Surgical treatment of an intradural and intramedullary arteriovenous malformation in a young Rhodesian Ridgeback

An 18‐month‐old, female, entire Rhodesian Ridgeback presented for evaluation of a 2‐month history of progressive, non‐painful paraparesis and pelvic‐limb ataxia. Neurological examination was compatible with an L4–S1 myelopathy. Magnetic resonance imaging of the vertebral column revealed multifocal, tortuous, tubular, well‐defined, T1W and T2W hypointense, non‐to‐moderately heterogeneously contrast‐enhancing structures in the subarachnoid space and intramedullary, extending from T1 to cranial L5 vertebrae. Differential diagnoses included developmental abnormalities of vascular origin, such as arteriovenous malformation or aberrant parasitic migration. Parasitology testing was negative. The arteriovenous malformation was surgically removed via a continuous T6–T10 left‐sided dorsal‐laminectomy and T10–T11 hemilaminectomy. After durectomy, the visible abnormal vascular structures were isolated, followed intramedullary, and removed via bipolar cauterisation. Histopathology of the abnormal vascular structures was compatible with the arterial wall. Ten‐month follow‐up revealed mild pelvic limb ataxia. This is the first report of successful surgical treatment for intradural and intramedullary arteriovenous malformation in a dog.