Needling procedures of trigger point injections in the management of myofascial pain syndrome: a narrative review

Introduction

Myofascial pain syndrome is a regional muscular pain characterized by localized deep tender areas within a taut band of skeletal muscle, tendon, or ligament, called trigger points (TrPs) (1). The presence of myofascial trigger points (MTrPs) is often the key to diagnosis, though some additional testing may provide supportive evidence. The myofascial system can be a source of pain and functional disability by creating symptomatic pain localized or referred to adjacent structures in an unclear way. Several theories have been proposed about TrP formation, such as the excessive activity of acetylcholine (ACh) and formation of taut bands, local hypoxia, and energy crisis (2-5), the role of peripheral and central sensitization (6,7), Cinderella theory (8), shift theory (9), as well as a possible role for descending modulation in myofascial pain (10,11). Pain arises from one or more MTrPs which are aggravated by physical palpation and increased functional demands.

A MTrPs can cause localized pain in that area and refer pain to another region known as a zone of reference. The zone of reference can be distant from the involved muscle and may not be within the same dermatome, meaning that the site and the source of pain are different (referred pain). As a result, TrPs are a common cause of headaches and persistent pain in the face and neck (12). Due to the low density of sensory afferents in muscle, muscle pain is diffuse and poorly localized (13). The convergence-projection theory further explains the possible mechanism behind referred pain, where afferent neurons from separate innervation areas converge onto the same second-order neuron in the central nervous system (CNS) resulting in the inability of the brain to accurately identify the actual source of the pain (12). With sensory involvement, the patient often experiences this referred pain (14). When the autonomic nervous system is affected, nasal congestion, blurring of vision, or excessive lacrimation may be evident (12). Therefore, various therapeutic approaches have been recommended for the management of skeletal muscle disorders such as patient education and self-care (15), physical medicine (16,17), injection techniques (18), pharmacotherapy (19), and behavioral modification (12,15,20,21).

Therapeutic injection techniques are mostly used in managing muscle pain, particularly pain originating from MTrPs. Two needling procedures are often used to manage TrPs: wet and dry needling. Wet needling refers to procedures that include the injection of a substance (usually a local anesthetic) into a TrP through a hypodermic, beveled-cutting-edge needle (22-29). In contrast, dry needling uses a thin filiform needle that penetrates the skin and disrupts the fibrous bands in the muscle by the repetition of the movement of the needle around the TrP (1,26). Various studies have been performed on patients with myofascial pain with TrPs, demonstrating the different types of TrP management. A study by Anjana G. et al. evaluated the effectiveness of dry needling and transcutaneous electrical nerve stimulation (TENS) in cervical pain intensity reduction and cervical range of motion improvement in patients who complained of neck pain due to MTrPs. The visual analog scale (VAS), neck disability index (NDI), and cervical range of motion (CROM) were used before, on days 14 and 28 days after the treatment. Moreover, they concluded that both treatments effectively reduced pain and improved the NDI and CROM. However, the study showed that a single session of dry needling is more advantageous and cost-effective than numerous TENS sessions (30). Another study compared the effectiveness of immediate and delayed superficial dry needling (SDN) and deep dry needling (DDN) on the function of the upper trapezius muscle and evaluated the patient’s pain and disability. Moreover, the study showed that both SDN and DDN could effectively reduce pain and disability in patients with active MTrPs of the upper trapezius muscle (31). A systematic review and meta-analysis reported low evidence suggesting a superior effect of TrP injection (wet needling) for decreasing pain in the short term as compared with dry needling for cervical muscle TrPs (32). Therefore, the present manuscript explores the methodology and evidence in the literature of needling techniques for myofascial pain patients, dry needling, and lidocaine TrP injections. We present this article in accordance with the Narrative Review reporting checklist (available at https://joma.amegroups.com/article/view/10.21037/joma-22-41/rc).

Methods

Electronic databases PubMed, EMBASE, Scopus, ISI Web of Knowledge, and Cochrane Library were searched without time restrictions up to and including May 2023. Keywords are combined using the Boolean operators (AND, OR) for the identification of relevant studies. Titles abstracts and full texts were screened as well as the reference lists of pertinent original studies were reviewed and screened for eligibility (Table 1).

Study selection and literature search protocol

Electronic databases PubMed, EMBASE, Scopus, ISI Web of Knowledge, and Cochrane Library were searched without time restrictions up to and including May 2023. Disagreements were resolved through discussion and consultation with a third researcher (J.K.). The following keywords were used: (I) dry needle trigger point; (II) trigger point injection; (III) myofascial pain with trigger point; (IV) lidocaine local anesthesia trigger point injection; (V) lidocaine trigger point injection; (VI) myofascial pain in neck and shoulder; (VII) muscles pain; and (VIII) trigger points in musculoskeletal muscles. These keywords were combined using Boolean operators (OR, AND) to expand the search results. Two authors (Z.A. and M.A.) screened the titles and abstracts of studies identified with the above-mentioned protocol, and full texts of relevant studies were read independently. Hand-searching the reference lists of relevant original studies and review articles was also performed to identify studies that might have been missed in the previous step.

