Intramuscular Electrical Stimulation for the Treatment of Trigger Points in Patients with Chronic Migraine: A Protocol for a Pilot Study Using a Single-Case Experimental Design.

Background and Objectives: Trigger points (TrPs) are prevalent in patients with migraine headaches. Needling interventions targeting TrPs in migraine patients may reduce the intensity and frequency of headaches, yet systematic reviews reveal a lack of robust evidence. Intramuscular electrical stimulation (IMES) is a modality that delivers electrical current into muscles and TrPs, with recent studies suggesting it may amplify the therapeutic effects of dry needling peripherally and centrally. This could be advantageous for patients with migraine and symptomatic TrPs. Materials and Methods: This study will implement a multiple baseline single-case experimental design (SCED). In a clinical setting, a SCED study lends itself to conducting research with only a few patients that each serve as their own controls. In this SCED study, four participants with chronic migraine will be enrolled in a non-concurrent manner and randomized to one of four baseline measurement periods (4, 5, 6 or 7 weeks), leading to four potentially different start dates for each participant in the intervention phase. During the intervention phase, patients will receive five sessions of dry needling with IMES, one session per week for five weeks. The primary outcome measure will be headache frequency, i.e., the reduction in the number of headache days over a one-month period using electronic headache diary data from the Migraine Buddy smartphone application. Secondary outcome measures will be changes in mean migraine pain intensity using a numeric pain rating scale (NPRS), migraine disability using the Migraine Disability Assessment Test (MIDAS), the Headache Impact Test (HIT-6), and changes in selected cervical musculoskeletal impairments including pressure pain thresholds (PPTs) over TrPs, the craniocervical flexion test (CCFT), and cervical active range of motion (AROM). Primary and secondary outcome measures will be analyzed separately using both visual and statistical analyses. Results: Actively recruiting participants. This project was approved by the Mass General Brigham Institutional Review Board (protocol #2023P000931) and is registered with ClinicalTrials.gov (NCT05893914). Conclusions: This study will seek to determine the effects of a five-week intervention period of IMES to TrPs in the posterior cervical muscles of subjects with chronic migraine.

Trigger Points and Contracture/Contraction Knots: What's in a Name? Reply to Dommerholt, J.; Gerwin, R.D. Contracture Knots vs. Trigger Points. Comment on "Ball et al. Ultrasound Confirmation of the Multiple Loci Hypothesis of the Myofascial Trigger Point and the Diagnostic Importance of Specificity in the Elicitation of the Local Twitch Response. Diagnostics 2022, 12, 321".

We are responding to the comment by Dommerholt and Gerwin that we have reverse-defined "myofascial trigger point" (MTrP) and "contracture/contraction knot." In attempting to maintain philosophical agreement with specific and implied aspects of their integrated hypothesis of trigger-point formation (namely a MTrP being ischemic and hypoxic), we referred to the MTrP as the small hyperechoic signal rather than the larger hypoechoic (and therefore hyperperfused) structure surrounding it. It was never our intent to re-define nor contribute to confusion. In making this concession with respect to Dommerholt and Gerwin's preferred nomenclature, however, we must instead now reconcile what we image as a hypoechoic (and therefore hyperperfused) MTrP with it being concurrently hypoxic.

Intramuscular Electrical Stimulation to Trigger Points: Insights into Mechanisms and Clinical Applications-A Scoping Review.

Intramuscular electrical stimulation (IMES) is a modality used by clinicians to treat myofascial pain. Recent studies have shown positive results for the use of IMES on pain outcomes, yet studies investigating the potential mechanisms of IMES directly to trigger points (TrPs) are lacking. We performed a scoping review of the literature to summarize the current evidence from human and animal studies on the mechanisms of IMES to the TrP location, and to identify gaps in the existing literature. Electronic literature searches were conducted across five databases from inception to 15 August 2022, including PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), Scopus and Cochrane Register of Controlled Trials. Four studies met our full criteria for inclusion in this review. Three studies assessed the effects of IMES to TrPs on human subjects with MPS, and only one study used an animal model with experimentally generated TrPs. Based on the results of the included studies, IMES within a TrP region was reported to normalize muscle blood flow, decrease endplate noise of the TrP and elicit antinociceptive effects, at least partially, through engaging supraspinal descending pain inhibitory systems. At present, no clinical implications can be determined on the use of IMES to TrPs due to the limited amount and quality of the available evidence. Further studies investigating the clinical effectiveness and also underlying mechanisms of IMES to TrPs are clearly needed.

