Bertolotti Syndrome

Excerpt

Back pain associated with an anatomical variant of the lumbosacral junction was first described by Bertolotti in 1917. Thus, low back pain in the presence of any lumbosacral transitional vertebra (LSTV) variant is termed “Bertolotti syndrome.” An LSTV refers to an aberrant articulation between the L5 vertebra and the sacrum. The most common type of LSTV is the enlargement of unilateral or bilateral L5 transverse processes with the fusion of one or more of those transverse processes to the sacrum.

The sacrum is the base of the vertebral column and is responsible for distributing upper-body mass across the pelvis. However, the sacrum’s ability to properly distribute the weight of the upper body is affected when it is irregularly fused with L5. Consequently, the L5 transverse processes are larger than patients without an LSTV in order to facilitate load bearing across the smaller sacral surface area. This prevents motion at the L5-S1 junction and leads to increased motion above the affected joint.

This increase in motion at anatomically normal vertebral levels leads to increased incidences of disc herniation and facet arthrosis. Ultimately, these anomalous connections between L5 and S1 lead to asymmetry of spinal movement and place greater stress on the preceding vertebral level, which is the suspected pain generator in most cases of Bertolotti syndrome.