Article Figures & Data
Figures
- Fig 1.
Graphic demonstrating our method for vertebral body numbering. When counting down from C2, patients with only 4 lumbar-type vertebral bodies (sacralized L5) have 23 PSV (A), patients with 5 lumbar-type vertebral bodies have 24 PSV (B), and patients with 6 lumbar-type vertebral bodies (lumbarized S1) have 25 PSV (C).
- Fig 2.
Schematic demonstrating the divisions of the lumbosacral plexus. The L4 nerve divides soon after exiting the neural foramen into peroneal (black) (A) and tibial (B) components, with the peroneal component joining the lateral fibers of L5 (gray) (C). The L4 nerve also contributes to both the femoral (D) and obturator (E) nerves. L5 is the only lumbar nerve that does not have a proximal division. Branches of L4–S2 make up the common peroneal nerve (F), and branches of L4–S3 make up the tibial nerve (G), which together comprise components of the sciatic nerve (not illustrated). The MRI morphology of the L4 peroneal component and L5 nerve are of special importance for localization; thus, they are shaded in this figure.
- Fig 3.
Consecutive cranial to caudal axial T2-weighted MR images demonstrate L4 and L5 nerve root anatomy. The L4 nerve root splits proximally into tibial and peroneal branches (solid arrows). The peroneal branch extends caudally and joins with the L5 nerve root (dashed arrow) along its anterolateral aspect at the level of the lateral sacrum.
- Fig 4.
Axial T2-weighted MR images at the level of the sacrum with corresponding graphics demonstrating how the caliber of the nerve roots along the sacrum can be used to identify the number of lumbar vertebral segments. In patients with 4 lumbar segments, the L4 nerve root is seen splitting over the lateral sacrum (A, arrows). In patients with 5 lumbar segments, the peroneal branch of L4 joins the L5 nerve root, which is twice the caliber of L4 (B, arrows). In patients with more than 5 lumbar segments, 2 nerves of similar caliber will be seen along the lateral sacral wing, representing L5 laterally and S1 medially (C, arrows).
Tables
- Table 1:
PABAK interrater reliability coefficients between each pair of raters with 95% CIa
Rater 2 3 4 5 1 0.91 (0.83–0.99) 0.96 (0.91–1.0) 0.91 (0.83–0.99) 0.89 (0.80–0.98) 2 0.94 (0.88–1.0) 0.85 (0.75–0.95) 0.83 (0.73–0.94) 3 0.91 (0.83–0.99) 0.85 (0.75–0.95) 4 0.83 (0.73–0.94) ↵a Interrater reliabilities between each pair of raters ranged from 0.83–0.96. The average coefficient was 0.89. The smallest 95% CI lower limit was 0.73, and the largest upper limit was 1.0. Although a formula for computing the PABAK interreliability for more than 2 raters simultaneously is not available, using this mean and range of confidence limits provides a reasonable approximation of the interrater reliability of the 5 raters simultaneously (PABAK, 0.89; 95% CI, 0.73–1.0).
Rater PABAK Coefficient (95% CI) 1 0.91 (0.83–0.99) 2 0.81 (0.70–0.92) 3 0.87 (0.78–0.96) 4 0.85 (0.75–0.95) 5 0.94 (0.88–1.0) Rater PABAK Coefficient (95% CI) 1 0.92 (0.85–0.99) 2 0.85 (0.75–0.95) 3 0.91 (0.83–0.99) 4 0.89 (0.80–0.98) 5 0.78 (0.65–0.89)
