An enlarged transverse process at L5 that partially fuses with the sacrum, causing mechanical low back pain. Frequently under-diagnosed — learn how Mr. Rath approaches it.
Bertolotti's syndrome is caused by an enlarged, elongated transverse process at the L5 vertebra that forms a pseudo-joint with the top of the sacrum or iliac wing. This anomaly is a transitional variation of the lumbosacral junction, present in roughly 4–8% of the population. The abnormal joint creates a mechanical pain source that is poorly responsive to standard back pain treatments, leading to years of misdiagnosis for many patients.
The key steps to diagnosis are:
Many people with the Castellvi Type I bony variant never develop significant pain. Those who do often present in young adulthood with one-sided low back pain that is mechanical, worse with activity, and does not fit the expected pattern for a disc prolapse. Without targeted treatment the pain tends to persist for years.
Mr. Rath is one of a small number of surgeons offering endoscopic resection of the anomalous joint as a day-case procedure — removing the source of pain with minimal soft-tissue disruption.
The bony anomaly is sometimes dismissed as a normal variant on imaging, and the pain pattern overlaps with disc disease. A targeted diagnostic injection at the transitional joint can confirm the source within minutes.
For the right patient — confirmed diagnosis and failure of at least one injection — endoscopic resection of the anomalous joint gives durable relief in most cases. Mr. Rath will review your imaging personally before recommending surgery.
Online and in-clinic consultations available across the North West.
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