Pain Management: What We Know and Don't Know

The ideal way to practice medicine would be for research to demonstrate the efficacy of therapies before they are widely used or become standard practice. Unfortunately, when it comes to pain management, the opposite is often true. First treatments are used, and then the research is performed to see if what we are doing is correct.

Over time, we have learned that widely used therapies such as spine surgeries and epidural steroid injections for back pain actually provide little benefit for most patients who undergo them. And it has been only in the wake of an epidemic of prescription opioid abuse and addiction that the dearth of research proving the efficacy of these drugs for chronic pain has come to the fore.

Some new studies should make us reassess several other frequently employed therapies.

The first is a study on patients who had acute nontraumatic, nonradicular low back pain (LBP) of less than 2 weeks’ duration.¹ All participants received naproxen, 500 mg bid, and then were divided into 3 groups also receiving oxycodone with acetaminophen, cyclobenzaprine (Flexeril), or placebo.

Adding the medications was found to provide no more pain relief or improvement in function than did the naproxen alone.

This study is important because it demonstrates that opioids like oxycodone often aren’t required for optimal analgesia. Unfortunately, many patients and even many physicians think that opioids are always the most efficacious analgesics. Patients with pain who don’t receive them may feel they are receiving suboptimal care because their physicians are too frightened to prescribe opioids or are refusing to do so because they think the patients are likely to abuse them.

The use of muscle relaxants like cyclobenzaprine for any forms of musculoskeletal pain remains controversial. Whether they actually provide any true direct relaxation of the muscles or their primary effects are related to the sedative effects (drowsiness is by far the most common adverse effect of cyclobenzaprine) that most possess is still an open question.

The second study examined one of the most commonly employed surgeries for pain, total knee replacement (TKR).² For patients with marked knee pain secondary to osteoarthritis, a TKR often is considered to be the only answer.

The study compared patients who had moderate to severe pain thought to be secondary to osteoarthritis. One group underwent unilateral TKR followed by a 12-week nonsurgical treatment program consisting of a combination of exercise, education, dietary advice, and insoles (and pain medication, if it was deemed necessary for participation in the exercise program). The other group only participated in the 12-week nonsurgical treatment program.

After 1 year, patients who underwent TKR did better with regard to pain and functionality than those who only had the nonsurgical program. However, the study also reported a number of important caveats.

Although 85% of the TKR patients reported at least a 15% improvement in pain, so did 68% of the nonsurgical patients. Furthermore, serious adverse events were 4 times more likely to occur in the TKR group. The serious adverse events included potentially life-threatening ones, such as deep venous thrombosis that occurred only in the TKR patients.

The authors of the study and of an accompanying editorial³ interpreted the results as demonstrating that there is no right or wrong answer as to whether a patient should undergo TKR. For many patients, the potentially greater relief with the surgery may be offset by the risk for adverse events, especially because many patients received marked relief with the nonsurgical treatments alone and without this accompanying risk.

The final study examined the benefits of early physical therapy for patients with acute, nonradicular LBP of less than 16 days’ duration in the absence of any “red flags” that would suggest a potentially serious underlying etiology for the pain.⁴ All the patients participated in an education program. Half also received 4 physical therapy sessions, which consisted of spinal manipulation and instruction in spinal range of motion exercises.

The primary outcome measure was the Oswestry Disability Index (ODI), a measure of functionality for patients with LBP. Pain intensity and health care utilization were among the secondary measures.

Although the group of patients who received the physical therapy performed better on the ODI at 4-week and 3-month follow-ups than those who did not, there was no difference between the groups after 1 year. The only significant difference on this measure between the groups occurred at the 4-week follow-up.

There was no difference in pain intensity between the 2 groups at any of the follow-up times, nor was there any difference with regard to health care utilization. Also, most of the patients in both groups rapidly improved.

Physical therapy can certainly benefit many patients with LBP. But this study indicates there is no need for quick referrals for this to maximize its benefits.

References:

1. Friedman BW, Dym AA, Davitt M, et al. Narpoxen with cyclobenzaprine, oxycodone/acetaminophen, or placebo for treating acute low back pain: a randomized clinical trial. JAMA. 2015;314:1572-1580.

2. Skou ST, Roos EM, Laursen MB, et al. A randomized, controlled trial of total knee replacement. N Engl J Med. 2015;373:1597-1606.

3. Katz JN. Parachutes and preferences-a trial of knee replacement. N Engl J Med. 2015;373:1668-1669.

4. Fritz JM, Magel JS, McFadden M, et al. Early physical therapy vs usual care in patients with recent-onset low back pain: a randomized clinical trial. JAMA. 2015;314:1459-1467.