Lumbosacral transitional vertebrae: prevalence in a southern European population and its association with low back pain.

Purpose: Lumbosacral transitional vertebra (LSTV) is a congenital anomaly of the lumbosacral junction. Its prevalence is variable in the literature such as its association with low back pain. The aim of this study was to identify the prevalence of LSTV in a southern European population, and its correlation with low back pain.

Methods: A retrospective review of 639 thoraco-abdomino-pelvic consecutive CT-scans between January 2019 and November 2020 was performed. The presence of LSTV was classified into type II, III, IV based on Castellvi's classification. To investigate the association with low back pain, Oswestry Low Back Disability Questionnaire (ODI) and the EuroQol-5D-3L questionnaire was applied.

Results: The prevalence of LSTV was 24.9% (142 of 571). 37,3% were type IIb, 31,0% were type IIa, 13,4% were type IIIa, 9.9% were type IIIb and 8.5% were type IV. Individuals with LSTV were more likely to report low back pain and have a higher ODI score (OR:0.392, 95% CI:0.192-0.802, p = 0.010), (OR: 1050, 95% CI: 1029-1072, p < 0.01). Castellvi's type IV showed a significantly higher ODI when compared to type II (OR:1059, 95% CI:1019-1100, p = 0,04). There was no statistical difference in the EuroQol-5D-3L score between two groups (OR:1085, 95% CI: 0.459-2.560, p = 0.852).

Conclusion: This population-based study adds to the literature the prevalence of LSTV in a southern European population. LSTV was associated with low back pain. However, this difference did not translate into a loss of quality life. Type IV was associated with higher functional disability when compared with type II.