Principles and Methods of Treatment
Treating the MTrP
Muscle, fascia, and their cellular components are important contributors to both MPS and the formation of the MTrP. Clinician-investigators recommend that treatments focus not only on the
FIGURE 11.5 Pinch and roll test for allodynia. The skin and subcutaneous tissue are gently pinched between the thumb and forefinger and rolled vertically across dermatornal borders. Elicitation of a painful response is indicative of allodynia. (Original art work.)
MTrP, but also on the surrounding environment, with the goals to reduce the size of the MTrP, correct underlying contributors to the pain, and restore the normal working relationship between the muscles of the affected functional units. According to Dommerholt, all treatments fall into one or both of two categories: a pain-control phase and a deep conditioning phase. During the pain-control phase, trigger points are deactivated, improving circulation, decreasing pathological nociceptive activity, and eliminating the abnormal biomechanical force patterns. During the conditioning phase, the intra- and inter-tissue mobility of the functional unit is improved, which may include specific muscle stretches, neurodynamic mobilizations, joint mobilizations, orthotics, and muscle strengthening.38
Current approaches for the management of MPS include pharmacological and non-pharmacolog- ical interventions. Among the pharmacological approaches are anti-inflammatory, analgesic, topical creams, and trigger point injections, which are now safer and more effective. Non-pharmacological interventions include manual therapies, such as post-isometric relaxation, counterstrain method,39 trigger point compression, muscle energy techniques, and myotherapy,40 along with other treatments like laser therapy,41 dry needling, and massage.42 43
Among the invasive therapies, dry needling, and injection of anesthetic, steroids, or botulinum toxin-A (BTA) into the MTrP have all been shown to provide pain relief in peer-reviewed clinical studies. Regardless of the method used, elicitation of a local twitch response (LTR), an involuntary spinal cord reflex that may be visually observable within a taut band, produces more immediate and longer-lasting pain relief than no elicitation of an LTR.44-49 Within minutes of a single induced LTR, Shah et al. found that the initially elevated levels of SP and calcitonin gene-related peptide within the active MTrP in the upper trapezius muscle decreased to levels approaching that of normal, uninvolved muscle tissue. The reduction of these biochemicals in the local muscle area may be due to a small, localized increase in blood flow or nociceptor and mechanistic changes associated with an augmented inflammatory response.13-31
Beyond the MTrP: Spinal Segmental Sensitization
Sometimes treating active MTrPs is insufficient. In these situations, segmental sensitization may be present and is determined by findings of allodynia, hyperalgesia, and measurable pressure pain sensitivity over the sensory, motor, and skeletal areas supplied by a particular spinal segment.
All forms of manual therapy include some form of mechanical pressure and are commonly employed as a first line of treatment before attempting more invasive therapies.50 While recent reviews and meta-analyses have focused on dry needling, manual therapy may be just as effective.50 For example, osteopathic manipulative medicine, and “spray and stretch” with pentafluoropropane or tetrafluoroethane are commonly used to treat myofascial pain and SSS.
Additionally, various forms of electrical stimulation including microcurrent, transcutaneous electrical nerve stimulation (TENS), and percutaneous electrical nerve stimulation (PENS) may alleviate SSS. Laser and ultrasound are also effective for pain management, but the effectiveness of these technologies for the deactivation of MTrPs is uncertain. Biofeedback and other relaxation techniques, like hypnotherapy, help patients with pain management. Other effective (but more invasive) treatments for SSS include paraspinous injection block techniques and paraspinous needling, as discussed below.
The paraspinous injection block technique and paraspinous needling are used particularly in chronic cases in which the physical examination reveals severe and persistent allodynia and hyperalgesia, suggesting multi-segmental dermatomal, myotomal, and sclerotomal manifestations of SSS (Figure 11.6). Often, these findings coincide segmentally, making diagnosis of the sensitized level relatively straightforward. However, when they do not, or if pain relief is only partial/persists after treatment, the affected segmental levels most closely aligned with the principal pain can be treated
FIGURE 11.6 Paraspinal needling. An acupuncture needle is inserted sagittally into the spinalis muscle and then manipulated as described. Multiple acupuncture needles may be inserted to create a paraspinous block at each affected segmental level. (Original art, but has been published in the textbook Fisioterapia Invasiva del Sindrome de Dolor Miofascial: Manual de puncion seca de puntos gatillo (Spanish Edition) by Orlando Mayoral del Moral [ISBN-13: 978-8498351033].) first with a technique such as paraspinous needling, which addresses the centrally sensitized component of pain. If the patient experiences little or no pain relief, adjacent segmental levels may be treated until the patient reports a decrease in pain. This subjective decrease in pain is typically accompanied by an objective improvement in segmental findings.
Effective management involves the identification and treatment of both the peripheral and central components of sensitization which includes any foci responsible for initiating or perpetuating the centrally sensitized segmental findings.
Paraspinal muscles can be facilitated by active MTrPs elsewhere in the body. However, MTrPs within paraspinal muscles can act as a source of peripheral nociceptive input, further sensitizing the paraspinal muscles. To desensitize the muscles along a specific segment, Fischer et al.’s (2002) paraspinous injection block technique utilizes a 1% lidocaine injection and a 25-gauge needle, of sufficient length to reach the deep layers up to the vertebral lamina.51 Once the affected levels are identified by physical examination, injection is performed between the spinous process levels. The needle is inserted in the sagittal plane through the paraspinal muscle to a maximal depth but before contacting the vertebral lamina. After aspiration confirms blood vessels were avoided, approximately 0.1 mL of anesthetic is injected. Next, the needle is withdrawn to a subcutaneous level and redirected in the caudal direction, about 5 mm from the initial anesthetic solution. One continues this procedure, going as far as the needle reaches. The same procedures are repeated going in the cephalad direction. The result of this technique is multi-segmental desensitization, by effectively blocking the medial branch of the posterior primary rami at the affected segmental levels.51
Many practitioners have observed improvement in pain levels after paraspinous block and paraspinous dry needling. However, randomized, double-blinded, placebo-controlled clinical trials examining the effects of paraspinous block and paraspinous dry needling are needed to assess its efficacy.