A 66-year-old previously well man presented with an 18-year history of upper thoracic spine pain. The pain was initially intermittent and mild, but in the 14 months prior to presentation, it had gradually increased in severity and persistence. The pain radiated to the left side of the neck, and when severe, spread around both sides of the chest. The patient reported two episodes of left arm weakness lasting a few hours with spontaneous resolution, but denied paresthesia, sensory loss, or sphincter disturbance. There was no history of spinal surgery, trauma, or spinal disorders. Clinical examination demonstrated an upper thoracic spine gentle kyphosis. There were no abnormal findings on neurological motor, sensory, and reflex examination. A suboptimal quality MRI of the thoracic spine performed at a different institution was interpreted as an intradural mid-thoracic lesion, with a described intradural extramedullary mass indenting the dorsal aspect of the spinal cord. These findings were initially thought to be a dorsal arachnoid cyst. Repeat MRI at our institution demonstrated findings consistent with the characteristic features of ISCH. T2-weighted images showed anterior kinking and mild flattening of the spinal cord at T5, with widening of the subarachnoid space posterior to the cord and pulsation artifact within the CSF space []. The patient was treated with conservative management, with clinical and radiological surveillance. The patient remained neurologically stable at 4 months after presentation.
A 52-year-old male fell 10 years before presentation from a scaffolding. Immediately after this fall, he noticed a diffuse sensibility loss in his right leg, which did not improve. Remarkably, he did not notice temperature changes or pain in that leg. Gradually, the strength in his left leg diminished. In recent years, this has clearly been progressive. In his lower left leg, he noticed paresthesias. He had a normal erectile function, but was unable to ejaculate.\nOn neurological examination, his left leg was slightly paretic. Vital and gnostic sensibility loss were present on the right side below T8. Within the L4 dermatoma on the left side, the vital sensibility was lost. The reflexes of both legs were pathologically increased with a Babinski’s sign on both sides. Radiological examination revealed a herniation of the SC at T4–T5 (Figure ).\nDuring surgery, the dura was opened after a midline approach with laminectomy T4 and T5. The dentate ligaments were transected on both sides, allowing some manipulation of the SC. On the ventral side, a defect of the dura was seen, along with many adhesions from the dura to the SC. These were sharply transected from both sides. Finally, the SC was freed from the dural defect and a mass originating from the ventral part of the SC was developed from the dural defect (Figure ). To prevent re-herniation, an artificial graft was gently placed in front of the SC covering the defect and was fixated laterally to the dural sleeve. Throughout the entire surgery, MEPs, SSEPs, and D-waves were monitored. During manipulation, the signals diminished twice. After waiting for several minutes, the signals returned to a normal level. Post-operatively, the patient did not notice any new complaints. The neurology is his right leg remained unaltered three months after surgery, whereas the symptoms in his left leg had improved.