(i) Myofascial pain syndrome MPS History In fact Mr. Duffy is a typical patient with lumbar square muscle syndrome, which is one of the most common causes of low back pain and is primarily due to tense contraction of the muscles of the lower back. The sides above the lumbar belt are the areas that the patient often presses after bending over for long periods of time to do housework or gardening. Myofascial pain is a common cause of chronic localized pain. As with other myofascial pains and chronic pain of myogenic origin, lumbar square muscle syndrome lacks the physical signs of radicular pain (e.g., radiating pain, numbness, and weakness in the extremities). Mr. has the typical signs of myofascial pain-trigger points, in which palpation of an area can elicit sharp, muscular spasmodic pain that can involve a specific range of muscle distribution and cause pain. In the above case, the patient presented with hip and buttock pain and was affected by muscle extension. Because the muscles in patients with myofascial pain syndrome are in a contracted state, patients often feel pain when the muscles first begin to stretch, and the pain decreases once the muscles are fully extended. Therefore, the key to treatment is to relax the contracted muscles through stretching techniques. Key Points 1. For patients with localized pain without arthritis or neuropathic symptoms, think of possible myofascial pain. 2. Myofascial pain syndrome cannot be diagnosed in patients who do not have positive signs on physical examination. 3, Patients with myofascial pain should have muscle trigger points and tension bands. 4.Stimulation of trigger points can cause a specific area of referred pain. The treatment of myofascial pain is mainly muscle active stretching and range of motion exercise therapy, but also can be supplemented by the application of physical therapy, injections and drugs. 1. Definition Myofascial pain is often diagnosed in certain patients with chronic pain who lack clinical and laboratory evidence of radiculopathy, neuropathy, and joint disease, if malignancy is excluded. In these cases, persistent myofascial pain is often caused by chronic changes in the muscles and their surrounding soft tissues. However, myofascial pain also has its own specific abnormal symptoms and signs and is not just a diagnosis of exclusion. The idiosyncratic symptoms of patients with myofascial pain are localized muscle contraction and tenderness, marked by trigger points. A trigger point is an area of tenderness located somewhere within a band of muscle tension that can produce an involuntary contraction when stimulated. Electromyography reveals spontaneous electrical activity in the muscles of the tension zone [2]. Muscle tension bands are important for differential diagnosis, and tense muscles can also limit normal muscle extension, thereby decreasing active range of motion and generating muscle strength Muscle tension bands are produced involuntarily and are an objective symptom of myofascial pain. Trigger points are different from pressure points, which are simply certain areas of increased sensitivity to stimuli. In patients with chronic pain without clear pathologic changes, many physicians often apply the terms myofascial pain (with trigger points) and fibromyalgia (with pressure points) confusingly with each other. However, both myofascial pain and fibromyalgia have their own diagnostic criteria (Table 1). (Additional information on fibromyalgia can be found in Chapter 10 of this book). The main difference between the two is that myofascial pain is a localized pain (e.g., pain in the low back or scapular girdle), whereas fibromyalgia is a generalized pain (covering a large area of the body). Because fibromyalgia can cause changes in posture, gait, and activity, patients with fibromyalgia can also present with a combination of myofascial pain (localized muscle spasms, trigger points, and muscle contractions that occur on top of widespread fibromyalgia). 2, Epidemiology In addition to the lumbar square and pear muscles, myofascial pain often involves the upper trapezius, rhomboids, rhomboids, scapular raisers, and serratus anterior muscles. Figure 5-9 shows common trigger points and sites of entrapment pain. Understanding the common sites of involvement pain in myofascial pain can help clinicians better recognize common pain syndromes. 3. Assessment Chronic localized pain is usually caused by several factors, including muscles and surrounding tissues (myofascial pain), joints (mechanical pain), or the nervous system (neuropathic pain). Patient assessment should be directed to these tissues (Table 2). The diagnosis of myofascial pain can only be made if there is a clear finding of abnormality on clinical examination. If the patient is unable to cooperate with the examination because of severe pain, the physician may suggest that he or she return to the hospital at an appropriate time. A complete and exhaustive evaluation of range of motion, posture, gait, muscle strength and sensation is necessary before diagnosing myofascial pain. If no abnormalities are found on physical examination, myofascial pain cannot be diagnosed. The diagnosis of myofascial pain in a patient with no laboratory or imaging abnormalities relies on a history of excitation or injury and physical examination findings of tense, compressed muscles, as well as the exclusion of mechanical instability and neurologic abnormalities. X-rays are performed in patients with suspected joint abnormalities, inflammation, and instability. x-ray plains can also reveal abnormal changes in bone structure in patients with chronic pain to rule out certain underlying bone diseases. Magnetic resonance examination is very meaningful to exclude spinal cord and nerve root diseases, and can also identify certain specific types of pathological changes. Physical therapy is the most basic approach to myofascial pain. An experienced physical therapist can accurately identify trigger points and areas of muscle tension through a thorough evaluation. Appropriate physical exercise methods and programs must be developed for each patient, especially for patients with postural abnormalities and myofascial changes, focusing on stretching activities and increasing range of motion, while some passive activities can also be performed by the therapist on the patient for therapeutic purposes. In addition to performing physical therapy, patients should be instructed to perform activities at home at least twice daily. Trigger point injection therapy, application of medications and other physiotherapy measures to effectively stretch the muscles can also be performed during exercise (see Box 2). 