Novel Use of Ultrasound Elastography to Quantify Muscle Tissue Changes After Dry Needling of Myofascial Trigger Points in Patients With Chronic Myofascial Pain.
OBJECTIVE
To compare a mechanical heterogeneity index derived from ultrasound vibration elastography with physical findings before and after dry-needling treatment of spontaneously painful active myofascial trigger points in the upper trapezius muscle.


METHODS
Forty-eight patients with chronic myofascial pain enrolled in a prospective interventional trial of 3 weekly dry-needling treatments for active myofascial trigger points. Trigger points were evaluated at baseline and at treatment completion using palpation, the pressure-pain threshold, and the mechanical heterogeneity index. Thirty patients were reevaluated at 8 weeks. Trigger points that "responded" changed to tissue that was no longer spontaneously painful, with or without the presence of a palpable nodule. Trigger points that "resolved" changed to tissue without a palpable nodule. The mechanical heterogeneity index was defined as the proportion of the upper trapezius muscle that appeared mechanically stiffer on elastography. Statistical significance for comparisons was determined at P < .05.


RESULTS
Following 3 dry needle treatments, the mechanical heterogeneity index decreased significantly for the 38 myofascial trigger points (79% of 48) that responded to treatment. Among these, the baseline mechanical heterogeneity index was significantly lower for the 13 trigger points (27% of 38) that resolved, but the decrease after 3 dry needle treatments did not reach significance. The pressure-pain threshold improved significantly for both groups. At 8 weeks, the mechanical heterogeneity index decreased significantly for the 22 trigger points (73% of 30) that responded and for the 10 (45% of 22) that resolved. The pressure-pain threshold improvement was significant for trigger points that responded but did not reach significance for resolved trigger points.


CONCLUSIONS
The mechanical heterogeneity index identifies changes in muscle tissue properties that correlate with changes in the myofascial trigger point status after dry needling.
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Diego
D
Turo
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Paul
P
Otto
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Murad
M
Hossain
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Tadesse
T
Gebreab
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Katherine
K
Armstrong
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
William F
WF
Rosenberger
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Hui
H
Shao
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Jay P
JP
Shah
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.).
Lynn H
LH
Gerber
Departments of Bioengineering (D.T., T.G., S.S.), Electrical and Computer Engineering (P.O., M.H.), and Statistics (W.F.R., H.S.) and Center for the Study of Chronic Illness and Disability (K.A., L.H.G.), George Mason University, Fairfax, Virginia USA; and Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland USA (J.P.S.). ssikdar@gmu.edu.
Siddhartha
S
Sikdar
D015670:Acupuncture Therapy / Q000379:methods*; D000328:Adult; D059350:Chronic Pain / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods; D005157:Facial Pain / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D016896:Treatment Outcome
dry needling; musculoskeletal ultrasound; myofascial pain syndrome; myofascial trigger points; ultrasound elastography