
Spinal Cord Stimulation
What is spinal cord stimulation, and how does it work?
Spinal cord stimulation (SCS) involves a minimally invasive procedure during which electrical leads are placed in the posterior epidural space (the area between the vertebral canal and the spinal cord) to stimulate the dorsal columns (the sensory pathway of the central nervous system) and other neural structures. SCS is believed to inhibit chronic pain by way of the gate control theory (the larger nerve fibers stimulated by the SCS travel more quickly and close the gate in the spinal cord to the smaller nerve fibers that carry the pain signals) as well as other neuromodulation.1 2
There are several types of SCS. Tonic SCS, an early type of stimulation, uses a consistent stream of pulses at a set frequency of 40-100Hz, pulse width, and amplitude to primarily target the spinal cord’s lateral pain pathways (responsible for the sensory aspects of pain, such as locating the pain). Pain relief, however, with tonic SCS is often accompanied by paresthesias (burning/tingling sensation) in the patient’s limb(s) which can be uncomfortable. Newer SCS devices have become more refined, allowing patients to experience more significant and paresthesia-free pain relief.3 4 Burst SCS utilizes closely spaced, high-frequency stimuli and is thought to provide more selective modulation of the spinal cord’s medial pain pathways (responsible for the emotional aspects of pain, such as how unpleasant it feels) in addition to the lateral pain pathways.5 6 High frequency SCS ulitizes constant stimulation frequencies of 10kHz and has been found to be superior to tonic stimulation for treating back and leg pain.7 Finally, adaptive and closed-loop systems provide automatic adjustments based on positional changes and spinal cord activation, respectively, and have shown promising results in recent studies.8 9
What is a spinal cord stimulator trial and implantation?
Before a permanent SCS is implanted, a SCS trial is conducted, during which a temporary implant is placed to help determine if a patient will benefit from the device. If the patient experiences significant pain relief and improvement in function during activities of daily living during the trial period, the patient will then be referred for permanent stimulator implantation.
During the trial procedure, the patient is first positioned comfortably, face down on the procedure table, and the back is cleaned and sterilized. An area of the skin is numbed, and fluoroscopic (x-ray) guidance is then used to visualize the spine and help the physician safely guide a needle into the epidural space within the spinal canal. Two stimulator leads are directed through the needle and advanced up to the thoracic spine. After positioning, the leads are then connected to an external battery pack and activated. Directly after the procedure, the patient meets with a SCS representative who adjusts the stimulator settings to provide the most pain relief. After a 4-7 day trial period, the patient returns for a follow-up visit with the provider to remove the trial stimulator and assess improvements in pain and function. If the trial is successful, the patient is then referred to a spinal surgeon for permanent SCS implantation.10 The SCS devices currently implanted are MRI conditional, meaning that it is safe to undergo an MRI with the device as long as certain conditions are met (MRI mode activated, stimulation off, etc). On average, SCS batteries need to be recharged once a week, though newer devices with improved battery technology are now recharge-free with a battery life lasting up to 10 years.11
Who would benefit from spinal cord stimulation?
Current covered indications for SCS include patients with chronic intractable pain which have not responded to medical management, including spinal nerve root injuries, post-surgical (i.e.post-laminectomy/failed back syndrome) and post-traumatic pain, complex regional pain syndrome, arachnoiditis, phantom limb syndrome, post-herpetic neuralgia, cauda equina injury, incomplete spinal cord injury, plexopathy, and end-stage peripheral vascular disease.12 Newer studies have also looked at using SCS to treat diabetic neuropathy pain, chronic pelvic pain, and even for motor recovery after spinal cord injury.13 14 15 SCS is not appropriate for patients who have pain that would best be managed surgically.
Is spinal cord stimulation safe?
A 20 year literature review performed in 2004 showed that SCS is generally a safe and effective treatment for chronic pain conditions, with the most common technical complication being electrode migration (13.2%), and the most common biological complication being infection (3.4%).16 An updated review in 2014 came to a similar conclusion that SCS is a safe procedure, with most complications being non-life-threatening and reversible.17
In conclusion:
Spinal Cord Stimulation is a minimally invasive procedure, which may be helpful in treating chronic spine and nerve pain that is not controlled with other non-surgical treatments. As board-certified specialists in Physical Medicine and Rehabilitation (PM&R), we are experts in the evaluation and conservative management of spinal, musculoskeletal and neuropathic (nerve-related) diagnoses. At Desert Spine and Sports Physicians, we take the time to determine the most appropriate, evidence based, non-surgical treatment for each patient. Spinal cord stimulator trials are performed at our Phoenix, Mesa, and Scottsdale locations. If you have any further questions, feel free to contact us at Desert Spine and Sports Physicians.
