Myofascial Pain Syndrome

Myofascial Pain is a syndrome arising from soft tissues associated with trigger points that produce pain in discrete patterns. The pain is regional (as opposed to diffuse, generalized pain seen in Fibromyalgia), often with taut palpable myofascial bands. Pressure to these trigger points often elicits a referred pain pattern. Referred pain patterns have been well described by various authors. Symptoms can begin after injury, chronic strain, or without clear insult.

Treatment of myofascial pain can include physical therapy, massage, myofascial release techniques, transcutaneous electrical nerve stimulation (TENS), and trigger point injections (TPI). Trigger point injections, though commonly performed, vary widely by provider. One systematic review by Cummings and White showed little difference between “Dry Needling” and injection of local anesthetic. Additionally, the addition of steroid to TPI has not been shown to have increased benefit.

Complex Regional Pain Syndrome

Complex Regional Pain Syndrome (CRPS) is a constellation of symptoms describing persistent pain in a particular body region/extremity with varying degrees of autonomic dysfunction.  CRPS has been divided in CRPS I (formerly reflex sympathetic dystrophy) and CRPS II (formerly causalgia).  The primary difference between CRPS I and II is the absence (CRPS I) or presence (CRPS II) of nerve injury.  CRPS I is associated with an inciting event (potentially minor) and the lack of nerve injury.  The exact pathophysiology is an area of ongoing debate, but is felt to involve peripheral and central sensitization, release of inflammatory mediators, and some degree of sympathetic nervous system involvement.  

The commonly accepted diagnostic criteria for CRPS was developed in 2007 and commonly referred to as the “Budapest Criteria”.  While originally developed as criteria to assist research, they have largely become the clinical definition used in the United States for diagnosis of CRPS.  Attempts to develop objective testing (sensory testing, doppler blood flow studies, triple phase bone scans) in CRPS has proved largely unsuccessful and CRPS remains a clinical diagnosis.

The treatment of complex regional pain syndrome (CRPS) is centered around a multidisciplinary team-based approach to control pain and restore function.  Early diagnosis and appropriate referral are crucial to improved outcomes. 

Similar to other pain syndromes, multimodal pharmacotherapy can prove useful as well for treatment of symptoms.  NSAIDs, Antidepressants, and Anticonvulsants have shown to have some benefit in CRPS.  While opioids as well have shown some benefit in the short term, long term benefit has yet to be established. The use of bisphosphonates is an area of promise with significant benefit shown in several RCTs.

While physical therapy remains the frontline modality, interventional pain techniques (sympathetic blocks) can prove useful to improve compliance with physical therapy where significant pain is present. Stellate Ganglion blocks are used for the arms and Lumbar Sympathetic Blocks are performed for the legs prior to physical therapy which allows for more intense physical therapy and desensitization. For patients that fail physical therapy, pharmacotherapy, and interventional pain techniques, the use of spinal cord stimulation has shown to provide benefit.

Discogenic Pain

Discogenic pain stems from degenerative disk disease (DDD), occurring without spinal deformity, radicular pain, neurologic symptoms, or spinal stenosis. Often it arises from disruption of the posterior annulus fibrosis (sparse fibers) that causes an inflammatory response that activate nociceptive nerve terminals. The neurological examination is typically normal, but structural exam may reveal limited ROM and/or antalgic gait as well as para-midline tenderness. Other authors have proposed spinous process tenderness and tuning fork vibratory provocation as having being helpful physical exam findings in discogenic pain. Pain may radiate to the buttocks, but generally does NOT extend below the gluteal folds. Pain is frequently exacerbated by standing or sitting and is relieved by lying down.

MRI has largely supplanted the use of other imaging modalities in the diagnosis of discogenic low back pain.  With discogenic low back pain, Magnetic Resonance Imaging (MRI) often show abnormal signal in vertebral end plates – so called “Modic Changes”. Modic changes are representative of edema progressing to sclerosis of the bone, and indicate of biochemical activity around the problematic disc.  Furthermore, classification of Modic changes (I, II, & III) is also helpful in classification of the relative bioactivity.  

While a much less common practice in the United States today, Discograms or Percutaneous Provocative Discography were once used to help diagnose discogenic pain. In this procedure, a needle is placed in the disc in question, contrast administered, and recording of subjective pain descriptions elicited from the patient. Minimum of two discs are provoked (one disc is a control). This practice is problematic and is associated with a number of issues, one of which being disruption of disc architecture in a potentially normal disc. Additionally, discography has a high potential rate of false positives – as high as 50% in some studies

Lumbosacral Radiculopathy

Radiculopathy is a syndrome predominantly characterized lancinating pain in a dermatomal distribution. Pain can be accompanied by sensory and motor deficits which should also be associated with a specific dermatome. Radiculopathy is caused compression or irritation of a nerve root.
Opioids, while commonly prescribed by primary care physicians for acute radicular pain are not commonly recommended, have been shown to have little benefit, and are associated with significant risk. NSAIDs, Acetaminophen, and Gabapentin are commonly accepted as first line medical treatment of lumbar radiculopathy.  Additionally, physical therapy or chiropractic care are considered conservative therapy and are commonly required by most insurance carriers prior to intervention.

If patients do not improve with the treatments listed above they may benefit from an epidural steroid injection. Often performed under fluoroscopy, a physician injects steroid medication into the epidural space adjacent to the involved nerves. This can help to rapidly reduce the inflammation and irritation of the nerve and help reduce the symptoms of radiculopathy. While the short term benefit of epidural steroids is well-documented, their long term efficacy is controversial.

If the above treatments are unsuccessful, and the symptoms remain severe, surgical intervention may be necessary. Surgical intervention is focused on removing compressive effects on the nerve effected. Depending on the cause of the radiculopathy, this can be done by a laminectomy or a discectomy. A laminectomy removes a small portion of the bone covering the nerve to allow it to have additional space. A discectomy removes the portion of the disc that has herniated out and is compressing a nerve.

Concerning history items and physical exam which should be elicited with every patient, so called "Warning" signs: Loss of Bowel/Bladder control, Progressive Neurologic (Sensory/Motor) Deficits, Fever associated with worsening back pain. These symptoms should always elicit further questioning and work-up.

Low Back Pain

Low back pain can be broadly separated into three categories – Mechanical, Nonmechanical and Referred/Visceral Pain. While mechanical low back pain is the most common, the other two categories represent sinister pathology that should be screened for by providers treating low back pain.  A careful history and physical should be able to delineate between common, relatively benign causes and those that are more insidious and deleterious - infectious, metabolic and malignant processes. These are often associated with constitutional complaints as well as dramatic exam findings.

While mechanical low back pain originates from a relatively few number of broadly grouped factors, the precise diagnosis of location and etiology can be difficult.  Mechanical low back pain can arise from discs, facets, nerve root compression/irritation, and muscle/soft tissues with other sources being less common.  

Imaging for low back pain varies by perceived cause and/or severity. Most recommend plain radiography for screening of most low back complaints.  Radiography allows for diagnosis of fractures, spondylolisthesis, and deformities. Radicular complaints, however, are best evaluated with magnetic resonance imaging (MRI). The increasing use of MRI is associated with significant cost and thoughtful utilization is helpful to avoid strain on limited healthcare resources. The addition of contrast to MRI studies should be employed with: history/concern of malignancy, infection, or previous spine surgery in area of interest. Computed Tomography (CT) can be an acceptable alternative to MRI in patients that are unable to receive such studies.

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