Accuracy of a drilling with a custom 3D printed guide or free-hand technique in canine experimental sacroiliac luxations.

Abstract

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&#x2009;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&#x2009;&#xb1;&#x2009;3.9&#xb0; and 3.9&#x2009;&#xb1;&#x2009;3.2&#xb0;, respectively; 3D 5.1&#x2009;&#xb1;&#x2009;5.1&#xb0; and 2.8&#x2009;&#xb1;&#x2009;2.3&#xb0;, respectively p&#xa0;=&#xa0;.0006) were lower compared to FHDT (CT 11.8&#x2009;&#xb1;&#x2009;4.0&#xb0;, p&#x2009;<&#x2009;.0001 and 8.9&#x2009;&#xb1;&#x2009;6.1&#xb0;, p&#xa0;=&#xa0;.01; 3D 12.4&#x2009;&#xb1;&#x2009;5.9&#xb0;, p&#xa0;=&#xa0;.0006 and 5.3&#x2009;&#xb1;&#x2009;5.24&#xb0;, p&#xa0;=&#xa0;.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&#xa0;=&#xa0;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.