Accuracy and Efficacy of a Patient-Specific Drill Guide Template System for Lumbosacral Junction Fixation in Medium and Small Dogs: Cadaveric Study and Clinical Cases

Abstract

Objectives: To develop drill guide templates as an intraoperative guide, and to evaluate the accuracy and safety of screw placement in the lumbosacral junction. Samples: Canine cadaveric specimens of the lumbosacral junction (n = 6), and clinical cases of lumbosacral instability (n = 3). Procedures: Computed tomography data of the lumbosacral region of cadaveric specimens and clinical cases were obtained. The optimum screw trajectories were determined and drill guide templates were fabricated using a three-dimensional printing system. Drill holes were made using the templates in cadaveric specimens and clinical cases, and lumbosacral fixation was performed in clinical cases. Computed tomography images were obtained to compare the planned and postoperative drill hole trajectories, and the accuracy and safety of drilling and screw placement in the lumbosacral junction were evaluated. Results: Thirty-six drill holes were made in cadaveric specimens. The overall mean drill hole deviation was 2.05 ± 1.32 mm. A total of 12 screws were placed in the lumbosacral junctions of three clinical cases. The overall mean drill hole deviation was 2.43 ± 1.09 mm. Clinical signs improved within 2 weeks in the clinical cases. All drill holes were completely located within the bone in cadaveric specimens and clinical cases. Conclusion and Clinical Relevance: The surgical procedures using the drill guide templates were performed safely with good clinical outcomes. The drill guide template system provided useful surgical guidance to safely and precisely perform screw placement for lumbosacral fixation surgery in small dogs.

Accuracy of three‐dimensionally printed animal‐specific drill guides for implant placement in canine thoracic vertebrae: A cadaveric study

“…The use of 3‐D printed guides may also increase the accuracy and may improve success rates when 3‐D printed guides are employed by less experienced surgeons. The results of this study augment results of other studies, 21,23‐27 providing evidence that the use of 3‐D printed guides is likely to improve the safety margin of placing vertebral implants in the canine spine. However, rigorous comparison with other techniques remains to be conducted, and this should be the basis of future work.…”

“…Researchers in previous veterinary studies have used a variety of materials to print drill guides 21,23‐27 . Two important material considerations are biocompatibility and sterilization methods that are compatible and readily available.…”

“…We used a composite material for the guides in this study that is not certified for steam sterilization. Ethylene oxide gas sterilization or possibly plasma (hydrogen peroxide) sterilization is a potential option for use in clinical cases, as others have demonstrated, 24,25,27 although the efficacy and safety of such methods with the various materials available remains to be shown. Researchers in several veterinary studies have used dental resins designed for human applications that are certified biocompatible and autoclavable for guide design 21,26,27 .…”

“…21,[23][24][25][26][27] These efforts have focused primarily on the cervical 26,27 and lumbosacral vertebrae. 23,24 We are aware of two studies in which researchers evaluated 3-D printed guides for implant placement in the canine thoracic spine. Fujioka et al 25 evaluated guides for T12 to L1 in beagle cadavers and in four clinical cases (three pugs and one cocker spaniel) for vertebrae spanning T11 to L4.…”

“…Researchers in previous veterinary studies have used a variety of materials to print drill guides. 21,[23][24][25][26][27] Two important material considerations are biocompatibility and sterilization methods that are compatible and readily available. Biocompatibility may seem to be a minor concern because these guides are not being left behind as implants.…”