Delayed spinal cord injury following microchip placement in a dog.

A three-year-old female, entire Yorkshire Terrier dog was examined because it had progressive non-weight-bearing left forelimb lameness and tetraparesis of two weeks duration. Clinical signs were first observed following mating. Examination confirmed non-weight-bearing left forelimb lameness and tetraparesis. Left forelimb muscle atrophy was also noticed. Survey radiography revealed a metallic foreign body consistent with a microchip in close proximity to the left articular facets between the fifth and sixth cervical vertebrae. Computed tomography identified the exact location of the foreign body encroaching on the left dorsolateral vertebral canal, and osteolysis of the lamina of the sixth cervical vertebra. Surgical removal of the foreign body was performed via a dorsal approach to the caudal cervical vertebral column. Two weeks following surgery the dog showed return of left forelimb function and resolving tetraparesis. Microchip implantation had been performed three years previously.