Spinal Cord Stimulation in St. Louis

A thin lead carrying electrical contacts is placed in the epidural space, just outside the spinal cord, and connected to a small generator implanted under the skin. The device delivers mild electrical impulses that alter how pain signals are processed as they travel toward the brain. Rather than treating the original injury, it changes the signal the nervous system is sending about it.

Nobody receives a permanent implant without first completing a trial. Temporary leads are placed percutaneously and worn for several days while normal daily activity resumes. The trial answers the only question that matters: does this reduce your pain enough, and reliably enough, to justify an implant? Patients who do not get a convincing response during the trial do not proceed.

The strongest candidates have neuropathic pain that has not responded to injections, medication or surgery. Common indications include persistent radicular leg pain, pain after spine surgery, and complex regional pain syndrome. It is generally considered after less invasive options such as epidural steroid injection have been tried.

Both the trial and the implant are outpatient procedures. Modern systems are programmable, so the stimulation pattern can be adjusted over time as your pain changes, and several waveform options exist if the first program is not the right fit. Device checks and reprogramming are part of ongoing care rather than a sign something has gone wrong.

The original rationale came from the gate control theory of pain proposed by Melzack and Wall in 1965, which held that stimulating large-diameter sensory fibers in the dorsal column could inhibit transmission of pain signals carried by smaller fibers. That model explained the tingling sensation older systems produced in the painful area, since the same fibers carry touch.

Modern understanding is broader. Stimulation also alters neurotransmitter activity in the dorsal horn and modulates supraspinal pathways, which is why newer high-frequency and burst waveforms relieve pain without producing any tingling at all. Practically, this means a device that does not feel like it is doing anything may still be working, and that a program producing no sensation is not a malfunction.

The landmark randomized comparison is Kumar and colleagues, published in Pain in 2007, a multicentre trial of spinal cord stimulation versus conventional medical management in failed back surgery syndrome, with results sustained at twenty-four months in the PROCESS follow-up. That evidence base is why persistent radicular pain after spine surgery is the best-established indication.

It is also why we insist on the trial period. The published outcomes come from populations selected by a successful trial, so a permanent implant placed without one is not supported by the same evidence. If your trial does not produce a convincing response, the honest conclusion is that the data predicting benefit does not apply to you.