Bertolotti's syndrome is characterized by sacralization of the lowest
lumbar vertebral body or the lumbarization of the uppermost sacral segment. It involves a total or partial unilateral or bilateral fusion of the transverse process of the lowest lumbar vertebra to the sacrum, leading to the formation of a transitional 5th
lumbar vertebra. The transitional anatomy results in one or both of the transverse process (i.e., look like wings on the vertebra) of the last lumbar segment to be enlarged. Consequently, the transverse process can come in contact with the
sacrum, the
iliac crest, or both. This results in limited / altered motion at the lumbosacral segment . This loss of motion will then be compensated for at segments superior to the transitional vertebra. In some cases, this altered biomechanics leads to degeneration,
herniation, or fissure of the L4 disc.
Scoliosis is frequently found to be associated.
Classification The different types of LSTV were first classified by Antonio Castellvi aptly named the Castellvi classification. In his classification, he identified 7 types of LSTV. However, this Castellvi developed this classification for the purposes of identifying risk of disc herniation in patients, not for Bertolotti's Syndrome patients The Jenkins classification is separated into 4 categories: Type 1, 2, 3, and 4 with subclassifications of: L (left) or R (right) prominence, A (unilateral), B (bilateral), or C (Type 2 with Type 1 and contralateral 2 anatomy or Type 4 with a gap > 10 mm and contralateral Type 3 anatomy), + L (left) or R (right) iliac contact.
Type 1: A dysplastic transverse process that shows a gap of less than 10mm, but greater than 2mm across the lumbosacral junction.
Type 2: Pseudo-articulation between adjacent transverse processes with a gap of less than 2 mm.
Type 3: Complete fusion lateral to the facet at the ala, without spontaneous fusion of the disk or facet joints, of the lumbosacral junction.
Type 4: Presence of unilaterally fused side with varying pseudoarticulation on the contralateral side (Type 4A, 4B, or 4C). == Diagnosis ==