Myofascial pain syndrome is a form of chronic pain condition characterized by the presence of myofascial trigger points. The condition is best managed through a rehabilitative approach with focus on core stability exercises. Injection treatments can be used to facilitate a rehabilitative approach and help break the pain cycle in patients who fail to make progress with conservative management.
Trigger point is a hyperirritable spot within a taut band of a skeletal muscle that is painful on compression, stretch or contraction of the tissue which usually responds with a referred pain or sensation.
As well as referred pain, other associated symptoms including numbness, coldness, stiffness, weakness, fatigue, motor dysfunction, dizziness and autonomic responses may be present. Trigger points may be active or latent.
There are several signs and symptoms that may aid diagnosis of trigger points:
Myofascial pain and FMS are clearly two different clinical entities, but there may be interactions. Myofascial pain is characterised by trigger points, and fibromyalgia is characterised by tender points causing widespread pain, sleep disturbances, fatigue, cognitive difficulties and other somatic complaints. It is clear that a patient with myofascial pain and trigger points should not be diagnosed as a patient with fibromyalgia syndrome. However, a patient with fibromyalgia can also exhibit trigger points, and may therefore be suffering from myofascial pain. The presence of trigger points in fibromyalgia does not mean that myofascial pain causes fibromyalgia.
The first step in management is to correctly target the aetiologic lesion, which can often be difficult because of the possibility of adjacent trigger points. After identifying and differentiating between active and chronic trigger points, inactivation should not be sought out in the acute stage unless pain is so severe that it prevents the localization of the aetiologic lesion. Correction of perpetuating factors including abnormal posture, chronic infection, stress and sleep disorders is a vital part of the over all management of myofascial pain.
One of the first lines of treatment for deactivation of trigger points is the muscle stretch techniques including spray and stretch, post-isometric isolation, and local tissue stretch. These techniques should be followed by functional training or exercise to maintain pain relief and to prevent further development of trigger points.
Drug therapy is directed mainly towards pain management in patients with myofascial pain syndrome. Nonsteroidal anti-inflammatory drugs (NSAIDs), opiates, muscle relaxants, and antidepressants are all agents that have been utilized for this purpose. Topically applied NSAIDs have been shown to be effective as well, whilst having less side effects. Antidepressants have been found to have an analgesic effect that is independent of their mood modulating effects. The effect is thought to be due to interactions in the spinal cord pathways between serotoninergic and noradrenergic brain stem and midbrain structures.
Trigger point injections and dry needling have consistently been shown to be the most effective inactivator of myofascial trigger points. Directed at loosening the taut band, trigger point inactivation provides rapid symptom relief. Attention must be paid to contraindications, including anticoagulation, bleeding disorders, local infection and local trauma.
Botulinum toxin works by blockage of presynaptic acetylcholine release at the synapse, thus allowing muscle relaxation. Its effect may be more sustained as compared to local anaesthetic and steroid injection, though there is lack of evidence to support this. Botulinum toxin has the advantage that it lacks the side effects associated with repeated steroid injections.
Acupuncture is one of the most commonly practiced alternative treatment options and may work because of pain input inhibition by other sensations, similar to the dry needling technique. The inhibition of pain perception may be caused by an increase in central nervous system opioid peptides.