Differential Diagnosis and Management of Low Back Pain in the Primary Care Setting

In the old days, primary care doctors typically referred patients with chronic low back pain to orthopedic surgeons. Now, less invasive approaches are more likely to be tried early on, says Peter Staats, MD, adjunct associate professor in the departments of anesthesiology, critical care medicine, and oncology at Johns Hopkins University School of Medicine. Part of the reason for this is that more conservative, yet effective therapies for chronic low back pain are now available.

It usually does not make sense to send patients with chronic low back pain to spine surgeons, because few of them are actually surgical candidates, says Staats, who founded the Division of Pain Medicine at Johns Hopkins University and now practices at Premier Pain Centers, based in Shrewsbury, NJ. Either that, or they haven’t undergone the full conservative treatment that is recommended before resorting to surgery, notes Frank Falco, MD, CEO and principal of Mid Atlantic Spine and Pain Physicians in Elkton, MD.

Finding the source of the pain

One mistake general practitioners sometimes make with patients who present with low back pain is to attempt to treat them using only analgesic medications, without first trying to identify the root cause(s) of the pain. Treating a complex condition such as low back pain requires a comprehensive approach that draws on the expertise of other health professionals. Family physicians often do not have the time or resources to coordinate care for these patients beyond the initial round of treatment. If the patient’s pain does not significantly improve within eight weeks after the first visit to a doctor, the patient should be referred to a pain specialist. Falco, who is also clinical assistant professor and director of Temple University Hospital’s Pain Management Fellowship Program, says that when family practitioners involve pain physicians early in the treatment process, they optimize outcomes and reduce the patient’s risk of developing chronic pain. According to Falco, “the best thing the primary care doctor can do is hand the baton off to a fellowship-trained pain physician.” The pain specialist can then identify the sources of the patient’s pain and coordinate the patient’s care.

Staats says that one significant change in the diagnosis of chronic low back pain is that now more emphasis is placed on evaluating the source of the pain and looking for different pathologies of the pain. He says it is more likely to be taken seriously these days, and not lightly dismissed as “nothing” or due to psychological factors only.

Charles Argoff, MD, professor of neurology at Albany Medical College and director of the Comprehensive Pain Center at Albany Medical Center in New York, says that getting at the root cause(s) of chronic low back pain can be like unraveling a mystery. There may be multiple causes; several levels of the spine may hurt. Sources of low back pain may include ligamentous injury, tendinous injury, muscle impairment, and disc or nerverelated problems. They may be amplified by psychological issues.

What’s more, “obvious” pain symptoms may not be the core issue. With back pain, the muscle spasms that a patient notices first may actually be a tertiary event in a cascade of events, says Staats. For example, “it is possible that the leak of inflammatory stuff inside of a disk is irritating a nerve, leading to muscle spasms,” he says.

If the pain radiates down the legs, something may be irritating the root, the nerve that comes out of the spine and into the leg, says Ricardo Cruciani, MD, PhD, vice chair of the Department of pain medicine and palliative care and director of the Pain Division at Beth Israel Medical Center in New York City. It is also possible that a disc herniation is compressing a nerve, causing pain. MRI or nerve conduction studies can help verify the diagnosis, says Laxmaiah Manchikanti, MD, chairman of the board and CEO of the American Society of Interventional Pain Physicians. Manchikanti is also medical director of the Pain Management Center of Paducah and clinical professor of anesthesiology and perioperative medicine at the University of Louisville. Bear in mind that radiculopathy may be an issue, although you may not see a disc pressing on the root, says Cruciani, who is also one of the American Pain Society’s directors at large.

Nonradicular pain can be harder to diagnose. According to Manchikanti, a diagnosis is achieved for only 20% of those patients. To diagnose nonradicular pain, he recommends multiple diagnostic blocks, based on the idea that most low back pain without sciatica arises from lumbar intervertebral discs, facet joints, sacroiliac joints, ligaments, fascia, muscles, and nerve root dura, all of which are capable of transmitting pain in the lumbar spine leading to low back and lower extremity pain symptoms.

In precision diagnosis of chronic low back pain, diagnostic blocks are limited to facet joints when lumbar facet joint nerve blocks are performed, intervertebral discs when lumbar provocation discography is performed, and sacroiliac joint pain when sacroiliac joint blocks are performed. Manchikanti says there is strong evidence supporting the effectiveness of lumbar facet joint nerve blocks in diagnosing pain coming from the facet joints and moderate evidence for the diagnostic power of sacroiliac joint blocks. However, provocation discography, in which pain is elicited by placing the needle and drug in the diseased disc, and analgesic discography, in which local anesthetic is injected to eliminate the pain and help the patient become functional again, are still controversial.

"Once you know there’s no serious medical problem such as cancer, an infection, or a significant fracture or disc herniation of the spine, you really need to get that person moving and active. That’s the focus of care, to facilitate function."

—Charles Argoff, MD

Sometimes those hoof beats really are zebras

Unresolved back pain that persists beyond three months, which is how The National Institute of Neurological Disorders and Stroke defines chronic back pain (http://1.usa. gov/CPNS2), warrants imaging studies even though neurological symptoms may not be apparent. In such cases, it is possible the patient may have a spinal disease, suffer from vertebral slippage that is causing low back pain, or even have a more severe condition.

