Pain, Pain Go Away

The pain response is a built-in warning system, nature’s way of protecting us from further harm. Chronic pain is more like nature’s nagging nuisance.

“It no longer serves a useful function,” says Steven P. Cohen, MD, chief of pain medicine at Johns Hopkins Medicine in Baltimore.

“It’s not a warning system that something is wrong, it becomes the disease in and of itself.”

Pain management specialists have a growing list of options to treat chronic pain. Here’s a review.

Neurostimulation or neuromodulation — the alteration of nerve activity through targeted delivery of a stimulus to a specific site in the body — can include things like spinal cord stimulation, dorsal root ganglion stimulation, deep brain stimulation and motor cortex stimulation.

For example, for spinal cord stimulation, 2 electrodes are placed at the back of the spinal cord, where they stimulate the dorsal columns to inhibit pain in the back of the legs.

“With spinal cord stimulators, people feel kind of a vibratory sensation or a tingling instead of pain,” says Dr. Cohen. “And because the nerve fibers in the nerves that transmit those sensations are much larger and travel faster, they crowd out the pain.”

With some newer systems, spinal cord stimulation can alleviate pain without eliciting any additional sensations, adds Dr. Cohen.

It’s a minimally invasive procedure that includes 2 steps:

• A trial where the electrodes are placed in the patient via an epidural needle. They’re left in for 5 to 7 days to see how much improvement the patient gets and if the patient likes the device.
• If the patient sees improvement and likes the device, then the device is implanted.

“The success rate is patient-dependent — all these treatments are patient-dependent — so it’s more or less the patient’s selection. If they do really well in the trial, the chances of success are really high,” says Dr. Ng.

The devices are used, says Dr. Ng, for patients who don’t benefit from conventional therapy to include injections and for those who are not candidates for surgery, including some people who have previously failed back surgery. “Of course, the patient has to be open-minded. If they are very focused and very determined that they get better, it can be successful,” he says.

People thought for a long time that radiofrequency ablations — an electrical current produced by radiowaves that is used to heat up a small area of nerve tissue, thereby decreasing pain signals from that specific area — or burning nerves, especially painful nerves, would be great for reducing pain.

But the problem with burning nerves is that nerves consist of many different types of nerve fibers, so you don’t want to burn a nerve that transmits sensations of light touch, for example. Or you don’t want to burn nerves that have motor fibers so that your muscles don’t work.

Thermocoagulation, or radiofrequency procedures, really are limited to arthritis, where they can target nerves that only transmit pain information, says Dr. Cohen. “Otherwise, if you burn nerves that contain normal sensory information, your leg would be numb, and you might be weak if there were motor fibers burned,” he says.

When you burn nerves that go to the joints in your back, you numb the nerves first because you want to see if the patient gets pain relief. They’re called prognostic — sometimes diagnostic — blocks, says Dr. Cohen. “It’s like a dry run. If the pain is coming from the joints in your back, you’ll feel better when we numb these nerves,” he says.

“If you look at placebo-controlled trials for this technique, people definitely feel better when you numb the pain nerves.”

If patients have pain from a herniated disc, and that disc is impinging on the nerve and causing it to fire, surgery to resect that small portion of the herniated disc can relieve the pain.

“Surgery definitely works compared to not having surgery,” says Dr. Cohen. “But it’s usually done in people who have failed to respond to non-surgical treatments.”

The risks are the same as for other surgical procedures — bleeding, infection and worsening back or leg pain, says Dr. Cohen. Post-surgical visits are needed, but there is no long-term follow-up required.

“It can provide fast relief of leg pain from nerve impingement, but is not a very effective treatment for back pain,” he says.

Non-opioid treatments for pain are different depending on the type of pain patients have. For neuropathic pain, for example, the treatments tend to be anti-epileptic drugs or anticonvulsants, because these drugs stop injured nerves from firing.

“The first-line treatments for these are anticonvulsants like Lyrica (pregabalin) and also drugs that enhance your own ability to inhibit pain signals,” says Dr. Cohen. “The latter are usually antidepressant drugs — tricyclic antidepressants — like Pamelor (nortriptyline) or Elavil (amitriptyline) or a newer drug, like Cymbalta (duloxetine).”

All these drugs, says Dr. Cohen, are approved for depression, but they’re also used for pain. They’re dosed differently and can relieve pain even in people who aren’t depressed.

“The doses tend to be higher for depression. And they work differently for pain than they do for depression,” he says.

Not only do these drugs enhance patients’ ability to inhibit pain signals, they can also be used to treat pain like arthritis. For example, the depression and anxiety drug Cymbalta is approved for musculoskeletal pain, which includes knee arthritis and lower back pain.

“Non-steroid anti-inflammatory drugs work very well, but they work much better for nociceptive pain, and really are better for acute pain rather than chronic pain,” says Dr. Cohen.

Other non-opioid treatments to reduce pain include 4 to 6 weeks of physical therapy in conjunction with non-opioids like muscle relaxants and integrative treatments such as acupuncture.

“Of course, the use of these treatments depends on the patient, pain condition and the severity of the pain problem,” says Dr. Ng. OSM