Table 2.
Accuracy measurements of the pedicle screw fixation
| Screw grade | RA group (n, [%]) | FH group (n, [%]) |
χ2 = 38.816, p < 0.001 Adjust P value(z test) |
|---|---|---|---|
| A | 340 (89.9) | 589 (74.9) | < 0.05 |
| B | 33 (8.7) | 136 (17.3) | < 0.05 |
| C | 4 (1.1) | 52 (6.6) | < 0.05 |
| D | 1 (0.3) | 9 (1.1) | |
| E | 0 (0.0) | 0 (0.0) | |
| A + B* | 373 (98.7) | 725 (92.2) | χ2 = 19.780; P< 0.001 |
Gertzbein-Robbins grading system: grade A screw is completely within the pedicle, grade B pedicle cortical breach < 2 mm, grade C pedicle cortical breach < 4 mm, grade D pedicle cortical breach < 6 mm, grade E pedicle cortical breach > 6 mm
*Means the RA group showed superior accuracy in “clinically acceptable” screws