Fig. 3.

a Lower-thoracic and lumbar spines were dissected to expose the pedicle, dura, and nerve roots. The transverse root angles (TRA) from T11 to L5 were measured between the axis of dura and nerve root and averaged. b The superior (S), inferior (I), medial (M), and lateral (L) distances between the cortex of the pedicle and neural structures were measured and averaged. No mobilization of neural structures during dissection was evident