Developmental malformations in the area of the lumbosacral transitional vertebrae and sacrum: differences in gender and left/right distribution.

Purpose: The aim of this study was to determine the incidence of congenital malformations of the lumbosacral transitional vertebrae in the general population, and the differences in their gender and left/right distributions.
Methods: The examined group comprised of all patients who underwent a pelvic X-ray during 2010 for any reason. The observed parameters included the following malformations: the presence of megatransversus at L5; sacralization of L5 or L6; a S1 lumbarization; the presence of six sacral vertebrae; or spina bifida at the level of L5, S1 or S2. In cases of megatransversus at L5, the lateral distribution was recorded. A total of 1,513 images were evaluated. Sex and lateral differences were evaluated using the Pearson's (χ (2)) test with a significance level of 5 %.
Results and Conclusions: A total of 478 malformations were found in 417 patients, which constituted 27.6 % of the entire group. Malformations occurred in 250 women (25.4 % of all women) and 167 men (31.6 % of all men) and the female to male ratio in affected individuals was 1.5:1. The predominance of the occurrence of malformations observed in men was statistically significant (p = 0.009). The most frequently occurring malformations were the presence of six sacral vertebrae (179 patients) and megatransversus at L5 (150 patients). The study confirmed a high incidence of congenital malformations in the area of the lumbosacral transitional vertebrae and demonstrated a higher incidence in males. Unilaterally occurring megatransversus at L5 was significantly more common on the left side.