Ultrasound Confirmation of the Multiple Loci Hypothesis of the Myofascial Trigger Point and the Diagnostic Importance of Specificity in the Elicitation of the Local Twitch Response.

The literature has hypothesized that a trigger point (TrP) area consists of a hyperperfused contracture knot with smaller hypoperfused TrPs within the contracture knot. By contrast, the only published ultrasound image of a TrP has it labeled hypoechoic (i.e., hyperperfused) with no commentary regarding smaller speckles of hypoperfusion within. Furthermore, the lack of clarity in objective definition of the terms associated with the TrP (namely, the palpable "contracture knot" and smaller nonpalpable "trigger point") has led to unnecessary communication difficulties between and among clinicians and researchers. In this case series of three muscles across two patients, by using high-definition musculoskeletal ultrasound imaging technology, we present what we believe to be the first reliable capture of palpable hypoechoic (e.g., hypoperfused) contracture knots (previously mislabeled as a hypoechoic TrP), and a visual support of the multiple loci hypothesis first proposed by Hong and Simons-the first reliable confirmation of the hyperechoic (i.e., hypoperfused) TrP within. Initially proposed by a histological study and supported by microdialysis study, this case series lends further support for the multiple loci hypothesis through visual confirmation of palpable hypoechoic contracture knots, with smaller hypoechoic TrPs "speckles" within.

Needling Interventions for Sciatica: Choosing Methods Based on Neuropathic Pain Mechanisms-A Scoping Review.

Sciatica is a condition often accompanied by neuropathic pain (NP). Acupuncture and dry needling are common treatments for pain, and the current literature supports acupuncture as an effective treatment for sciatica. However, it is unknown if the mechanisms of NP are considered in the delivery of needling interventions for sciatica. Our objective was to assess the efficacy and the effectiveness of needling therapies, to identify common needling practices and to investigate if NP mechanisms are considered in the treatment of sciatica. A scoping review of the literature on needling interventions for sciatica and a review of the literature on mechanisms related to NP and needling interventions were performed. Electronic literature searches were conducted on PubMed, MEDLINE, CINAHL and Cochrane Database of Systematic Reviews from inception to August, 2020 to identify relevant papers. Reference lists of included papers were also manually screened and a related-articles search through PubMed was performed on all included articles. Mapping of the results included description of included studies, summary of results, and identification of gaps in the existing literature. Ten articles were included. All studies used acupuncture for the treatment of sciatica, no studies on dry needling were identified. Current evidence supports the efficacy and effectiveness of acupuncture for sciatica, however, no studies considered underlying NP mechanisms in the acupuncture approach for sciatica and the rationale for using acupuncture was inconsistent among trials. This review reveals that neuropathic pain mechanisms are not routinely considered in needling approaches for patients with sciatica. Studies showed acupuncture to be an effective treatment for sciatic pain, however, further research is warranted to explore if needling interventions for sciatica and NP would be more effective if NP mechanisms are considered.

The local twitch response during trigger point dry needling: Is it necessary for successful outcomes?

BACKGROUND: Myofascial trigger point (MTrP) injection and trigger point dry needling (TrPDN) are widely accepted therapies for myofascial pain syndrome (MPS). Empirical evidence suggests eliciting a local twitch response (LTR) during needling is essential. OBJECTIVE: This is the first review exploring the available literature, regardless of study design, on the neurophysiological effects and clinical significance of the LTR as it relates to reductions in pain and disability secondary to MTrP needling. METHODS: PubMed, MEDLINE, Science Direct and Google Scholar were searched up until October 2016 using terms related to trigger point needling and the LTR. RESULTS: and Discussion: Several studies show that eliciting a LTR does not correlate with changes in pain and disability, and multiple systematic reviews have failed to conclude whether the LTR is relevant to the outcome of TrPDN. Post needling soreness is consistently reported in studies using repeated in and out needling to elicit LTRs and increases in proportion to the number of needle insertions. In contrast, needle winding without LTRs to MTrPs and connective tissue is well supported in the literature, as it is linked to anti-nociception and factors related to tissue repair and remodeling. Additionally, the positive biochemical changes in the MTrP after needling may simply be a wash out effect related to local vasodilation. While the LTR during TrPDN appears unnecessary for managing myofascial pain and unrelated to many of the positive effects of TrPDN, further investigation is required.

