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7 Articles in Volume 4, Issue #6
Atypical Earache Otomandibular Symptoms
Atypical Facial Neuralgias
Chronic Pain, Osteoporosis, and Bone Density Testing
Pelvic Floor Tension Myalgia (PFTM)
Promising Therapies Using Botulinum Toxin
The IP Network: A Case for Intractable Pain Centers Part II
Trigger Point Low Level Laser Therapy

Trigger Point Low Level Laser Therapy

A case study documents a trapezius trigger point eradication after three sessions of far infrared laser irradiation and confirms with anatomic "before-and-after" diagnostic ultra-sonographs.

The last two decades of medicine has seen the emergence of a group of conditions presumably thought to be primarily of soft tissue origin and affecting a growing number of people. Of importance has been the relative paucity in hard diagnostic criteria that practitioners require to identify these disorders. The terms fibrositis, myofascitis, myalgic syndrome, and fibromyositis syndrome have all attempted to take their turn as consensus diagnostic labels used to describe the characteristic focal pain and tenderness in soft tissues. The taxonomy has been forced to change over time to accommodate the growing empirical evidence, as well as the continued clinical disparity that surrounded these diagnostic labels. Some authors have even termed them “functional syndromes” due, in part, to their alleged lack of reliable objective clinical markers including lab analysis and/or imaging methods.

A common problem in trigger point studies to date has been that the study populations used may not always have been adequately described by the investigators. The reader is not always confident that they are treating the problem of a TP versus other similar, yet different, clinical conditions that manifest with localized soft tissue pain and tenderness. This is a problem that other authors have also alluded to.1 There have been numerous treatment regimens endorsed for the treatment of trigger points. Included in this list are injections, acupuncture, continuous ultrasound, myofascial release, massage therapy, positional releases, pharmacologic treatments, spray and stretch, TENS, and most recently, laser therapy.3

Trigger Point Pathophysiology

In a previous Practical Pain Management article, Dunteman1 provided a detailed explanation on the distinctive features between fibromyalgia and myofascial syndromes. Using this description as a premise, one can understand that the trigger point is the defining clinical feature of myofascial pain syndromes. Simons and Travell2 have pioneered the original investigations of trigger points and provided us with an extensive explanation of TP pathophysiology and behavior. There are major and minor diagnostic criteria available to help guide clinicians in the proper identification of TPs since soft tissue pain and tenderness alone are common manifestations of many other pathologies.

The absence of research evidence validating a set of reliable diagnostic radiologic markers however, continues to relegate the existence of TPs, and perhaps myofascial syndromes in general, to being recognized by some, but rejected by others. The axiom “we only diagnose what we recognize” may well be modified to include “and we only recognize what we deem has good evidence.” Some clinicians/payors will continue to hold a higher evidentiary standard requirement to TPs before their existence is fully accepted. The application of criteria devoid of any quantitative element continues to be a barrier for more complete acceptance in all sectors of the clinical/legal and payor communities acknowledging TPs as the primary pathological entity in the myofascial syndromes.

The following case report describes what is felt to be not only an effective method of TP treatment (cold laser), but also an effective method of TP corroboration that goes beyond a practitioner’s palpatory prowess. A safe and reliable method to radiologically verify trigger points should prove more convincing to skeptical practitioners, and may add even greater diagnostic accuracy to those practitioners already familiar with TP phenomenon via palpation.

Case Description

The patient was a 42-year-old male who complained of pain and dysfunction in the right mid trapezius muscle after having sustained a strain to the area a few months past, from a work-related exertional effort. A typical activity that can lead to such an injury might be related to a shoulder shrug action under load, such as when attempting to lift a heavy weight from waist to shoulder levels. This was the case with the patient. The patient presented with generalized right shoulder and neck pain but predominantly in the trapezius muscle. Palpation of the specific muscle bundle was exquisitely tender with increasing pressure causing pain radiation into the arm and scapula, as well as cephalad to the para-cervical musculature. The pain increased during both stretch and tension application to the trapezius — a method described originally by Cyriax and known as selective tissue tension testing. A jump sign was also elicited with localized pressure application to the mid trapezius. A palpable nodule was identified in the right trapezius which also correlated with the most tender area of the muscle. The neck and entire right extremity were cleared for any referred pain phenomenon. This patient was otherwise healthy with no other medical problems and was not taking any medication.

Trigger Point Localization and Verification

The initial examination used the traditional method of trigger point localization described by many authors in the past and based largely on patient complaints, pain description and application of the major and minor trigger point criteria as described by Simons and Travell.2 The clinical characteristics included: pain elicited on passive or active stretch of the muscle most involved leading to restricted joint AROM or muscle excursion itself; muscular contraction leading to pain; tenderness and dysesthesias referred in commonly defined zones; palpatory pressure elicits the “jump sign” leading to wincing, withdrawing, or vocalizing; and local fasciculation or twitching during firm pressure.

