The role of manual therapies in equine pain management

Pupillometry to show stress release during equine sports massage therapy

Anecdotal reports state that wellness treatments for horses, such as massage therapy, relaxes the treated animal. Massage therapists and horse owners typically report an "improvement" without verifying or quantifying the treatment results. This paper shows that the effect of wellness treatment and stress release can be measured with pupillometry. One of the horse's pupils was photographed at the beginning and end of the treatment to determine the changes in the balance between the sympathetic and parasympathetic system activities. The owners assigned horses to two experimental groups: animals receiving a massage (N = 18) and horses standing with a person next to the horse for the time of a massage in the stable lane (N = 10). Six animals in the experimental group were excluded from the analysis because the pupils could not be traced. We opened the images of the pupil with Fiji (ImageJ) and used the elliptical selection tool to measure the pupils' and iris' areas. The ratio between the pupils' aperture and the iris' area was a normalized measure for pupil size. At the end of the experiment, we compared the normalized size of the pupils with a two-tailed paired t-test within groups and a two-tailed t-test between groups. For the experimental group, it was before and after the treatment, and for the control group, before and after the horse was placed in the stable lane. Comparisons between the experimental and control groups were made at the procedure's beginning and end. The treatment significantly decreased the normalized pupil area in the experimental group, on average, by a factor of 0.78 ± 0.15 (P = 0.042). For the horses in the control group, the pupil size increased, on average, by a factor of 1.14 ± 018. Changes were statistically not significant (P = 0.19). The initial pupil size of the horses in the experimental group was 1.88 times larger than that in the control group. After the treatment, the difference was reduced to a factor of 1.25. At the beginning of the experiment, the horses in the experimental group had, on average, larger pupil sizes than the horses in the control group, indicating that the horses in the experimental group were more stressed before the treatment than the control animals. The observed changes in pupil size in the experimental group likely resulted from enhanced parasympathetic and diminished sympathetic activity resulting from the treatment. Observed changes in pupil size agree with the anecdotal horse owner reports and the therapist's treatment notes.

Veterinary Spinal Manipulative Therapy or Animal Chiropractic in Veterinary Rehabilitation

Veterinary rehabilitation is a multimodal diagnostic and treatment approach that is recommended and provided to patients daily. One therapeutic modality that may be beneficial (diagnostically and therapeutically) is veterinary spinal manipulative therapy or animal chiropractic (AC). AC is a receptor-based health-care modality being provided more frequently in veterinary practices. All clinicians should strive to understand the mode of action, indications, contraindications, how it affects the patient from the neuro-anatomical and biomechanical point of view, and most importantly, when not to provide the requested modality, as further diagnostics may be indicated.

The Effect of Capacitive-Resistive Electrical Therapy on Neck Pain and Dysfunction in Horses

Neck pain and stiffness are increasingly recognized in horses and often treated using multimodal pharmaceutical and rehabilitation approaches. In humans, deep tissue heating is reported to reduce neck pain and increase flexibility. The objective of this project was to determine the effects of capacitive-resistive electrical therapy on neck pain and stiffness in horses. A blinded, randomized, controlled clinical trial with 10 horses assigned to active and 10 horses assigned to sham treatment groups. Neck pain, stiffness, and muscle hypertonicity were assessed by manual palpation. Forelimb postural stability was evaluated using a portable media device with built-in inertial sensing components. All outcome parameters were recorded once weekly for four weeks. Using manufacturer recommendations, the treatment group received active capacitive-resistive electrical therapy to the lower cervical region (C4-C7), twice weekly for a total of six treatments, while the control group received a sham (inactive) treatment. Data was analyzed using a mixed model that was fit separately for each response variable. There were no significant differences noted over time or between groups for any outcome parameter evaluated. While neck pain and stiffness decreased by week three in both groups, the improvement was not significant. Limitations include the lack of a definitive pathoanatomic diagnosis of cervical pathology and in vivo temperature measurements. Capacitive-resistive electrical therapy was ineffective in reducing neck pain and dysfunction using the recommended treatment protocols. No short-term adverse effects were noted. Specific clinical applications and effective treatment parameters need further evaluation.

