By Felise Milan, MD
The lifetime prevalence of low back pain in industrialized nations is 70%.1 More than one-third of those afflicted with low back pain seek care from a health care provider.2 Low back pain is the second most common reason for office visits to primary care providers and the most common reason for visits to orthopedists, neurosurgeons, and occupational medicine physicians.3 This results in 17.4 million visits to physicians per year with an estimated cost of $190 million per year.4
Low Back Pain in Women
Although some reports suggest an equal incidence of low back pain in men and women,5 others have found that women are at greater risk for low back pain.1 Risk of low back pain in women is associated with older age, smoking, parity, and occupational factors.1 One study in the Netherlands found a 26% prevalence of low back pain in women who worked in nursing homes, with frequent recurrences over a year.6 In older women, there is an especially strong association between back symptoms and functional limitations. One study found more than half of functional limitations were attributable to back symptoms in older women.7
There has been some exploration of the role of female sex hormones and their influence on joint laxity in women.1 Although there is not a clear causative mechanism in humans, there is some evidence from animal models that estrogen interacts with articular cartilage.1 Increased pelvic laxity during pregnancy has been demonstrated and prevalence of low back pain during pregnancy was 49-67% in one study.1 Another study found 68.5% of pregnant women reporting low back pain and 58% reporting sleep disturbance and impaired daily living secondary to low back pain.8 Although low back pain is prevalent in pregnancy and the postpartum period, the relationship between epidural anesthesia and low back pain remains controversial.9
No difference in the incidence of low back pain has been found in women taking oral contraceptives (OCPs),10 but postmenopausal women who took OCPs in the past may be at increased risk for low back pain.11 In one study of more than 7,000 older women, postmenopausal estrogen use was associated with increased rates of low back pain. This association was stronger in current hormone replacement therapy users and independent of vertebral fractures.1
Chiropractic: Background Information
Spinal manipulation as a technique for treating musculoskeletal pain has been documented as far back as ancient China and Greece. The profession of chiropractic was developed in 1895 by Daniel David Palmer, a grocer and magnetic healer in Davenport, Iowa. Chiropractic (Greek for done by hand) was founded on the principle that joint dysfunction and misalignment of the spine may play a significant role in heath and disease. Spinal manipulation, therefore, can correct these problems and facilitate the return of health and equilibrium. Early in its history, the profession experienced a theological split between two factions. The "straight" chiropractors insisted on remaining true to the original theories proposed by Palmer, while the "mixers" felt that it was more realistic to incorporate other theories of health and disease, such as infection, which were being adopted by the scientific community of the time. This lack of uniformity within the field continues today.12
There are 17 accredited colleges of chiropractic in the United States with a total of 2,000 graduates per year. Two years of college is required for admission and the five-year curriculum requires 4,000 hours of basic science instruction and 1,000 hours of clinical internship for graduation. The National Board of Chiropractic Examiners administers a three-part licensing exam. Most states also require a practical exam for state licensure.13 All 50 states require licensure, but individual states vary with regard to their permitted scope of practice. For example, all states allow a spine-focused history and physical exam, X-rays, and spinal manipulation, and 90% also permit a more general history and physical, health advice, and ordering tests (ranging from blood work to CT scans). It is advisable for any physician to find out from his/her own state’s licensing body what his/her state allows.
Chiropractic: Efficacy Data for Low Back Pain
The literature for chiropractic undoubtedly has been the most scrutinized of all the complementary and alternative medicine fields. Chiropractic research has faced the same challenge as other therapies that involve strong doctor-patient interactions and hands-on and individualized therapy with criticism of its methodology. An expert panel assembled for the RAND Corp. critically reviewed the literature on the efficacy of spinal manipulation for acute and chronic low back pain, neck pain, and headache. Although several of the studies had poor research design, the consensus of the panel was that for acute, uncomplicated low back pain, spinal manipulation hastens recovery and decreases work time lost. Its long-term effect either in preventing chronic low back pain or a recurrence of acute low back pain is unknown at present.14 Two more recent reviews concluded that there was limited evidence to suggest that spinal manipulation is better than placebo, physical therapy, and exercise in the treatment of acute low back pain.15,16 These same authors, however, felt that there was strong evidence of efficacy in the treatment of chronic low back pain.
