ObjectiveTo determine the accuracy of pedicle screw placement in the thoracic spine of dogs with spinal deformities with three‐dimensionally (3D) printed patient‐specific drill guides.Study designRetrospective study.Sample populationSix dogs in which sixty pedicle screws were placed in the thoracolumbar spine.MethodsMedical records were searched between June 2017 and June 2018 for dogs with clinical signs associated with a thoracolumbar vertebral malformation. Inclusion criteria included MRI and computed tomography (CT) data that were used to create 3D printed patient‐specific drill guides. All dogs were stabilized dorsally with guided bicortical pedicle screws and polymethylmethacrylate. Accuracy of screw placement was assessed by immediately postoperative CT according to a modified Zdichavsky classification.ResultsFive pugs and one French bulldog met the inclusion criteria. Sixty bicortical pedicle screws were placed; 96.7% were graded as I (optimal placement), and 3.3% were classified as IIa (partial penetration of the medial pedicle wall) according to a modified Zdichavsky classification.ConclusionThree‐dimensionally printed patient‐specific drill guides allowed safe and accurate placement of pedicle screws in the thoracolumbar spine in dogs with vertebral malformation.Clinical significanceThree‐dimensionally printed patient‐specific drill guides are a safe and effective method of placing pedicle screws in dogs with thoracolumbar vertebral malformations.

A two-year-old Cocker Spaniel was presented for investigation of lethargy and cranial nerve deficits. Neurological examination revealed multiple cranial nerves deficits and haematology and serum biochemistry revealed mild anaemia. MRI of the brain revealed caudoventral cerebellar herniation and cervical syringohydromyelia, while both MRI and CT revealed hyperostosis of the calvarium and narrowing of the calvarial foramina. Radiographs demonstrated marked osteosclerosis of the skull, vertebrae, sternebrae, ribs and long bones of the limbs. Further biochemistry revealed total calcium, ionised calcium and vitamin D levels to be unremarkable. This led to a diagnosis of osteopetrosis. Osteopetrosis is an extremely rare condition in dogs, with only sporadic cases being reported previously in the literature.