1. PT is significantly related to LLL instead of LL according to PI.
