Accuracy of a Drilling with a Custom 3D Printed Guide or Free-Hand Technique in Canine Experimental Sacroiliac Luxations

Objective To improve the accuracy of drilling during the repair of sacroiliac luxations (SILs) with a 3D-printed patient-specific drill guide (3D-GDT) compared to free-hand drilling technique (FHDT). Study design Blinded, randomized, prospective ex vivo study. Sample population Sixteen canine cadavers (20-25 kg). Methods Dorsal, bilateral SILs were created. Pelvic CT was performed pre- and post-drilling. The FHDT was drilled followed by 3D-GDT. CT and 3D measurements of craniocaudal and dorsoventral angles were compared between FHDT and 3D-GDT, as well as deviations of entry and exit points relative to optimal trajectory. Results Mean craniocaudal and dorsoventral angles for both CT- and 3D-measured 3D-GDT (CT 4.2 +/- 3.9 degrees and 3.9 +/- 3.2 degrees, respectively; 3D 5.1 +/- 5.1 degrees and 2.8 +/- 2.3 degrees, respectively p = .0006) were lower compared to FHDT (CT 11.8 +/- 4.0 degrees, p < .0001 and 8.9 +/- 6.1 degrees, p = .01; 3D 12.4 +/- 5.9 degrees, p = .0006 and 5.3 +/- 5.24 degrees, p = .05). Entry dorsoventral and end craniocaudal, dorsoventral, and 3D linear deviations were reduced with 3D-GDT. Sacral corridor disruption was present in 20% (3/15) for FHDT compared with 0% for 3D-GDT. CT and 3D analyses were in strong agreement (r = 0.77). Conclusion Deviations of drill trajectories were minimized relative to optimal trajectories with 3D-GDT compared to FHDT in the dorsoventral and craniocaudal planes. Clinical significance The use of 3D-GDT improves accuracy of sacral drilling compared with FHDT in canine cadavers. These results justify further evaluation in a clinical, prospective study.