Castellvi classification of lumbosacral transitional vertebrae

Last revised by Sonam Vadera on 6 Mar 2024

The Castellvi classification is used for lumbosacral transitional vertebra (LSTV):

  • type I: enlarged and dysplastic transverse process (at least 19 mm)

    • Ia: unilateral

    • Ib: bilateral

  • type II: pseudoarticulation of the transverse process and sacrum with incomplete lumbarization/sacralization; enlargement of the transverse process with pseudoarthrosis

    • IIa: unilateral

    • IIb: bilateral

  • type III: transverse process fuses with the sacrum and there is complete lumbarization or sacralization, enlarged transverse process with complete fusion

    • IIIa: unilateral

    • IIIb: bilateral

  • type IV: type IIa on one side and type IIIa on the contralateral side

History and etymology

This classification system was initially described by Castellvi et al in 1984, in a study examining the association of lumbosacral transitional vertebrae with herniated lumbar discs 3.

Related pathology

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