Accuracy of 3D-printed drill guides for dog spine screw placement

Abstract

OBJECTIVE:  The aim of this study was to report the accuracy of pedicle screw placement using three-dimensional (3D)-printed, patient-specific drill guides in the lumbosacral region of dogs. STUDY DESIGN:  This was a retrospective study. Thirty-two pedicle screws were placed in five dogs. Medical records were reviewed between November 2015 and November 2018 for dogs showing clinical signs associated with cauda equina syndrome. Inclusion criteria included preoperative magnetic resonance imaging, pre- and postoperative computed tomography (CT) and dorsal stabilization, with pedicle screws placed using 3D-printed, patient-specific drill guides and polymethylmethacrylate. Screw placement was evaluated for medial or lateral breaching on postoperative CT. RESULTS:  Five dogs met the inclusion criteria. Four had degenerative lumbosacral stenosis and one had discospondylitis. All dogs had failed medical management prior to surgery. Of 32 bicortical pedicle screws placed, 30 were fully contained inside the pedicle and 2 were partially breaching the vertebral canal (less than one-third of the screw diameter). Postoperative CT revealed good alignment of L7-S1 in all planes. CONCLUSION:  This technique enabled an accurate and safe placement of pedicle screws in the lumbosacral region of dogs with lumbosacral disease. Three-dimensional, printed patient-specific drill guides are a safe and effective method of placing pedicle screws in dogs with lumbosacral disease.