MRI and clinic significance of the disc between the lumbosacral transitional vertebrae and the sacrum

Objective To explore MRI features and clinic significance of the disc between the lumbosacral transitional vertebrae(LSTV)and the sacrum.Methods The MRI and X-ray data from 52 patients with lumbosacral transitional vertebrae,and the average age of 49.3 years,were analyzed.Results The LSTV types ofⅠ,Ⅱ,ⅢandⅣwere 23.1%(12 cases),17.3%(9 cases),48.1%(25 cases)and 11.5%(6 cases)respectively according to the Castellvis classification.The disc between LSTVⅠand the sacrum were significantly less degenerative than the disc immediately above the LSTV,more like the remnant compared with the disc at the other levels.However,the lumbar discs immediately above the LSTV were more significantly degenerative than the disc at the other levels.Conclusions The disc between the LSTV and the sacrum is a kind of remnant and less degenerative,especially in theⅢandⅣtypes,for its'stability between the transitional vertebrae and the sacrum could be preserved by the articulation or bony union between the LSTV and the sacrum through its transverse process,which protect the disc from the degeneration in the long term.