Table 4.
Anatomic parameters of distance of the pedicle to the dura sac and nerve root (mean ± standard deviation)
| Pedicle | Superior distance to nerve root (mm) | Inferior distance to nerve root (mm) | Medial distance to dura sac (mm) | Lateral distance to nerve root (mm) | ||||
|---|---|---|---|---|---|---|---|---|
| Left | Right | Left | Right | Left | Right | Left | Right | |
| T11 | 4.5 ± 0.6 | 4.7 ± 0.7 | 3.0 ± 0.3 | 3.1 ± 0.4 | 1.0 ± 0.1 | 1.3 ± 0.2 | a | a |
| T12 | 5.0 ± 1.2 | 5.3 ± 1.4 | 3.4 ± 0.4 | 3.8 ± 0.5 | 1.1 ± 0.2 | 1.5 ± 0.2 | a | a |
| L1 | 5.7 ± 1.1 | 5.8 ± 1.0 | 2.6 ± 0.3 | 2.6 ± 0.5 | 2.0 ± 0.3 | 2.0 ± 0.2 | 9.4 ± 2.1 | 9.6 ± 2.5 |
| L2 | 5.5 ± 0.9 | 5.8 ± 0.8 | 2.6 ± 0.6 | 2.5 ± 0.4 | 1.8 ± 0.1 | 2.0 ± 0.1 | 4.5 ± 1.2 | 4.7 ± 1.1 |
| L3 | 6.1 ± 1.2 | 6.1 ± 1.6 | 2.3 ± 0.5 | 2.6 ± 0.6 | 1.7 ± 0.2 | 1.8 ± 0.1 | 4.2 ± 0.4 | 4.3 ± 0.5 |
| L4 | 4.7 ± 0.6 | 5.0 ± 0.4 | 2.0 ± 0.4 | 2.2 ± 0.3 | 1.9 ± 0.3 | 2.1 ± 0.2 | 3.5 ± 0.4 | 3.5 ± 0.3 |
| L5 | 4.1 ± 0.3 | 4.7 ± 0.4 | 2.0 ± 0.2 | 1.9 ± 0.3 | 1.9 ± 0.2 | 1.9 ± 0.1 | 2.4 ± 0.2 | 2.6 ± 0.4 |
aThe direction of nerve root is parallel to the direction of rib cage. Long lateral distance (>10 mm) to the nerve root in T11and T12 pedicles are noted