Back to Basics: Treatment of Acute Low Back Pain in the ED

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+ Take away points

  1. Nonspecific, acute low back pain can be thought of as a diagnosis of exclusion and other etiologies should be considered first.
  2. The majority of people at some point in their lives experience low back pain, although it often improves significantly over the 1-3-month period that ensues. Unfortunately, there are high recurrence rates.
  3. Treatment of acute low back pain in the ED is different than treatment of chronic low back pain.
  4. Pharmacologic therapy can be combined with non-pharmacologic therapy for improved outcomes (ex. patient education).
  5. NSAIDs show some mild benefit for analgesia and disability reduction. Acetaminophen has no recent, strong evidence supporting its use in acute low back pain.
  6. Muscle relaxants have mixed results for treatment of acute low back pain, and have significant side effect profiles.
  7. Lidocaine patches may provide significant benefit without burden of systemic adverse effects although there is not enough evidence to strengthen the argument for its routine use yet.
  8. Treatment-focused patient education, especially regarding prognosis and expectations, is an essential component of nonpharmacological therapy for acute low back pain.

Focus of this review

The breadth and depth of the treatment of back pain is expansive, and often focused on specific diagnoses. An especially challenging subtype of acute low back pain (ALBP) to treat is nonspecific low back pain, as it by definition has no easily identifiable pathologic or anatomic cause. Thus, there are no specific treatments that can target an etiology for nonspecific low back pain, which remains a diagnosis of exclusion. This review focuses on emergency department-relevant treatment of this subtype of acute back pain rather than the treatment of specific etiologies of back pain. A careful history and physical examination is essential in the evaluation of low back pain to assess for potential life-threatening causes first, such as spinal epidural abscess, malignancy, cauda equina syndrome or abdominal aortic aneurysm.

Definition

Acute low back pain is variably defined in the literature; many studies delineate acute low back pain as a less than three-to-six-week period of pain which is located between the lower rib cage and inferior gluteal folds.(1)

Why it matters

Low back pain (LBP) represents one of the leading causes of disability – worldwide – and has a significant socioeconomic impact. Low back pain also holds a spot in the top ten injuries and/or diseases accounting for the highest number of disability-adjusted life years (which represents the sum of years of life lost plus years lost due to disability).(2) There is a wide range of reported numbers of the true financial cost of LBP, with some estimates exceeding $100 billion per year, the majority of which is associated with lost wages and work productivity.(2,3)

 Epidemiology & natural history

Low back pain is a complaint that approximately 50-80% of adults experience during their lives at least once, and 15-20% of adults yearly.(4)  ALBP has a favorable prognosis with significant improvement in disability and pain over the first one-month period from onset although recurrence is a common phenomenon. One systematic review from 2003 demonstrated rapid pain decrease in low back pain within one month of onset with slower improvement in pain over the subsequent three months, at which point pain levels plateaued.(5) Disability associated with low back pain decreased by 33-83% of onset disability levels during the first one-month period. Recurrence within a one-year period ranged from 66-84%. (5)

Who will seek out care for LBP? Many people with LBP do not pursue treatment and evaluation; patients who do seek out care are more commonly women, have poorer general health, more severe or disabling pain associated with LBP episodes, and have a prior history of back pain.(6)

Risk factors

Not only are there physical and work-associated risk factors for low back pain, such as non-ergonomic lifting, but also psychological factors which increase the risk of perpetuating chronic pain and long-term disability, including inappropriate attitudes and beliefs about back pain, psychiatric illnesses, work-related problems or compensation issues (including work dissatisfaction), and maladaptive pain behaviors (pain-associated fear avoidance behavior).(1) Thus, psychological factors and patient education have significant roles in the treatment of acute low back pain. For those who do present to the emergency department, one US study found that 81% of episodes of LBP began at home with lifting representing the most common inciting event.(7)

Prevention

There is minimal formal literature on the effectiveness of preventive measures such as braces, ergonomic furniture, and lifting assistance devices.(3)  One 2016 JAMA systematic review evaluated preventive measures for low back pain. The review included 21 trials and 30,850 participants. Data was assessed for quality using a standardized score. Moderate quality evidence demonstrated that exercise + education reduces the risk of an episode of LBP in the next year by 45%.(8) Exercise alone was found to reduce the risk for LBP in next year by 35% and the risk for utilization of sick leave by 78% based on low quality evidence.(8) Education alone was found, based on moderate quality evidence, to have no protective effect at neither short nor long term follow up.(8) Back belts, shoe insoles, and ergonomic adjustments had minimal evidence for evaluation and thus have uncertain roles in prevention of LBP and utilization of sick leave.(8)

Treatment

Treatment is focused on symptom reduction and reduction of disability. The basic approach involves education, reassurance, analgesic medication therapy, non-pharmacological therapy, and follow-up with additional adjustment of the treatment approach as appropriate. Traditionally, clinical practice guidelines followed the WHO analgesic ladder, which started with simple analgesics and progressing to more complex and higher risk therapies.(1)

The short and sweet version of upcoming information: NSAIDs are mainstay first-line therapy for ALBP. Acetaminophen has, in recent years, been demonstrated to have little to no benefit for ALBP. Skeletal muscle relaxants appear to provide some benefit, although have relatively challenging side effect profiles. Lidocaine patches have scant although relatively strong encouraging evidence for use in ALBP. Several non-pharmacologic therapies are emerging as contenders for treatment of ALBP in the ED setting.