When doing a workup on a patient with low back pain, doctors should keep unconventional diagnoses in mind. Christopher Gharibo, MD, medical director of pain medicine at the Hospital for Joint Diseases at NYU Langone Medical Center, says that about 1 in 1,000 cases may be due to something unexpected and turn out to be intra-abdominal in origin and related to an infection or malignancy that manifests as musculoskeletal. Gharibo says he encounters several cases each year that seem innocuous, but turn out to be tumors.

If the patient’s pain seems to travel from the back to the knee, the pain may be related to facet joints or the sacroiliac joints, Cruciani says. But the big missed diagnosis is arthritis/ arthrosis of the hip. Physical maneuvers and imaging should help clarify the problem. If the hip is the issue, a steroid injection, a product that regenerates cartilage, or hip replacement may be called for. Cruciani says he has come across several hip replacement candidates who were first misdiagnosed as chronic low back pain patients.

Customize treatments

Pain management specialists vary in their preferences when it comes to treatment options and modalities. Some focus more on managing chronic pain with medications, physical therapy, and/or cognitive behavioral therapy. Interventional pain specialists are oriented to finding the source of the pain and eliminating the problem using minimally invasive diagnostic and therapeutic interventions, Staats says. Most patients who present with low back pain can be conservatively managed with analgesics and physical therapy, and perhaps some basic injections, without being referred to anybody else, says Gharibo.

“Once you know there’s no serious medical problem such as cancer, an infection, or a significant fracture or disc herniation of the spine, you really need to get that person moving and active. That’s the focus of care, to facilitate function.”

Where treatment is concerned, Gharibo advises doctors to “be as conservative as possible.” With interventions, he says it is best not to be overly experimental, doing something on a patient that’s not necessarily well validated. Several of the pain experts interviewed for this article noted the lack of efficacy studies for many interventional pain treatments, even those that are frequently used in practice.

Treatment choices must be customized to the individual patient. While many patients benefit from just one epidural steroid injection or from surgical intervention, others manage well on an anti-inflammatory. Other patients who have tried many medications, exhausted several medical interventions, and become depressed and anxious, perhaps facing disability issues, may benefit from a more multidisciplinary approach to treatment. Having a team that works together to cover medical management, mental health or psychological treatments, and physical rehabilitation increases the chance of improvement, says Robert Jamison, PhD, anesthesiologist at Brigham and Women’s Hospital and professor in the departments of anesthesia and psychiatry at Harvard Medical School.

Falco says that surgery for disc herniations that lead to radiculopathy work well, with a 92% success rate (http://bit.ly/HeKGnA). However, Cruciani says that unless there is an emergency such as evidence of core compression or severe weakness, a radical approach to address radicular pain is not needed. “If the patient has only pain and some tingling or numbness, there’s no real reason to do a surgery,” he says. An epidural injection to deal with inflammation, followed by physical therapy and/or medications would help the patient reach the same endpoint as surgery six months out.

"The best thing the primary care doctor can do is hand the baton off to a fellowship-trained pain physician. The pain specialist can then identify the sources of the patient’s pain and coordinate the patient’s care."

—Frank Falco, MD

Physical therapy and regaining function

Cruciani says that many patients would benefit from physical therapy, and reminds physicians not to overlook this important component of pain management. For muscle spasms, he says he often prescribes alternating heat and cold or massage to relax the area so it can recover function. Other approaches offered by physical therapy include ultrasound, traction, core strengthening, and cardiovascular rehabilitation.

Argoff notes that if the muscles, ligaments, and tendons of the abdomen and back are not used properly, it can “throw off” the patient’s biomechanics and exacerbate the chronic pain. Staats says that patients suffering with chronic low back pain often become deconditioned, so after treating them he tries to get them engaged in physical therapy to strengthen their bodies. Patients with chronic low back pain also often need to make lifestyle changes in order to minimize further injury, including how they sit, walk, and lift things, Gharibo says.

Although many interventional pain physicians may claim that injections are the best option for managing pain, Argoff says that a rigorous, structured physical rehab program that gets a person moving and functional again can deliver more long-term benefits than treatment with epidural steroid injection, facet injection, or radiofrequency injection. “A person may benefit from an injection in the short term, but in the long term they will benefit by strengthening themselves overall,” he says. Plus, if the pain does return, it will not be linked to the same sense of doom or lack of control, because these patients will have already developed good coping programs and can start using them again.

“Once you know there’s no serious medical problem such as cancer, an infection, or a significant fracture or disc herniation of the spine, you really need to get that person moving and active. That’s the focus of care, to facilitate function,” Argoff says.

Role of psychology

Psychology can play a key role in decisions that inform how you treat chronic pain patients. Should you enroll the patient into a cognitive behavioral therapy program? Would exercise, medications, minimally invasive surgical procedures, or more invasive surgery be more appropriate? Consider your patient’s psychological status before choosing treatments.

“I think we’re never going to divorce ourselves from the fact that pain affects people emotionally,” says Jamison. People who are depressed and anxious tend to fare worse on traditional medical interventions. Catastrophizing and stress can affect a patient’s health and lead to increased pain. Strategies that help them cope with their condition and begin to accept a stubborn problem are important.

Staats notes that people suffering from major stress, anxiety, or depression can benefit from dampening the emotions around their pain through biofeedback, cognitive behavioral therapies, and stress management. Giving opioids, muscle relaxants, anti-inflammatory drugs; sending somebody for a surgical consult; or doing an injection is not going to get at the root cause of a pain problem if the patient is stressed out or anxious. Says Argoff: “You need to address the whole person.”