engleski

Lumbosacral Transitional Vertebrae

Objectives: Identification, classification, correct numbering and clinical relevance of the lumbosacral transitional vertebrae (LSTVs). Background: LSTVs are congenital spinal anomalies defined as either sacralization of the lowest lumbar segment or lumbarization of the most superior sacral segment of the spine. Bertolotti syndrome, the association between an LSTV and low back pain, is still controversial since Bertolotti first described it in 1917. Castellvi et al described a radiographic classification system identifying 4 types of LSTVs on the basis of morphologic characteristics. O’Driscoll et al developed a 4-type classification system of S1–2 disk morphology by using sagittal MR images, depending on the presence or absence of disk material. Inaccurate numbering may lead to an interventional procedure or surgery at an unintended level. Findings: Establishing whether an LSTV is a lumbarized S1 or a sacralized L5 can often be problematic, especially on MR images alone. Several numbering techniques have been suggested. Only radiographs of the entire spine allow the radiologist to count from C2 inferiorly and to differentiate hypoplastic ribs from lumbar transverse processes and correct identification of the L1 vertebral body. But, it is rare to have radiographs of the entire spine. Hahn et al first described the use of the MR localizers to evaluate an LSTV instead of the whole-spine MRI. Milicic et al proposed MRI of the sacrococcygeal region and counting the vertebrae from S5 upwards. The other suggested techniques used to correctly number an LSTV are locating the iliolumbar ligaments, the position of the aortic bifurcation, the right renal artery or the conus medullaris as the landmarks. But, these anatomic markers are widely believed to be less than satisfactory. Conclusion: Essentially without high-quality imaging of the entire spine, there is no foolproof method for accurately numbering an LSTV. Therefore, identification, communication with the referring clinician, and correlation of intraoperative and preoperative imaging seem to be crucial.

lumbosacral spine; transitional vertebra; imaging

nije evidentirano