Clinical-imaging aspects of the spinal arachnoid diverticulum in dog

Spinal arachnoid diverticulum is a focal, dilatative lesion of the arachnoid membrane, filled with cerebrospinal fluid and which can cause spinal cord compression of varying degrees. It can present as a primary or secondary, single or multiple lesion. Commonly, it affects the cervical segment in large dogs and the thoracolumbar segment in small dogs. The clinical picture is dominated by progressive proprioceptive ataxia with varying degrees of tetraparesis or paraparesis. The diagnosis of the lesion involves the use of myelography or CT-myelography to identify and locate the intradural arachnoid diverticulum. However, the gold standard method is represented by the MRI exam that determines the degree of damage to the spinal cord, as well as the identification of associated conditions.