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Acute Low Back Pain: How to Evaluate and Treat
Abstract and Commentary
By Matt Shores MD, St. Joseph's Hospital and Medical Center, Family Medicine Residency, Phoenix, AZ, is Associate Editor for Urgent Care Alert.
Dr. Shores reports no financial relationships relevant to this field of study.
Synopsis: The management of acute low back pain is conservative once red flag symptoms and signs have been eliminated. In addition, there is good evidence supporting particular modalities in treating low back pain.
Source: Kinkade S. Evaluation and treatment of acute low back pain. Am Fam Physician. 2007;75:1181-1188.
In Scott Kinkade's article in the April 15th edition of American Family Physician, he presents a succinct review of the evaluation and treatment of acute lumbar pain. Kinkade defines acute low back pain "as pain that occurs posteriorly in the region between the lower rib margin and the proximal thighs, and that is less than 6 weeks' duration." On any given day, low back pain may affect almost 6% of adult Americans. Approximately 60-70% of people will experience low back pain at some point in their lifetime. The majority of patients with low back pain present to their PCP, and in a system that makes it difficult to get an urgent appointment with a PCP, a growing number of patients with low back pain present to emergency departments and urgent care centers.
The most important step in evaluating acute low back pain is recognizing red flag signs and symptoms in an attempt to sift out serious conditions, including neoplasm, infection, and visceral disease. A patient that presents with low back pain and a history of weight loss, with spine tenderness on exam, must be evaluated for neoplasm. On the other hand, if a patient does have spine tenderness on exam, but presents with a history of constitutional symptoms such as fever, chills, and sweats, then the possibility of infection needs to be explored. Non-spinal or visceral disease should be easier to sort out, but is nonetheless imperative. For example, patients with GI ailments, such as pancreatitis or cholecystitis, may have acute back pain but should also have abdominal pain symptoms and abdominal signs on exam. In addition, aortic aneurysms may present as back pain, but a pulsatile mass may be felt on exam. All in all, mechanical low back pain accounts for 97% of the causes of low back pain, whereas visceral disease only accounts for 2% and non-mechanical spinal conditions, such as neoplasm, account for only 1%.
Once the search for red flag symptoms and signs has come up empty, and serious conditions have been ruled out, the evaluation and treatment of low back pain may take a more conservative approach. Mechanical low back pain includes lumbar strain, degenerative disk, herniated disk, compression fracture, spinal stenosis, and spondylolisthesis. Lumbar strain accounts for more than 70% of mechanical low back pain. When no red flag symptoms or signs are present, it is safe to attack the management of low back pain conservatively and treat for 4-6 weeks prior to further investigation, with imaging or more aggressive treatment modalities.
Treatment for acute low back includes a wide variety of options, some of which have a great deal of support, and others that have little to no support, if not support against their use. Non-steroidal anti-inflammatory drugs have consistent, good quality patient-oriented evidence supporting their use, and there is strong evidence that shows equal efficacy among various NSAIDs. The use of acetaminophen as an alternative has conflicting support, but may be used as an adjunct. The use of opioids also has some conflicting evidence in regards to their use in treating acute low back pain. Several small studies have shown no significant advantage of opioid use as compared to NSAIDs. However, it is commonly accepted that some patients with acute low back pain, and specifically sciatica, may require opioids initially in treating their pain. Opioids should only be used for a short period, if used at all. Muscle relaxants do have strong evidence (rating A) supporting their use, and their use is most beneficial in the first 2 weeks of treatment. Common muscle relaxants include Skelaxin and Flexeril. Kinkade notes that Flexeril may be used at lower doses (5mg tid) to offer good symptom relief with significantly less adverse side effects. Oral corticosteroids have no evidence to support their use in treating acute low back pain.
The use of medications is only a small aspect in treating low back pain. It is thought by many that bed rest is essential in recovering from a low back strain. However, the evidence contradicts this thought. In fact, there is consistent, good quality, patient-oriented evidence that shows bed rest greater than 2-3 days is ineffective, and may be harmful. Patients should be advised to stay active, as they will likely have less time missed from work, improved functioning, and less pain. In addition to the misconception in regards to bed rest, it is often thought that specific back exercises may be helpful in improving function after an acute low back strain. Again, there is consistent, good quality, patient-oriented evidence that contradicts this thought. Specific back exercises have, in fact, been shown to not be helpful. In terms of heat and ice therapy, there is inconsistent or limited quality, patient-oriented evidence that supports the use of heat, and there is no evidence that supports the use of ice. Finally, it is difficult to evaluate the use of physical therapy because the actual modalities that physical therapy programs use varies a great deal from one program to the next.
Acute low back pain is a common reason for patients to present to an urgent care center. Patients strain their back and often cannot get in with their PCP for immediate evaluation and treatment. It then falls on the shoulders of the urgent care physician to properly evaluate the patient and begin treatment. Although the majority of acute low back pain may be approached conservatively, it is essential that red flag symptoms and signs are picked up when present. Typically, in the absence of red flags, imaging is not necessary in evaluation low back pain. Once serious or threatening conditions are ruled out, conservative treatment may be started. Given an evidence rating of A (consistent, good quality, patient-oriented evidence), it may be appropriate to treat a patient that presents to an urgent care center with acute low back pain in the following manner: the patient may be started on an NSAID and a skeletal muscle relaxant (flexeril at 5 mg offers relief with less adverse side effects). The patient should be advised to stay active, as bed rest is often ineffective and may be harmful. The patient may be told that no specific back exercises have been shown to be beneficial. Finally, the patient may receive some relief from the use of heat, but ice has not been shown to be helpful.
Of course, there are multiple modalities that patients and physician use in treating acute low back pain. Although this article details which treatment options have strong evidence-based support, many forms of therapy may still have strong anecdotal support among both patients and physicians. It is often the case that there is no contraindication in using alternative treatment options as long as the patients' best interest is kept in mind and no harm is brought to the patient. Ultimately, it is difficult to argue against strong, patient-oriented evidence. In treating low back pain, it should be remembered that 95% of patients improve in 12 weeks. Patients should be reassured, but close follow-up should ensue 4-6 weeks after therapy is started.