Abstract and Introduction
Study Design. Systematic review of randomized controlled trials (RCTs).
Objectives. To determine the effectiveness of herbal medicine for nonspecific low back pain (LBP).
Summary of Background Data. Many people with chronic LBP use complementary and alternative medicine (CAM), visit CAM practitioners, or both. Several herbal medicines have been purported for use in treating people with LBP. This is an update of a Cochrane Review first published in 2006.
Methods. We searched numerous electronic databases up to September 2014; checked reference lists in review articles, guidelines and retrieved trials; and personally contacted individuals with expertise in this area. We included RCTs examining adults (over 18 years of age) suffering from acute, sub-acute, or chronic nonspecific LBP. The interventions were herbal medicines that we defined as plants used for medicinal purposes in any form. Primary outcome measures were pain and function. Two review authors assessed risk of bias, GRADE criteria (GRADE 2004), and CONSORT compliance and a random subset were compared with assessments by a third individual. Two review authors assessed clinical relevance and resolved any disagreements by consensus.
Results. Fourteen RCTs (2050 participants) were included. Capsicum frutescens (cayenne) reduces pain more than placebo. Although Harpagophytum procumbens (devil's claw), Salix alba (white willow bark), Symphytum officinale L. (comfrey), Solidago chilensis (Brazilian arnica), and lavender essential oil also seem to reduce pain more than placebo, evidence for these substances was of moderate quality at best. No significant adverse events were noted within the included trials.
Conclusions. Additional well-designed large trials are needed to test these herbal medicines against standard treatments. In general, the completeness of reporting in these trials was poor. Trialists should refer to the CONSORT statement extension for reporting trials of herbal medicine interventions.
Level of Evidence: N/A
Low back pain (LBP) and its related disability are major public health problems across industrialized nations. As a result, research efforts have intensified to identify effective treatment and management strategies for people with LBP. Point prevalence estimates of LBP vary widely depending on the methodology used, but range from 12% to 40% of the population. In addition, several studies indicate that LBP prevalence is increasing over time. Data from a United States national survey from 2002 reported a 3-month prevalence of 26.4%, with higher prevalence among American Indians and Alaskan Natives (35.0%), and lower prevalence among Asian Americans (19.0%). LBP prevalence peaks between the ages of 45 to 64 years and is more common among lower socioeconomic status groups, as defined by income and education. Lifetime prevalence of LBP is estimated at 67%.
In the United States, back pain accounts for 19 million physician visits, 250 million workdays lost, and $14 billion (USD) in direct expenditures. Indirect costs, excluding short- and long-term disability, are estimated at up to $100 billion (USD) per year. LBP-related disorders caused 2.63 million annual emergency department (ED) visits, or 2.3% of all visits to EDs in the United States. This amounts to substantial societal productivity losses and an economic burden for health care systems in many industrialized countries.
Wide variations in the medical and surgical management of LBP reflect widespread professional uncertainty about optimal care of people with LBP. Over 1000 randomized controlled trials (RCTs) have been published evaluating all types of conservative, complementary, or surgical treatments for LBP that are commonly used in primary and secondary care. A special focus issue of The Spine Journal reviewed 25 categories of treatment presented for the management of chronic LBP. Several interventions are included in clinical practice guidelines on LBP, including: back schools, nonsteroidal anti-inflammatory drugs (NSAIDs), the McKenzie method, needle acupuncture, spinal manipulation, trigger point injections, and watchful waiting. A summary of European clinical guidelines for chronic LBP includes cognitive behavior therapy, supervised exercise therapy, educational interventions, biopsychosocial treatment, and short-term use of NSAIDs and weak opioids.
Although systematic reviews suggest that few of these interventions have sufficient evidence to suggest benefit, it does appear that acute LBP can usually be effectively managed by encouraging activity, reassurance, and short-term symptom control (analgesics or NSAIDs). Treatments that demonstrate some effectiveness for the management of chronic LBP include exercise therapy, behavioral treatment, and multidisciplinary treatment programs, as well as short-term use of analgesics or NSAIDs.
Research in complementary and alternative medicine (CAM) has increased over the last 15 years. Rigorous literature is growing steadily and is subsequently clarifying the validity of these techniques. Specifically, the number of randomized trials of complementary treatments has doubled approximately every 5 years, and currently the Cochrane Complementary Medicine Field Trials Registry contains over 43,000 records. In addition, CAM teaching institutions are now beginning to teach principles of evidence-based medicine and clinical epidemiology.[10,11] These initiatives are well placed, given the large number of visits to CAM practitioners.[12,13] A recent population survey in Canada found that 12.4% of Canadians visited a CAM practitioner in the year they were surveyed, between 2001 and 2005. A review article on the international acceptance and use of CAM found prevalence rates between 5.0% and 74.8%, with an overall average prevalence of 32.2%. Follow-up studies indicate a steady increase in CAM use. More CAM users are women, middle-aged, educated, and experiencing chronic disease.[12,13] Back pain or back problems are one of the five most common medical conditions for which CAM has most often been used. Among people reporting back problems, between 16.8% and 57.2% seek CAM treatments.
Several herbal medicines are reported treatments for various types of pain. These include Commiphora molmol (myrrh), Capsicum frutescens (capsicum), Salix alba (white willow bark), Melaleuca alternifolia (tea tree), Angelica sinensis (don quai), Aloe vera (aloe), Thymus officinalis (thyme), Menthe peperita (peppermint), Arnica montana (arnica), Curcuma longa (curcumin), Tanacetum parthenium (feverfew), Harpagophytum procumbens (devil's claw), and Zingiber officinale (ginger). Many have been the subject of extensive biochemical research, resulting in the delineation of their pharmacological and physiological effects. For example, the mechanism of C. frutescens is partially related to its ability to deplete substance P, a neurotransmitter for pain perception.S. alba is a platelet inhibitor and analgesic, and H. procumbens has analgesic and anti-inflammatory properties. In addition, some of these herbal species have been clinically tested for the relief of symptoms of LBP.[15,18–20]
Given the large public health and economic burden LBP causes and the large number of people with LBP who regularly visit CAM practitioners, a systematic review of these herbal medicines was warranted.
Spine. 2016;41(2):116-133. © 2016 Lippincott Williams & Wilkins