Resident in Neurology/Neurosurgery University of Illinois Veterinary Teaching Hospital Urbana, Illinois
Performance Comparison Between Three-Dimensionally Printed Patient-Specific Drill Guides and the Conventional Free-Hand Technique for Vertebral Implant Placement in the Canine Thoracolumbar Spine: An Ex Vivo Study. Guevara F1, Harper T1, Moran C1, Hague DW1, Hamel P.2, Schaeffer D1, Foss K1. 1University of Illinois Urbana-Champaign, College of Veterinary Medicine, Urbana, IL; 2Boundary Bay Veterinary Specialty Hospital, Vancouver, BC, Canada.
Surgical stabilization of the vertebral column is often indicated for dogs with severe myelopathic signs and or refractory pain secondary to spinal instability. Pin or screw and polymethyl methacrylate (PMMA) constructs are used most commonly in veterinary medicine. Although this technique is an accepted standard of care, it is technically challenging and can lead to life-threatening complications. The objective of this study was to compare performance between 3D printed patient-specific drill guides (3DPG) and the conventional freehand technique (FH) for vertebral implant placement in canine cadaveric thoracolumbar spines. We hypothesized that 3DPG will demonstrate better accuracy of implant placement than the traditional FH method. Twenty-four medium-to-large-breed canine cadavers were collected. Computed tomography (CT) of each cadaveric spine was performed and optimal implant trajectories were established bilaterally from T10 through L6. CT data was used to create patient-specific drill guides for the vertebrae of interest. Each cadaver was randomly assigned to one of six veterinarians (board-certified and resident neurologists and surgeons) with varying levels of experience. For each cadaver, vertebrae were randomly assigned a surgical order and technique (3D or FH) for each side. Following implant placement, postoperative CT images were acquired, and accuracy of pin placement was assessed using a modified Zdichavsky classification. Pin placement with 3DPG was significantly more accurate (P < 0.001) than FH. The results of this study suggest that 3DPG is an effective technique for vertebral pin placement in the canine cadaveric spine. Evaluation of this technique in the clinical setting is warranted.