References:
- Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965;150(3699):971-979. doi:10.1126/science.150.3699.971
- Nahm FS. From the torpedo fish to the spinal cord stimulator. Korean J Pain. 2020;33(2):97-98. doi:10.3344/kjp.2020.33.2.97
- Grider JS, Manchikanti L, Carayannopoulos A, et al. Effectiveness of Spinal Cord Stimulation in Chronic Spinal Pain: A Systematic Review. Pain Physician. 2016;19(1):E33-E54.
- Mekhail N, Levy RM, Deer TR, et al. Long-term safety and efficacy of closed-loop spinal cord stimulation to treat chronic back and leg pain (Evoke): a double-blind, randomised, controlled trial. Lancet Neurol. 2020;19(2):123-134. doi:10.1016/S1474-4422(19)30414-4
- De Ridder D, Plazier M, Kamerling N, Menovsky T, Vanneste S. Burst spinal cord stimulation for limb and back pain. World Neurosurg. 2013;80(5):642-649.e1. doi:10.1016/j.wneu.2013.01.040
- Kulkarni B, Bentley DE, Elliott R, et al. Attention to pain localization and unpleasantness discriminates the functions of the medial and lateral pain systems. Eur J Neurosci. 2005;21(11):3133-3142. doi:10.1111/j.1460-9568.2005.04098.x
- Kapural L, Yu C, Doust MW, et al. Novel 10-kHz High-frequency Therapy (HF10 Therapy) Is Superior to Traditional Low-frequency Spinal Cord Stimulation for the Treatment of Chronic Back and Leg Pain: The SENZA-RCT Randomized Controlled Trial. Anesthesiology. 2015;123(4):851-860. doi:10.1097/ALN.0000000000000774
- Schultz DM, Webster L, Kosek P, Dar U, Tan Y, Sun M. Sensor-driven position-adaptive spinal cord stimulation for chronic pain. Pain Physician. 2012;15(1):1-12.
- Mekhail N, Levy RM, Deer TR, et al. Long-term safety and efficacy of closed-loop spinal cord stimulation to treat chronic back and leg pain (Evoke): a double-blind, randomised, controlled trial. Lancet Neurol. 2020;19(2):123-134. doi:10.1016/S1474-4422(19)30414-4
- Spinal cord stimulation (updated) – desertspineandsports.com. https://www.desertspineandsports.com/wp-content/uploads/2020/06/SPINAL-CORD-STIMULATION-updated.pdf. Accessed May 2, 2022.
- Proclaim™ XR recharge-free SCS System. Proclaim™ XR Recharge-Free SCS System. https://www.neuromodulation.abbott/us/en/products/neurostimulators-chronic-pain/proclaim-xr-recharge-free-scs-system.html. Accessed May 1, 2022. Spinal cord stimulation (updated) – desertspineandsports.com. https://www.desertspineandsports.com/wp-content/uploads/2020/06/SPINAL-CORD-STIMULATION-updated.pdf. Accessed May 2, 2022.
- Spinal cord stimulation for chronic pain. CMS.gov Centers for Medicare & Medicaid Services. https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdId=36035&ver=26. Accessed April 18, 2022.
- Duarte RV, Nevitt S, Maden M, et al. Spinal cord stimulation for the management of painful diabetic neuropathy: a systematic review and meta-analysis of individual patient and aggregate data. Pain. 2021;162(11):2635-2643. doi:10.1097/j.pain.0000000000002262
- Tate JL, Stauss T, Li S, Rotte A, Subbaroyan J. A Prospective, Multi-Center, Clinical Trial of a 10-kHz Spinal Cord Stimulation System in the Treatment of Chronic Pelvic Pain. Pain Pract. 2021;21(1):45-53. doi:10.1111/papr.12932
- Harkema SJ, Legg Ditterline B, Wang S, et al. Epidural Spinal Cord Stimulation Training and Sustained Recovery of Cardiovascular Function in Individuals With Chronic Cervical Spinal Cord Injury. JAMA Neurol. 2018;75(12):1569-1571. doi:10.1001/jamaneurol.2018.2617
- Cameron T. Safety and efficacy of spinal cord stimulation for the treatment of chronic pain: a 20-year literature review. J Neurosurg. 2004;100(3 Suppl Spine):254-267. doi:10.3171/spi.2004.100.3.0254.
- Bendersky D, Yampolsky C. Is spinal cord stimulation safe? A review of its complications. World Neurosurg. 2014;82(6):1359-1368. doi:10.1016/j.wneu.2013.06.012