CAVITATION SOUNDS DURING CERVICOTHORACIC SPINAL MANIPULATION.

BACKGROUND: No study has previously investigated the side, duration or number of audible cavitation sounds during high-velocity low-amplitude (HVLA) thrust manipulation to the cervicothoracic spine. PURPOSE: The primary purpose was to determine which side of the spine cavitates during cervicothoracic junction (CTJ) HVLA thrust manipulation. Secondary aims were to calculate the average number of cavitations, the duration of cervicothoracic thrust manipulation, and the duration of a single cavitation. STUDY DESIGN: Quasi-experimental study. METHODS: Thirty-two patients with upper trapezius myalgia received two cervicothoracic HVLA thrust manipulations targeting the right and left T1-2 articulation, respectively. Two high sampling rate accelerometers were secured bilaterally 25 mm lateral to midline of the T1-2 interspace. For each manipulation, two audio signals were extracted using Short-Time Fourier Transformation (STFT) and singularly processed via spectrogram calculation in order to evaluate the frequency content and number of instantaneous energy bursts of both signals over time for each side of the CTJ. RESULT: Unilateral cavitation sounds were detected in 53 (91.4%) of 58 cervicothoracic HVLA thrust manipulations and bilateral cavitation sounds were detected in just five (8.6%) of the 58 thrust manipulations; that is, cavitation was significantly (p<0.001) more likely to occur unilaterally than bilaterally. In addition, cavitation was significantly (p<0.0001) more likely to occur on the side contralateral to the clinician's short-lever applicator. The mean number of audible cavitations per manipulation was 4.35 (95% CI 2.88, 5.76). The mean duration of a single manipulation was 60.77 ms (95% CI 28.25, 97.42) and the mean duration of a single audible cavitation was 4.13 ms (95% CI 0.82, 7.46). In addition to single-peak and multi-peak energy bursts, spectrogram analysis also demonstrated high frequency sounds, low frequency sounds, and sounds of multiple frequencies for all 58 manipulations. DISCUSSION: Cavitation was significantly more likely to occur unilaterally, and on the side contralateral to the short-lever applicator contact, during cervicothoracic HVLA thrust manipulation. Clinicians should expect multiple cavitation sounds when performing HVLA thrust manipulation to the CTJ. Due to the presence of multi-peak energy bursts and sounds of multiple frequencies, the cavitation hypothesis (i.e. intra-articular gas bubble collapse) alone appears unable to explain all of the audible sounds during HVLA thrust manipulation, and the possibility remains that several phenomena may be occurring simultaneously. LEVEL OF EVIDENCE: 2b.

Pathoanatomical characteristics of temporomandibular dysfunction: Where do we stand? (Narrative review part 1).

Temporomandibular dysfunction (TMD) is a complicated and multifactorial condition that affects the temporomandibular joint (TMJ) and muscles of mastication, resulting in pain and disability in 5-12% of the population. The condition involves genetic, anatomic and hormonal factors and is propagated, in part, by trauma, habitual activity, psychosocial components and occlusal variation. Yet, the exact etiology of TMD is still unknown and the most strategic conservative management of the condition is still a topic of debate. The purpose of this paper, the first of a two part series, is to provide greater insight into the pathoanatomical factors associated with TMD. Consistent with Scully (2008, 2013), degenerative changes seem to disrupt the relationship between the TMJ capsule, articular disc and muscles of mastication. The resulting position of the articular disc coincides with three primary classifications of TMD: Type 1 (muscle disorders), Type 2a/b (disc displacement with and without reduction), and Type 3 (any joint pain). Given the association of the lateral pterygoid with both the joint capsule and articular disc, the superior and inferior head seem to play a key role in TMD. Both heads undergo biological changes associated with the vicious cycle, pain adaptation and integrated pain adaptation, making the muscle a key pain generator associated with TMD. Clinicians must understand the pathoanatomic features associated with TMD so as to choose appropriate treatment strategies, leading to optimal short and long-term outcomes. While the former is discussed in part 1 of this narrative review, the latter will be considered in part 2.

Changes in shoulder pain and disability after thrust manipulation in subjects presenting with second and third rib syndrome.