Table 1: Summary of primary pharmacologic therapies' risk, benefit profiles in acute low back pain

Pharmacologic treatment 

NSAIDs - Acetaminophen - Muscle Relaxants - Steroids - Lidocaine - Opiates

NSAIDs

Monotherapy

NSAIDs have been the longstanding first-line therapy for nonspecific low back pain. A 2020 Cochrane review revisited the efficacy for NSAIDs in acute low back pain. NSAIDs do appear to have some limited, minimal benefit for patients with ALBP.(9) They were found to be slightly more effective in reducing pain and disability on a 3 week or less time period compared to placebo. Low quality evidence supports slight increase in global improvement than placebo for NSAIDs. Low-quality evidence demonstrated no difference in the proportion of patients with ALBP who experienced adverse medication-associated effects with COX-2 specific vs nonselective NSAIDs, and there was no demonstrable difference in pain reduction between selective and nonselective NSAIDs.(9)

Combination therapy

An RCT published in 2015 compared pain reduction between a ten-day course of naproxen alone, naproxen + oxycodone 5mg/acetaminophen 325mg, versus naproxen + cyclobenzaprine in patients with non-radicular, non-traumatic low back pain presenting to the ED. Results demonstrated no significant benefit for addition of either cyclobenzaprine or oxycodone/acetaminophen to naproxen in analgesia or functional outcomes at one-week follow-up.(10)  Another study evaluated the utility of adding acetaminophen to NSAID regimens for treatment of ALBP in the ED and found no substantial benefit.(11)

Acetaminophen

Although traditionally considered another first-line therapy for ALBP due to its low side-effect profile and over-the-counter availability, recent studies have demonstrated little to no efficacy for acetaminophen for ALBP.(3,17,18) The 2014 Paracetamol for Acute Low Back Pain (PACE) trial demonstrated that paracetamol had no effect compared with placebo for acute low back pain although due to patient noncompliance, result interpretation was somewhat limited.(19) A follow up study published in 2019 evaluated paracetamol in patients with low back pain who are compliant in completing medication regimens with paracetamol, and again demonstrated lack of efficacy in analgesic effect for acute low back pain at maximal safe doses.(19)

Muscle Relaxants

A 2003 systematic review of double-blinded and/or randomized control trials studying efficacy of muscle relaxants in nonspecific low back pain was conducted. Muscle relaxants were found to be effective in pain management of low back pain although adverse effects were prominent for the muscle relaxant groups.(13) No certain relaxant was found to be significantly more or less effective than others.(13) A Cochrane review assessed found improvement in pain relief for short-term (2-4 days) in acute low back pain for skeletal muscle relaxants.(14) Two other systematic reviews reached similar conclusions, although notably one included data on cyclobenzaprine for more chronic or subacute low back or neck pain with ultimately mixed results compared to placebo.(14) Another study demonstrated patients with ALBP treated with cyclobenzaprine to be nearly five times as likely to report symptom improvement at the second week of back pain compared to placebo, although with small effect size in evaluated domains of global improvement.(15) A 2019 randomized, double-blind, parallel-group four-arm study was conducted in two emergency departments to compare ibuprofen plus placebo versus ibuprofen plus one of the following: tizanidine, metaxalone, baclofen. Adding these agents to ibuprofen does not appear to improve pain or functioning any more than placebo by one week after discharge from the ED.(16)

Glucocorticoids

Several studies have found corticosteroids ineffective in treatment of ALBP. A randomized, double-blind placebo-controlled clinical trial published in 2006 evaluated the role of corticosteroid therapy in a controlled group of patients with acute non-radicular, non-traumatic low back pain. No benefit was found for a single dose of long-acting methylprednisolone on pain, disability, medication use, and healthcare utilization.(20)  Another double-blind, placebo-controlled trial in 2014 demonstrated similar findings of lack of benefit of corticosteroids in musculoskeletal low back pain although employed oral corticosteroids in the form of a five-day course of prednisone 50mg daily or placebo at five days.(21) The treatment group had an increase in seeking additional treatment in the prednisone group versus placebo (40% versus 18%).(21)

Lidocaine patch

There is limited although promising formal data for lidocaine patch efficacy in ALBP. A 2005 prospective, six-week, multicenter, open label non-randomized pilot study was performed to evaluate efficacy and safety of 5% lidocaine patch in patients with low back pain in addition to current analgesic therapy. Average daily pain scores were significantly improved at both 2-week and 6-week time points. Safety was also assessed; no systemic significant adverse effects were reported, although there were few that experienced mild side effects.(12)