TrPs

TrPs are tender taut bands in skeletal muscles that range from 2 to 5 in diameter and can be palpated using continuous, deep, single fingertip pressure of 2 kg for 6 to 10 seconds (12). The palpation might increase or decrease the pain, and the response may happen immediately or after several seconds (32). Moreover, palpation of TrPs might show as a jump sign or local twitch response (33). The jump sign is a spontaneous reaction that can manifest as a verbal response or withdrawal of the patient’s head (34). In contrast, local twitch response is a rapid, transient muscle contraction elicited by “snapping palpation” of the taut band at the location of the TrP (35). Snapping palpation is performed by grasping the muscle (e.g., upper trapezius, sternocleidomastoid) between the forefinger and thumb and then rolling the muscle under the fingers (12,14,36). There are two types of TrPs, active and latent; usually, TrPs cycle between an active and latent state (11,12). An active TrP is tender to palpation and might cause spontaneous referred pain during regular muscle use (37). While, a latent TrP is more tender than normal muscle tissue but not like an active TrP and does not cause referred pain during normal daily activities but will elicit referred pain symptoms when palpated (11,29). The management of MTrP pain might be achieved by TrP injection (38). There are two types of injections, diagnostic and therapeutic injections (39). Diagnostic injections differentiate between the site and the source of pain. In comparison, therapeutic injection aims to relieve tightness and pain by inactivating the involved muscle’s TrPs (40).

TrP injections are not only effective in the head and neck region but other parts of the body including trunk, shoulder, glutes, and legs (41-43). Piriformis syndrome causes lower back pain and numbness of the lower limbs because of the pressure exerted on the sciatic nerve, abnormalities of the sciatic nerve and piriformis muscle, piriformis muscle injury, hypertrophy, and muscle spasms. Piriformis syndrome has a negative impact on most patients’ daily lives making it difficult walking and the inability to maintain a sitting or supine posture. Different types of treatment methods have been used to treat PS patients, such as local anesthetic injection, steroid injection, and local botulinum toxin injection. Hydro-dissection by ultrasound-guided injection of a very low concentration of local anesthetic is effective and has a lower risk of adverse effects, thus making it more convenient for the treatment of piriformis syndrome than conventional treatments, such as local anesthetics, steroids, and botulinum toxin injection (44).

TrP injections

TrP injections have used throughout the body for managing pain and discomfort. These can include anesthetics, Botox or corticosteroids in some cases. Prior studies do not indicate any technique being superior, but wet needling does provide an immediate and, in some cases, a sustained analgesic effect that can last for a few weeks (45). However, larger sample sized studies are required. Injection techniques are commonly used for muscle pain, particularly MTrP pain, they aim to inactivate TrP and relieve pain and tightness in the affected muscle (46). It includes “dry needling” (no pharmacologic agent used) or injection with a pharmacologic agent such as a local anesthetic (47). Dry needling is performed by repeatedly moving a needle around the TrP to disrupt the fibrous bands mechanically (48). The local anesthetic injection may help reduce muscle pain by disrupting the taut bands of tissue via hydrostatic pressure of the solution and blocking pain input to encourage normal muscle movement (49). The combination of Dry needling and local anesthetic might reduce post-injection soreness (50,51). Therefore, providing a TrP injection with local anesthesia is recommended (52). Previous studies have looked at the effect of needle size on TrP injections and found no differences (53). However, the length of a needle should not need full length insertion. A 21–25-gauge needle is the most often reported for the injections.

The local anesthetic (lidocaine) TrP injection

Lidocaine local anesthesia potentially exhibits pain reduction properties in various painful situations by blocking the voltage-gated sodium channels, resulting in a reversible block of action potential propagation (54). When the local anesthetic is tied up to the sodium channel, the flow of Na⁺ is discontinued, and action potential generation and propagation are inhibited (55). However, there are several contraindications to the injection therapy, such as allergy to the local anesthetic, inflammation of infection in the muscle (myositis), acute muscle injury or trauma, and prolonged bleeding tendency or use of anticoagulant medications (56). A clinical protocol and technique have been elicited in Figures 1,2.

Figure 1 Once the trigger point is located and area sterilized, insert the needle tip superficially and then in depth of the tight muscle band. Aspiration is important to ensure no entry in a blood vessel. Once a small amount of anesthetic is initially deposited, the needle is withdrawn and anesthetic is deposited in a fan like shape with repeated insertions and withdrawals of the needle. Once the procedure is complete, pressure should be applied in the area of insertion. These images are published with the participant’s consent.

