• Pulsed radiofrequency. A pulse of radiofrequency heat at 42 degrees Celsius (107.6 degrees Fahrenheit) for two minutes “can get to pain fibers selectively, such as dorsal root ganglia [nerves] without causing damage,” says Dr. Cope. This treatment, which deadens painful nerves, may be helpful for people with disc pain, low back pain or whiplash pain in their neck. “We can go deeper, closer to the spinal cord.”


What’s on the Way?
Research on new pain-fighting drugs, new applications for existing drugs, as well as more effective delivery methods for these drugs that may lower side effects, may give pain specialists more weapons in the near future. Here are some intriguing developments now being studied.

Slow-release anesthetics and opioids through designer liposome cells. Researchers at Children’s Hospital Boston, in a 2009 study funded by the National Institutes of Health, created a specially designed liposome, or drug delivery cell, to carry the potent anesthetic drug saxitoxin. This innovation allows doctors to insert the liposomes into the body so it could slowly release the drug and create a nerve block where inserted, shutting down a painful nerve or nerve cluster for days or weeks, even months.

In addition, a 2011 study at the University of Wisconsin, Madison, showed that inserting liposomes filled with hydromorphone, an opioid, via an epidural into rats with arthritis provided extended pain relief. The rats appeared to have improved function, such as reduced lameness, after the treatment.

Milnacipran (Savella).  A 2011 study in Spain looked at the effectiveness of milnacipran (Savella) a serotonin-norepinephrine reuptake inhibitor (SNRI) at treating chronic arthritis pain in arthritis. The drug was recently approved in the U.S. to treat fibromyalgia, Researchers injected the drug into arthritis-affected rats and found that tests, including paw pressure, proved the drug provided pain relief. They concluded it could be useful for treating pain in chronic, inflammatory arthritis.

Venoms and toxins. Some substances used by animals for self-defense are now being studied as methods for fighting painful nerves. Researchers at the University of Queensland in Australia published a study in 2011 looking at the effectiveness of two types of cone snail venom for treating cancer pain. One compound, Xen2174, was used in patients with severe chronic pain and “relieved pain quickly over an extended period of time,” and was well tolerated. Xen2174 is now being studied as a treatment for pain after removal of bunions.

In addition, Chinese researchers at Soochow University School of Pharmacy are studying CTX, a neurotoxin derived from Thailand cobra venom, in rats with inflammatory pain induced in their right hind paws. The results were positive, showing that CTX could reduce sensitivity to pain.

Pamidronate (Aredia). Researchers in Lyon and Valence, France, reported positive results for intravenous bisphosphonates in children with motor impairments who also have osteoporosis. These children have a higher risk of fractures, and often report pain, although pain is not normally associated with osteoporosis. Twelve children received infusions of pamidronate, and researchers observed a decrease in their pain, even total relief in some cases. Adverse effects of the drug were minor and quickly reversed. Identifying children who have osteoporosis and are in pain is key, the doctors stressed, so treatment can begin early to prevent bone loss.