A lumbosacral transitional vertebra is present in about one lumbar spine in ten. When the enlarged transverse process forms a pseudoarticulation with the sacrum and that articulation is the pain generator, the condition is Bertolotti syndrome. Most patients reach an interventionalist after years of treatment aimed at the disc, the facet or the sacroiliac joint. This guide sets out, for pain physicians and interventional radiologists in Australia, what the published evidence supports: the diagnostic local anaesthetic block of the pseudoarticulation and how to interpret it, image guidance and the place of SPECT-CT, therapeutic injection, epidural and transforaminal injection where the transitional anatomy narrows the foramen, radiofrequency of the pseudoarticulation, and the point at which intervention ends and surgical referral begins. It covers the Medicare items that apply, the pitfalls of level numbering, and what the referrer and the patient need from the procedure record. Each clinical statement is referenced, and the notes at the end say what could and could not be verified. Written by a patient who was diagnosed after forty-eight years, it is one of a series of guides for the clinicians who see this condition.