Symptomatic Lumbosacral Transitional Vertebrae (Bertolotti Syndrome) as a Cause of Low Back Pain: Classification and Imaging Findings

Objective: To determine the most common pathologies of lower back pain and the proportion of Bertolotti syndrome (BS) among these pathologies and to reveal possible gender-age differences, and to group the lumbosacral transitional vertebrae (LSTV) according to Castellvi classification and find their prevalence rates. Method: The images and reports of 357 patients who underwent magnetic resonance imaging (MRI) of the sacroiliac joint between March 2020 and October 2021, mostly due to low back pain, were evaluated by a radiologist specialized in musculoskeletal radiology. Results: The mean ages of patients with and without BS were 43.9 years old and 44 years old, respectively, and there was no correlation between BS and patient age (P = 0.976). The age range of patients with BS was 15–77 years old. Twenty per cent of the patients with BS were younger than 30 years old and 50% were younger than 40 years old. No gender difference was observed among patients with BS (P = 0.572). The prevalence rates if LSTVs according to Castellvi classification, were 10% in Type 1a, 11.4% in Type 1b, 35.7% in Type 2a, 17.1% in Type 2b, 4.3% in Type 3a, 12.9% in Type 3b and 8.6% in Type 4. The main pathologies causing lower lumbar pain were active-chronic sacroiliitis, vertebral and disc degenerations, and facet joint arthrosis, while BS comes after, with 2.8%. In BS, the pain originated from the lumbosacral transitional vertebrae. Conclusion: According to our results, BS starts to be seen below the age of 30 years, but there is no significant relationship with age or gender. BS is one of the most common causes of lower lumbar pain after sacroiliitis, vertebral degeneration, and discopathy. There are different hypotheses in the literature about the etiology of BS and there is no common opinion. Therefore, there is a need for multicenter studies with large sample sizes.