Outcomes
| Control (n=42) | Holographic (n=41) | Mean difference (95% CI) | P value*† | |
| Procedure time (min) (primary outcome) | 7.3 (6.0) | 4.5 (4.6) | 2.8 (0.4, 5.2) | 0.02‡ |
| Image acquisition (min) | 2 (0) | 2.1 (1.5) | N/A | N/A |
| Needle punctures | 1.5 (1.0) | 1.3 (0.5) | 0.2 (−0.2, 0.6) | 0.31 |
| Needle passes | 14.4 (16.3) | 7.2 (7.9) | 7.3 (1.7, 12.9) | 0.01‡ |
| Bone contacts | 12.2 (16) | 6 (8.0) | 6.2 (0.6, 11.8) | 0.03 |
| Procedural pain | 2.6 (1.6) | 2.8 (2.3) | −0.3 (−1.2, 0.6) | 0.56 |
| Pain in PACU | 2.6 (3.0) | 2.4 (2.8) | 0.2 (−1.1, 1.5) | 0.78 |
| Epidural failure | 3 (7) | 0 (0) | N/A | 0.24 |
| Complications | 0 | 0 | N/A | N/A |
Data presented as mean (SD) or count (%).
*P value compares control versus holographic technique.
†Independent samples t-test, χ2 test, or Fisher’s exact as per variable type and count in methods.
‡Statistically significant primary outcome or secondary outcome after correcting for multiple comparisons via Holm-Bonferroni.
N/A, not available; PACU, postanesthesia care unit.