Morphometric study of the true S1 and S2 of the normal and dysmorphic sacralized sacra.

BACKGROUND/AIM This study aimed to generate data for the S1 and S2 alar pedicle and body and the alar orientations for both dysmorphic and normal sacra. MATERIALS AND METHODS The study comprised two groups: Group N consisted of 53 normal sacra and Group D included 10 dysmorphic sacra. Various features such as alar pedicle circumference; anterior, middle, and posterior axis of the sacral ala; sacral body height and width; and sagittal thickness were measured. RESULTS In group N, the median anterior axis of the alae was observed to be 30° on the right and 25° on the left, the median midline axis was found to be 20° on the right and 15° on the left, and the median posterior alar axis was -15° on the right and -20° on the left. The true S1 and S2 alar pedicle circumferences were observed to be significantly smaller in group D, which demonstrated a shorter S1 alar pedicle mean circumference, significantly narrower S1 body mean width, and considerably tapered sagittal thickness. CONCLUSION Our analysis indicated that dysmorphic sacra have a lower sagittal thickness and width of bodies and smaller alar pedicles, which explains the difficulties in their percutaneous fixation.