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Spine and Back Health

Transitional L5 with Partial Sacralization



Can a transitional L5 vertebra with partial sacralization cause unilateral, chronic back cramps and spasm in the lumbar and buttock region?

I am told that a transitional vertebra is a birth anomaly. However, I have had three MRI`s, each with progressive findings. 1998 there was minimal facet arthrosis at L5/S1. 2005 they called it a transitional L5. 2009 they call it a transitional L5 with partial sacralization. So I guess my second question would be can a normal vertebra become transitional in some individuals? If so, what could cause such a situation? Thank you!


Hello, thank you for your question. You need to be cautious how you interpret your MRI reports. Unless all three films were read by the same radiologist (I doubt it), you are probably not dealing with progressive findings as much as differences in terminology. The radiologist in 1998 probably just didn't comment on the transitional vertebra (since it is something that often complicates how you assign numbering but is not often clinically relevant), whereas seven years later the radiologist mentioned the anatomy being different but didn't go into detail.

Finally, the most recent report has specified that the transitional vertebra is 'partially sacralized'. This is NOT something that develops or progresses in people; it is congenital, meaning that people are born that way. On the other hand, due to the unusual 'biomechanics' (how the spine handles strain and shear forces) caused by the transitional vertebra, it can lead to progressive disc degeneration and possibly arthritis (what was referred to as 'facet arthrosis' in the 1998 report) in the lower lumbar spine.

It is more likely that your symptoms are related to this kind of arthritis and/or disc degeneration, +/- muscle tightness, but not directly caused by the atypical anatomy. If your symptoms are causing you trouble, you should get checked out by a spine specialist to see if there is treatment to help you. Good luck.

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Response by:

David J Hart, MD David J Hart, MD
Associate Professor of Neurosurgery
School of Medicine
Case Western Reserve University