SPINAL CORD STIMULATION
Spinal cord involves placing permanent electrodes in the spinal column as a long relieving modality. It is theorized to work by blocking the transmission of pain sensation to the brain. There is a similarity to transcutaneous electrical nerve stimulation (TENS) whereby electrical current is passed through surface electrodes in the region of ongoing pain thereby reducing that pain. However, spinal cord stimulation or more correctly dorsal column stimulation is a more effective and applicatable modality in the treatment of chronic daily pain. This technology has been around since the early 1970s and has helped thousands of patients in the treatment of various pain conditions.
The spinal cord stimulation system consists of one or two spinal leads and an implantable generator. If the patient is deemed a good candidate by their pain physician, the first step is to perform a trail of the stimulation. This involves placing one or two small leads in the spinal canal. The leads are secured to the patient’s back to an external generator.
A trial may go one for several days up to one week, but no longer due to the risks of infection (you don’t want to have leads entering the spinal region from the outside for too long a period of time).
A trial would be deemed successful if the following occur:
- Is the correct area of pain “covered”.
- Does the patient not find the sensation unpleasant?
- Does the stimulation alleviate a majority of the pain?
If all three questions are answered “Yes” then permanent implantation of the device can be performed. This would involve a second procedure whereas incisions are made to implant the entire system (leads in the spinal canal and the generator in subcutaneous tissue).
I have treated many patients with this device for both chronic neck and low back pain of various causes, with or without upper and lower extremity pain. Appropriate candidates are ones where conservative treatments, both medications and injection therapy, have failed; where surgery would not be beneficial; or where the patient is attempting to avoid surgery. Contraindications include patients with coagulation disorders or the use of blood thinners, for example.
Indications include patients with various conditions of the spinal column and nerves including such as degenerative disk disease, spinal stenosis, disk herniations with nerve impingement, vertebrogenic pain, reflex sympathetic dystrophy, or patients who have failed back surgery (so called “post-laminectomy pain syndrome”).
The advantages of this modality are that during the trial period the patient can see what the device “feels like” and how much pain is alleviated before entertaining permanent placement. This is opposed to surgery where once you’ve had it, you can’t take it back. Additionally, the device is 100% reversible. So even if you’ve had it for a time, the device can be removed at any time thereafter and you’re back to square one. It is safe for long term use and can improve patient’s pain, function, and quality of life. The device is controlled with an external patient programmer. Recently the device has become more sophisticated such that different programs can be set for different types of pain the patient may experiences at various times. For example there may be times that greater back pain is experienced, and others where leg pain occurs, and the stimulation can be changed by the patient to meet him/her needs in a dynamic fashion. Lastly, the device does not utilize medications and therefore there are no drug side effects such as drowsiness, disorientation, nausea or other problems such as drug addiction. It treats the specific are of pain without affecting the entire body.
Short term risks of both trial and permanent placement include infection, bleeding, headaches, failure to relieve pain, issues with the hardware, and nerve injury. Long term complications can involve device failure either involving a mal-position of the spinal leads leading to a lack of proper stimulation, or damage or other malfunction to the generator. Presently, there is a rechargeable battery which as a reported life span of nine years. Thereafter replacement of the generator through a minor surgical procedure is required. It must be realized that spinal cord stimulation is a palliative treatment in that it does not eliminate the source of pain but reduces the pain the patient experiences. There is no way of predicting who will receive benefit and who will not, which is why a trial is performed.
In conclusion, in the appropriate patient, spinal cord stimulation can be a very good pain relieving modality as part of an overall comprehensive pain management program. It is a very good treatment option in patients with conditions refractory to more conservative treatments and who wish to avoid or have failed surgery. I have personally used this to treat many patients improving their ability to function, perform various activities, and lead a more normal life.