Efficacy of Manual Therapies in the Treatment of Thoracolumbar Dysfunction

The realm of manual therapy includes diagnostic and treatment methods from a diverse array of healthcare professions, which include touch therapies, massage, physical therapy, osteopathy, and chiropractic methods. All of these techniques were originally developed for use in humans and subsequently, have been applied to horses. All forms of manual therapy have variable reported levels of effectiveness for treating musculoskeletal issues in humans. Currently, there is only limited evidence supporting the effectiveness of massage, spinal mobilization, and manipulation in reducing pain and muscle hypertonicity and increasing spinal mobility in horses. Author’s address: Gail Holmes Equine Orthopaedic Research Center, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, 300 West Drake Road, Colorado State University, Fort Collins, CO 80523; e-mail: [email protected]. © 2011 AAEP.

1. Introduction

The use of touch, massage, or manipulation of painful articulations or tense muscles is arguably one of the oldest and most universally accepted forms of therapy to relieve pain and suffering.¹  Firmly grasping an acutely injured thumb after a misdirected hammer blow or rubbing a sore muscle or stiff joint after a long day’s work are simple and often effective methods of providing short-term pain relief in humans. Similarly, animals lick, scratch, or rub wounds or areas of irritation in an apparent attempt to reduce pain and suffering. Horses are known to respond favorably to grooming, stretch, roll on their backs, and rub up against objects, presumably because these activities provide some sense of comfort. Over time, both lay and licensed practitioners have developed a spectrum of manual methods, which involve the application of the hands to the body, with a therapeutic intent.²  Chiropracty, osteopathy, physical therapy, massage therapy, and touch therapy all use forms of manual therapy, which have been developed for the diagnosis and treatment of musculoskeletal disorders in humans and transferred for use in horses. Abdominal and rectal palpation, soft-tissue and bony palpation of musculoskeletal structures, or movement of an articulation through its expected range of motion are considered essential diagnostic manual techniques that are used routinely in veterinary medicine. The goal of manual therapy is to restore normal joint motion, stimulate neurological reflexes, and reduce pain and muscle hypertonicity. Comparisons of sensitivity to palpation, muscle tone, and joint motion are made before and after treatment to evaluate the response to and effectiveness of manual therapy. Therapeutic effects may be generalized to the entire body by inducing relaxation or altering behavior; regional effects may include alterations in pain perception or neuromuscular control, or effects may be localized to specific tissues and cellular responses.² The challenge is in selecting the most appropriate and effective form of manual therapy to produce the desired physiological effect within an individual patient, such as increasing joint range of motion, reducing pain, or promoting general body relaxation. Anecdotally, all forms of manual therapy have reported levels of effectiveness in humans and horses. Unfortunately, most of these claims have not been supported by high levels of evidence such as randomized, controlled trials or systematic reviews of the literature. However, considerable advances have been made in conducting investigations into plausible mechanisms of action and assessing the clinical efficacy of manual therapies. The purpose of this article is to review the scientific literature for evidence of efficacy, safety, and common mechanisms of action of massage, soft-tissue and joint mobilization, and spinal manipulation, with specific focus on the thoracolumbar region and potential translational applications for treating equine back pain and dysfunction.

2. Diagnosis of Back Problems

Owners or trainers often complain that their horse has back problems. Veterinarians also frequently describe a horse as having poor performance, nonlocalized lameness, or altered gait of some sort, and therefore, they provide a diagnosis of possible back problems. Unfortunately, the use of the term back problems is very nonspecific and is comparable with terms like colic, lameness, skin problems, and “ain’t doing right”. However, with proper diagnostics (e.g., abdominocentesis, serum chemistries, exploratory surgery, nerve and joint blocks, or skin biopsies), a definitive diagnosis can often be provided for the ailment of interest. Regrettably, the diagnosis of a back problem in both humans and horses is neither straightforward nor definitive. Horses with back pain often present with vague signs of poor performance, lack of impulsion, stiffness, or avoidance of tack.^3,4 Even with recent advances in high-tech diagnostic imaging, approximately 90% of human patients have no identifiable cause of their back pain and are subsequently categorized as having nonspecific back pain.⁵ The probability that a human back pain patient has a specifically related radiographic finding is less that 1%, which provides little guidance to the development of treatment options.⁶ The basic elements of joint or spinal dysfunction include altered articular neurophysiology, local biochemical alterations, pathological changes within the joint capsule, and articular degeneration, which are all difficult to diagnose or image within the axial skeleton.

Another factor contributing to the problem of definitive diagnosis is the poor correlation between structural changes identified on diagnostic imaging and actual functional capabilities. A common example is the radiographic diagnosis of impinged dorsal spinous processes in horses. Severe proliferative and sclerotic changes may be present at multiple vertebral levels; however, the affected horse is able to continually perform at a high level of athletic activity.⁷ Conversely, a horse may have mild signs of impinged spinous processes with small lytic areas confined to only one or two intervertebral sites, which seemingly cause severe functional limitations. Despite my hope for the future use of routine magnetic resonance imaging (MRI) and computed tomography (CT) imaging of the adult equine axial skeleton and pelvis, it may be unlikely that the prevalence of definitive diagnosis of back or sacroiliac joint pain in horses will be any higher than those diagnoses reported in humans with similar conditions. Anecdotally, some equine spinal imaging centers claim that they can identify significant spinal lesions in up to 75% of cases presented for back problems using radiographs, ultrasound, and nuclear imaging. However, a definitive diagnosis cannot be established by using diagnostic imaging alone without the use of small amounts of local anesthetic placed adjacent to sites of perceived clinically significant pathology and the immediate return to a prior level of functional athletic performance.

Given the above situation, the equine profession is not in a position of being able to make substantial advances in the diagnosis of structural or functional causes of back problems. However, if we begin to consider back problems as a syndrome characterized by pain, muscle hypertonicity, and stiffness (all of which can be somewhat objectively measured), then we can make substantial diagnostic and therapeutic advances in the profession. A syndrome refers to the association of several clinically recognizable features that often occur together, and the presence of one of these features should alert the examiner to the possibility of the development or finding of other clinical signs. Some of these clinical signs are considered major signs, which are essential to the diagnosis; others are considered minor signs, which may or may not be present. A syndrome can also refer to a set of detectable characteristics where the reason for their common occurrence has not yet been discovery (i.e., pathophysiology). In equine practice, there are many identifiable syndromes, some of which include head shaking, wobbler’s disease, stringhalt, shivers, tying up, and cauda equina syndrome. As medical progress continues, the etiology of many syndromes can be identified as a single causative agent (e.g., glycogen synthase mutation contributing to polysaccharide storage myopathy).⁸ After a distinct etiology has been identified, then specific treatment or management protocols can be developed for that syndrome or seemingly unrelated collection of signs.

The formal description of a syndrome typically specifies the minimum number of major and minor findings that are required for a diagnosis. The cardinal signs of acute inflammation include swelling, heat, altered function, redness, and pain. [...]