The U.S. Agency for Health Care Policy and Research17 and its British equivalent, the Clinical Standards Advisory Group,18 both have suggested that spinal manipulation is better documented as an effective treatment for acute mechanical low back pain than any other except nonsteriodal anti-inflammatory drugs (NSAIDs).
A recent meta-analysis of 39 randomized controlled trials (n = 5,486) compared spinal manipulative therapy to sham therapy, therapies considered ineffective (traction, bed rest, corset, home care, topical gel, and diathermy), and therapies conventionally advocated (physical therapy, exercise, back school, care by general practitioners, and analgesics).19 The authors found that spinal manipulative therapy (SMT) was more effective than either sham or ineffective therapies in relieving short-term pain for both acute and chronic low back pain. For chronic low back pain, SMT was more effective for relieving short- and long-term pain as well as improving short-term function. (See Figures 1 and 2.) SMT was equally as effective as all therapies conventionally advocated on all outcome measures.19
Spinal manipulative therapy for acute low back
pain compared to sham, ineffective therapies19
Spinal manipulative therapy for chronic low back
pain compared to sham, ineffective therapies19
There has been some work recently to develop20 and validate21 a clinical prediction rule to identify which patients with low back pain are the most likely to benefit from spinal manipulation. Although having a clinical prediction rule potentially would be useful, it has been studied in a military population with physical therapists administering a standardized manipulation therapy,21 making it difficult to generalize the results to the general population receiving individualized SMT from chiropractors.
One of the myths about chiropractic is that spinal manipulation, especially cervical, is actually dangerous. In fact, the estimated risk of a major complication from cervical spine manipulation is 6.39 per 10 million manipulations and 1 per 100 million manipulations for lumbar spine manipulation.22 This compares quite favorably to the other forms of therapy for the same conditions. The rate of serious complications for spinal surgeries is 15.6 per 1,000 surgeries and 3.2 per 1,000 subjects for NSAIDs.22 Although serious complications from manipulation of the lumbar spine are exceedingly rare, there has been much concern about case reports of vertebral artery stroke attributed to cervical spine manipulation. The incidence of this has been estimated to anywhere from 1 in 0.5 million to 1 in 5.85 million cervical manipulations.23,24 The rarity of vertebral artery stroke makes this association very difficult to study.
Contraindications to manipulative therapy include severe rheumatoid arthritis with ligamentous laxity, bleeding disorders or anticoagulation therapy, and conditions that render the bony structures susceptible to trauma such as acute fractures, bone tumors, and severe osteoporosis. It is not unusual for patients to report benign effects from manipulation such as increase in symptoms, myalgias, and fatigue. These effects usually are transient and need not prohibit further manipulation treatments.
As mentioned above, the field of chiropractic is not unified in the philosophies that it promotes. This manifests itself in varying practice styles and practices among different chiropractors. Before making a chiropractic referral, it is useful to find out what you and your patient can expect from the practitioner. (See Table 1.) Some chiropractors limit their practice to spinal manipulation, and others may use any variety of other therapeutic interventions including exercise, dietary changes, and dietary and nutritional supplements. Some promote the idea of routine spinal manipulation on an ongoing basis (maintenance therapy), while others believe it is inappropriate and focus on successfully treating the presenting problem. Some tout the use of chiropractic for any and all physical problems, but others use it almost exclusively for musculoskeletal problems and perhaps for other problems for which chiropractic has been proven efficacious.
What to ask a chiropractor
Spinal manipulative therapy is safe and as effective as any of the more conventional therapies that routinely are recommended for the treatment of low back pain. Patient satisfaction with chiropractic for the treatment of low back pain is consistently higher than for patients who visit physicians. This may be explained by the relative inadequacy of the explanation that physicians are able to provide and paucity of self-care advice provided compared to chiropractors. It also may be due, in many patients, to an actual improvement in their pain and function. In the future, it may be clearer which patients are likely to benefit from chiropractic. As fears of additional adverse effects from analgesics (NSAIDs and COX-2 inhibitors) commonly used for low back pain increase, chiropractic should be considered as an attractive alternative for patients with this very common complaint.
Dr. Milan, Associate Professor of Clinical Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, is on the Editorial Advisory Board of Alternative Therapies in Women’s Health.
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