Objective: Implantation of a spinal cord stimulator (SCS) is one option for pain control in individuals with chronic lumbosacral radicular or axial lumbar pain. The expected positioning of SCSs based on the location of pain, the types of electrodes (percutaneous vs surgical paddle), and the types of electrode arrays and the potential complications have not been described to date in the radiology literature.
Materials and methods: A 5-year retrospective review of the radiology information system at our institution revealed 24 patients with images of 36 SCSs. Those images were reviewed to identify the location and type of electrodes as well as the location of the lead within the spinal canal. Not all implantable pulse generators were within the radiologic field of view. Complications identified by reviewing medical records were correlated with imaging findings.
Results: Fourteen different types of electrodes were identified. Most were placed in the thoracic spine only, but six thoracolumbar and two cervical spine electrodes were also present. We measured the position of the electrodes within the spinal canal on 26 CT studies of the 24 patients. On 22 of 26 CT studies, the electrodes were placed in the epidural space in the posterior one third of the spinal canal. Complications included misplaced, retained, and broken leads; puncture of the thecal sac; infection; and hematoma.
Conclusion: Radiologists should be familiar with the different types of electrodes and typical spinal locations of electrodes, leads, and implantable pulse generators. Improper placement of electrodes may lead to ineffective pain relief or to other complications.