A 58-year-old woman was referred for neurosurgical evaluation because of a 2-year history of rapid decline in bilateral motor functioning. Ten years earlier, she underwent an L4 and L5 laminectomy for cord detethering at an outside facility but had no meaningful improvement. Since then, she had experienced a gradual deterioration in her ambulation. Magnetic resonance imaging (MRI) demonstrated persistent evidence of cord tethering, with an L4/L5 lipomyelomeningocele extending to the sacral hiatus. Notably, prominent flow voids were also seen within the ventral subarachnoid space, with the most caudal draining vessel extending below the S2 sacral body. She had 3/5 strength in her left leg, 4/5 strength in her right, globally diminished sensation to light touch, and pin prick, as well as some bladder urgency. The patient did endorse some lower back pain but also has a history of chronic lower back pain. A diagnostic spinal angiogram showed evidence of a DAVF with arterial feeders from the bilateral lateral sacral arteries and right internal iliac artery with venous drainage to a dilated perimedullary vein. The patient underwent Onyx embolization of both feeding right and left lateral sacral arteries.\nThree months later, the patient exhibited marked improvement in her leg strength and sensation, improved 4-5/5 strength throughout her lower extremities, improved walking with assistance, and marked improvement in balance. At her 6-month follow-up, however, she reported stagnant functional capacity, with worsening of her left leg function that began after a ground-level fall. Physical examination revealed stable to improved right leg strength with subtle worsening of left leg strength (3-4/5). MRI revealed decreased flow voids compared with those seen on the prior study with no evidence of a new abnormality; however, one month later, evaluation revealed globally decreased lower extremity strength (3/5). Repeat spinal angiogram and lumbar MRI revealed new collateralized supply from the right internal iliac artery and lateral sacral branches. The DAVF now extended into the lipomyelomeningocele with dilated draining veins rostrally and spinal canal involvement.\nThe findings of redeveloping DAVF and the patient's clinical condition prompted us to recommend lipomyelomeningocele exploration/resection, DAVF ligation, and cord detethering. A standard midline approach was utilized, and a grossly abnormal fatty myelomeningocele was circumferentially dissected (). Intradural exploration demonstrated diffuse blood supply tracking through the lipomyelomeningocele with a large draining vein ventral to a tethered filum. The filum was sectioned, and the DAVF was clipped and ligated well into the arterialized vein. The remaining lipomyelomeningocele was mobilized and resected ().\nSix months after surgery, the patient regained full motor function of her proximal lower extremities with 5/5 strength throughout and 5/5 and 4/5 strength in her distal right and left lower extremities, respectively. MRI of the thoracic spine demonstrated marked improvement in the appearance of the spinal DAVF, with the tortuous vessels no longer evident. Follow-up spinal angiogram showed no evidence of residual DAVF or early draining vein ().
A 53-year-old man with no significant past medical history was admitted to our hospital because of pain in the lower-extremities and gait disturbance. His gait disturbance noticed by his family when he was 30 years of age. At age 51, he was found to have a spinal lipoma at a neighboring hospital and was referred to our institution. His lower extremity pain and gait disturbance worsened while he was under observation and he was admitted for further examination. Manual muscle testing revealed lower limb paresis that was more pronounced on the right side. The patellar tendon reflex was not exaggerated on either side, but the Achilles tendon reflex was hyperactive and the Babinski sign was positive on both sides. There was no evidence of bladder or bowel disturbance, and the lumbar JOA score was 10/29. MRI of the spine revealed a spinal lipoma at the L2/3 level and a flow void dorsal to the spinal cord at the level of the conus medullaris (Fig. ). MRA revealed tortuous blood vessels within the spinal lipoma, as in Case 1 (Fig. ). Subsequent angiography revealed an arteriovenous shunt from the right second lumbar artery. The radiculopial artery entered the spinal canal from its ventral aspect to form a arterio-venous shunt within the lipoma. A vein from the shunt region drained into the juxtamedullary vein within the spinal canal, and formed a congestion of the venous circulation (Fig. ).\nDiagnosis was sAVF arising within the spinal lipoma, and embolization and possible surgery was scheduled. First, embolization was performed for the second lumbar artery, the feeding artery for the shunt. A xylocaine test at the feeding artery showed transient depression of MEP (as in Case 1) in the right leg muscles. However, we carried out embolization therapy as we judged the risk would be low as long as embolization was confined solely within the shunt. Because of the presence of multiple feeding arteries, the minor feeder was embolized with a coil first and then N-butyl-cyanoacrylate was injected through one of the main feeders into the shunt zone to occlude it. This did not achieve complete embolization, and surgical excision was deemed necessary. The shunt-containing lipoma was resected as far as possible. An abundance of blood vessels was confirmed within the lipoma. Intraoperative angiography confirmed there was no remaining shunt after the resection.\nAfter surgery, lower limb pain and muscle strength were improved on both sides. At 1month after surgery, lumbar JOA score was 14/29. At 1 year, angiographic examination showed no vascular abnormalities. Although the patient’s low back pain and leg numbness persisted, muscle strength and ADL score were improved. His lumbar JOA score was further improved to 17/29.