Cervical cord compression due to delayed scarring around epidural electrodes used in spinal cord stimulation

The authors report on 2 cases of delayed compression of the cervical spinal cord by dense scar tissue forming around epidural electrodes implanted for spinal cord stimulation (SCS). This complication has not been previously reported. Myelopathy developed in 2 patients 5 and 16 years after the surgical placement of a cervical epidural electrode. Prior to myelopathy, both patients experienced a tolerance phenomenon. Magnetic resonance imaging in both cases showed severe compression of the spinal cord by the electrode. At surgery, thick scar tissue surrounding the electrode and compressing the posterior aspect of the cord was discovered. Both patients experienced a full recovery following the removal of both scar tissue and the electrode. Medical and paramedical staff dealing with SCS should be aware of this severe and delayed complication. In addition, the development of epidural fibrosis can explain the occurrence of tolerance.