{"id":4104,"date":"2019-06-07T07:43:24","date_gmt":"2019-06-07T11:43:24","guid":{"rendered":"https:\/\/todaysveterinarynurse.com\/?post_type=articles&p=4104"},"modified":"2022-06-24T19:42:50","modified_gmt":"2022-06-24T19:42:50","slug":"myofascial-trigger-points-in-veterinary-patients","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarynurse.com\/rehabilitation\/myofascial-trigger-points-in-veterinary-patients\/","title":{"rendered":"Myofascial Trigger Points in Veterinary Patients"},"content":{"rendered":"

The concepts of myofascial trigger points (MTrPs) and myofascial pain syndrome (MPS) were first introduced by Dr. Janet Travell more than 65 years ago.1<\/sup> These syndromes have yet to be recognized in mainstream veterinary and human medicine as initial diagnostic criteria; however, understanding them can help in recognizing signs of pain in veterinary patients.<\/p>\n

Credentialed veterinary nurses are often able to create a bond with their patients by building trust through the use of appropriate behavioral assessments\/low-stress handling skills.2<\/sup> The nursing staff (especially in a rehabilitation setting) have more time in the examination room than the veterinarian and see patients on a recurring basis. This gives veterinary nurses an excellent opportunity to see patients without the influence of the \u201cwhite coat\u201d effect.<\/p>\n

Observation of a patient\u2019s movement and preferred postures with an understanding of abnormal movement and compensation patterns provides the first clues for identifying myofascial trigger point zones or regions in companion animals. The history obtained from pet owners is not always conclusive or consistent with the presenting complaint; therefore, by watching a patient\u2019s movement patterns, veterinary nurses may be better able to determine and identify underlying MTrPs and MPS.<\/p>\n

Appropriate therapy to reduce activation of MTrPs may help veterinary patients regain normal range of motion; maintain appropriate posture, balance, and correct use of limbs (independent ambulation); and experience better, more sound sleep due to increased comfort while in the resting position.<\/p>\n

Understanding Myofascial Trigger Points, Myofascial Pain Syndrome, and Fascia<\/h2>\n

Myofascial Trigger Points<\/h3>\n

An MTrP is defined as a hyperirritable spot or \u201cknot\u201d located in a taut band of a muscle, capable of producing referred pain and a local twitch response (LTR) with direct palpation or dry needling.3-5<\/sup> An LTR is a spinal cord reflex and cannot be controlled; it is thought to be transmitted by central and local pathways.6<\/sup> It is a rapid contraction of the taut band within the muscle belly and is evident when the MTrP is stimulated.7<\/sup><\/p>\n

In dogs and cats, the taut band is identified in the muscle belly by palpating perpendicular to the affected muscle fibers. Once the taut band is indicated, the practitioner palpates along the taut band to locate the nodule, or \u201cknot.\u201d An MTrP is a discrete area that feels like an intensely contracted structural unit within the muscle, or sarcomere, while adjacent muscle groups may feel supple. An MTrP is not to be confused with a muscle spasm or contracture (increased neuromuscular tone of the entire muscle due to a nerve-initiated contraction).7<\/sup><\/p>\n

MTrPs typically form after muscle injury or repetitive overuse of muscles. It has been proposed that sustained low-level contractions cause a decrease in perfusion, hypoxia, and ischemia and that cellular responses occur due to stimulation of activating chemical substances, which affect neuropeptides. Specific neuropeptides, including calcitonin gene-related peptide and substance P, may facilitate an increased release of regulatory compounds, resulting in excessive acetylcholine (ACh). It is hypothesized that the excessive ACh release, sarcomere shortening, and inappropriate changes in receptor activity lead to development of a taut band and subsequent MTrPs.7<\/sup><\/p>\n

Persistent muscle fiber contraction can also be an adaptive response caused by low-level muscle contractions, unaccustomed eccentric contractions (e.g., lowering the weight in a biceps curl), muscle overload from shifting cranially due to hip or stifle pain, or slight postural adjustments.<\/p>\n

For example, a dog with a digital amputation may shift weight to other body regions to compensate, which promotes changes in other muscle groups. This overload forces cellular deregulation of ions causing chronic cellular changes in specific parts of the muscles.<\/p>\n

MTrPs can be located within the belly, origin, or insertion of a muscle and are known to cause decreased changes in range of motion, muscle weakness, and postural imbalance as the patient develops gait pattern changes in order to function without pain.<\/p>\n

Myofascial Pain Syndrome<\/h3>\n

MPS is associated with a type of pain within skeletal muscle and its fascia; people describe it as deep, dull, aching pain. It is diffuse and not easy to localize because MPS is a referred type of pain within the musculoskeletal and fascial system. Veterinary patients may display subtle alterations in gait function due to primary muscle fatigue and muscle weakness.8<\/sup> They may also posture with an arched or hunched back, move stiffly in all limbs, prefer a lowered head position, and have an unidentifiable source of pain.<\/p>\n

Fascia<\/h3>\n

The definition of fascia as it relates to MTrPs is difficult as there is no consensus yet among researchers. Fascia supports, penetrates, and is distributed within body systems. It is found in bone and meningeal tissue and covers organs and skeletal muscles, creating many independent layers.9<\/sup> When injured through trauma, inflammation, or stress, it can become tense and firm, altering its ability to perform its physiologic function. An observable example of fascial restriction is as follows: a patient that is stretching forward for a food lure while sitting in a sphinx position shows a ripple or twitch in the back (paraspinal muscles), then retracts back to neutral and shifts forward by rising or crawling instead of stretching further. The stretch induces discomfort, so the patient chooses to move its entire body forward and compensate to avoid pain (FIGURE 1<\/strong>).<\/p>\n

\"\"<\/a>

Figure 1. Poodle in sphinx position. The examiner will lure the dog forward to watch reaction\/fasciculations along the paraspinal muscles and to assess length of stretch before making adjustments or repositioning.<\/p><\/div>\n

Discovering Myofascial Trigger Points<\/h3>\n

During a rehabilitation evaluation, it is common for practitioners to evaluate the patient\u2019s posture and movement before physical palpation. When asking for a simple command such as \u201csit,\u201d attention is paid to a few key responses, posture, and behavior in performing the task (BOX 1 and FIGURE 2<\/strong>). When findings are abnormal, such as in compensatory movements during the stand-to-sit posture, an important consideration is the history of the patient back to the earliest time their handler or owner can remember. \u201cDid they always sit off to the side? Did they ever sit with straight posture?\u201d MTrPs create a posture imbalance or shift due to pain and are perpetuated by mechanical stressors, including underlying disease processes (BOX 2<\/strong>).<\/p>\n

BOX 1 Observing Patient Motions and Postures for Signs of Pain<\/div>
Head Position During Movement<\/strong><\/p>\n

Is it …<\/p>\n