Up to 90% of Americans have an episode of low back pain at some time in their life.1This symptom is second only to the common cold as the reason for the most office visits to primary care physicians in the United States.2 Although other health care professionals can have a role in providing relief from low back symptoms, the primary care physician guides the patient's recovery.
Our focus here is on what you need to know to successfully care for patients with low back pain. We review the key aspects of the initial evaluation, with an emphasis on "red flags" that signal serious conditions. We also describe a treatment approach designed to hasten the return to normal daily functioning and to minimize long-term disability. Included in this approach is an aggressive exercise regimen, the details of which we present in our article on page 1029.
A BRIEF OVERVIEW
Low back pain can be categorized as:
Acute low back pain. Episodes of acute low back pain generally occur in young and middle-aged adults; the peak incidence is between ages 45 years and 64 years.1Some patients who have an acute episode report a specific causative event (eg, a sudden twisting motion or the lifting of a heavy object); however, many cite a trivial event as the apparent cause (eg, sneezing, coughing, bending over)-or are unable to identify a cause. The severity of the injury does not necessarily correlate with the intensity of the trauma. Nominal stress, for example, can produce clinically significant disk herniation. A growing body of evidence suggests that acute low back pain usually results from repeated microtrauma caused by poor posture, inappropriate bending and lifting mechanics, deconditioned musculoskeletal elements, and repeated flexion injury.1
Chronic low back pain. An acute episode of low back pain develops into a chronic condition in up to 10% of patients. Chronic low back pain is the most common cause of disability in patients younger than 45 years.1
Between 80% and 85% of patients with low back pain do not receive a specific diagnosis.3The vast majority of such episodes are attributable to mechanical causes (Table 1). Nonetheless, when caring for patients with low back pain, a "wait-and-see" attitude is not acceptable. It is essential to perform a thorough clinical evaluation and look for red flags (Table 2) and risk factors (Table 3) that can suggest a potentially serious condition.
History. Take a careful medical history. Focus especially on the following 5 questions:
Physical examination. In the review of systems, be alert for clues to systemic causes of low back pain. These can include:
Next, proceed to a detailed musculoskeletal examination. If possible, assess station and gait when the patient enters the examining room and while he or she disrobes. An antalgic gait or the inability to stand comfortably suggests a back problem.
The remainder of the examination requires the patient to stand, kneel, sit, and lie down; its extensiveness is determined by the degree of pain he is experiencing. Carefully inspect the back for masses, skin lesions, discoloration, kyphosis, and scoliosis. Follow this with palpation and percussion of bone and soft tissue. Vertebral tenderness may suggest fracture or osseous pathology, whereas soft tissue tenderness of the paraspinal muscles is more typical of mechanical low back pain. Assess active and passive range of motion to determine functional capacity. Because hip, knee, ankle, and foot pathologies can produce secondary back problems, include the lower extremities in the examination.
During the neurovascular evaluation, assess motor abilities, sensation, tone, reflexes, and pulses (femoral, popliteal, posterio tibialis, and dorsalis pedis). For example, radiating pain that extends below the knee indicates sciatica. Also, be sure to auscultate and palpate the abdominal aorta.
Imaging studies. These are not necessary for most patients initially.Radiographs have low specificity and sensitivity; most patients older than 40 years have anatomic problems that are not related to the cause of their pain. Plain films identify a clinically relevant problem in only about 1 in 2500 patients.1Moreover, radiographs involve significant radiation exposure and expense, and a false-positive result may lead to a spate of unnecessary consultations, tests, and even surgery.
However, consider imaging in the following settings:
CT and MRI are appropriate for confirming a physiologically grounded diagnosis and planning interventional surgery. MRI is the preferred modality for soft tissue conditions, including disk disorders; CT is preferred for bony pathology. Bone scanning is useful if you suspect an infection, occult fracture, or tumor; how- ever, this modality is contraindicated in pregnancy.
Between 80% and 90% of patients with low back pain spontaneously recover within 2 months.1Nonetheless, timely intervention remains important. Fewer than 50% of persons who are out of work for 6 months because of low back pain never work again. However, more than 75% of those who are out of work for a year because of chronic low back pain never return to work.1
In the past, patients with back pain were often hospitalized in traction and given narcotics and antispasmodics by intravenous drip. Today, early exercise-rather than bed rest-is the cornerstone of therapy.After no more than 4 days-preferably 1 or 2-of relative bed rest, have patients begin a formal rehabilitation program. Even during the initial resting period, encourage them to get up and move around and advise them simply to avoid activities that produce pain. Bear in mind that 2 days of physical activity are needed to reverse the deconditioning that results from 1 day of bed rest.
Physical modalities. During the period of acute pain, have patients apply cold/ice packs over a moist towel or washcloth to the affected area for 15 to 20 minutes every few hours. The application of heat (eg, heating pad, warm shower, hot pack) for 5 to 10 minutes may provide additional relief.
Pharmacotherapy. Medications on a fixed dosing schedule are also useful during the acute period. Most patients respond to acetaminophen or an NSAID. Muscle relaxants have not been shown to be more effective than NSAIDs; however, a muscle relaxant in combination with an NSAID may produce better analgesia than a muscle relaxant alone.4 Because of the anticholinergic effects of muscle relaxants, use caution when prescribing these agents for older patients.
Tramadol is a nonopioid, centrally acting analgesic that may be helpful in selected patients-for example, those with chronic low back pain. Antidepressants and epidural corticosteroid injections may also be appropriate for selected patients with chronic low back pain. Severe or resistant pain may warrant the short-term use of narcotics.
Rehabilitation/physical therapy. Passive care does not adequately address underlying dysfunction and can foster dependence on the health care system. A drug treatment plan in conjunction with an aggressive rehabilitation program hastens the return to daily functioning and minimizes long-term disability. For a detailed description of such a program, see our article on page 1029.
Manipulation and alternative therapies. Up to 1 month of manipulation can be helpful in patients who have low back pain that is not associated with radiculopathy.1 Although well-designed clinical trials have not demonstrated the efficacy of such alternative medicine approaches as transcutaneous electrical nerve stimulation (TENS), trigger point injections, biofeedback, relaxation techniques, magnets, acupuncture, or therapeutic traction, these measures may be helpful on a short-term basis.
Surgery. Consider surgical referral for patients with spinal stenosis, sciatica that persists beyond 12 weeks despite conservative therapy, or acute disk herniation with a profound neurologic deficit.
Follow-up. This is a mandatory part of effective treatment. A follow-up visit after 3 to 7 days is appropriate if the patient has severe pain, inconsistent findings because of guarding or pain with movement, mild neurologic abnormalities, or a history of progressive symptoms. Follow-up after 10 to 14 days is reasonable for patients with no neurologic compromise.