Short- and long-term outcome and magnetic resonance imaging findings after surgical treatment of thoracolumbar spinal arachnoid diverticula in 25 Pugs

Background: There is a successful outcome after surgical management of spinal arachnoid diverticula (SAD) in up to 82% of cases. Hypothesis/Objectives: We hypothesized that Pugs have favorable short-term and poor long-term prognosis after surgical treatment of thoracolumbar SAD. The aim of the present investigation was to describe clinical findings, short- and long-term outcomes, and follow-up magnetic resonance imaging (MRI) findings in Pugs with thoracolumbar SAD. Animals: Twenty-five client owned Pugs with 12-month follow-up information after surgical treatment of thoracolumbar SAD. Methods: Multicenter retrospective case series. All medical records were searched for Pugs diagnosed with SAD. Data regarding signalment, history, surgical procedure, outcome, histopathology, and follow-up MRI results were extracted. Results: Mean age at presentation was 7.32 (range 2-11) years, 80% were males. Short-term outcome was available in 25 dogs, and improvement was confirmed in 80% of dogs. Long-term outcome was available in 21 dogs, and deterioration was confirmed in 86% of cases, with late-onset recurrence of clinical signs after initial postsurgical improvement affecting 85% of Pugs. A moderate correlation (r = 0.50) was found between duration of clinical signs and outcome. In 8 dogs with deteriorating clinical signs, follow-up MRI revealed regrowth of the SAD in 2 cases, new SAD formation in 2 cases, and intramedullary T2W hyperintensity/syringomyelia in 6 cases. Conclusions and Clinical Importance: This study suggests that Pugs with thoracolumbar SAD do not have a favorable long-term prognosis after surgical treatment for reasons yet to be determined.