- Email: [email protected]
Re: “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain”
PM R 8 (2016) 1225-1227
www.pmrjournal.org
Letters to the Editor
Re: “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” To the Editor, The study by Gerber et al titled “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” [1] raises several concerns, which limit the conclusions of the paper, and should be addressed. Foremost, the primary outcome reported of a myofascial trigger point (MTrP) transitioning from active to either latent or absent has been shown repeatedly to be unreliable. The references used by the authors to justify MTrPs being an objective and reliable finding do not support this conclusion. Some of those references were merely a review of the hypothetic construct of trigger points with no mention of diagnostic reliability [2] or are from textbooks that do not contain research data [3,4]. The authors reference Tough et al [5], who concluded “there is as yet limited consensus on case definition in respect of MTrP pain syndrome. Further research is needed to test the reliability and validity of diagnostic criteria.” Maigne et al [6] actually showed that palpation as diagnostic criteria had no identifiable reliability. In addition, the systematic review by Myburgh et al [7] showed “the methodologic quality of the majority of studies for the purpose of establishing trigger point reproducibility is generally poor.” These studies do not present a strong argument that trigger points are reliably identified. The authors’ claim that experience makes the examiners more calibrated also disregards the evidence. Even when experience was taken in to account, the study by Myburgh et al [8] could only yield a kappa of 0.63. Other systematic reviews of the literature on palpation of trigger points show greater degrees of variability between clinicians. Gerber et al [1] list a kappa of 0.74, significantly greater than what the literature has shown, but there was also no blinding or asymptomatic control with which to compare.
D.M. Disclosure: nothing to disclose
Second, the authors’ conclusions regarding clinically significant reduction in pain are not supported robustly by the data. The majority of statistically significant changes in pain, disability, and range of motion frequently failed to even reach a minimally clinical detectable difference. Measures such as cervical range of motion had differences below 5 , which is within the standard error of measure of the device. Third, the authors did not perform an intention-totreat analysis and excluded those who were lost to follow-up. Even more concerning was that the subjects were dichotomized into responders and nonresponders, but it was not disclosed how this was done. This results in the n for every group in Table 3 being less than the sum of the patients in the study. One must wonder whether the authors included nonresponders would these small changes still even be statistically significant. This study also did not have a control group or even an independent assessor, which significantly increases the risk of bias. Furthermore, the authors’ conclusion of dry needling being an effective treatment is not corroborated by the references cited. In their systematic review, Tough et al [5] actually stated that “needling was not found to be significantly superior to placebo.” The other citation, by Kietrys et al [9], does indeed recommend the use of dry needling in the conclusion of its abstract, yet the study showed that at 4 weeks dry needling was less effective than lidocaine and no more effective than sham when accounting for the 95% confidence interval. What is more interesting as to the effectiveness of dry needling is the link shown between patient expectations and effectiveness of dry needling. The review performed by Linde et al [10] showed there is a direct correlation between patient expectations and attitudes and effectiveness of treatment, even at 6month follow-up. Lee et al [11] took this one step further and conducted a study using the exact same treatment but varying the verbal instructions. The patients who were instructed that the needles were a treatment displayed greater activation of the ventral
1934-1482/$ - see front matter ª 2016 by the American Academy of Physical Medicine and Rehabilitation
1226
Letters to the Editor / PM R 8 (2016) 1225-1227
striatum on functional magnetic resonance imaging than those who were given neutral instructions. The literature alludes that it is the context of the treatment, not the treatment itself, that elicits a response. Collectively, this study by Gerber et al [1] has multiple flaws, including a lack of control group, long-term follow-up, and accounting for nonresponders. These flaws, combined with unreliable outcome measures, clinically insignificant changes, and even a misrepresentation of the literature limit its usefulness to the scientific community. Derek Miles, PT, DPT Sports Medicine University of Florida Gainesville, FL http://dx.doi.org/10.1016/j.pmrj.2016.07.533
References 1. Gerber LH, Shah J, Rosenberger W, et al. Dry needling alters trigger points in the upper trapezius muscle and reduces pain in subjects with chronic myofascial pain. PM R 2015;7:711-718. 2. Simons DG. Review of enigmatic MTrPs as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol 2004;14:95-107.
