Poster Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

Background and Purpose: Spinal alignment imbalance is a prevalent issue among the elderly population, with osteoporotic vertebral fractures being a contributing factor. While numerous studies have focused on global alignment, research on thoracolumbar transitional alignment is limited. Consequently, the aim of this study was to establish the normative data for thoracolumbar spine alignment in healthy elderly subjects.

Methods: Beginning in 2016, participants aged 65 years and older were recruited from Ikoma city, Japan, through a community announcement. Inclusion criteria included the ability to visit the hospital for assessment, independent ambulation, and consent to participate in the study. Following the procurement of written informed consent, a total of 164 men and 245 women were enrolled. We assessed the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for low back pain (LBP). Sagittal and pelvic alignment parameters were measured using standing whole spine radiographs. Participants with a VAS for LBP greater than 40 mm and an ODI less than 40% were categorized as the non-LBP group. The sagittal thoracolumbar kyphotic angle (TL) between T10 and L2 was measured using Surgimap Spine software. The Receiver Operating Characteristic (ROC) curve analysis was utilized to determine the TL cut-off value predictive of LBP.

Results: A total of 409 individuals were analyzed, with 277 classified in the non-LBP group. A significant difference was observed in the TL between the LBP and non-LBP groups (18.4 ± 18.6 vs. 12.2 ± 15.1; p=0.001). A multiple logistic regression model, adjusted for age, gender, pelvic incidence, and lumbar lordosis, identified TL as an independent predictor of LBP. The mean TL values were 9.8 ± 12.1, 12.5 ± 14.1, 13.0 ± 18.7, and 18.0 ± 15.6 for the age groups 65-69, 70-74, 75-79, and 80+ years, respectively (Figure). There was a significant correlation between TL and age (p=0.014; Pearson correlation test). The TL cut-off value was determined to be 20 degrees. The logistic regression model revealed a significant increase in the odds ratio for TL values greater than 20 degrees (1.83; 95% confidence interval: 1.13-2.97).

Conclusions: The increase in TL was significantly associated with LBP. The cut-off value of TL was 20 degrees. A cut-off value of 20 degrees for TL was identified. Notably, the average TL in healthy subjects demonstrated an increase with advancing age. This finding may prove crucial in informing clinical decisions pertaining to corrective surgery at the thoracolumbar junction.