Opiates

There is very limited literature regarding opiate use in the RCT setting for acute low back pain, and very little utility in therapy for ALBP. One 2016 systematic review and meta-analysis evaluating the effects of opioid analgesics for low back pain found no placebo-controlled RCTs evaluating opiates in acute low back pain.(22) Although subacute and chronic low back pain are outside the scope of this review, briefly, this same study found moderate-quality evidence demonstrating opioid analgesia reduction of pain in the short term although clinically significant pain relief was not observed within the 40-240mg morphine equivalent-per-day range (within guideline recommended doses). One additional study corroborated the lack of efficacy of opiates (oxycodone/acetaminophen).(10) Yet, they are frequently prescribed from U.S. emergency departments for low back pain.(23) It is worth mentioning the importance of continued vigilance and efforts to reduce inappropriate opioid prescriptions in light of the current opioid epidemic.

Injectable therapies

Several types of injections have been used in low back pain, although nonspecific low back pain has limited data for use of injections in analgesia. There is more data for injections in pain associated with sciatica and disc compression (spinal epidural injections, facet joint injections). There is minimal evidence from one small, randomized study in support of trigger point injections over parenteral NSAID therapy for low back pain.(24)

Antidepressants

There is very limited evidence for acute low back pain given delayed duration to therapeutic efficacy. 

Anti-epileptic drugs

AEDs are typically considered more so in subacute or chronic back pain. Even then, a 2018 systematic review and meta-analysis demonstrated that topiramate, gabapentin, and pregabalin compared to placebo are ineffective for treatment of low back pain and lumbar radicular pain. (25) Gabapentinoids also were reported to carry high risk for adverse medication effects and similarly to skeletal muscle relaxants, have messy side effect profiles.(25)

Non-pharmacologic treatment

Acupuncture

Acupuncture has emerged over recent years as a potential therapy useful for back pain of multiple stages of acuity. In the last several years, there have been several studies examining the utility and feasibility of implementing acupuncture in the ED for treatment of acute pain with generally positive results supporting efficacy in analgesia for ALBP. Overall, data has shown mild to moderate benefit of acupuncture for acute low back pain, including in the emergency department setting; one study showed non-inferiority to pharmacotherapy.(18,26,27)    

Spinal manipulation

A 2017 systematic review and meta-analysis of spinal manipulative therapy for acute low back pain examined 26 randomized controlled trials. Spinal manipulative therapy was found to have significant benefits in both pain and function of modest magnitude at up to six weeks. No significant events were reported in the reviewed randomized control trials but minor, short-duration events including headache, stiffness, and transiently-increased pain occurred.(31) Of note, cervical manipulation therapy does carry a risk of vertebral artery dissection, and thus, if included in the manipulation therapy session, is not an entirely benign treatment.

Massage

A 2015 Cochrane systematic review evaluated the effects of massage therapy for patients with nonspecific low back pain. Twenty-five trials were included in total, although only one trial specifically for acute low back pain (the others included subacute and acute). Evidence was assessed as low to very low in quality due to risk of bias and imprecision associated with inability to blind participants and measured outcomes. For acute LBP, massage therapy mildly improved pain in the short-term compared to inactive controls although did not improve patient functionality.(35)

Heat or ice?

A 2006 Cochrane systematic review evaluated the effects of superficial heat and cold therapy for low back pain in adults. Both randomized and non-randomized trials were included. Nine total trials were analyzed including 1,117 participants. Two trials including both acute and subacute low back pain demonstrated that heat wrap therapy significantly reduced pain after five days compared to oral placebo. Another trial demonstrated significant decrease in acute low back pain immediately after application of a heated blanket. There was insufficient evidence to determine the effects of cold therapy for low back pain.(28)

Physical therapy and exercise therapy

This can include both at-home exercises or supervised exercises in the physical therapy setting. These exercises may have the potential benefit patients who have risk factors for progression of acute back pain to subacute and even chronic back pain, including prior poor baseline of functional status, psychiatric co-morbidities, and high chronic health condition burden, although this has not been formally established in literature. Overall, systematic reviews of the available literature have not demonstrated consistent, sustained, clear benefits in pain or functionality for exercise therapy.(32,33)

Traction

Traction historically was used as an adjunct, non-pharmacologic therapy for treatment of low back pain. A 2013 Cochrane review evaluated the literature for assessment of therapeutic benefit of traction for low back pain and demonstrated no little or no difference in pain intensity between traction and sham treatment. At the time of this review there were no studies evaluating changes in disability secondary to back pain, global improvement, or return to work. (34)

Patient Education

Two studies corroborate the importance of trust, diagnosis, being believed, and good communication are essential components to healthcare for patients with chronic musculoskeletal pain.(29,30)

Article by Lauren Gillespie, MD

Dr. Gillespie is a PGY-1 in Emergency Medicine at the University of Cincinnati

Peer Review and Post by Trevor Skrobut, MD and Ryan LaFollette, MD

Dr. Skrobut is a PGY-4 in EM at the University of Cincinnati and Ryan LaFollette is an Assistant Program Director and Co-Editor of tamingthesru.com

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