OBJECTIVE: The purpose of this preliminary study was to investigate changes in shoulder pain, disability, and perceived level of recovery after 2 sessions of upper thoracic and upper rib high-velocity low-amplitude (HVLA) thrust manipulation in patients with shoulder pain secondary to second and third rib syndrome. METHODS: This exploratory study evaluated 10 consecutive individuals with shoulder pain, with or without brachial pain, and a negative Neer impingement test, who completed the Shoulder Pain and Disability Index (SPADI), the numeric pain rating scale (NPRS), and the global rating of change. Patients received 2 sessions of HVLA thrust manipulation targeting the upper thoracic spine bilaterally and the second and third ribs on the symptomatic side. Outcome measures were completed after the first treatment session, at 48 hours, 1 month, and 3 months. RESULTS: Patients showed a significant decrease in SPADI (F = 59.997; P = .001) and significant decrease in resting shoulder NPRS (F = 63.439; P = .001). For both NPRS and SPADI, there were significant differences between the pretreatment scores and each of the postintervention scores through 3-month follow-up (P < .05). Large within-group effect sizes (Cohen's d ≥ 0.8) were found between preintervention data and all postintervention assessments in both outcomes. Mean global rating of change scores (+6.8 at 3 months) indicated "a very great deal better" outcome at long-term follow-up. CONCLUSION: This group of patients with shoulder pain secondary to second and third rib syndrome who received upper thoracic and upper rib HVLA thrust manipulations showed significant reductions in pain and disability and improvement in perceived level of recovery.

Dry needling: a literature review with implications for clinical practice guidelines.

BACKGROUND: Wet needling uses hollow-bore needles to deliver corticosteroids, anesthetics, sclerosants, botulinum toxins, or other agents. In contrast, dry needling requires the insertion of thin monofilament needles, as used in the practice of acupuncture, without the use of injectate into muscles, ligaments, tendons, subcutaneous fascia, and scar tissue. Dry needles may also be inserted in the vicinity of peripheral nerves and/or neurovascular bundles in order to manage a variety of neuromusculoskeletal pain syndromes. Nevertheless, some position statements by several US State Boards of Physical Therapy have narrowly defined dry needling as an 'intramuscular' procedure involving the isolated treatment of 'myofascial trigger points' (MTrPs). OBJECTIVES: To operationalize an appropriate definition for dry needling based on the existing literature and to further investigate the optimal frequency, duration, and intensity of dry needling for both spinal and extremity neuromusculoskeletal conditions. MAJOR FINDINGS: According to recent findings in the literature, the needle tip touches, taps, or pricks tiny nerve endings or neural tissue (i.e. 'sensitive loci' or 'nociceptors') when it is inserted into a MTrP. To date, there is a paucity of high-quality evidence to underpin the use of direct dry needling into MTrPs for the purpose of short and long-term pain and disability reduction in patients with musculoskeletal pain syndromes. Furthermore, there is a lack of robust evidence validating the clinical diagnostic criteria for trigger point identification or diagnosis. High-quality studies have also demonstrated that manual examination for the identification and localization of a trigger point is neither valid nor reliable between-examiners. CONCLUSIONS: Several studies have demonstrated immediate or short-term improvements in pain and/or disability by targeting trigger points (TrPs) using in-and-out techniques such as 'pistoning' or 'sparrow pecking'; however, to date, no high-quality, long-term trials supporting in-and-out needling techniques at exclusively muscular TrPs exist, and the practice should therefore be questioned. The insertion of dry needles into asymptomatic body areas proximal and/or distal to the primary source of pain is supported by the myofascial pain syndrome literature. Physical therapists should not ignore the findings of the Western or biomedical 'acupuncture' literature that have used the very same 'dry needles' to treat patients with a variety of neuromusculoskeletal conditions in numerous, large scale randomized controlled trials. Although the optimal frequency, duration, and intensity of dry needling has yet to be determined for many neuromusculoskeletal conditions, the vast majority of dry needling randomized controlled trials have manually stimulated the needles and left them in situ for between 10 and 30 minute durations. Position statements and clinical practice guidelines for dry needling should be based on the best available literature, not a single paradigm or school of thought; therefore, physical therapy associations and state boards of physical therapy should consider broadening the definition of dry needling to encompass the stimulation of neural, muscular, and connective tissues, not just 'TrPs'.