3D Printed Patient-Specific Drill Guide for Percutaneous Pedicle Screw Fixation in Lumbosacral Vertebrae in Dogs: A Cadaveric Study and Clinical Case Report

OBJECTIVE:To evaluate the feasibility, accuracy, and safety of percutaneous pedicle screw fixation (PPSF) in the canine lumbosacral junction using three-dimensional (3D)-printed patient-specific drill guides (PSGs). STUDY DESIGN:Cadaveric study and clinical case report. SAMPLE POPULATION:A total of 13 Beagle cadavers and one 5-year-old German Shepherd. METHODS:In each cadaver, one side underwent 3D-PSG-assisted PPSF by a novice surgeon and freehand PPSF on the contralateral side by an experienced surgeon. Outcomes included operative time (min), fluoroscopic counts, incision length (mm), vertebral canal breach (grade 0-2; grade 2 defined as relevant), and angular deviation (degrees). The clinical case underwent unilateral biportal endoscopy laminectomy and discectomy followed by 3D-PSG-assisted PPSF. RESULTS:Operative times were comparable (PSG: 22.65 ± 2.71 min; freehand: 24.82 ± 5.00 min; p = .139). Fluoroscopic acquisitions were fewer with 3D-PSG (median 5 [5-8]) than freehand (9 [7-14]; p = .003). At L7, canal breach occurred in 1/13 (PSG) and 6/13 (freehand; p = .073); relevant were 1/1 and 4/6, respectively. At S1, breach rates did not differ: 3/13 (PSG) and 2/13 (freehand; p = 1.000); relevant were 1/3 and 1/2, respectively. Angle deviations at L7 were smaller in the 3D-PSG (sagittal 2.58° and 5.82°, p = .018; transverse 6.4° and 12.8°, p = .036). No significant differences at S1. In the clinical case, minor breaches occurred at L7 left (medial) and S1 right (cranial). The dog exhibited normal gait at 3 months. CONCLUSION:3D-PSG-assisted PPSF at the canine lumbosacral junction was feasible, with improved screw placement accuracy at L7 and reduced fluoroscopic exposure. CLINICAL SIGNIFICANCE:3D-PSGs may standardize screw trajectory control across surgeon experience levels.