Myofascial Elements of Low Back Pain
Low back pain is one of the most significant health care issues in western society. Each year billions of dollars are expended, and millions of various office visits required for treating various aspects of low back pain. Despite such a significant impact on society and the focus by modern health care, the evaluation and treatment approaches remain far from uniform. In fact, a recent review of physicians in a tertiary academic medical center reported that “…the results found little agreement regarding low back pain judgments, and that the individual physicians held consistently to their opinions.” The conclusion was that “Management of low back pain may be idiosyncratic, potentially compromising patient care.”1
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Despite the specialization and sub-specialization of various medical disciplines to address pain specifically, the contemporary approaches continue to often bear little agreement between different pain management sub-specialties. In fact, differences between sub-specialists within a discipline may bear limited similarities. Many agencies are coming to the conclusion that the most effective approach to chronic pain treatment requires a multidisciplinary approach, where areas of expertise for each discipline may be incorporated for a more robust outcome.
Responses to various interventional ‘pain blocks’ often show more efficacy when combined with concurrent therapies that addresses contributing musculoskeletal and postural factors. For example, after leg-length discrepancy is corrected, trigger point injections may have a much more prolonged effect. Such a combined approach may be ‘curative’ rather than solely ‘pain treatment.’
It behooves the pain specialist to evaluate the multiple kinetic issues that may lead to recurrent stress or injury to the low back region. The purpose of this article is not to review the numerous postural, gait, and movement contributors to low back pain pathology, nor serve as a primer for treating low back pain. Instead, the focus is to raise the curiosity of the pain specialist to explore the multiple contributing factors — often classically within the realms of other allied specialists — before planning interventions. By learning and incorporating a few of the ‘pearls’ of multiple disciplines, a more complete evaluation and treatment plan will result.
Etiologies of Chronic Low Back Pain
The etiologies of chronic low back pain are many, and sometimes diverse. While herniated disc, spinal stenosis, spondylosis, and facet arthropathy are often considered along with myofascial origins, myofascial trigger points (TrPs) have been shown as coexisting with the other commonly accepted causes. Injection of active and painful myofascial trigger points from any origin may produce variable decreases in pain and improvements in mobility. Therefore, myofascial trigger point injections (TrPIs) are considered a significant treatment adjunct to low back pain.2
Often trigger point injections are carried out in a ‘follow the pain’ pattern, addressing primary and secondary trigger points and muscle spasms. Unfortunately, limited regard may be given to considering if the trigger point is in a shortened spastic muscle, or one that is weakened and overstretched from the opposing spastic muscles. Chronic postures may promote muscle force imbalances between the antagonistic muscle groups that lead to repetitive stretch trauma of the weaker muscle groups. As an example, shortened hamstring muscles may force secondary overstretching of lumbar extensor muscles during low back flexion. Therapies that address only those regional trigger points by promoting generalized lumbar extensor mobility, may actually promote excessive stretching of the already weakened over-stretched muscles, as well as contribute to more TrP formation. Moreover, if there is asymmetry of muscle strength and length between sides such approaches may also lead to areas of disproportionate relative mobility between individual spinal segments that may impact on less elastic non-muscular components. In situations of advanced muscle force imbalances, aggressive lumbar flexion exercises and TrPIs may also further weaken or overpower the posterior supporting ligamentous structures to allow segmental spinal movements which can lead to spondylosis and more pain generating processes.
Most spinal dysfunction is the product of cumulative microtrauma in multiple regional tissues from problems in trunk stabilization, alignment, and movement patterns. Core and spinal stabilization depends on balanced isometric support and movement control primarily provided by trunk musculature.3-5 When low back pain arises, one goal should include evaluation of directions for trunk and spinal alignment, stress, and movements that produce or increase pain.
A common denominator for most spinal related pain is an excessive relative flexibility at specific segments, rather than reduced flexibility from such factors as spasm.5,6 Those segments with reduced flexibility promote compensatory motion at the most flexible regions. While vertebral column pathology (disc herniations and bulges, spondylosis, facet arthropathy, and nerve compression) can promote pain independently, addressing trunk musculature issues first, and then those secondary abnormal spinal stresses, may reduce or alleviate the pain completely.5 The trunk muscles must hold the vertebral column and pelvis in optimal alignment, as well as prevent potentially injurious segmental movement. Therefore, observing body mechanics during various positions and movement may shed light on relative flexibility of various regions, and the impact on spinal stresses which produce pain. In some less chronic back pain syndromes, addressing posture, such as how one wears a backpack, may be the only intervention required to produce a cure.7