Permanent monoparesis in a dog after intramedullary injection of iohexol into the lumbar spinal cord.

CASE HISTORY: An 8-year-old, spayed, Doberman Pinscher bitch presented for assessment of acute hindlimb paresis. CLINICAL FINDINGS: During a lumbar myelographic contrast study a small volume of iohexol contrast agent was inadvertently injected into the cord parenchyma. After surgical hemilaminectomy for an intervertebral disc extrusion at L1-2 the dog recovered use of one hindlimb, but had ongoing extensor weakness of the left hindlimb. Left femoral nerve function had not returned after 14 months. DIAGNOSIS: EMG findings 14 months after the incident indicated persistent femoral neuropathy consistent with the intramedullary contrast injection at L3-4. CLINICAL RELEVANCE: Inadvertent deposition of iohexol into spinal cord parenchyma may be rare, but if it occurs it can have long-lasting consequences.