A Spinal Cord Stimulator (SCS) is an implanted medical device designed to manage chronic pain by delivering low-level electrical impulses to the spinal cord. This electrical current modifies the pain signals traveling to the brain, often replacing the sensation of pain with a mild tingling feeling or providing pain relief without any sensation. While SCS therapy offers a promising alternative for individuals whose pain has not responded to conservative treatments, it is an invasive procedure involving hardware placement. It is important to understand the potential complications, limitations, and disadvantages that can occur with this form of chronic pain management.
Risks Associated with the Implant Procedure
The process of implanting a Spinal Cord Stimulator involves surgery, which carries inherent risks. One serious risk is infection, which can occur superficially at the incision site or more deeply around the implanted components. Deep infection often necessitates the complete removal of the device and the interruption of therapy to prevent serious health issues, such as spinal infection or sepsis.
Another risk involves bleeding, which can result in a collection of blood (hematoma) in the epidural space or around the pulse generator site. Though rare, placing the leads near the spinal cord can cause temporary or permanent nerve damage or neurological injury, though imaging during placement helps reduce this possibility. A cerebrospinal fluid (CSF) leak is also possible if the protective layer surrounding the spinal cord is punctured during lead placement, causing severe headaches that worsen when sitting or standing.
Device Malfunction and Hardware Issues
Device-related complications are a significant disadvantage of SCS therapy, often requiring additional surgical procedures to correct the problem. The most frequently reported hardware issue is lead migration, where the implanted electrodes shift from their intended position near the spinal cord. This movement can drastically reduce the pain-relieving effect or cause the stimulation to be felt in an uncomfortable or ineffective area.
Beyond movement, the leads themselves can suffer mechanical failure, such as breakage or insulation failure, which interrupts the electrical signal delivery. The Implanted Pulse Generator (IPG), which contains the battery, can also malfunction or fail prematurely. Rechargeable IPGs require frequent recharging, and non-rechargeable batteries have a finite lifespan, often lasting around four to five years. The depletion of the battery necessitates a replacement surgery, meaning patients must undergo at least one additional operation during the system’s lifetime.
Adverse Stimulation Effects and Efficacy Failure
Even when the hardware is functioning correctly, patients can experience drawbacks related to the electrical stimulation itself and the therapeutic outcome. Some individuals find the tingling sensation generated by older SCS systems to be bothersome, distracting, or uncomfortable. Worse, patients may experience sudden, unwanted sensations described as jolting, burning, or shocking, which often signal a slight shift in the lead’s position or a programming issue. This erratic or unpleasant stimulation can be highly disruptive to daily life.
Pain at the generator implant site, even without infection, is another common biologic complication that can cause chronic discomfort. A major concern is the failure of the device to provide adequate pain relief, either immediately after implantation (primary failure) or over time (loss of efficacy). This gradual loss of pain relief, sometimes referred to as tolerance, can occur due to changes in the surrounding neural tissue or the body’s adjustment to the stimulation, often requiring complex and frequent reprogramming.
Long-Term Restrictions and Revision Needs
Living with an implanted medical device introduces ongoing limitations that affect a patient’s medical care and lifestyle. A significant restriction involves diagnostic imaging, as not all SCS systems are compatible with Magnetic Resonance Imaging (MRI) machines. Using a non-compatible MRI can seriously damage the device or cause severe tissue injury. While newer devices are often “MRI-conditional,” this still imposes restrictions on the type of scan, field strength, and body area that can be safely imaged.
The presence of the device also means a continuous risk of electromagnetic interference from external sources, which can temporarily disrupt the stimulation. Furthermore, the initial cost of the device, the procedure, and the long-term maintenance, including battery replacements and programming appointments, represents a substantial financial disadvantage. The most significant long-term disadvantage is the high probability of needing subsequent surgery. Studies indicate that a substantial percentage of patients require a revision procedure due to hardware complications, and in some cohorts, more than half eventually have the entire SCS system removed due to recurring complications or complete loss of pain relief.