A 30-year-old female presented with a 10-year history of pain in the lumbosacral spine; she had had casual radiation to both lower limbs. After her first delivery, she developed back pain. The MRI demonstrated a tethered cord at the L4 level and a filum terminale lipoma. The MRI also showed tortuous veins on the spinal cord surface (Figure ). Nine years later, during the second pregnancy, she noted weakness and sensory loss, imbalance with urinary and fecal incontinence. On admission, she had bilateral plantar flexion weakness (grade 4 according to modified Medical Research Council system) and reduced sensation in the gluteal regions and legs, and plantar response. The Babinski and Rossolimo signs were present bilaterally. A repeat MRI revealed intraspinal T2 hyperintensive changes in the thoracic spine and conus (Figures ). Those changes were consistent with neurologic deficit and, after exclusion of inflammatory demyelinating diseases, based on a brain MRI and an aquaporin-4 antibody test, diagnosed as myelopathy. Due to described torturous veins on the spinal cord surface (Figure ), the patient underwent spinal digital subtraction angiography (DSA). The range of DSA was from the Th6 level to the coccygeal artery. The results did not reveal any vascular malformation. Therefore, the preliminary diagnosis was symptomatic TCS and filum terminale lipoma. In view of weakness and neurological deficit surgical spinal cord de-tethering, without lipoma resection was planned.\nThe sacral canal was opened with a median incision. The dura was thin and transparent. After a midline dura and arachnoid incision, a tumor was visualized that appeared to be a lipoma. It engulfed the filum terminale and spinal nerve roots caudally, to the S2 level. The S1 and S2 nerve roots were positioned lateral to the tumor. A thickened, tortuous, bright-red vessel was also noted on the filum terminale, running in the cranial direction. The external surface of the dura was explored bilaterally at the sacral level in search for a SDAVF. A clearly visible nidus was identified at the S3 level on the left side. An empirical test was performed to support this finding. A clip was placed on the arterialized vein, intradurally, for a few minutes. Then, the vessel on the filum terminale clearly changed color, from bright red into bluish gray, and its tension decreased. The SDAVF was then intradurally disconnected, and the nidus was extradurally coagulated. In addition, the filum terminale was cut, and samples of lipoma were taken for histology. The dura was sutured in a watertight fashion, and the wound was closed in layers.\nThe postoperative course was uneventful. A few days later, the patient was discharged. A follow-up MRI showed resolution of the myelopathic changes (Figures –). At the 1-year follow-up, the patient had considerably improved, with no incontinence or motor deficit.
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.