Intramedullary Hemorrhage Caused by Lumbosacral Epidural Arteriovenous Fistula with Dual Retrograde Perimedullary Venous Draining Routes: A Case Report and Review of the Literature.

BACKGROUND: Spinal epidural arteriovenous fistulas (SEAVFs) are rare lesions with a low risk of hemorrhage. Most patients with lumbosacral SEAVFs with hemorrhagic events will develop a spinal epidural hematoma from epidural venous pouches. To the best of our knowledge, we have reported the first case of a lumbosacral SEAVF presenting with remote intramedullary hemorrhage in the conus medullaris. CASE DESCRIPTION: A 56-year-old man presented with sudden-onset severe paraparesis and bowel/bladder dysfunction. Magnetic resonance imaging of the thoracic and lumbosacral spine showed acute intramedullary hemorrhage in the conus medullaris surrounded by spinal cord congestion extending to T8, with perimedullary flow voids along the ventral and dorsal cord surfaces. Magnetic resonance angiography and spinal angiography confirmed the presence of a SEAVF with a large lumbosacral epidural venous lake supplied by dorsal somatic branches of bilateral L4 segmental arteries. Initially, the intradural venous drainage had been misinterpreted as a single route. The patient underwent surgical interruption of the dilated intradural draining vein after embolization of the feeding vessels. Another small intradural venous drainage route was found on the follow-up angiogram. The second operation with occlusion of the initial part of the epidural venous lake was sufficient to cure this lesion. CONCLUSIONS: With the significant improvement of our patient after treatment of the SEAVF, we speculated that the intramedullary hemorrhage, which had occurred in the area of spinal cord edema, might have resulted from severe venous hypertension, rather than hemorrhagic infarction of the spinal cord. Careful evaluation of the angioarchitecture of SEAVFs is imperative to determine the most effective treatment modality.

Safe resection of arteriovenous malformations in eloquent motor areas aided by functional imaging and intraoperative monitoring.

BACKGROUND: Arteriovenous malformations (AVMs) proximal to motor cortical areas or motor projection systems are challenging to manage because of the risk of severe sensory and motor impairment. Surgical indication in these cases therefore remains controversial. OBJECTIVE: To propose a standardized approach for centrally situated AVMs based on functional imaging and intraoperative electrophysiological evaluation. METHODS: We conducted a retrospective analysis of 15 patients who underwent surgical treatment for AVMs in motor cortical areas or proximal to motor projections. Preoperative assessment included functional magnetic resonance and 3-dimensional tractography. Operations were performed under continuous electrophysiological monitoring aided by direct brain stimulation. We identified critical bloody supply to the motor areas by temporary occluding the feeding vessels under electrophysiological monitoring. Clinical outcome was evaluated with the modified Rankin Scale. RESULTS: Total resection was achieved in 12 cases, whereas electrophysiology limited total extirpation in 3 cases. A significant reduction of motor evoked potentials by up to 15% of the initial values was associated with good recovery of motor function; in contrast, the disappearance of potentials correlated with long-term impairment. The mean follow-up time was 13 months, and clinical assessments revealed overall functional improvement (P < .05). After surgery, 11 patients were asymptomatic or presented with only minor neurological deficits. CONCLUSION: Surgical resection of AVMs in eloquent motor areas can be considered a safe option for selected cases when performed in conjunction with a detailed functional assessment. Possible selection criteria for surgical treatment are discussed in light of the presented clinical data.