Spinal arachnoid diverticula in cats: clinical presentation, diagnostic imaging findings, treatment, and outcome

Spinal arachnoid diverticulum (SAD) is considered a rare disease in cats. Previous reports mainly classified feline SAD as acquired.
Hypothesis/Objectives
The aim of this study was to describe the signalment, clinical presentation, diagnostic imaging findings and outcome in a group of cats with SAD.
Animals
Twenty-one client-owned cats.
Methods
Multicenter observational retrospective review of the medical records of cats diagnosed with SAD by magnetic resonance imaging.
Results
Most cats were Domestic Short Hair (67%), male (63%), and had a wide range of ages (18 weeks to 13 years old). Neuroanatomical localization was consistent with a T3-L3 myelopathy in 18 cats (86%) and C1-C5 myelopathy in 3 cats (14%). One cat with a C1-C5 myelopathy demonstrated bilateral vestibular clinical signs. One cat (5%) had fecal incontinence. Most cats demonstrated a chronic, progressive, non-lateralized, non-painful myelopathy. No underlying previous or concurrent spinal condition was found in 48% of the cats. No difference in age, body weight, breed, sex, treatment, or outcome was found between cats with or without a concurrent spinal disorder. One cat was euthanized after diagnosis. Six cats improved, one deteriorated and one remained static after surgery, while three cats improved, five deteriorated and four remained static after medical management on the short-term outcome. Overall, 73% (8/11) of the cats deteriorated on available long-term follow up information.
Conclusions and clinical importance
This is the first report of presumably primary SAD diagnosed in cats. Although prognosis was considered favorable after treatment in the short-term outcome, a large proportion subsequently deteriorated.