Implantable Pain Control Devices: The Inside Story
WebMD Live Events Transcript
When pain controls your life, implantable devices from nerve stimulators to intrathecal drug delivery systems can help conquer pain from within. Pain management expert Leo Kapural, MD, PhD, explained how these devices work, who can benefit from them, and more when he joined us on Dec. 9, 2004.
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Welcome to WebMD Live, Dr. Kapural. Thanks for joining us today. How long have implantable pain devices been in use?
They've been around for a relatively long time. I remember that a mentor of mine, Dr. Stanton Hicks, implanted one in 1981, but the design and the quality of those devices were not that great and the failure rate was incredibly higher. Over the last six years the devices became so well made that we are now very comfortable in implanting, especially spinal cord stimulating systems.
What are the primary types of implantable devices used to treat chronic pain?
There are two groups of implantable devices:
- Spinal cord and peripheral nerve stimulators, which use electric current to decrease the pain.
- Intrathecal and epidural subcutaneous devices, referred to as pumps.
How would you know you're a candidate for the implant? What qualifications are there or is it just up to the pain management doctor?
Well, there are certain pains that respond to stimulation, and some pains that do not. For example, acute pain following surgery would not respond to spinal cord stimulation. Inflammatory pains in general would not respond to spinal cord stimulation. On the other hand, if you have a pain from nerve injury, that in general responds to stimulation.
It's a different story with intrathecal devices, like the pumps, where a large range of those pains do respond to intrathecal infusion.
So how is the decision made to use one type instead of another?
On initial evaluation we examine the patient, look into all of the diagnostic evaluations done in the past, and then we come up with an idea of where the pain is coming from and then decide which way to go. In addition, a psychological evaluation is done to determine if the patient is fit to have an implantable device.
I am scheduled to have the temporary stimulator in my lower back tomorrow morning. What can I expect?
The temporary stimulation, or trial stimulation, determines if the electrical stimulation will be successful in treating your pain. Therefore when we implant the spinal cord stimulator with a temporary lead with a battery, we leave the patient home for seven to 14 days to try that device, and he has to report back to us on two different entities: pain relief and functional capacity, or how well they can do things.
So what you can expect tomorrow during the trial is the positioning of that device in your back and then after that you will be discharged from the outpatient setting and left for at least a week to try that stimulating device.
How long does the procedure take?
To position the lead for the trial takes only 20 to 40 minutes. To have a full implant after we find out the trial was successful takes about 2 hours. For the pump it's similar, about two hours for the whole procedure.
Is this why a trial run is done with a stimulator? Not just to place the leads but also to test for effectiveness?