Effectiveness of cranial osteopathy therapy on nociception in equine back as evaluated by pressure algometry

A horse needs to move in different gaits and carry a rider during riding. Therefore, the equine back must be in a good functional state. Preventing back disorders is one of the keys to ensuring a horse’s health. This study aimed to assess cranial osteopathy therapy as a treatment and prevention method for preventing and reducing back pain. Thirty-two thoroughbred horses were categorised by their backs’ functional status (16 without back pain and 16 with back pain). The mechanical nociceptive threshold was determined before and after osteopathic treatment by an algometer (pain test FPX 100) with pressure points between T14-T15, T18-L1, and L5-L6. The data were analysed with a significance of P < 0.05. The study found that cranial osteopathic therapy raised the mechanical nociceptive threshold average in 83.3% measured points for horses without back pain and in 50% measured points for those with back pain. This study revealed that both horses without back pain and horses with back pain had a positive response to cranial osteopathic therapy, as evidenced by the increased nociceptive threshold limits, indicating that osteopathic therapy can be used as a primary or additional treatment method for back dysfunction.

Dangerous Behavior and Intractable Axial Skeletal Pain in Performance Horses: A Possible Role for Ganglioneuritis (14 Cases; 2014-2019)

Introduction: Dangerous behavior is considered an undesired trait, often attributed to poor training or bad-tempered horses. Unfortunately, horses with progressive signs of dangerous behavior are often euthanized due to concerns for rider safety and limitations in performance. However, this dangerous behavior may actually originate from chronic axial skeleton pain. This case series describes the medical histories and clinical presentations of horses presented for performance limitations and dangerous behavior judged to be related to intractable axial skeleton pain. Material and Methods: Fourteen horses that developed severe performance limitations resulting in euthanasia were included. A complete spinal examination and behavioral responses, gait and neurologic evaluations, diagnostic imaging, gross pathologic and histopathologic examinations of the axial skeleton were performed on all horses. A tentative diagnosis of the affected spinal region was formulated using medical records, owner and trainer complaints, and antemortem examination findings. The selected spinal regions were further examined with gross and histopathologic evaluations of the associated osseous, soft tissue and neural tissues. Results: Ten horses showed severe behavioral responses during the myofascial and mobilization examinations. Based on an aggregate evaluation, the cervicothoracic and lumbosacral regions were the most common regions believed to be the primary area of concern. All horses had moderate to severe ganglionitis present at multiple vertebral levels. Subdural and epidural hemorrhage or hematomas were a common finding (71%) in the cervicothoracic and lumbosacral regions. Discussion: In this case series, neuropathic (i.e., structural) pain was judged to be the underlying cause of dangerous behavior. The dorsal root ganglia (DRG) serve an important role in relaying peripheral sensory information to the central nervous system and ganglionitis has been associated with neuropathic pain syndromes. This series highlights the need for more in-depth understanding of pain behavior and its clinical presentation and progression in chronic or severely affected horses. Limitations of the study are the lack of age-matched control DRG and the incomplete collection of DRG from every vertebral level of interest.

A Systematic Review of Musculoskeletal Mobilization and Manipulation Techniques Used in Veterinary Medicine

Simple Summary

Neck and back pain are common ailments in animals. While there are medical and surgical treatment options available for select patients, conservative care is the most common form of management of pain, stiffness and muscle spasms. Physical therapists, osteopaths and chiropractors use mobilization and manipulation techniques to evaluate and treat muscle and joint problems in both humans and animals, but there seems to be little scientific evidence available to support their use in veterinary medicine. This study reviews the scientific literature with the goal of identifying the clinical indications, dosages, outcome parameters, and efficacy of mobilization and manipulation techniques in dogs and horses. Fourteen articles were included in this review of which 13 were equine and one was a canine study. There was a large variability in the quality of evidence that supports the use of joint mobilization or manipulation in treating pain, stiffness and muscle hypertonicity in horses. Therefore, it was difficult to draw firm conclusions despite all studies reporting positive effects. Future studies need to establish standardized methods to evaluate the optimal dosages of mobilization and manipulation for use in animals.

Abstract

Mobilization and manipulation techniques are often used in small animal and equine practice; however, questions remain concerning indications, dosing and efficacy. A bibliographic search was performed to identify peer-reviewed publications from 1980 to 2020 that evaluated the clinical effects of musculoskeletal mobilization and manipulation techniques in dogs, cats and horses. The search strategy identified 883 papers for review. Inclusion and exclusion criteria were applied. The clinical indications, dosages, outcome parameters, and reported efficacy within each publication were recorded and categorized for comparison with scientific quality assessed according to a standardized grading system. Fourteen articles were included in this systematic review of which 13 were equine and one was a canine study. Seven of these were cohort studies and seven were randomized controlled clinical trials. The canine study involved carpal immobilization-remobilization and all equine studies focused on the effects of passive mobilization (n = 5) or manipulation (n = 8) of the axial skeleton. Study quality was low (n = 4), moderate (n = 7), and high (n = 3) and included a wide array of outcome parameters with varying levels of efficacy and duration of therapeutic effects, which prevented further meta-analysis. Therefore, it was difficult to draw firm conclusions despite all studies reporting positive effects. Optimal technique indications and dosages need to be determined to improve the standardization of these treatment options.

