Arteriovenous fistula of the filum terminale misdiagnosed and previously operated as lower lumbar degenerative disease

Abstract

Filum terminale arteriovenous fistula (FTAVF) presenting as a cause of failed back surgery syndrome is a rare entity. We report a 48-year-old male patient who presented with clinical features of a conus medullaris/cauda equina lesion. He had upper and lower motor neuron signs in both the lower limbs with autonomic dysfunction. The patient was misdiagnosed and was operated twice earlier for lumbar canal stenosis and disc prolapse. After reviewing his clinical and radiological findings a diagnosis of FTAVF was made. He underwent surgery and there was a significant improvement in his neurological functions. We discuss the case and review the literature on FTAVF's.

Keywords: Failed back surgery syndrome; Filum terminale arteriovenous fistula.

Fig. 1

Sagittal (A) and coronal (B) T2-weighted magnetic resonance imaging showing hyperintense intramedullary changes in the lower thoracic cord extending to the conus medullaris with superficial dilated tortuous vessels.

Fig. 2

Spinal angiogram anteroposterior (A) and lateral (B) view showing two large calibre vessels with fistulous connection.

Fig. 3

(A) Sagittal magnetic resonance imaging images done in 2008 showing dilated vessels in the subarachnoid space with evidence of previous surgery and (B) intramedullary signal changes in the lower thoracic spinal cord.

Fig. 4

Intraoperative image showing two large calibre vessels along the filum terminale with prominent tortuous vessels over the cauda equina.