🔍 Key Findings
- 3D-printed drill guides (3D-GDT) significantly reduced craniocaudal and dorsoventral drilling angle deviation compared to free-hand drilling technique (FHDT), with statistical significance (p < .0001 and p = .01 respectively).
- No sacral corridor breaches occurred with 3D-GDT, whereas FHDT resulted in 20% drill exit incidences (3/15 cases).
- 3D-GDT had lower deviation from optimal drill trajectory at end points in all axes: craniocaudal (1.84 ± 1.6 mm vs. 4.18 ± 2.4 mm), dorsoventral (1.11 ± 1.0 mm vs. 2.4 ± 1.5 mm), and 3D linear (2.47 ± 1.4 mm vs. 5.35 ± 2.2 mm), all statistically significant.
- Strong correlation (r = 0.77) between CT and 3D software measurements validated method reliability.
- 3D guide trajectories showed consistent proximity to the optimal trajectory, especially at drill endpoints, indicating reduced variability in execution.
- 3D-GDT was developed using open-source software and inexpensive materials, supporting future clinical application.
- Major errors in FHDT occurred primarily at the drill endpoint, underscoring the challenge of maintaining optimal angulation during free-hand drilling.
- The sacral corridor was recharacterized as pyramidal (not quadrilateral), with implications for safer implant placement.

