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Electromyography-Assisted Acupuncture:
A Quantitative Assessment Of Myofascial Pain Therapy
Richard D. Serano, MD
Christopher S. Corella, BS
Albert W. Kenney, PA-C
ABSTRACT
Mechanisms underlying the pathophysiology and subsequent course of myofascial pain syndromes are unclear. Denervation potentials are routinely observed in the clinical neurophysiology laboratory during routine electromyography (EMG). We describe a novel technique in which these potentials are identified while needling myofascial fibrous cords, alleged tender points. Acupuncture needles followed by EMG needles in the same site allow localization of spontaneous fibrillations, positive sharp waves, or complex repetitive discharges. The EMG needle is then repetitively stimulated electrically until the potentials disappear. Both proximal (axial) and distal (limb) muscles must be stimulated to completely resolve the abnormal potentials. Case histories of both subacute and chronic myofascial pain syndromes involving the piriformis muscle are presented to illustrate the effectiveness of this quantitative acupuncture.
KEY WORDS
Quantitative Acupuncture, Myofascial Pain, Piriformis Syndrome, Electromyogram, Trigger Point Injection, Myofascial Fibrous Cords, Electroacupuncture
INTRODUCTION
Mechanisms underlying the pathophysiology and subsequent course of myofascial pain syndromes are unclear. Animal models suggest disinhibition of the gamma motor neuron circuitry as a potential explanation.1 Denervation potentials are routinely observed in the clinical
neurophysiology laboratory during routine electromyography (EMG).2
Acupuncture techniques for myofascial pain or Bi Syndromes may be due to Blood Stasis and, as such, usually require direct needling as part of the treatment strategy. The intramuscular stimulation protocol of Dr. Chan Gunn involves vigorous repetitive piquiring of both proximal and distal muscles segmentally related.3 This is very effective for treating chronic myofascial pain syndromes. However, drawbacks include severe discomfort, multiple treatments, and uncertainty that the entire tender point has been treated because the intense needling over a relatively wide area makes it difficult to determine what is nodule and what is traumatized surrounding tissue. It is a qualitative but not a quantitative approach.
The existence of myofascial syndromes has been legitimized by the discipline of rheumatology in the development of criteria for fibromyalgia, which some consider to be a diffuse form of myofascial pain syndrome.4 Animal models suggest that the localized syndrome may be related to disinhibition or dysregulation in the gamma motor neuron circuitry,1 although whether the lesion is in the muscle spindle, the I-A afferent limb, the gabanergic interneuron, or the gamma efferent limb is debatable. Clinically, patients behave as if they have denervation hypersensitivity often with spontaneous muscle spasms and increased deep tendon reflexes.
Anecdotally, some patients report decreased pain after routine EMG for uncertain reasons. Findings in chronic myofascial pain syndromes may be interpreted as mild to moderate cervical or lumbar radiculopathies by EMG criteria with findings of spontaneous and persistent positive potentials such as fibrillations, positive sharp waves, complex repetitive discharges, myotonic potentials, and fasciculations identifiable in both proximal paraspinal muscles as well as distal limb musculature. If tender points in myofascial pain syndromes could be identified by the presence of such abnormal potentials, it might shed some light on myofascial pathophysiology. In addition, if real-time resolution of such persistent potentials by direct electrical stimulation were possible, a quantitative assessment of acupuncture effectiveness might be developed.
We report a novel union of EMG and acupuncture as a less traumatic, more efficient, and quantitative variation of Gunn's intramuscular stimulation. As a quantitative assessment of normalization of muscle physiology, it may have predictive value regarding prognosis in myofascial pain syndromes.
