Fact: Muscle injuries can result in Chronic Myofascial Pain Syndrome with Trigger Points of pain lasting indefinitely.
Chronic Myofascial Pain Syndrome (MPS) is a real-live clinical entity which is well-documented in the literature and poorly recognized in much of the medical community.
The textbook, Myofascial Pain & Dysfunction-The Trigger Point Manual, by Travell and Simons is the bible.
Foreman & Croft, Whiplash Injuries-The Cervical Acceleration/Deceleration Syndrome (3rd Ed, 2002) is also very reliable on this subject.
MPS is well recognized in the medical literature, but poorly recognized by the medical community. Perhaps the most succinct description of MPS is found in the AMA Continuing Education publication entitled Pain Management of Persistent Nonmalignant Pain.
Fact: MPS (M79.1) is a respected medical entity.
The AMA publication, Pain Management of Persistent Nonmalignant Pain describes the entity as follows:
Myofascial Pain Syndrome.
Myofascial pain syndrome is a condition of mild to severe muscle pain associated with trigger points, the pain is typically localized, often to a single muscle. The syndrome commonly follows “muscle overload” such as may occur with acute injury (e.g., following a near fall or intense exertion). Patients complain of a deep, aching pain that is worsened by activity. Postural muscles are often affected. The pain may wax and wane, but it is usually always present and at times can be severe.
Assessment and Diagnosis of Myofascial Pain
Trigger points are the diagnostic feature of the syndrome. On physical exam, there will be muscle tenderness and limited range of motion, and these may be associated with palpable trigger points, or “taught bands.” Helping the trigger point produces a local twitch (a visible shortening of the muscle), and referred pain. Myofascial pain, most often involves the posterior neck, low back, shoulders, and chest. Chronic pain in the muscles of the posterior neck and referred to muscles in the head and cause persistent headaches; trigger points in the lower back muscles can cause referred pain into the leg that mimics sciatica.
Fact: Recent research data has demonstrated structural muscle changes in patients with WAD.
There has been a substantial body of research investigating the motor, muscle and senorimotor changes in individuals following whiplash injury, including loss of movement, altered muscle recruitment patterns, and morphological changes in neck muscles. (Sterling)
Biomedical research has proven that muscles injured in WAD trauma do not always heal.
Recent research data has provided evidence of structural changes in patients with chronic WAD that were not found to be present in those with non-traumatic neck pain or in healthy controls. These findings were found only in patients with chronic WAD symptoms. Muscle fatty infiltration in the neck extensor muscles of patients with chronic WAD were detected using MRI. (Elliott)
Fact: WAD trauma can result in permanent nerve damage.
WAD can cause damage to the dorsal root ganglion, resulting in hypersensitivity following WAD injury.
“Peripheral nerve injury is followed by change in expression of neurotransmitters, neuromodulators…in primary afferent neurons located in the dorsal root ganglion of the spinal cord.”
“Traumatic injury…of the peripheral nervous system often leads to persistent pathophysiological pain states” leading to a permanent “rewiring” of the pain pathways from the peripheral nerves to the brain. (Davis)
As noted below, internal injury to the intervertebral discs can produce nerve ingrowth into the fissures, producing chronic discogenic pain.