The affected vertebra is termed a “transitional vertebra” because it shares features of lumbar and sacral verebrae.
Features of Bertolli Syndrome:
(1) large congenital transverse apophysis on a lumbar vertebra with an anomalous articulation
(2) presence of low back pain as a result of degenerative change, which may be in the articulation, a contralateral facet or an intervertebral disc
The onset can occur during childhood and may go undiagnosed for some time.
The transverse apophysis is usually unilateral, on L5 and articulates with the sacrum.
Variations:
(1) transverse apophysis arising from another lumbar vertebra
(2) articulation with the ilium
(3) bilateral disease
The diagnosis is usually made on imaging studies (X-ray, CT, MRI or SPECT/TC).
