What is Bertolotti’s Syndrome?
What is Bertolotti’s Syndrome?
Bertolotti’s Syndrome (BSy) is a spinal condition that arises from a congenital (present at birth) anatomical variation in the lower spine, known as a lumbosacral transitional vertebra (LSTV). This variation alters the normal structure and function of the junction between the lumbar spine and the sacrum—the base of the spine that connects to the pelvis.
In simple terms, this means that the last lumbar vertebra (usually L5) or the top part of the sacrum (S1) doesn't look or behave the way it typically should. These structural anomalies can place unusual stress on the spine and surrounding tissues, sometimes leading to chronic lower back pain, which is referred to as Bertolotti’s Syndrome when LSTV is the primary source of pain.
Not all LSTV causes BSy
It’s essential to understand that having an LSTV does not automatically mean someone has Bertolotti’s Syndrome.
LSTV is a relatively common anatomical variant, observed in 4–30% of the general population (Alonzo et al., 2018).
However, only about 4–8% of people with chronic lower back pain are found to have symptoms clearly linked to LSTV—qualifying as true Bertolotti’s Syndrome (Kapetanakis et al., 2017).
This means that many people with LSTV are completely symptom-free, and LSTV is often discovered incidentally during imaging for other issues.
Clinically, it is crucial for healthcare providers to determine whether the LSTV is actually the source of the patient's pain, or merely an incidental finding.
To better understand and categorize the anatomical variations seen in lumbosacral transitional vertebrae (LSTV), radiologist Alberto Castellvi developed a classification system that is widely used in both clinical practice and research. This system divides LSTVs into four main types (I–IV) based on how the transverse processes of L5 interact with the sacrum (sacral ala). Please see the next section for further details.
You can read more about spinal anatomy at this website: https://spinehealth.org/article/spine-anatomy/
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References:
Alonzo, F., Cobar, A., Cahueque, M., & Prieto, J. A. (2018). Bertolotti’s syndrome: An underdiagnosed cause for lower back pain. Journal of Surgical Case Reports, 2018(10), rjy276. https://doi.org/10.1093/jscr/rjy276
Castellvi, A. E., Goldstein, L. A., & Chan, D. P. K. (1984). Lumbosacral Transitional Vertebrae and Their Relationship With Lumbar Extradural Defects. Spine, 9(5), 493.
Jenkins, A. L., O’Donnell, J., Chung, R. J., Jenkins, S., Hawks, C., Lazarus, D., McCaffrey, T., Terai, H., & Harvie, C. (2023). Redefining the Classification for Bertolotti Syndrome: Anatomical Findings in Lumbosacral Transitional Vertebrae Guide Treatment Selection. World Neurosurgery, 175, e303–e313. https://doi.org/10.1016/j.wneu.2023.03.077
Kapetanakis, S., Chaniotakis, C., Paraskevopoulos, C., & Pavlidis, P. (2017). An Unusual Case Report of Bertolotti’s Syndrome: Extraforaminal Stenosis and L5 Unilateral Root Compression (Castellvi Type III an LSTV). Journal of Orthopaedic Case Reports, 7(3), 9–12. https://doi.org/10.13107/jocr.2250-0685.782
McGrath, K., Schmidt, E., Rabah, N., Abubakr, M., & Steinmetz, M. (2021). Clinical assessment and management of Bertolotti Syndrome: A review of the literature. The Spine Journal, 21(8), 1286–1296. https://doi.org/10.1016/j.spinee.2021.02.023
Zhu, W., Ding, X., Zheng, J., Zeng, F., Zhang, F., Wu, X., Sun, Y., Ma, J., & Yin, M. (2023). A systematic review and bibliometric study of Bertolotti’s syndrome: Clinical characteristics and global trends.