METHODS
An EMG machine was used with concentric 37-, 50-, or 75-mm EMG needles (Xltek; Oakville, Ontario, Canada), depending on degree of obesity and depth of myofascial fibrous cords. A standard handheld nerve stimulator was used for treatment (Figure 1). The affected muscle tender points in myofascial pain syndromes were palpated and then anchored with a 30-gauge acupuncture needle (Viva). Such points feel like fibrous cords, which tend to roll away from the larger EMG needle, analogous to a percutaneous venipuncture. With the EMG machine assessing real-time data acquisition, the EMG needle was passed as close to the acupuncture needle as possible (Figure 2). Depth and angle were changed slightly to examine a wide area of the cord if spontaneous positive potentials were not readily identified by the EMG needle. The muscle must be at rest during evaluation to distinguish from voluntary contraction, spasm, and true denervation potentials, e.g., fibrillations, positive sharp waves, and complex repetitive discharges (Figure 3 & Figure 5). Once identified with real-time EMG, the machine was turned to nerve conduction mode and the handheld stimulator was activated using 5 to 60 mA for 0.2 milliseconds at 2 Hz. Twenty to 30 stimulations were delivered and then we analyzed the efficacy of the stimulation epoch using real-time EMG oscilloscope assessment. The EMG needle was withdrawn only when all spontaneous abnormal positive potentials in the cords were either silenced (Figure 4) or replaced by negative potentials. Occasionally, no abnormal potentials were elicited from the myofascial fibrous cords; sometimes there is a spasm pattern. In these situations, the cord is electrically stimulated to trigger repetitive contractions that may result in the activation or uncovering of positive potentials. The fibrous cord is then repeatedly stimulated until the positive potentials disappear or are transformed.
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Table 1. Electromyographic Study of Case 3
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Muscle
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Left L4
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Left S1
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Left S2
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Left Gluteus Medius
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Left Piriformis
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Insertional activity
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None
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None
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Increased
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None
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Increased (CRD)
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Fibrillations
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0
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0
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2+
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2+*
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1+
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Positive
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sharp waves
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0
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0
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0
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0
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0
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Polyphasics
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0
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0
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0
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0
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0
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Abbreviation: CRD, complex repetitive discharges.
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*Initial insertion was silent; myofascial fibrous cords sampling detected fibrillation potentials.
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Paraspinal muscles segmentally involved in the clinical situation (i.e., for the piriformis syndrome, the L4, L5, S1, and possibly S2) were always treated initially, checking each level for tender and usually palpable myofascial fibrous cords. Usually, the muscle required stimulation at several depths. Then the involved girdle and limb muscles (piriformis, gluteus medius, gastrocnemius, etc.) were needled as above.
Results may include immediate and/or delayed pain relief, increased range of motion, increased muscle bulk where there was atrophy, modulation of paresthesias, and increased strength. Often, the original pain sensation is replaced by a different kind of soreness for a few days. The end point of a course of treatment occurs when repeat acupuncture no longer elicits abnormal potentials in any of the tender myofascial fibrous cords (Figure 4). The average number of treatments was 2 in the cases presented below for symptom resolution.
Because both acupuncture and EMG are standard procedures performed in our clinics, informed consent, both verbally and in writing, was obtained in the usual manner. The local institutional review board was not involved because of the routine nature of the individual aspects of the technique.
CASE REPORTS
Case 1
A 40-year-old woman with multiple sclerosis and uveitis, treated with azathioprine and interferon beta, presented with subacute right lower extremity radicular pain, right hip and thigh pain, and a right foot drop. She had undergone lumbar laminectomies on the left in 1990 and on the right in 2004. Prior treatment with epidural steroids, long-acting morphine sulfate, baclofen, gabapentin, and therapeutic massage provided limited relief. Inpatient neurosurgical evaluation demonstrated right L4 and L5 disk disease on magnetic resonance imaging; intravenous narcotics gave temporary relief but the foot drop persisted. Following discharge, electroacupuncture was performed using Extraordinary Meridians GV and CV with SI 3, BL 62, LU 7, and KI 6. Then ST 36, ST 38, ST 40, GB 31, GB 34, GB 35, and GB 36 were piquired on the right side only. Anatomical electroacupuncture of the right piriformis muscle with stimulation at 150 Hz (Ito IC 1170 device; Tokyo, Japan) for 20 minutes completed the treatment. EMG/nerve conduction study then demonstrated decreased amplitude in the right peroneal nerve, acute denervation potentials in the right piriformis, and right tibialis anterior and chronic denervation in the right tensor fascia lata and peroneus longus muscles. All of the above muscles were treated with quantitative acupuncture. Dorsiflexion of the foot and radicular pain improved immediately and continued to improve over the next month. Sustained-release narcotics were discontinued and the patient no longer required a cane to walk.