Figure 2 The muscle to be injected should be grasped using the pincer or pincher technique. An understanding of the anatomy is important to avoid damage and insertion in unwanted regions. An aspirating syringe using a 25- or 27-gauge needle is suggested. Hemostasis with pressure is important post injection along with thermal compress. These images are published with the participant’s consent.

Dry needling TrP injection

Dry needling is an acupuncture-like needle that penetrates the skin and disrupts the tout bands by repeating the movement of the needle around the TrP in the skeletal muscle (57). Determining the puncture spot relies on manually palpating the muscles’ bellies or digitally using a digital algometer (58). It allows for defining the localization of the TrP and evaluation of the accurate reach of the muscles (59). It has been suggested that dry needling might activate the enkephalinergic inhibitory dorsal horn interneurons through stimulation of alpha-delta nerve fibers, causing opioid-mediated pain suppression (29,60). However, the dry-needling mechanical effect is still being debated. Some studies have suggested that when a localized twitch response is elicited during dry needling, it will show a better result in pain reduction and increase the range of motion (6,61,62). Additionally, in the same study, it has been suggested that the gate control theory of pain may play a role in pain reduction (63).

Decisions about site localizations are based on the anatomy of the muscle. Approaches suggested in the analyzed material include injections as follows:

• Ask the patient to clench, over the most prominent area of the muscle, across 2 cm of skin surface (64).
• Regularly across the muscle mass (65) into the area over the greatest cross-section surface of both masseter bellies (66) along the long axis lower part of the masseter muscle (67,68).

Moreover, most of the analyzed clinical trials described a specific number of injection sites per muscle, although it differed from 2 to 5 for the masseter and from 2 to 3 for the temporalis (69). This discrepancy is due to the difference in volume, mass, and surface of these muscles. Placing a few injection spots, usually about 1 cm apart, also finds its justification. The administered substances could infiltrate the surrounding tissues (70). However, dry needling should not be administered in the following patient scenarios: a patient with needle phobia, an unwilling patient, a patient who is unable or unwilling to give consent, a patient with a history of an abnormal reaction to needling or injection. In a medical emergency, a patient who is on anticoagulant therapy, or who has thrombocytopenia, and into an area or limb with lymphoedema (71).

Wet versus dry needling

Injection techniques are commonly used for muscle pain, particularly MTrP pain, they aim to inactivate TrP and relieve pain and tightness in the affected muscle (46). It includes “dry needling” (no pharmacologic agent used) or injection with a pharmacologic agent such as a local anesthetic (47). Dry needling is performed by repeatedly moving a needle around the TrP to disrupt the fibrous bands mechanically (48). The local anesthetic injection may help reduce muscle pain by disrupting the taut bands of tissue via hydrostatic pressure of the solution and blocking pain input to encourage normal muscle movement (49). The combination of dry needling and local anesthetic might reduce post-injection soreness (50,51). Therefore, providing a TrP injection with local anesthesia is recommended (52). Previous studies have assessed the efficacy of acupuncture/dry needling in the management of TrPs in various body regions (72). Areas studied include the upper quarter, lower back, and lower extremities. Overall results indicate limited evidence that dry needling has an overall effect when compared to standardized care (73). Another meta-analysis (66) that included 4 studies compared the efficacy of dry needling versus sham (placebo), reported no statistical significance between both interventions. However, the results suggested that dry needling had an overall positive treatment effect on TrP pain (66). Moreover, studies conducted by the American Physical Therapy Association reported that the discomfort during and after lidocaine anesthetic injections was found to be significantly low (74). The pain was reported only by 20% of the patients in the injection groups (74). Utilization of the local anesthetic in the TrP injections could be the reason behind the decreased sensation of discomfort reported by the patients (75). This can be explained by the effect of the local anesthetics on the relative refractory period of the peripheral nerves by lengthening it and limiting the impulse conduction’s maximum frequency (56). Additionally, utilizing local anesthetics in TrP injections can lead to a reduction in pain initially, hence increasing the patient’s confidence in the physician as well as their compliance with exercise program post injections (76). Safety is a favorable outcome that is highly relevant when it comes to the application of needling intervention (76). Most studies (77-79) have reported an adverse effect of post-needling soreness after either dry needling or TrP injections. Boyce et al. (80) reported that minor adverse events post dry needling can be seen in up to 37% of the patients, with bleeding (16%), bruising (7.7%), and pain during dry needling (5.9%) being the most frequent (81). Post-needling soreness is due to tissue damage during the insertion of the needle (82). A study by Nowak and Chęciński (59) showed that needling therapies for masticatory muscle pain provide a satisfactory effect in pain reduction.

