Filar arteriovenous fistula mimicking upper motor neuron palsy: A case report with review of the literature

BACKGROUND: Filar A-V fistula is a rare entity. It requires a high degree of suspicion to diagnose. Magnetic resonance imaging (MRI) findings are often nonspecific and spinal angiogram is required to diagnose it. CASE DESCRIPTION: A 63-year-old male patient presented with Grade 4 spastic paraplegia and significant sensory disturbance below D8 level along with severe vesicorectal dysfunction. On imaging flow voids were present at lower dorsal and lumbar level in MRI (T2 sequence). Patient underwent spinal digital substraction angiography (DSA) which was suggestive of filar fistula at L4-L5 level. Patient underwent surgical exploration with L4-5 laminectomy. Feeding artery was identified using indigocyanine green (ICG) dye and excised along with filum and dilated vessels. Patient recovered symptomatically in postoperative period. CONCLUSION: Filar fistula is a rare lesion and it presents with long standing progressive congestive myelopathy. It requires a high degree of suspicion to diagnose it. DSA is the gold standard for diagnosis and management planning. Surgical approach utilizing the ICG dye is best treatment options in such cases.