J Korean Orthop Assoc.  2022 Dec;57(6):473-481. 10.4055/jkoa.2022.57.6.473.

Characteristics of the L1 Slope in the Thoracolumbar Sagittal Parameters of Degenerative Spondylosis

• Lim SA
• Shim SW
• Baek SN
• Park TG
• Choi YS

• KMID: 2537060
• DOI: http://doi.org/10.4055/jkoa.2022.57.6.473

Abstract

Purpose
To identify the characteristics of the L1 slope in the thoracolumbar sagittal parameters of degenerative spondylosis through comparison with healthy young people.
Materials and Methods
Thirty-six patients who had chronic back and lower back pain were classified as Group I and twenty healthy people were as Group II. The average age of subjects in the Group I was 72.00±10.00 years and that of, Group II was 29.3±4.97 years. Radiographic parameters such as the C7 sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), T1 slope, sacral slope (SS), pelvic tilt (PT), pelvic incidence, and L1 slope were measured on whole-spine lateral radiographs taken with the patient standing. We analyzed the relationships between the L1 slope and other parameters.
Results
There were significant differences between the two groups. the mean L1 slope was 2.70±12.66° in Group I and 12.24±4.08° in Group II (p<0.001). In the healthy young group, the T1 slope and TK had a positive correlation with the L1 slope (R ^{T1 slope} =0.448, R ^TK =0.537). In the degenerative spondylosis group, the L1 slope had a positive correlation with TK, LL and SS (R ^TK =0.480, R ^LL =0.774, R ^SS =0.385) and a negative correlation with C7-SVA (R C7-SVA =-0.529). Taking both groups together, the L1 slope had a positive correlation with TK, LL and SS (R ^TK =0.466, R ^LL =0.790, R ^SS =0.409) and a negative correlation with C7-SVA and PT (R ^C7-SVA = - 0.608, R ^PT = - 0.364).
Conclusion
In degenerative spondylosis, LL may decrease, which leads to a decrease in the TK, an increase in the C7-SVA, and a decrease in the L1 slope. These results suggest that the L1 slope could be helpful in understanding the thoracolumbar sagittal alignment.

Keyword

thoracolumbar spine; degenerative spondylosis; sagittal parameters; L1 slope