Customized 3-D-printed drill guide casts enable accurate wire placement for external skeletal fixation in the canine antebrachium.

Abstract

Objective: To evaluate the feasibility and accuracy of customized 3-D-printed casts, created using virtual surgical planning, to guide wire placement for external skeletal fixation in the canine radius.

Methods: This experimental cadaver study used normal forelimbs from medium-sized canine cadavers (19 to 23 kg). Computed tomography scans were performed to generate 3-D bone and soft tissue models. Customized 3-D-printed casts with cylindrical drill guides were designed and applied to each forelimb. Wires were drilled through the casts at distal, middle, and proximal locations along the radius and subsequently removed. Postprocedural CT scans were obtained. Pre- and postdrilling bone models were superimposed to calculate wire angle errors in the frontal and transverse planes and the distance between the planned and actual points of wire intersection (wire intersection error).

Results: Both forelimbs of 6 cadavers were used. Of 72 planned wires, 70 were successfully placed. Median wire error angles were 1° in the frontal plane and 2° in the transverse plane. The median wire intersection error was 1 mm (range, 0 to 5 mm). Wire placements at proximal locations had greater error than those at middle and distal sites. No procedural complications were identified.

Conclusions: Customized 3-D-printed drill guide casts enabled accurate wire placement in the canine radius with minimal deviation from planned trajectories. Proximal locations showed slightly reduced accuracy.

Clinical relevance: This technique may facilitate precise and repeatable application of external skeletal fixator wires in dogs, potentially improving outcomes for limb deformity correction.