Spinal cord stimulation, or SCS, has been around longer than I have. It was first used to treat pain in 1967, although it didn’t become widely used until the 1980s and FDA approved in 1989. SCS is used to treat pain that is traditionally from neuropathic pain (injury or damage to nerves). This includes peripheral neuropathy and CRPS. Other indications for SCS are pain after spine surgery, the term for this is failed back surgery syndrome. Now, before my surgical colleagues get mad at me, this term, failed back surgery syndrome does not mean that the work they did was incorrect, ineffective, or useless. What it means is that, even though they surgical repaired the defects in the discs or stabilized the spine with pedicle screws, the patient still has pain. This isn’t too uncommon. Many patients will tell me that after surgery, they no longer have drop foot or other weakness but the pain is still present. These patients are great candidates for SCS.
Let’s dig deeper into this topic. We will discuss the procedure to SCS, the effectiveness, and complications. There are a few major companies that are in the SCS space, they include Boston Scientific, Abbott, Medtronic, and Nevro as well a few newer contenders in the space, Nalu, Stim Wave, and Saluda. The differences in their capabilities is a post for another time but we will focus on Boston Scientific and use some of their images for this post.
On procedure day, the patient will enter into a pre-operative room where paperwork is completed as well as an IV started (sedation is recommended but not required). The patient will then be brought into the OR and placed face down on an OR bed. The patient will be sedated at this point if they elected to have this service. From here, the staff will sterilize the skin of the back or neck and apply sterile drapes to cover the area. A fluoroscopy (x-ray) unit will then take a picture of the T12-L1 interspace where the epidural needles will be inserted. The patient will then be administered lots of local anesthetic at the skin and deeper tissues to significantly minimize any procedural pain. Once the epidural needles are placed, the physician will insert the trial electrodes through the epidural needle (similar to what happens for a labor epidural, the difference benign an electrode versus a catheter that can drip medication into the epidural space).
The electrodes will be steered up the spine to about the T8 region. X-ray pictures will be taken to confirm that the electrodes are in the back of the epidural space, that they are almost perfectly midline, and that they end at the appropriate level. Once this is complete, the patient will wake from the sedation so that the company representative can ask the patient some questions. These questions evaluate electrode placement, questions like, do you feel a sensation on the right leg and left leg? Is that sensation equal? Do you feel it in the areas where you normally feel pain? Assuming that everything is in place and the patient feels it where they need it, then the needles are removed, the wire stylet inside the electrode is removed as well, but the electrodes remain in place. Everything is then sterilely secured to the skin. The patient will then have a remote to toggle through different programs to see how this affects their pain. The electrodes will be left in place for 5-7 days and then completely removed. This is the trial phase of the SCS procedure. If the patient notices success with the treatment, 50% or greater reduction in pain, better quality of life, decreased use of opioids (if taking), better sleep, etc. then the spinal cord stimulator can be surgical placed where the electrodes and the battery (also called the Implantable Pulse Generator or IPG) are completely buried under the skin, similar to a pacemaker.
The HALO study that was completed with Boston Scientific shows that average pain scores went from 8.2 pre-SCS to 2.5 with SCS. That is a dramatic reduction in pain and the technology has continued to get better. That same study also shows that with monotherapy, the responder rate is 71% but when combination therapy is used (multiple simultaneous waveforms targeting different pains) the responder rate increased to 88%. What does that mean to a potential patient? It means that they are very likely to get the pain relief they desire.
What are the drawbacks or complications? Well luckily, they are few. They do include the possibility for infection or nerve damage but the use of sterile technique and anti-biotics pre-surgery, as well as fluoroscopy, significantly decrease the likelihood of these issues. Bleeding is another possibility but unlikely, we will have patients stop all blood thinners (after discussion with that doctor) including NSAIDs and Aspirin prior to the procedure. Migration of the electrodes can occur but is unlikely as the surgically introduced electrodes are shorter and paddle-shaped.
SCS is safe and effective to treat pain in the neck/arms as well as the legs/low back. This treatment is helpful often when other therapies are not. SCS has changed the lives of my patients and has helped them to be themselves again.