4.1 Physiotherapy Initially, light muscle stretching activities and exercises to increase active range of motion are performed. Passive stretching exercises given by a therapist may also be effective, but the current treatment of patients with myofascial pain is based on the patient performing voluntary activities. Twice a day, the patient needs to stretch the entire body and the painful area, stretching the muscles until there is a sensation of being pulled, but not overstretching. Stretching can help shortened muscles return to their normal state, allowing the tension bands and trigger points to disappear. The strength of the activity can be mildly increased after a few weeks. Studies have confirmed that physical therapy treatment with active exercise and passive massage of trigger points for 4 weeks significantly reduces the number of trigger points and decreases trigger point pain scores (Figure 10) [4]. There are several other treatments for myofascial pain (see Table 3). Studies on the treatment of myofascial pain in the neck have found that all of the treatments used significantly reduce pain (Figure 11) [5]. Supplementing any treatment with hot packs and exercises to increase active range of motion was highly effective. It was found that the simultaneous application of transcutaneous electrical nerve stimulation or interferential currents and other methods resulted in excellent treatment of pain. It is worth noting that no single treatment was used in this study, suggesting that the simultaneous application of both treatments can lead to better results based on exercise. 4.2 Injection treatment It refers to infiltrating the local anesthetic drug into the trigger point, and using a 22-25G puncture needle to pierce the skin 1cm away from the trigger point, and then puncture to the trigger point. After confirming that there is no puncture blood vessels, injection of local anesthetic 0.1 ~ 0.2 ml, and then partially backed up the puncture needle, adjust the direction of the puncture needle, continue to puncture the trigger point of the other regions of the advancement, until the disappearance of local convulsive response and muscle tension relief or the total amount of local anesthetic to reach 0.5 ~ 1.0 ml. After the injection of local compression to avoid the emergence of hematomas, coagulation disorders of the patient is contraindicated to conduct the Injections are contraindicated in patients with coagulation disorders. It is not clear whether the application of corticosteroids can prolong pain relief. Puncturing the trigger point with a dermal needle can assist in the treatment of myofascial pain [6].Hong’s study found that injection of local anesthetic into the trigger point or puncture alone provided significant relief of shoulder myofascial pain [7]. It was found that puncture of the trigger point alone without injection of medication was highly effective [8]. 4.3 Medication Medication is an adjunct to physical therapy. In case of failure of stretching exercise therapy, tizanidine- a muscle relaxant can be applied [9]. Most muscle relaxants are ineffective for chronic pain, but tizanidine can effectively treat chronic myofascial pain [10]. Tizanidine also has a mild sedative effect and can improve a patient’s sleep when taken at bedtime. Analgesic medications can be used when pain flares up, however they are ineffective if applied daily and can also produce gastric complications and nephrotoxicity in the long term [11, 12]. 4.4. Comprehensive treatment of pain Patients suffering from myofascial pain for a long period of time can develop complications such as severe depression, withdrawal and incapacity to work. It has been found that prolonged pain, reduced social activity and incapacity can affect the efficacy of treatment with trigger point injections [13]. Comprehensive treatment methods such as psychotherapy and occupational training should be used for these patients in addition to physical therapy. 5, Summary Myofascial pain is a pain syndrome characterized by muscle tension and pressure with tension bands and tender trigger points. Patients with myofascial pain differ from mechanical pain in the absence of arthropathic changes, from neuralgia in the absence of neurologic dysfunction, and from fibromyalgia in the absence of generalized widespread pain. Myofascial pain is a localized pain syndrome. Understanding the range of involvement pain typical of myofascial pain (e.g., lumbar square and pyriformis syndromes) helps to differentiate it from other common pain syndromes. The primary treatment is stretching activities and exercises to increase range of motion, along with other adjunctive treatments such as passive activities, injections, and oral medications, to name a few. Patients with chronic myofascial pain can have comorbid depression and loss of work capacity, and should be treated with complementary measures such as psychotherapy and occupational training.