Pauline Anderson

February 23, 2016

PALM SPRINGS, California — A procedure that involves radiofrequency ablation of sensory nerves in the degenerated lumbar disc may give many patients with chronic low back pain significant relief.

Researchers have now collected up to 12 months of data on patients undergoing the procedure — called intradiscal biacuplasty (IDB) — and it shows improved pain scores, functioning, and quality of life.

"It's probably the only study in the area of interventional pain that showed consistent improvement over time, many months after the treatment is completed," said lead author Michael Gofeld, MD, a pain management specialist and anesthesiologist at St Michael's Hospital and Women's College Hospital, Toronto, Ontario, Canada, and president of the World Academy of Pain Medicine Ultrasonography.

Dr Michael Gofeld

"Typically, interventional pain management studies show 3- to 6-month improvement and then the pain returns."

Dr Gofeld, who was one of the first doctors to use the procedure, presented his findings during a plenary session on research highlights at the American Academy of Pain Medicine (AAPM) 2016 Annual Meeting.

Huge Problem

According to Dr Gofeld, 60% to 90% of North Americans will experience lower back pain at some point in their life. About 40% of people with chronic low back pain have discogenic pain, he said, "so it's a huge segment of the population."

Disc degeneration and injury cause centripetal growth of nerve fibers into the disc. Compared to normal lumbar discs, severely degenerated discs have extensive disc innervation.

In 2006, Baylis Medical, a Canadian company, developed a device (TransDiscal System) that uses heat to deactivate nervous tissue in the posterior and posterolateral region of the disc. The device is now manufactured in the United States by Halyard Medical.

The simple, 30-minute outpatient procedure involves "very precise" placement of thermal probes into the back part of the disc that ablate the area causing pain.

"The degenerated disc will not get better, but patients can restore their functional status and can get back to work and a normal active life," said Dr Gofeld.

The technology is similar to that used to destroy tumors. "It's nothing new under the sun" but is a new tool to treat back pain, said Dr Gofeld.

An earlier efficacy sham-controlled trial, carried out at the Cleveland Clinic in Ohio, showed "amazing results" at 6 months that were also sustainable after 1 year. However, the placebo-controlled research results were limited to a meticulously selected group of patients, said Dr Gofeld.

A pragmatic prospective open-label trial randomly assigned 63 patients with discogenic lumbar back pain to IDB supplemented by conventional medical management (CMM) (n = 29) or CMM alone (n = 34). CMM could include anything the physician recommended except surgery, such as lumbar-epidural injections, sacro-iliac joint injections, physical therapy, behavioral therapy, and pharmacologic management.

The study showed consistent improvement for the IDB plus CMM group on the visual analog scale (VAS) pain score at 6 months, as well as improvement on the 36-item short-form physical functioning scale (SF-36-PF) and on quality of life. The results of this first stage were recently published in Spine.

After 6 months, the CMM group members were allowed to cross over to the intervention group. Of the original 34 randomly assigned to CMM, most (n = 25) crossed over.

The current, final stage of the study included 12-month results among 22 patients of the original IDB and the same number of patients who elected to cross over. It found a statistically significant (P = .001) difference in VAS scores: from a mean of 6.7 at baseline to 4.4 at 12 months. A statistically significant pain reduction on the VAS is more than 2 points.

Change in SF-36-PF was also significant (P = .003): from a mean of 48 to 62. A significant change on this score is an increase of 15 or more points.

As for the Oswestry Disability Index, the change was also significant (defined as a decrease of 10 or more points): from 42 to 30 (P = .002). Change on the Patient Global Impression of Change scale was significant as well (P < .001).

What was impressive, Dr. Gofeld said, was that the VAS scores remained lowered from month to month, as did the SF-36-PF functional outcome.

"This is the only study I know of that shows that the results are improving over time, so at 12 months, patients actually did better than after 1 month," he said.

The results indicate that the procedure is an option for patients who continue to have discogenic pain despite medical management. As an example, Dr Gofeld pointed to the case of an Air Canada pilot whose discogenic pain was so severe he was unable to work for about a year. He had tried several interventions and was taking narcotic medication, but nothing worked.

However, 6 months after having a single IDB, "his opioids were discontinued and the pilot was back on transatlantic flights," said Dr Gofeld.

"The results of the study are not only statistically significant, but also clinically meaningful."

In general, no complications were related to the procedure, although outside the study end-plate damage causing transient pain has been reported. "These were related to the fact that physicians were so eager to start doing this procedure that they were doing it on inappropriate patients, those with very degenerative discs," commented Dr Gofeld.

The ideal patient for this procedure has level 1 or 2 degenerative disc disease, a disc height (thickness) of more than 50%, and no sciatica.

"Patients with multilevel degenerations are not candidates because this problem has a rather genetic origin and radiofrequency of multiple discs has not shown benefits," explained Dr Gofeld. "A relative preservation of disc height is important, too, to assure procedural safety."

Dr Gofeld and his colleagues are now planning a cost-effectiveness study to demonstrate benefits of this procedure.

Few Good Treatments

Session chair, James C. Watson, MD, associate professor of neurology, Mayo Clinic, Rochester, Minnesota, told Medscape Medical News that the study is important for several reasons. One is that "very few if any" good treatments — medicines or other interventions — are available to specifically or directly treat discogenic pain.

Many patients with this condition, who tend to be younger, end up undergoing spinal fusion. Evidence suggests that results from spinal fusion "are not as good as people thought they were," said Dr Watson.

Also, spinal fusion inevitably results in degenerative changes near the fusion site, sometimes called "adjacent segment disease." "It may take a few years or more than a few years, but eventually, you will get degenerative changes that occur above and below the fusion because you've changed the normal mechanics of how the back moves," said Dr Watson. "So fusion is not a benign procedure."

Dr Gofeld and his colleagues have not only shown that IDB is effective but also that it has a sustained response, said Dr Watson.

"Unfortunately, most pain studies — whether they're looking at medication interventions or surgeries — don't give us a lot of good long-term data," said Dr Watson.

While 12 months "is short in the grand scheme of life," it represents a long study for any research looking at pain interventions, he added.

The study is also important because it might help convince payers to reimburse for the procedure.

Another procedure, intradiscal electrothermal annuloplasty, which involves cauterizing the nerve endings within the disc to help block pain signals, "was overutilized and probably poorly utilized," and, likely because of that, had less than good outcomes, said Dr Watson.

Unfortunately, as a result, "payers stopped paying for anything that addressed disc-related pain," he said. "It's one thing to have the technology, but no one will use the technology if no one will reimburse for it."

But these new positive and durable long-term data on IDB might convince payers that this is a different technique that addresses "a very distinct pain entity," said Dr Watson.

The hope is that eventually clinicians will have a tool that they can actually use to treat this debilitating and common condition.

The study was funded by Halyard Health Inc. Dr Gofeld has disclosed no relevant financial relationships.

American Academy of Pain Medicine (AAPM) 2016 Annual Meeting. Poster 123. Presented February 19, 2016.


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