Dorsal myelopathy secondary to epidural fibrous scar tissue around a spinal cord stimulation electrode

The authors describe a patient with delayed thoracic spinal cord compression due to fibrous scar tissue around an epidural electrode used in spinal cord stimulation (SCS). One year after implantation of the system the stimulation became ineffective, and 1 year later the patient developed progressive paraparesis. There was no evidence of device-related complications on plain radiographs and CT scans, so the system was removed to perform MRI studies. These studies showed a dorsal myelopathy secondary to scar tissue around the electrode. At surgery thick scar tissue was resected, and the patient's neurological symptoms improved. The histological examination confirmed fibrosis, and microbiological studies excluded chronic infection. As far as the authors are aware, this complication has never been reported before at the thoracic level. Scarring around SCS electrodes should be considered as a late complication and as a possible cause of the tolerance phenomenon.