Overview
Masticatory muscle disorders (MMD) are a type of temporomandibular disorders (TMD), which are collectively referred to as TMJ disorders along with structural disorders, inflammatory diseases and osteoarthrosis. It occurs in young adults between 20 and 30 years of age, and is more common in women, with a prevalence of between 20% and 50%. Masticatory muscle disorders include myofascial pain, myositis, unclassifiable localized myalgia, and degenerative contracture of muscle fibers.
Myofascial pain, also known as myofascial pain dysfunction syndrome, is primary masticatory muscle pain, characterized by facial myofascial trigger point pain, accompanied by myalgia and limited temporomandibular joint motion.
Etiology and pathogenesis
The temporomandibular joint is closely related to the masticatory muscles, ligaments, jawbone and teeth occlusion, and they coordinate with each other in order to exercise normal physiological functions. If there is a dysfunction or structural change, TMJ disorder syndrome can occur. The common related factors are as follows.
I. Trauma factors Many patients have a history of local trauma. For example, acute trauma such as external impact, sudden biting of hard objects, excessive mouth opening (e.g. yawning), frequent chewing of hard food, night grinding and unilateral chewing habits. These factors may cause joint contusion or strain, masticatory muscle group dysfunction also has a certain impact on the occurrence of this disease.
Second, occlusal factors many patients have obvious occlusal relationship disorders. For example, the tip of the teeth is too high, excessive wear of teeth, too many missing molars, bad dentures, and low intermaxillary distance. Disturbance of the occlusal relationship can disrupt the balance of function between the internal structures of the joint and contribute to the occurrence of the disease.
Clinical manifestations
There is localized persistent pain in the masticatory muscles, dull pain in the ear or preauricular region, radiating to the temporal region, forehead, eye, mandibular angle, lateral neck or occipital region. There is trigger point pain and the muscle stiffens when palpated along the long axis of the affected muscle. The pain is mild in the early morning, gradually worsens, and increases with chewing or wide mouth opening. The jaw movement is restricted and the opening pattern is biased to the affected side.
There is no pressure pain in the joint area, and simple myofascial pain without joint popping. Bilateral myofascial pain, no deflection of the opening pattern, significant reduction of the opening to 1 cm, significant pain during passive opening, and increased opening. It may be accompanied by temporal pain, dizziness, tinnitus, etc.
Diagnosis
Ask the patient in detail about the history of facial trauma, mental tension, biting hard objects, clenching teeth, night grinding, and sudden disorder of dental relations. Clinical examination of muscle palpation, hardened striae, pressure or trigger points and radiating pain along the long axis of the masticatory muscles, restricted opening, and myofascial pain with passive opening but increased opening. Diagnostic closure of nerves and muscles may make the pain disappear. Clinical and joint x-rays as well as biochemical examinations are free of pathological changes within the temporomandibular joint.
Treatment
The main treatment is conservative. In the early or acute phase of pain, the patient should eat a soft diet and rest or reduce the activity of the jaw. Chloroethane is used to spray, heat and physiotherapy on the affected masticatory muscles, and oral anti-infective drugs are administered. In the later or chronic stage, open mouth training, adjunctive closure therapy, acupuncture, sedative drugs, and dental pads are performed.
Closure therapy can be performed with 0.25-0.5% procaine 3~5ml for closure of the extra pterygoid muscle. The puncture point is at the midpoint of the sigmoid notch, vertical needle, depth of about 2.5-3cm, and inject the drug when there is no blood in the retraction. It is often used for patients with overly large open mouth. Acupuncture points: Shimonoseki, Hegong, Cheek Chee, Hegu, with Medical Wind and Sun.
Myofascial pain syndrome (MPS)
Myofascial Pain Syndrome (MPS) is a chronic painful condition caused by localized adhesion contractures of the myofascial membrane.
(1) Localized muscle pain: chronic persistent soreness, swelling or dull pain, pain with tightness or heavy pressure, can occur in the lower back, back, sacrum, buttocks, legs, knees, soles, neck, shoulders, elbows or wrists.
(2) Ischemic pain: pain can be induced by local cold or general fatigue or cold weather, waking up with pain during late night sleep, stiffness and pain in the morning, relieved after activity but often aggravated after long working hours or in the evening, and pain can also be aggravated when inactive for a long time or overly active or even in bad mood.
(3) Fixed pressure point: During physical examination, the patient is found to have tension, spasm, bulge, contracture or stiffness in one side or local muscle. The location of the pressure point is often fixed near the starting point of the muscle or at the intersection of two groups of muscles in different directions, and painful hard nodes or painful muscle cords may be felt deep in the pressure point.
(4) There may be a history of local or adjacent injury, and the onset is more frequent in women than in men.
The diagnostic criteria for MPS in the United States are
1. There are fixed painful areas and pressure points on the attachment points of tendons or on the muscle belly. Pressure on the painful point may cause regional discrete pain not distributed by nerve root sensation.
