A 51-year-old man with no significant past medical history was admitted to our hospital because of gait disturbance and dysuria. He had a 2-year history of low back pain and numbness in both legs. His symptoms worsened 1 week earlier and he suddenly developed gait disturbance associated with bilateral leg weakness. On admission, manual muscle testing revealed paresis with distal dominance. Patellar tendon and Achilles tendon reflexes were not exaggerated. He had urinary retention and his lumbar Japanese Orthopedic Association (JOA) score was only 2/29, indicating severe physical impairment (the lower the score, the more severe the impairment). MRI of the spine revealed a spinal lipoma at the L5 level and a flow void dorsal to the spinal cord at approximately the level of the conus medullaris (Fig. ). MRA revealed tortuous blood vessels within the spinal lipoma (Fig. ). Subsequent angiography showed an arteriovenous shunt from the right lateral sacral artery. The feeding artery entered from the dorsal aspect into the lipoma, and then passed the shun zone, and entered the spinal canal primarily via the juxtamedullary vein (Fig. ).\nDiagnosis was a sAVF within a spinal lipoma, and the patient underwent ligation of the draining vein combined with embolization. Under general anesthesia, a catheter was inserted into the lateral sacral artery and advanced to just before the shunt of the fistula. Because a provocation test with lidocaine hydrochloride (hereafter, xylocaine test) showed depression of the motor-evoked potentials (MEP) in the left anterior tibial and anal muscles, embolization using any liquid embolic agent was deemed to be high risk and, we performed only proximal artery occlusion with a coil. Angiography of the internal iliac artery after embolization revealed slight remaining density in the shunt. Therefore, ligation of the draining vein was additionally performed under microscopic view, with transection of two draining veins in the lipoma. Postoperative angiography confirmed there was no remaining shunt.\nPostoperatively, bilateral lower limb muscle strength was slightly improved, but there was no appreciable improvement in vesico–rectal disturbances. At 1 month after surgery, his lumbar JOA score had improved to 10/29, but angiography revealed an arteriovenous shunt via a collateral route from the right lateral sacral artery (Fig. ). The patient experienced no aggravation of symptoms thereafter. Although his low back pain, leg numbness, and bladder dysfunction persisted, intermittent claudication, muscle weakness, and the ADL score were improved at 1 year after surgery. His lumbar JOA score was further improved to 13/29.
A 46-year-old male was admitted to our institute due to a history of progressive paraparesis for 2 weeks. Eight months earlier, he experienced severe left buttock pain radiating to left leg for 2 weeks. He was admitted to other private hospital and underwent discectomy L5-S1. Five months later, he suffered from right leg pain and urinary retention. He went back to the same private hospital and underwent revised surgery with spinal fusion L5-S1. Two weeks before hospitalization, he developed progressive paraparesis and constipation. He was unable to walk more than about 100 m. The patient went to another private hospital and was transferred to Prasat Neurological Institute for further investigation and proper treatment after performing MRI of the lumbosacral and thoracic spine. The neurological examination revealed the evidence of spastic paraparesis (muscle strength 3/5) and the lack of pinprick sensation below T10 level, impairment of proprioception, hyperreflexia, and presence of Babinski's sign in the lower extremities. The previous series of MRI of the lumbosacral and thoracic spine were retrospectively reviewed and revealed spinal canal stenosis and bilateral lateral recesses stenosis at L5-S1 level due to moderate diffuse annular disc bulging with moderate enlargement of facet joints and thickening of the ligamentum flavum []. There was an abnormal hyperintense T2 signal with patchy enhancement representing spinal cord congestion extending from the conus medullaris to the level of T4 with subtle perimedullary flow voids along ventral and dorsal cord surfaces [Figures and ]. Magnetic resonance (MR) myelography also showed “worm-like” appearance of the area from thoracic level to the conus medullaris []. MR angiography (MRA) of the thoracolumbar spine demonstrated early opacification of perimedullary venous plexus along anterior and posterior surfaces of spinal cord []. Furthermore, there was a curvilinear flow void, probably the dilated vein of the filum terminale, running from lower lumbar level to the conus medullaris []. Spinal angiography demonstrated SDAVF at the level of L5-S1, probably located on the left S1 nerve root sleeve, which is supplied by the left lateral sacral artery (LSA) originating from the internal iliac artery with venous drainage through the dilated radicular vein into the dilated vein of the filum terminale [Figure and ]. The artery of Adamkiewicz arose from the left L2 lumbar artery and left T9 intercostal artery. Transarterial embolization with N-butyl-cyanoacrylate (NBCA) through the left LSA was successfully performed with NBCA filling across the fistula into the proximal draining vein []. The patient had gradually improved until being the ability to walk independently 3 months later. His bowel and bladder controls had completely regained. Six months after the embolization, follow-up MRI of the thoracolumbar spine also confirmed completely regression of spinal cord congestion [].