Idiopathic herniation of the thoracic spinal cord: a case report and technique note. Ulivieri S., Oliveri G., Petrini C., D'Elia F. 2, Cuneo G.L. 3, Cerase A. 4 Units of Neurosurgery, and 4 Neuroradiology, Santa Maria alle Scotte Hospital, Siena, Italy 2 Unit of Radiology, and 3 Section of Neuroradiology, Department of Neurology, San Donato Hospital, Arezzo, Italy A 35-year-old man presented with insidiously progressive and disabling pain in the left leg. There was no history of trauma or surgery; neurological examination revealed features suggestive of thoracic level Brown-Squard syndrome. The patient underwent a thoracic laminectomy at T9T10. The dura was opened under the microscope and an atrophic spinal cord displaced to the left was visible. The spinal cord was incarcerated through a 2.5 cm wide anterolateral dural defect and had an exophytic edematous appearance. In order to perform an anterior untethering, the dentate ligament was transected and the nerve roots were preserved. The spinal cord was gently mobilised out of the dural defect. Notably, there were no major adhaesions and thus there was no need to manipulate the cord. Then, it was decided to position hemostatic material (Spongostan) and glue (Tissucol) around the defect and finally a sheet of collagenous membrane (DuraGen) anterior to the spinal cord. The wound was closed in layers without external cerebrospinal fluid drainage. No spinal cord monitoring was used. The initial post-operative neurological deficit was unchanged and there was no sign of cerebrospinal fluid leakage. The patient was discharged seven days after surgery to rehabilitation.