In this study, researchers review five years’ worth of results from using epidural spinal cord stimulation (SCS) units. All patients had chronic, intractable pain. The specific focus of the study was to identify causes of hardware failure. The hope is to design a better unit with fewer patient complications.
SCS systems consist of wires and electrodes (leads). They are implanted in the spine. Most of the 289 patients in this study had a diagnosis of complex regional pain syndrome (CRPS). The SCS unit was in the cervical (neck) or thoracic (mid-back) spine.
There were many problems with the SCS systems. Almost half of the patients had to have at least one more surgery. One of the most common causes of system failure was lead breakage.
Unit migration was also reported. Migration means it moved from where it was implanted and shifted to someplace else. Infection and poor pain control were two other complications. In some cases, the unit had to be repositioned because of pain or discomfort from the location of the device.
The authors took a close look at the causes and types of SCS failure. They noticed that surgical leads were more likely to break compared to percutaneous (under the skin) leads. A higher rate of lead migration and breakage in the cervical spine may be due to greater motion in this area.
Motion-induced stress on the SCS device is a major challenge to hardware engineers. The authors suggest with an overall hardware failure rate of 33.5 per cent, new designs for the hardware are needed. Patients should be told the risks of failure with SCS before having this operation. Success of revision surgeries is not optimal either.