Lumbosacral transitional vertebrae incidence; contribution of the sagittal servicothoracic scout image and iliolumbar ligament in numbering transitional vertebrae

A transitional vertebrae is a common congenital variation in the lumbosacral area. The objective of this study was to evaluate the contribution of level of the iliolumbar ligaments and sagittal scout MRI images in numbering lumbosacral transitional vertebrae (LSTV).Between July 2010 and November 2010 lumbal MRI of 156 patients were included in this study. The exclusion criteria were a history of spinal-pelvic trauma, infection, previous lumbar spine surgery or stage 2 and over spondilolystesis.T1-weighted sagittal cervicothoracic scout and T2-weighted sagittal images were assessed for the presence of an LSTV and T1-weighted axial-oblique images of lumbosacral region were assessed for the level of origin of the iliolumbar ligament.Statistical analyses were performed using SPSS 13.0 (Chicago, IL;USA). Descriptive statistics were generated and quantitative values were calculated using student-t test and chi-square test.Of the 156 patients, 118 (%75.6) had normal lumbosacral segmentation and 38 (%24.4) had a transitional lumbosacral vertebrae.The ILL generally orginates from the transverse process of the L5 of the normal group. However in more than half of the LSTV group, the position of ILL was at alevel other than L5. Therefore ILL position can not be used to assign lumbar levels in a patient with LSTV. An accurate counting of segments in each spinal area may be accomplished with a full spine radiographic examination or MRI.