Tomographic, cadaveric and clinical study of safe corridors for insertion of implants in the thoracolumbar spine of dogs and cats using a lateral approach

Objectives: This study aimed to: describe a lateral vertebral corridor (T6-L7) for the implantation of screws and polymethylmethacrylate to treat thoracolumbar vertebral injuries; assess the feasibility and safety of this approach using computed tomography; assess the learning curve of this technique in canine cadavers; and assess the outcomes in injured dogs and cats in a retrospective clinical study. Materials and Methods: Tomographic study: Lateral vertebral corridors were defined using computed tomography images of normal canine spines in the transverse plane. Cadaveric study: Corridors were drilled by a novice neurosurgeon on the cadavers, and deviation from an angle of 90° was evaluated on computed tomography in chronological order to assess the learning curve. Clinical study: The medical records (from 2008 to 2022) of dogs and cats treated for thoracolumbar vertebral injury using the lateral approach were reviewed. Results: Computed tomography revealed that the lateral corridors were safe and effective. A progressive reduction in the deviation between the measured and ideal insertion angles was observed in the cadaveric part of the study. Overall, 17/30 animals (56.7%) regained the ability to walk without assistance postoperatively and 3/11 animals (27.3%) that had lost deep pain sensation. There were 3/30 (10%) minor complications and 8/30 (26.7%) major complications, including perioperative death and euthanasia. Clinical Significance: Lateral vertebral corridors with an orientation angle of 90° may be safely used in caudal thoracic and lumbar vertebrae (T6-L7) in a freehand technique to treat vertebral fractures and/or luxations in dogs and cats.