Lumbarization or sacralization-?. Concept of lumbosacral transitional vertebra

Lumbarization or sacralization-?. Concept of lumbosacral transitional vertebra by MRI

Lumbosacral transitional vertebrae (LSTV) occur when the last lumbar vertebra shows elongation of its transverse process, with varying degrees of fusion to the first sacral segment. The term “LSTV” is used to avoid having to decide whether such a vertebra is a “sacralized L5” or a “lumbarized S1.” Although LSTV can be sensitively identified on sagittal lumbar spine MRI, based on abnormal morphology of the lumbosacral junction  no standard method is established for their numbering. Techniques that have been used include the addition of cervicothoracic localizer scans and determining lumbar levels by identification of the right renal artery(in relation to the L1-2 disk space ). These techniques are prone to substantial error.Both anatomic and MRI studies have indicated that the iliolumbar ligament (ILL) arises almost exclusively from the L5 transverse process  However, these studies are limited by relatively small numbers  .if ILLs can be reliably identified on routine axial MR images through thelumbosacral junction and if they arise solely from L5, then their level of origin can serve as a marker of lumbar levels, which may enable the confident numbering of LSTV.
The ILLsappear as either a single or a double hypointense band arising from the transverse process and extending to the posteromedial aspect of the iliac crest.  If an LSTV is present, it is numbered as a transitional L5 or transitional S1 segment based on the following method. When the ILL  arises at
the level above the LSTV, the vertebral level of origin of the ILL was labeled L5 and, consequently, the LSTV was numbered S1 . If the ILL is not visualized, the LSTV is numbered L5  This numbering system was based on the hypothesis that in the presence of healthy lumbosacral segmentation, the ILL always arises from L5

and is therefore a marker of the L5 level.

Using identification of the iliolumbar ligaments as a marker of the L5 vertebral level, we can number LSTV as L5 transitions and S1 transitions. The iliolumbar ligament is readilyidentifiable on axial lumbar spine MRI and always arises from L5.We suggest that its position can be used to confidently assign lumbar levels in patientswith LSTV.


7 comments on “Lumbarization or sacralization-?. Concept of lumbosacral transitional vertebra

  1. Educative article but exbound on management and treatment.


  2. Charles J. Shuck Sr. (ghostwriter) says:

    My son just went through getting his spine fused, Oct. 08, 2010. He is 21 years of age. He had x-rays done on 5/14/03 and the doctor he was going to at the time said he was having growing pains. That everything would be okay as he got older. He has O.C.D. and A.D.H.D, so when he’s friends went into the milatery and lost weight he decided to lose weight to, so shortly after lossing the weight he was exercizing and he started to have more pain in his back then he did before. Needless to say L-6 slide foreward because it never developed the upper fingers that hold the vertebra in place. While waiting to have the surgery the lower disc went,(pressing on his bladder), and he had to be cut front and back. I want to thank you for this web site, it was the only place I could find any information about what had happened to him. I found the x-rays and report by accident, the doctor never told us anything that it could lead to a problem! I do have one question, could this have been taken care of earlier in his life, so he could have avoided this operation? Again Thank You for the information.


  3. Hung Ho Quang says:

    Dir sirs,
    Im am very interested in your answer. But i don’t understand why we should not use the T12 as a marker. Because T12 vertebra is the last having the rib. Then, when we count down from the T12, if we have 4 lumbar vertebra, we say it is the case of L5 sacralisation. If we have 6 lumbar, it is the case of S1 lumbarisation.


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