Equine Rehabilitation: A Scoping Review of the Literature

Simple Summary

When a horse is diagnosed with a locomotor disorder, the veterinarian treats the specific injury to restore the horse to soundness. Even after the injury has healed, however, the horse may not be fully functional due to persistent limitations in movement or strength in specific areas of the body. As in people, rehabilitation seeks to optimize function and reduce any existing disability using a variety of methods including manual therapy, the use of physical and mechanical agents, and specialized exercise regimes. This study has reviewed the scientific literature with the goal of identifying which types of physical therapy have been described in horses over the past 20 years. The most frequently reported techniques were exercise, electrotherapy, and hydrotherapy but there are relatively few publications describing details of their use and outcomes in clinical cases. This study reviews the methodology and outcomes of rehabilitation in clinical cases. The results highlight the paucity of clinically-based reports on the practical applications of equine rehabilitation and physical therapy.

Abstract

Injuries to the locomotor system are a common problem in athletic horses. Veterinarians address these injuries using appropriate medical, surgical, and pharmacological treatments. During or after recovery from the initial injury, horses may be treated for functional locomotor deficits using specific rehabilitation techniques aimed at restoring full athletic performance. This study reviews the literature to identify which rehabilitative techniques have been used most frequently in horses over the past 20 years, the protocols that were used, and the outcomes of the treatments in naturally occurring injuries and diseases. Publications were identified using keyword selection (Equine Athlete OR Equine OR Horse) AND (Rehabilitation OR Physiotherapy OR Physical Therapy). After removing duplicates and screening papers for suitability, 49 manuscripts were included in the study. The majority of publications that met the inclusion criteria were narrative reviews (49%) in which the authors cited the relatively small number of published evidence-based studies supplemented by personal experience. Observational/descriptive studies were also popular (35%). Randomized control trials accounted for only 10%. The most frequently reported rehabilitation techniques were exercise, electrotherapy, and hydrotherapy. The findings highlight the need for further information regarding type of intervention, parameterization, and outcomes of equine rehabilitation in clinical practice.

Generation of Domains for the Equine Musculoskeletal Rehabilitation Outcome Score: Development by Expert Consensus

Simple Summary

Within rehabilitation, measurements taken before, during and after treatments are used to judge patient progress and the effectiveness of prescribed treatments. To know which measurements to use for a given health condition, practitioners must have knowledge of what should be measured, which measurement tools are available and accurate, alongside what they intend to measure. Composite outcome measures (OMs) are tools which use grouped measurement tests to monitor patient progress; they have been tested for a variety of human and canine conditions but none have been designed or tested for use in physical rehabilitation in horses. This study asked leading equine veterinarians, physiotherapists and researchers which measures should be included in an OM for use in the rehabilitation of horses. Using a process to evaluate agreement, ten areas of measurement were included in the final model: lameness, pain at rest, pain during exercise, behaviour during exercise, muscular symmetry, performance/functional capacity, behaviour at rest, palpation, balance and proprioception. Existing reliable tests used to measure these areas were evaluated and potential new measures discussed and now should be taken forward to testing as a composite outcome score to see if they are effective in measuring effectiveness of treatment.

Abstract

Outcome measures (OMs) are a requirement of professional practice standards in human and canine physiotherapy practice for measurement of health status. Measures such as pain and functional capacity of specific regions are used to track treatment impact and can be used to develop optimal management strategies. To achieve comparable patient care in equine physiotherapy, OMs must be incorporated into practice; however, no reliable and valid OMs exist for equine rehabilitation. This study utilised the experience and opinion of a panel of experts working in the equine rehabilitation sphere to gain consensus on the core areas (domains) to be included in a model, to lead to an OM scale for horses undergoing rehabilitation. The Delphi method and content validity ratio testing was used to determine agreement with domains reaching the critical value required for inclusion. The expert panel agreed on ten domains to be included in the OM scale: lameness, pain at rest, pain during exercise, behaviour during exercise, muscular symmetry, performance/functional capacity, behaviour at rest, palpation, balance and proprioception. An OM with these domains would provide a holistic objective assessment tool which could be used by equine rehabilitation professionals in clinical practice.