The author confirmed this palpatory finding with diagnostic ultra-sonography (DUS) a technique that is evolving rapidly as a first line soft tissue screening test.4 The author used a basic Hitachi 2-D ultrasound unit utilizing a moderately high frequency transducer (7.5 MHz) without added high resolution capabilities, doppler, or harmonic imaging option. The sonographic “signature” of a trigger point is neither obvious nor identified with absolute certainty in all cases. Unlike a tendon or muscle tear, both of which are relatively easier to detect ultrasonically, a subtle lesion such as a TP is somewhat more challenging. In this case the scan was confined to the most tender area of the involved trapezius muscle.

Figure 1a presents the instrument’s scan when the transducer was positioned directly over the tender area. A trained sonographer detected two distinctive features characteristic of a possible problem in the muscle tissue. First, careful examination reveals a heterogeneity (dissimilarity) between the inside of the area marked D1/D2 (designated by the asterisks), and outside that area. In addition, the inside of the marked region is moderately and more consistently darker (hypoechoic) than outside that region, indicating probable fluid build up within the area. When pressure is applied to this spot, the dark region displaces, but does not disappear. This “pressure test” can help rule out the existence of a tear, which closes upon pressure, versus a tense bursal effusion and/or cystic lesion, which merely displaces with compression. Lesion compression without dispersion of the hypoechoic (dark) area is characteristic of an encapsulated structure, since a small unencapsulated fluid collection would simply disperse under pressure. The use of diagnostic ultra-sonography simply contributes an added dimension in the diagnostic profiling of a lesion — not necessarily to establish diagnosis, but simply to confirm one.

“...this case demonstrates the clinical utility of cold laser in the treatment of trigger points with the added dimension of anatomical visualization both pre- and post-irradiation.”

Protocol

The protocol consisted of three laser treatments applied directly over the trigger point (nodule) using a continuous 810nm beam emitted from a GaAlAs diode laser for a duration of 300 seconds per treatment session. The author used a Jarek Ultra Laz 800 cold laser system (far infra-red laser radiation at a wavelength of 810nm) to irradiate the symptomatic trapezius muscle and applied a 100mW beam over the TP for 300 seconds yielding a total dosage of 30 joules. The spot size for our laser probe was .25cm2. It was estimated that approximately half that energy is absorbed at the skin, with energy attenuation increasing as depth of penetration increases. With this particular laser device, the manufacturer’s technical specifications was used to estimate total energy output needed to get the desired energy at the TP site (3-4 joules). The equation is, in simple terms: total energy emitted at probe minus known energy loss points such as, skin color, depth of target tissue, tissue texture (hard callus or soft skin), beam divergence angle (less is better), beam incidence angle and generally accepted energy loss rates for light at dermal interfaces through absorption (about 50%). In this case, it was estimated that it would take approximately 30 joules of total energy at the probe-skin interface to get approximately 3.5 to 4 joules of energy 4cm deep into the tissue. The target tissue depth was calculated using ultra-sonography. The three sessions spanned the course of a week with no other potentially confounding treatment interventions.

Results

The trapezius muscle was re-scanned after the third treatment because the patient reported complete remission from pain. Figure 1b shows the same area of trapezius muscle tissue a week later and after three cold laser treatments. There is no physical nor sonographic evidence of anything other than normal muscle architecture.

Figure 1a. Diagnostic ultra-sonography (DUS) of a hypoechoic encapsulated area coninciding with the palpatory finding of a trigger point.
Figure 1b. Post-treatment DUS of the same area shows only normal tissue.

Conclusion

The findings presented should be interpreted with caution since this was not a randomized controlled clinical trial. However, this case demonstrates the clinical utility of cold laser in the treatment of trigger points with the added dimension of anatomical visualization both pre- and post-irradiation. These findings are consistent with other published data that examined cold laser’s effectiveness in treating trigger points.3

It is important to reiterate that when using cold laser devices, the specific operating parameters (lasing characteristics) should always be identified so replication of studies and protocols can take place. The use of diagnostic ultrasound for soft tissue scanning is also introduced in this article so that readers may acquaint themselves with this inexpensive and patient-friendly form of imaging. Using a valid diagnostic imaging test as an outcome measure in assessing the effectiveness of a therapeutic intervention is consistent with evidence-based practice paradigms. In this case study, DUS supports the laser mediated eradication of a trigger point, as well as providing visual confirmation that palpatory TP protocol is indeed accurate.

Last updated on: January 5, 2012
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