3. Simons DG, Travell JG, Simons LS. Travell & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed. Baltimore, MD: Williams & Wilkins; 1999. 4. Mense S, Masi AT. Increased muscle tone as a cause of muscle pain. In: Mense S, Gerwin RD, eds. Muscle Pain: Understanding the Mechanisms. Heidelberg: Springer; 2011; 207-249. 5. Tough EA, White AR, Cummings TM, Richards S, Campbell J. Variability of criteria used to diagnose myofascial trigger point pain syndromedevidence from a review of the literature. Clin J Pain 2007;23:278-286. 6. Maigne JY, Cornelis P, Chatellier G. Lower back pain and neck pain: Is it possible to identify the painful side by palpation only? Ann Phys Rehabil Med 2012;55:103-111. 7. Myburgh C, Larsen AH, Hartvigsen J. A systematic, critical review of manual palpation for identifying myofascial trigger points: Evidence and clinical significance. Arch Phys Med Rehabil 2008;89: 1169-1176. 8. Myburgh C, Lauridsen HH, Larsen AH, Hartvigsen J. Standardized manual palpation of myofascial trigger points in relation to neck/ shoulder pain; The influence of clinical experience on interexaminer reproducibility. Man Ther 2011;16:136-140. 9. Kietrys DM, Palombaro KM, Azzaretto E, et al. Effectiveness of dry needling for upper-quarter myofascial pain: A systematic review and meta-analysis. J Orthop Sports Phys Ther 2013;43: 620-634. 10. Linde K, Witt CM, Streng A, et al. The impact of patient expectations on outcomes in four randomized controlled trials of acupuncture in patients with chronic pain. Pain 2007;128:264-271. 11. Lee I, Wallraven C, Kong J, et al. When pain is not only pain: Inserting needles into the body evokes distinct reward-related brain responses in the context of a treatment. Physiol Behav 2015;140:148-155.
Reply Thank you for the opportunity to respond to the letter by Derek Miles, PT, DPT, who raised several issues about the design, validity, and purpose of our group’s publication titled “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” [1]. We believe that there may have been some misunderstanding on Dr Miles’ part about the intent of our study, the methodology used to calibrate the examiners, or the primary outcome measure of our study. As clearly stated in the paper, this study was not designed or executed with the intent of demonstrating clinical effectiveness. The study was undertaken to assess the effect of a commonly used intervention (dry needling treatment) to elicit a change in myofascial trigger point (MTrP) status. Almost any intervention thought to affect change might have been selected for the same purpose, but we have had decades of experience with dry needling and, as a convenience, selected this one. The primary outcomes, change in J.S. Disclosure: nothing to disclose S.S. Disclosure: nothing to disclose L.G. Disclosure: nothing to disclose
level of pain, and status of the MTrP were used to power the study. The analyses were directed toward determining the relationships among needling and measures of pain reduction and MTrP statusdour primary outcome measures. All other measures were secondary outcomes. We definitively showed there was a clinically and statistically significant reduction in pain and a change in MTrP status after dry needling. Dr Miles is correct in his comments that we used palpation, a physical diagnostic assessment, as a diagnostic and outcome measure. Perhaps Dr Miles has misused the term “objective” with “reliable.” Most investigators would agree that palpation is indeed an objective measure, although its reliability may be in question. Unfortunately, there is a lack of agreement among clinicians and investigators on criteria for diagnosing myofascial pain syndrome (MPS), which measures are appropriate for clinical research outcomes, which tissue should be the treatment target, and which measures are best for determining efficacy and whether they should be objective and/or self-reported outcomes. We selected palpation as the outcome of choice for our study.
