Introduction: Technical complications of spinal cord stimulators (SCS) related to device breakage or mechanical failure persist despite improvements in surgical technique and hardware design. Anchoring technique is often blamed for lead body fractures and migration. Mechanical destruction of the lead due to high forces along the anchor-fascia complex may also occur. Studying such failures will direct improvements in design and implantation technique that may mitigate the potential for failures requiring reoperation.
Methods: A literature search for cases of SCS failure secondary to lead-anchor-fascia complex disruption did not yield any reports of this mechanism. We present two cases where the structure of the SCS paddle electrode was severely compromised.
Results: A 62 year-old male who had undergone high cervical SCS paddle lead placement sustained a motor vehicle collision. Imaging revealed migration of the paddle lead. The patient described worsening neck and arm pain, and revision was therefore performed. The paddle electrode had separated from the lead body at the junction. It appeared that traction on the lead had drawn it through the anchor, delaminating the paddle. A 40 year-old male reported loss of stimulation efficacy six months after thoracic SCS implantation. Plain films revealed the lead partially withdrawn from the epidural space, but programming adjustments regained effective coverage. Two months later, when efficacy was again lost, further out-migration of the lead with separation of the contacts from the paddle was noted on imaging. In both instances, paddle electrode damage appeared related to the proximity of the anchor.
Conclusions: Given that lead-anchor-fascia disruption is a possible failure mechanism for SCS, improvements in product design and surgical technique are necessary to avoid similar failures. Wireless technology, new “stretchy” lead materials, strategic placement of strain relief loops, and better lead-anchor design represent means by which this type of failure might be mitigated.
Patient Care: Many patients receive spinal cord stimulator devices to help improve pain and function. We try our best to prevent mechanical failure of these devices so that a reoperation can be avoided. However, mechanical failure does occur, and it is important to study these failures to help improve patient care. Here we demonstrate a failure mechanism that has not been described before. We introduce this failure point into the literature such that discussion about these failures will lead to new solutions that will prevent such mechanical failures in the future.
Learning Objectives: 1. Review of points of possible failure within the spinal cord stimulator system.
2. Describe two cases of failure at the lead-anchor-fascia complex.
3. Review of emerging changes to current technology as well as current surgical technique to improve on current stimulator systems to mitigate such failures.