Myofascial Pain Syndrome, myofascial trigger points and trigger points in veterinary medicine: a review / Revisão: Síndrome Dolorosa Miofascial, pontos gatilhos miofascial e pontos gatilhos na medicina veterinária

Myofascial Pain Syndrome (MPS) a is a painful condition related to myofascial trigger points (TP) in skeletal muscle. The aim of this study was to perform a literature review on the etiology, pathophysiology, diagnosis and treatment of MPS in veterinary medicine. The research sites used for this purpose were: Scientific Electronic Library, PubMed and Medline. The inclusion criteria for the papers were: must be written in English; published between 1990 and 2018; include the following keywords: myofascial pain syndrome veterinary/dog/canine/cat/feline/horse/equine, trigger points veterinary/dog/canine/cat/feline/horse/equine. Through the review, it was observed that veterinary clinical studies are scarce, and the articles found lack information such as MPS description, incidence and specific treatment techniques in dogs and horses, and no studies in cats were found.(AU)

Síndrome Dolorosa Miofascial (SDM) é uma condição dolorosa relacionada aos pontos gatilhos miofasciais (PG) no músculo esquelético. Este trabalho tem como objetivo realizar uma revisão bibliográfica sobre a etiologia, fisiopatogenia, diagnóstico e tratamento na medicina veterinária. Foram utilizados sites de pesquisas Scientific Electronic Library, Pubmed e Medline. Os critérios de inclusão estabelecidos foram: ser escrito em inglês; no período de 1990 a 2018; ter as palavras chaves para busca: myofascial pain syndrome veterinary/dog/canine/cat/feline/ horse/equine, trigger points veterinary/dog/canine/cat/feline/horse/equine. Após a revisão observa-se que faltam estudos clínicos em medicina veterinária, sendo que os artigos encontrados se limitam à descrição, incidência e técnicas pontuais em cães e equinos, não sendo encontradas referencias em felinos.(AU)

Introduction to myofascial trigger points in dogs.

In dogs, muscles make up 44%-57% of total body weight and can serve as source of both pain and dysfunction when myofascial trigger points are present. However, rarely is muscle mentioned as a generator of pain in dogs, and even less mentioned is muscle dysfunction. The veterinary practitioner with interest in pain management, rehabilitation, orthopedics, and sports medicine must be familiar with the characteristics, etiology, and precipitating factors of myofascial trigger points. Additionally, the development of examination and treatment skill is needed to effectively manage myofascial trigger points in dogs.

Needle electromyographic activity of myofascial trigger points and control sites in equine cleidobrachialis muscle--an observational study.

BACKGROUND: Myofascial trigger points are commonly described in humans, and many studies have shown abnormal spontaneous electrical activity, spike activity and local twitch responses at these sites. Myofascial trigger points have only rarely been described in horses, and studies of their electrophysiological characteristics have not previously been published. The objective of this study was to explore the electromyographic (EMG) and other characteristics of myofascial trigger points in equine muscle, and to compare them with normal muscle tissue. METHODS: Four horses with chronic pain signs and impaired performance were examined. They had previously been examined at the second author's practice, and showed signs compatible with the diagnosis of myofascial trigger points in their cleidobrachialis (brachiocephalic) muscle, ie localised tender spots in a taut band of skeletal muscle which produced a local twitch response on snapping palpation. They had therefore been selected for treatment with acupuncture. Needle EMG activity and twitch responses were recorded at 25 positions at the trigger point and at a nearby control point during the course of each horse's acupuncture treatment. RESULTS: All subjects demonstrated objective signs of spontaneous electrical activity, spike activity and local twitch responses at the myofascial trigger point sites within taut bands. The frequency of these signs was significantly greater at myofascial trigger points than at control sites (P<0.05). CONCLUSION: Equine myofascial trigger points can be identified, and have similar objective signs and electrophysiological properties to those documented in human and rabbit skeletal muscle tissue. The important differences from findings in human studies are that referred pain patterns and the reproduction of pain profile cannot be determined in animals.

Trigger point therapy.

Trigger points (TP) are objectively demonstrable foci in muscles. They are painful on compression and trigger pain in a referred area. This area may be the only locus of complaint in humans. In dogs we cannot prove the existence of referred zones of pain. Therefore, we can only diagnose a TP-induced claudication if we cannot find bone, joint, or neurologic abnormalities, and we do find TP that disappear after treatment together with the original lameness. Several methods have been developed to demonstrate TP existence objectively. These are pressure algometry, pressure threshold measurements, magnetic resonance thermography, and histology. In humans, 71% of the TP described are acupuncture points. TP treatment consists of TP stimulation with non-invasive or invasive methods such as dry needling or injections. In the dog, ten TP are described in two categories of clinical patients. First, those with one or few TP reacting favorably on treatment (+/- 80% success in +/- 2-3 weeks). Second, those with many TPs reacting badly on treatment. Most probably the latter group are fibromyalgia patients.

Trigger points in 48 dogs with myofascial pain syndromes.

Seven foci of pain (trigger points) were identified in the triceps brachii, infraspinatus, adductor-pectineus, peroneus longus, gluteus medius, ileocostorum lumborum, and quadriceps femoris muscles in 48 lame dogs. The dogs had been lame for 1 day to 150 weeks (mean, 24 weeks). Thirty-one dogs had been treated unsuccessfully with corticosteroids, nonsteroidal anti-inflammatory drugs, analgesics, or acupuncture. Palpating the trigger points induced severe pain. Treatment consisted of weekly stimulation of the trigger points by needling or injection of a local anesthetic. The mean treatment period was 2.8 weeks. Excellent results and complete recovery were observed in 34 dogs (60%).