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Figure 1. Xltek Hand-Held NCV Stimulator Being Applied to both EMG and Acupuncture Needles
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Figure 2. Closeup of Post Stimulation Area in the Quadratus Lumborum; Note Erythema Surrounding Insertion Area
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Case 2
A 49-year-old woman presented for acupuncture treatment of failed back syndrome after 2 lumbar laminectomies 1 year apart did not resolve the numbness and pain in her left foot as well as left back and buttock pain. Cyclobenzaprine, 10 mg, and oxycodone hydrochloride (OxyContin; Purdue Pharma, Stamford, CT) 40 mg 3 times daily, enabled her to work part-time. Magnetic resonance imaging revealed lumbar stenosis. EMG/nerve conduction study demonstrated decreased amplitudes in the right peroneal and tibial nerves with normal left-sided potentials; chronic denervation in the right tensor fascia lata and biceps femoris muscles, and acute denervation in the left piriformis, left L4, L5, and S1 paraspinals. All left- sided muscles were treated with quantitative acupuncture and the left leg and back pain were so improved that the right lumbar pain became this patient's worse pain. Several subsequent acupuncture treatments and baclofen helped,5 but not as dramatically as the quantitative acupuncture. Persistent right flank pain required total hysterectomy for extensive endometriosis.
Case 3
A 48-year-old woman presented with a 10-year history of left hip pain. Magnetic resonance images of the hip were unremarkable and chiropractic and physical therapy did not provide continued pain relief. Daily function was maintained with 2400 mg/d of ibuprofen, but the patient was unable to exercise. EMG/nerve conduction study demonstrated decreased amplitude in the left lateral femoral cutaneous nerve (meralgia paresthetica), and the right peroneal nerve showed slowed conduction velocity. The right sural nerve showed decreased amplitude. EMG was performed only on the left side and the gluteus medius, piriformis, and S1 and S2 paraspinals showed denervation (Table 1). These muscles were treated with quantitative acupuncture and all abnormal potentials were transformed into normal-appearing potentials or silenced (Figure 5). Improvement of the patient's longstanding left hip pain was immediate and so dramatic that she became aware of right shin pain. Three weeks later, EMG was repeated on her right leg and denervation potentials were found in the right tibialis anterior, right peroneus, right L4 and right L5 paraspinals. All muscles were treated with quantitative acupuncture and pain relief was instant. Ibuprofen use decreased to 400 mg/d or less.
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Figure 3. Several Intractable Positive Sharp Waves Are Elicited During the Insertion of the EMG Needle in Figure 2.
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Figure 4. Oscilloscope on Xltek EMG machine Showing Electrical Silence Post Stimulation
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Figure 5. EMG from Case 3 demonstrating progression from complex repetitive discharges (CRDs) after needle insertion ( top line) to positive sharp waves after initial stimulation (middle line) to electrical silence after further stimulation (bottom line).
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DISCUSSION
Study of laboratory animals suggests that the etiology of myofascial pain syndromes involves some component of the deep tendon reflex arc,1 possibly denervation hypersensitivity of the gamma motor efferent loop. Intramuscular stimulation has proven to be an effective treatment of the most stubborn chronic myofascial pain syndrome.2 Its success is due to the approach to treat both proximal and distal musculature as well as the extensive therapeutic injury to the myofascial cord, which seems to reverse whatever processes make up the pathophysiology of myofascial pain syndromes. Clinically, the therapeutic injury to paraspinal muscles restores regulation in the disinhibited gamma loop.