www.pmrjournal.org
Letters to the Editor
Re: “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” To the Editor, The study by Gerber et al titled “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” [1] raises several concerns, which limit the conclusions of the paper, and should be addressed. Foremost, the primary outcome reported of a myofascial trigger point (MTrP) transitioning from active to either latent or absent has been shown repeatedly to be unreliable. The references used by the authors to justify MTrPs being an objective and reliable finding do not support this conclusion. Some of those references were merely a review of the hypothetic construct of trigger points with no mention of diagnostic reliability [2] or are from textbooks that do not contain research data [3,4]. The authors reference Tough et al [5], who concluded “there is as yet limited consensus on case definition in respect of MTrP pain syndrome. Further research is needed to test the reliability and validity of diagnostic criteria.” Maigne et al [6] actually showed that palpation as diagnostic criteria had no identifiable reliability. In addition, the systematic review by Myburgh et al [7] showed “the methodologic quality of the majority of studies for the purpose of establishing trigger point reproducibility is generally poor.” These studies do not present a strong argument that trigger points are reliably identified. The authors’ claim that experience makes the examiners more calibrated also disregards the evidence. Even when experience was taken in to account, the study by Myburgh et al [8] could only yield a kappa of 0.63. Other systematic reviews of the literature on palpation of trigger points show greater degrees of variability between clinicians. Gerber et al [1] list a kappa of 0.74, significantly greater than what the literature has shown, but there was also no blinding or asymptomatic control with which to compare.
D.M. Disclosure: nothing to disclose
Second, the authors’ conclusions regarding clinically significant reduction in pain are not supported robustly by the data. The majority of statistically significant changes in pain, disability, and range of motion frequently failed to even reach a minimally clinical detectable difference. Measures such as cervical range of motion had differences below 5 , which is within the standard error of measure of the device. Third, the authors did not perform an intention-totreat analysis and excluded those who were lost to follow-up. Even more concerning was that the subjects were dichotomized into responders and nonresponders, but it was not disclosed how this was done. This results in the n for every group in Table 3 being less than the sum of the patients in the study. One must wonder whether the authors included nonresponders would these small changes still even be statistically significant. This study also did not have a control group or even an independent assessor, which significantly increases the risk of bias. Furthermore, the authors’ conclusion of dry needling being an effective treatment is not corroborated by the references cited. In their systematic review, Tough et al [5] actually stated that “needling was not found to be significantly superior to placebo.” The other citation, by Kietrys et al [9], does indeed recommend the use of dry needling in the conclusion of its abstract, yet the study showed that at 4 weeks dry needling was less effective than lidocaine and no more effective than sham when accounting for the 95% confidence interval. What is more interesting as to the effectiveness of dry needling is the link shown between patient expectations and effectiveness of dry needling. The review performed by Linde et al [10] showed there is a direct correlation between patient expectations and attitudes and effectiveness of treatment, even at 6month follow-up. Lee et al [11] took this one step further and conducted a study using the exact same treatment but varying the verbal instructions. The patients who were instructed that the needles were a treatment displayed greater activation of the ventral
1934-1482/$ - see front matter ª 2016 by the American Academy of Physical Medicine and Rehabilitation
1226
Letters to the Editor / PM R 8 (2016) 1225-1227
striatum on functional magnetic resonance imaging than those who were given neutral instructions. The literature alludes that it is the context of the treatment, not the treatment itself, that elicits a response. Collectively, this study by Gerber et al [1] has multiple flaws, including a lack of control group, long-term follow-up, and accounting for nonresponders. These flaws, combined with unreliable outcome measures, clinically insignificant changes, and even a misrepresentation of the literature limit its usefulness to the scientific community. Derek Miles, PT, DPT Sports Medicine University of Florida Gainesville, FL http://dx.doi.org/10.1016/j.pmrj.2016.07.533
References 1. Gerber LH, Shah J, Rosenberger W, et al. Dry needling alters trigger points in the upper trapezius muscle and reduces pain in subjects with chronic myofascial pain. PM R 2015;7:711-718. 2. Simons DG. Review of enigmatic MTrPs as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol 2004;14:95-107.
