Communicating hydrocephalus caused by an unruptured perimedullary arteriovenous fistula in the lumbar region of an infant

Abstract

Spinal arteriovenous malformations are rare in children, although perimedullary arteriovenous fistulas (PMAVFs) may account for up to 24% of spinal arteriovenous malformations in this age group. Reported presentations of PMAVFs have included progressive or acute myelopathic symptoms, pain, hematomyelia, and subarachnoid hemorrhage. No known reports of an unruptured PMAVF causing communicating hydrocephalus have been previously published. A 17-month-old girl presented to the authors' clinic with a 6-month history of back and leg pain, gait regression, constipation, and marked lumbar hyperlordosis due to a PMAVF. A brain MRI study also demonstrated advanced hydrocephalus. The patient underwent embolization with Onyx of 2 feeding arteries from the right L-1 and 1 feeding artery from the left L-1 lumbar arteries. Postembolization follow-up imaging demonstrated a reduction in size of the L-1 pedicles and no residual supply of the fistula. Three-year clinical follow-up showed normal bowel and bladder function with significant improvements in the patient's back pain, gait, and hyperlordosis. The patient's ventricular enlargement improved without direct management of her hydrocephalus. To the authors' knowledge, this is the first reported case of communicating hydrocephalus caused by an unruptured PMAVF. The authors postulate that the origin of hydrocephalus was either central venous hypertension caused by the high-flow fistula or a change in fluid dynamics reducing CSF resorption through arachnoid granulations in the lumbar region of the spinal cord. The exact role that spinal arachnoid granulations play in CSF resorption is not currently known. Regardless of pathogenesis, initial treatment should focus on management of the fistula with additional hydrocephalus management only when necessary.