Finding apparent denervation potentials in myofascial fibrous cords raises several issues for acupuncturists and neurophysiologists alike. Since the active area of denervation in these nodules is so focal, does this speak to the necessity of exact localization when needling acupoints, at least in Bi Syndromes caused by Blood Stasis? If acupuncture can be quantitated, could treatment protocols be more accurately designed for both researcher and clinician?
Since denervation potentials are conventionally reflective of either neuropathic or myopathic processes, does this imply that myofascial conditions may share a common pathophysiology with these processes? Does the transformation or reversibility of denervation potentials have diagnostic and prognostic value? Do myofascial syndromes and radiculopathies, particularly chronic radiculopathies, have an underlying common pathogenesis?
CONCLUSIONS
Although quantitative acupuncture requires specialized equipment to perform, several physicians perform both acupuncture and EMG/nerve conduction mode routinely. The major differences are that quantitative acupuncture is not random muscle assessment, the handheld nerve conduction device is used to stimulate abnormal muscles, and apparent persistent denervation potentials may be subject to conformational change. Further studies are required to determine to what extent quantitative acupuncture will assist in the understanding of myofascial pain syndromes and if it will have a practical place in the armamentarium of acupuncturists.
ACKNOWLEDGEMENTS
I thank Larry Lynn whose technical and artistic assistance was invaluable. This contribution is dedicated to my deceased friend and pain scientist, Dr Timothy Toomey.
REFERENCES
- Gunn CC. Treating Myofascial Pain: Intramuscular Stimulation (IMS) for Myofascial Pain Syndromes of Neuropathic Origin. Seattle, WA: Multidisciplinary Pain Center of Washington Medical School; 1989.
- Donalson CC, Nelson DV, Schulz R. Disinhibition in the gamma motorneuron circuitry: a neglected mechanism for understanding myofascial syndromes. Appl Psychophysiol Biofeedback. 1998;23(1):43-57.
- Kimura J. Electrodiagnosis in Diseases of Nerves and Muscles: Principles and Practice: Edition 2. Philadelphia, PA: FA Davis Co; 1989.
- Wolfe F, Smythe HA, Yunnus HR, et al. American College of Rheumatology 1990 criteria for the classification of fibromyalgia. Arthritis Rheum. 1990; 33(2):160-172.
- Serano RD. Impact of baclofen on pain and insomnia in myofascial pain syndromes: a pilot study. Am J Pain Med. 2001;11:17-20.
AUTHORS' INFORMATION
Dr Richard D. Serano is a Board-Certified Neurologist in private practice at Highland Neurology Center, is Medical Director of Eastcoast Diagnostics and Research in Fayetteville, North Carolina, and is Chief of the Neurology Section in the Cape Fear Valley Health System in Fayetteville.
Richard D. Serano, MD, FAAMA*
Highland Neurology Center and Eastcoast Diagnostics and Research
3645 Cape Center Dr
Fayetteville, NC 28304
Phone: 910-483-9200 • Fax: 910-483-5678
E-mail: hncpa@earthlink.net
Christopher S. Corella is Chief Technologist at Eastcoast Diagnostics and Research in Fayetteville, North Carolina.
Christopher S. Corella, BS, END
Phone: 910-860-8378
Albert W. Kenney is a partner at Highland Neurology Center in Fayetteville, North Carolina, and has privileges in Acupuncture and Neurology in the Cape Fear Valley Health System in Fayetteville.
Albert W. Kenney, PA-C
Highland Neurology Center
PO Box 44035
Fayetteville, NC 28309
*Correspondence and reprint requests
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