3. Simons DG, Travell JG, Simons LS. Travell & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed. Baltimore, MD: Williams & Wilkins; 1999. 4. Mense S, Masi AT. Increased muscle tone as a cause of muscle pain. In: Mense S, Gerwin RD, eds. Muscle Pain: Understanding the Mechanisms. Heidelberg: Springer; 2011; 207-249. 5. Tough EA, White AR, Cummings TM, Richards S, Campbell J. Variability of criteria used to diagnose myofascial trigger point pain syndromedevidence from a review of the literature. Clin J Pain 2007;23:278-286. 6. Maigne JY, Cornelis P, Chatellier G. Lower back pain and neck pain: Is it possible to identify the painful side by palpation only? Ann Phys Rehabil Med 2012;55:103-111. 7. Myburgh C, Larsen AH, Hartvigsen J. A systematic, critical review of manual palpation for identifying myofascial trigger points: Evidence and clinical significance. Arch Phys Med Rehabil 2008;89: 1169-1176. 8. Myburgh C, Lauridsen HH, Larsen AH, Hartvigsen J. Standardized manual palpation of myofascial trigger points in relation to neck/ shoulder pain; The influence of clinical experience on interexaminer reproducibility. Man Ther 2011;16:136-140. 9. Kietrys DM, Palombaro KM, Azzaretto E, et al. Effectiveness of dry needling for upper-quarter myofascial pain: A systematic review and meta-analysis. J Orthop Sports Phys Ther 2013;43: 620-634. 10. Linde K, Witt CM, Streng A, et al. The impact of patient expectations on outcomes in four randomized controlled trials of acupuncture in patients with chronic pain. Pain 2007;128:264-271. 11. Lee I, Wallraven C, Kong J, et al. When pain is not only pain: Inserting needles into the body evokes distinct reward-related brain responses in the context of a treatment. Physiol Behav 2015;140:148-155.
Reply Thank you for the opportunity to respond to the letter by Derek Miles, PT, DPT, who raised several issues about the design, validity, and purpose of our group’s publication titled “Dry Needling Alters Trigger Points in the Upper Trapezius Muscle and Reduces Pain in Subjects with Chronic Myofascial Pain” [1]. We believe that there may have been some misunderstanding on Dr Miles’ part about the intent of our study, the methodology used to calibrate the examiners, or the primary outcome measure of our study. As clearly stated in the paper, this study was not designed or executed with the intent of demonstrating clinical effectiveness. The study was undertaken to assess the effect of a commonly used intervention (dry needling treatment) to elicit a change in myofascial trigger point (MTrP) status. Almost any intervention thought to affect change might have been selected for the same purpose, but we have had decades of experience with dry needling and, as a convenience, selected this one. The primary outcomes, change in J.S. Disclosure: nothing to disclose S.S. Disclosure: nothing to disclose L.G. Disclosure: nothing to disclose
level of pain, and status of the MTrP were used to power the study. The analyses were directed toward determining the relationships among needling and measures of pain reduction and MTrP statusdour primary outcome measures. All other measures were secondary outcomes. We definitively showed there was a clinically and statistically significant reduction in pain and a change in MTrP status after dry needling. Dr Miles is correct in his comments that we used palpation, a physical diagnostic assessment, as a diagnostic and outcome measure. Perhaps Dr Miles has misused the term “objective” with “reliable.” Most investigators would agree that palpation is indeed an objective measure, although its reliability may be in question. Unfortunately, there is a lack of agreement among clinicians and investigators on criteria for diagnosing myofascial pain syndrome (MPS), which measures are appropriate for clinical research outcomes, which tissue should be the treatment target, and which measures are best for determining efficacy and whether they should be objective and/or self-reported outcomes. We selected palpation as the outcome of choice for our study.