Perimedullary arteriovenous fistulas (PMAVFs) of the conus medullaris are rare and
usually manifest with progressive myelopathy secondary to venous congestion resulting
from retrograde arterialization of the draining vein into the spinal cord. We present
a rare case of conus PMAVF presenting with remote intramedullary spinal cord hemorrhage
in the thoracic cord. A 37-year-old woman was transferred to our institute due to
sudden severe pain in the left lower leg and weakness of the lower extremities following
progressive paresthesia of the lower extremities. Magnetic resonance imaging of the
thoracic and lumbosacral spine revealed spinal cord congestion extending from the
conus medullaris to the level of T6 with intramedullary hemorrhage at the level of
T8–9 on the left side of the spinal cord. There were abnormal serpiginous intradural
flow voids along the anterior surface of the spinal cord extending from the level
of L2 to the lower cervical with venous varix at the level of T8–9, probably being
the source of hemorrhage. Spinal angiography confirmed conus PMAVF at the distal end
of the conus medullaris supplied by the sulco-commissural artery arising from the
enlarged anterior spinal artery originating from the left T11 intercostal artery with
cranial drainage through the dilated anterior spinal vein into the tortuous perimedullary
veins up to the lower cervical level. The patient underwent successful endovascular
treatment with N-butyl cyanoacrylate and had gradually improved until being ability
to walk independently without residual pain of the left lower leg. We speculated that
an increased venous flow into a varix may be considered an important risk factor of
hemorrhage.
Key-words:
Conus medullaris - filum terminale arteriovenous fistula - intramedullary hemorrhage
- perimedullary arteriovenous fistula - Type IV spinal cord arteriovenous malformations
