Spinal cord stimulation: what is it and how does it work?
The spinal cord is a vital part of the central nervous system, acting as a communication highway between the body and the brain. It transmits both sensory information, such as touch, temperature, and pressure, and also pain signals. In many cases of chronic pain, the spinal cord becomes overly sensitive or processes pain signals abnormally, even in the absence of ongoing tissue damage.
This altered processing can lead to persistent pain, often disproportionate to any clear physical injury. When traditional pain treatments have failed or provided only limited relief, spinal cord stimulation may play a valuable role in providing relief, as a consultant in pain medicine describes in this article.
What is spinal cord stimulation?
Spinal cord stimulation (SCS) is a medical treatment designed to interrupt pain signals before they reach the brain. This is achieved by delivering mild electrical impulses directly to the spinal cord using a device called a spinal cord stimulator.
The device consists of three main components: a small pulse generator implanted under the skin, thin wires (electrodes) placed near the spinal cord, and a handheld remote control. The stimulation does not remove the source of pain but modifies how pain is perceived, often replacing it with a mild tingling sensation or significantly reducing its intensity.
Conditions treated with spinal cord stimulation
Spinal cord stimulation is most often considered when other therapies—such as medication, physiotherapy, or injections—have not provided sufficient relief. It is commonly used to manage:
- Failed back surgery syndrome (persistent pain after spinal surgery)
- Complex regional pain syndrome (CRPS)
- Peripheral neuropathic pain (such as diabetic nerve pain)
- Post-surgical nerve pain
- Ischaemic pain, including some cases of angina or peripheral vascular disease
It is important to note that not all types of pain respond to spinal cord stimulation. The suitability of this treatment depends on careful patient selection and a thorough assessment by a pain specialist.
The implantation procedure
Before the device is permanently implanted, patients undergo a trial period, usually lasting five to ten days. During this time, temporary electrodes are inserted through a needle into the epidural space near the spinal cord. The wires are connected to an external stimulator, allowing the patient to assess how well the treatment manages their pain.
If the trial proves successful (typically defined as at least 50% reduction in pain) patients may proceed to permanent implantation. This is done in a sterile operating theatre, often under local anaesthesia with sedation. The permanent electrodes are placed in the same location, and a small generator is implanted, usually in the lower back or abdomen. The patient can control the device using a wireless remote.
What to expect after spinal cord stimulation
Recovery from the procedure is usually quick, with most patients resuming light activity within a few days. However, strenuous activity, particularly bending and twisting, should be avoided for several weeks to allow the electrodes to stabilise.
As with any medical procedure, there are potential risks. These include infection, bleeding, movement of the electrodes, and, rarely, nerve injury. Some patients may find the tingling sensation from stimulation unpleasant or develop tolerance over time, requiring adjustments to the device settings.
On the other hand, many patients experience significant improvements in pain, increased mobility, and reduced reliance on pain medication. A successful outcome often requires close follow-up and occasional reprogramming of the device to maintain optimal results.