Dispatches From Pain Management’s Front Lines

Pain management is both a hotbed of innovation and controversy. Here are some timely dispatches from the front lines of this critical orthopedic specialty.

1. Surgery patients use only a fraction of their prescribed opioids

However, they used more if prescribed more, says a new University of Michigan study, Association of Opioid Prescribing With Opioid Consumption After Surgery in Michigan, published November 7, 2018 in JAMA Surgery.

“In this study, 2392 patients (mean age, 55 years; 1353 women [57%]) underwent 1 of 12 surgical procedures. Overall, the quantity of opioid prescribed was significantly higher than patient-reported opioid consumption (median, 30 pills; IQR, 27-45 pills of hydrocodone/acetaminophen, 5/325 mg, vs 9 pills; IQR, 1-25 pills; P < .001). The quantity of opioid prescribed had the strongest association with patient-reported opioid consumption, with patients using 0.53 more pills (95% CI, 0.40-0.65; P < .001) for every additional pill prescribed,” an abstract of the study says.

Among the factors associated with higher opioid use: history of tobacco use. The findings are consistent with a study just published by Johns Hopkins in the Journal of the American College of Surgeons(see that story).

2. “Nonaddictive drug compound could replace opioids for chronic pain sufferers”

It’s the big, bold headline atop a Purdue University news releaseabout a compound which “shows unparalleled selectivity in inhibiting the adenylyl cyclase 1 (AC1), making it a potential target for treating pain and reducing the dependency on opioids for pain management.”

Purdue received U.S. patent #10,100,001for the technology on October 16, 2018.

The release cites a research article, “Identification of a selective small-molecule inhibitor of type 1 adenylyl cyclase activity with analgesic properties,” published in February 2017 in ScienceSignaling; the news release says they’ve discovered new compounds since then.

So far, it has worked on mice. It’s not the first effort at isolating an alternative to opioids and blocking opioid dependency using adenylyl cyclase inhibitors; articles can be found online going back to 1994. A key hurdle the Purdue researchers seem to have surmounted: some of these compounds cause adverse cardiac events.

Purdue researcher Val J. Watts, Ph.D., Associate Dean for Research, College of Pharmacy, said in an email interview that these compounds can be produced inexpensively—a necessity for a serious large-scale alternative to opioids. They “have the potential to replace opioids for chronic inflammatory pain (arthritis, drug or disease-induced neuropathy),” he wrote.  “However, they would not be useful in acute pain (severe injury, surgery, etc).”

3. Becoming more pain-sensitive causes osteoarthritis knee pain to endure

This is according to a new study by researchers at Université de Montréal and its affiliated Maisonneuve Rosemont Hospital Research Centre (CRHMR), in collaboration with researchers at Boston University.

The study, “Pain susceptibility phenotypes in those free of knee pain with or at risk of knee osteoarthritis: the multicenter osteoarthritis study,” by Lisa C. Carlesso, Ph.D., et al, was published October 11, 2018 in Arthritis & Rheumatology.

4. Marijuana extract pain relief without the euphoria

Well, patients who find relief might feel euphoric about that, but there’s a way to relieve pain with cannabinoid without the marijuana high, say researchers from the Research Institute of the McGill University Health Centre (MUHC) and McGill University, Montreal, Quebec.

The study, “Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain, “PAIN, August 27, 2018, says it pinpointed effective dosages of marijuana plant extract cannabidiol (CBD). But is it legal?

“CBD is readily obtainable in most parts of the United States, though its exact legal status is in flux. All 50 states have laws legalizing CBD with varying degrees of restriction, and while the federal government still considers CBD in the same class as marijuana, it doesn’t habitually enforce against it. In December 2015, the FDA eased the regulatory requirements to allow researchers to conduct CBD trials. Currently, many people obtain CBD online without a medical cannabis license. The government’s position on CBD is confusing,” says Harvard’s Peter Grispoon, M.D., in this blog.

5. Radio waves to treat osteoarthritis-related knee pain

“[A]dditional long-term prospective clinical trials are necessary to further characterize how C-RFA can best be used to treat chronic knee pain,” says an article by researchers in the Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri.  An abstractof their article “Cooled Radio Frequency Ablation for the Treatment of Osteoarthritis-Related Knee Pain: Evidence, Indications, and Outcomes,” links to the full article (paywalled), published in The Journal of Knee Surgery. They reviewed “two prospective trials, one retrospective cohort study, and five case reports or case series” on the use of C-RFA.

6. Intensive patient education for low back pain: The clinical trial result was…

It didn’t do squat for 101 patients. No difference in the outcome for 101 others who received what was called “placebo education.”

So says a November 5, 2018 article in JAMA Neurology, “Effect of Intensive Patient Education vs Placebo Patient Education on Outcomes in Patients With Acute Low Back Pain – A Randomized Clinical Trial.”

“[I]ntensive patient education to first-line care of patients was no better at improving pain outcomes than a placebo intervention. Meaning: Intensive patient education should not be offered to patients with acute low back pain who are receiving first-line care,” the authors wrote.