Multimodality imaging in Bertolotti's syndrome: an important cause of low back pain in young adults.

To cite: Neelakantan S, Anandarajan R, Shyam K, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2016217121 DESCRIPTION A 30-year-old woman presented to the orthopaedics outpatient department with low back pain (LBP) for 4 weeks, not relieved on medications. She had no known comorbidities. On examination, there was movement restriction of the lower spine and focal right posterior lumbar tenderness. Blood routines showed raised acute inflammatory markers. Imaging work-up included a routine frontal radiograph of the lumbar spine which showed a lumbosacral transition vertebra with enlarged right transverse process (figure 1). Sacroilliac joints appeared normal. Plain MRI of the lumbar spine was performed which revealed lumbosacral transitional vertebra (LSTV) with enlarged transverse process articulating with the sacral ala bilaterally forming diarthroidal joint (Castellvi type IIb) and the subchondral bone of this joint showed T2 short τ inversion recovery hyperintense signals and hypointense signals on T1-weighted images, which was suggestive of marrow oedema. The intervening cartilage was also hyperintense. There were no signal abnormalities on the left side. Rest of the lumbar spine was normal. These features were suggestive of inflammatory changes occurring in an underlying pseudoarthrosis between the right transverse process of L5 and right sacral ala (figures 2–4). Thus, a diagnosis of Bertolotti’s syndrome (BS) was made. Correlative plain multidetector CT scan of the lumbar spine was performed to demonstrate subtle osseous alterations at the site of pseudoarthrosis, which revealed a lumbosacral transitional vertebra (Castellvi type IIb) and a pseudoarthrosis between the right transverse process of L5 vertebra and the right sacral ala with minimal marginal spurring and reactive bone sclerosis (figures 5 and 6). The patient was managed with anti-inflammatory medications and percutaneous steroid injections, and she was symptom-free at discharge. BS is characterised by the presence of a fifth lumbar (L5) vertebra anatomic variation with a Figure 1 Frontal radiograph of the lumbar spine showing a lumbosacral transition vertebra with enlarged right transverse process (arrow). Sacroilliac joints appeared normal.