2. The pain is aggravated by a decrease in temperature or fatigue.
3. Treatment to increase blood flow to the muscle may reduce the pain.
4. Exclude local occupying or destructive lesions.
The principles of treatment for MPS are.
(1) Remove the cause: such as anti-rheumatoid, anti-inflammatory, loosening the scar ;
(2) improve blood supply: exercise, massage, heat therapy (infrared, laser, cupping, acupuncture), etc. effective but not healing, high recurrence rate;
(3) Anti-inflammatory and analgesic: can reduce symptoms and improve the quality of life;
(4) Elimination of tenderness points: the application of minimally invasive techniques to loosen local adhesions can prevent recurrence and aggravation of MPS, with good long-term effects. Minimally invasive treatment techniques include Kawasaki block for acute pain, small needle separation for those with limited pain in the chronic phase, intensive warm mass needle release for those with widespread pain, radiofrequency thermocoagulation release for dangerous areas, and so on.
(5) Physical exercise: anti-gravitational muscle exercise.
(6) Antidepressant treatment.
Muscles and ligaments are the power base of various human activities, and their end devices are their respective muscles attached to the bones at the power transmission hub that drives the bones and joints, and also the parts where stresses are concentrated and intersected, so they are highly susceptible to injury.
Repeated injury to the local muscle, when the injury healed can leave scars or adhesions, scar tissue can reduce the number of local blood vessels or small diameter, the occurrence of local microcirculation blood flow regulation ability to reduce the muscle blood supply and anaerobic work ability to lose.
The local ischemia of the muscles causes pain due to stimulation of the peripheral nerves, and the patient cannot tolerate prolonged physical activity or even sedentary activities. For example, long-term incorrect posture or psychological depression can cause physiological contracture at the level of local muscle segments, long-term repeated muscle spasm causes muscle ischemia, sterile exudation, scar formation, local myofascia often undergoes postural load and extreme tension, fatigue causes postural injury, repeated exertion causes micro-tearing muscle damage, and pain-causing substances appear around the microvascular reaction zone of myofascia.
Rheumatoid myositis, ankylosing spondylitis or viral myositis cause peripheral nerve compression due to muscle swelling, which may form nociceptive sensitive points or painful muscle sclerosis for a long time and experience a complex intertwined reaction process of long-term local irritation, inflammation, healing, hyperplasia or scarring, with painful local tissues and calcification of inflammatory exudate deposits and development of myoclonus.
Hypoxia or lack of energy metabolism may be secondary to a decrease in local blood flow and is an important mechanism of CMPS painfulness that can cause muscle dysfunction and tissue destruction, therefore any means of improving microcirculation to the muscles and nerves even local massage or walking can provide some relief from the painful symptoms of CMPS.
Pathological features of painful nodules.
(i) a bundle of muscle fibers in a muscle surrounded by a sterile inflammatory myofibrils that are stiffer.
(ii) A lesioned dermal nerve.
(iii) Hyperplastic inflamed fatty connective tissue that is closely attached to the deep fascia.
(iv) The site where the motor nerve enters the muscle. Painful nodules mostly occur in the supraspinous ligament, interspinous ligament, posterior laminae, supraspinous muscle group, intertransverse muscle group, occipital ring fascia, levator scapulae, trapezius, rhomboid, psoas, sacrospinous, etc.
Treatment method
Release of local adhesions of the myofascia is the basic technique to eradicate the tenderness point of MPS. Patrick believes that the key to needling is the mechanical destruction of the pain trigger point rather than what potion is injected and advocates that the injection should be done by allowing the needle tip to repeatedly explore the area to separate the tissue and mechanically destroy the pain trigger point.
Surgical separation of myofascia was popular in the 1950s, and although effective, it is now largely replaced by minimally invasive techniques.
Currently, the following are available for MPS: saline injection at the point of pain (Kawasaki therapy) for hydrodynamic separation, steroid injection (closure therapy) for lysis of local tissues, microethanol or phenol glycerin injection for the separation of myofascial adhesions by destroying local tissue proteins, and pneumatic needle therapy for the elimination of myofascial scars, especially for areas containing important nerves such as the neck or buttocks. Myofascial release treatment.
Eighty-five percent of patients with chronic pain disorders have primary or secondary CMPS, such as osteoporosis, disc herniation, cervical spondylosis, posterior branch syndrome, osteoarthritis, or ankylosing spondylitis.
Pain relief in the myofascial component is an important part of the overall treatment plan, so it is important to clarify the diagnosis and plan and understand the patient before treatment begins. Elderly or frail patients with myofasciitis in multiple areas of the body, often with hypertension, diabetes mellitus, cardiopulmonary, cerebrovascular, psychiatric or psychological disorders, should be treated in a planned and comprehensive manner.