Two Multicenter Surveys on Equine Back-Pain 10 Years a Part

Despite back-pain being a common cause of poor performance in sport horses, a tailored diagnostic workflow and a consolidated therapeutic approach are currently lacking in equine medicine. The aim of the study was to assess the evolution in the veterinarian approach to diagnose and treat back-pain over a 10 years period. To investigate this topic, two surveys were addressed to equine veterinarians working in practice throughout Europe 10 years apart (2006 and 2016). The answers were organized in an Excel dataset and analyzed. There were 47 respondents in 2006 and 168 in 2016, from 8 European Countries. The main reasons for examining horses with back-pain were poor performance (76%), behavioral issues (68%), and lameness (50%). When assessing back pain, 97% of respondents applied careful digital pressure over paravertebral muscles, 90% of them used digital back mobilization, and 69% was detecting areas of localized heat. The use of diagnostic analgesia to confirm the source of pain was rarely employed. Radiography and ultrasonography were the most frequent diagnostic imaging modalities used to investigate the causes of back-pain in both surveys. Obtaining a definitive diagnosis in horses with back-pain is considered challenging due to the reduced accessibility of the area and the variability in the pain manifestations. Corticosteroids injections were used for local treatments by 80% of respondents in 2006 and 92% in 2016. Recently, ultrasonography has been extensively used during the injections of the vertebral articular facets and sacroiliac joints region. The use of complementary therapies was restricted to a low percentage of respondents in the first survey (20%) but it increased over the decade. In 2016, a wider percentage of respondents considered osteopathy (40%), kinesiotherapy (29%), and acupuncture (22%) when treating back disorders compared to 2006. The structural differences of the two surveys did not enable a direct data comparison. Based on the results of this surveys, however, veterinarians should be sensitized to the back-pain problems and seek to integrate findings from clinical research studies in their daily practice.

The deep fascia and retinacula of the equine forelimb - structure and innervation

Recent advances in human fascia research have shed new light on the role of the fascial network in movement perception and coordination, transmission of muscle force, and integrative function in body biomechanics. Evolutionary adaptations of equine musculoskeletal apparatus that assure effective terrestrial locomotion are employed in equestrianism, resulting in the wide variety of movements in performing horses, from sophisticated dressage to jumping and high-speed racing. The high importance of horse motion efficiency in the present-day equine industry indicates the significance of scientific knowledge of the structure and physiology of equine fasciae. In this study, we investigated the structure and innervation of the deep fascia of the equine forelimb by means of anatomical dissection, histology and immunohistochemistry. Macroscopically, the deep fascia appears as a dense, glossy and whitish lamina of connective tissue continuous with its fibrous reinforcements represented by extensor and flexor retinacula. According to the results of our histological examination, the general structure of the equine forelimb fascia corresponds to the characteristics of the human deep fasciae of the limbs. Although we did find specific features in all sample types, the general composition of all examined fascial tissues follows roughly the same scheme. It is composed of dense, closely packed collagen fibers organized in layers of thick fibrous bundles with sparse elastic fibers. This compact tissue is covered from both internal and external sides by loosely woven laminae of areolar connective tissue where elastic fibers are mixed with collagen. Numerous blood vessels running within the loose connective tissue contribute to the formation of regular vascular network throughout the compact layer of the deep fascia and retinacula. We found nerve fibers of different calibers in all samples analyzed. The fibers are numerous in the areolar connective tissue and near the blood vessels but scarce in the compact layers of collagen. We did not observe any Ruffini, Pacini or Golgi-Mazzoni corpuscles. In conclusion, the multilayered composition of compact bundles of collagen, sparse elastic fibers in the deep fascia and continuous transition into retinacula probably facilitate resistance to gravitational forces and volume changes during muscle contraction as well as transmission of muscle force during movement. However, further research focused on innervation is needed to clarify whether the deep fascia of the equine forelimb plays a role in proprioception and movement coordination.

Pain Management in Horses

There has been great progress in the understanding of basic neurobiologic mechanisms of pain, but this body of knowledge has not yet translated into new and improved analgesics. Progress has been made regarding pain assessment in horses, but more work is needed until sensitive and accurate pain assessment tools are available for use in clinical practice. This review summarizes and updates the knowledge concerning the cornerstones of pain medicine (understand, assess, prevent, and treat). It highlights the importance of understanding pain mechanisms and expressions to enable a rational approach to pain assessment, prevention, and management in the equine patient.

Pain: Its Diagnosis and Management in the Rehabilitation of Horses

This article provides a brief overview of pain physiology and its relevance to equine patients. Objective and subjective techniques for assessing pain in the horse are described in depth. Pharmacologic and interventional pain modulation treatments are discussed with a focus on the rehabilitating horse.