Conclusions

TrP injections are a minimally invasive and targeted approach that can be used as a diagnostic and therapeutic tool in management of myofascial pain. Both techniques have shown advantages and disadvantages regarding clinical efficacy and post needling soreness. However, regardless of the technique used it is beneficial in immediate and gradual relief of pain. TrP injections with lidocaine do indicate a slight advantage over dry needling due to its immediate analgesic effect but side effects reported are same. Future studies are required to investigate the management and efficacy of TrPs injections.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editor (Mythili Kalladka) for the series “Orofacial Pain: Diagnostic and Therapeutic Topicals, Nerve Blocks and Trigger Point Injection” published in Journal of Oral and Maxillofacial Anesthesia. The article has undergone external peer review.

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://joma.amegroups.com/article/view/10.21037/joma-22-41/rc

Peer Review File: Available at https://joma.amegroups.com/article/view/10.21037/joma-22-41/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://joma.amegroups.com/article/view/10.21037/joma-22-41/coif). The series “Orofacial Pain: Diagnostic and Therapeutic Topicals, Nerve Blocks and Trigger Point Injection” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were performed in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this article and accompanying images.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Kamanli A, Kaya A, Ardicoglu O, et al. Comparison of lidocaine injection, botulinum toxin injection, and dry needling to trigger points in myofascial pain syndrome. Rheumatol Int 2005;25:604-11. [Crossref] [PubMed]
2. Gerwin RD, Dommerholt J, Shah JP. An expansion of Simons' integrated hypothesis of trigger point formation. Curr Pain Headache Rep 2004;8:468-75. [Crossref] [PubMed]
3. Simons DG. Review of enigmatic MTrPs as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol 2004;14:95-107. [Crossref] [PubMed]
4. Jafri MS. Mechanisms of Myofascial Pain. Int Sch Res Notices 2014;2014:523924. [Crossref] [PubMed]
5. Hubbard DR, Berkoff GM. Myofascial trigger points show spontaneous needle EMG activity. Spine (Phila Pa 1976) 1993;18:1803-7. [Crossref] [PubMed]
6. Shah JP, Thaker N, Heimur J, et al. Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective. PM R 2015;7:746-61. [Crossref] [PubMed]
7. Shah JP, Gilliams EA. Uncovering the biochemical milieu of myofascial trigger points using in vivo microdialysis: an application of muscle pain concepts to myofascial pain syndrome. J Bodyw Mov Ther 2008;12:371-84. [Crossref] [PubMed]
8. Minerbi A, Vulfsons S. Challenging the Cinderella Hypothesis: A New Model for the Role of the Motor Unit Recruitment Pattern in the Pathogenesis of Myofascial Pain Syndrome in Postural Muscles. Rambam Maimonides Med J 2018;9:e0021. [Crossref] [PubMed]
9. Kadefors R, Forsman M, Zoéga B, et al. Recruitment of low threshold motor-units in the trapezius muscle in different static arm positions. Ergonomics 1999;42:359-75. [Crossref] [PubMed]
10. Ossipov MH, Dussor GO, Porreca F. Central modulation of pain. J Clin Invest 2010;120:3779-87. [Crossref] [PubMed]
11. Kalladka M, Young A, Khan J. Myofascial pain in temporomandibular disorders: Updates on etiopathogenesis and management. J Bodyw Mov Ther 2021;28:104-13. [Crossref] [PubMed]
12. Gross SG, Pertes RA. Clinical Management of Temporomandibular Disorders and Orofacial Pain. Chicago: Quintessence; 1995:368.
13. Chung MK, Wang S, Yang J, et al. Neural Pathways of Craniofacial Muscle Pain: Implications for Novel Treatments. J Dent Res 2020;99:1004-12. [Crossref] [PubMed]
14. Schiffman E, Ohrbach R, Truelove E, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network* and Orofacial Pain Special Interest Group†. J Oral Facial Pain Headache 2014;28:6-27. [Crossref] [PubMed]
15. Sharav Y, Benoliel R. editors. Orofacial Pain and Headache. 2nd ed. Chicago: Quintessence Pub Co.; 2015.
16. Christidis N, Lindström Ndanshau E, Sandberg A, et al. Prevalence and treatment strategies regarding temporomandibular disorders in children and adolescents-A systematic review. J Oral Rehabil 2019;46:291-301. [Crossref] [PubMed]
17. Roldán-Barraza C, Janko S, Villanueva J, et al. A systematic review and meta-analysis of usual treatment versus psychosocial interventions in the treatment of myofascial temporomandibular disorder pain. J Oral Facial Pain Headache 2014;28:205-22. [Crossref] [PubMed]
18. Yilmaz O, Sivrikaya EC, Taskesen F, et al. Comparison of the Efficacy of Botulinum Toxin, Local Anesthesia, and Platelet-Rich Plasma Injections in Patients With Myofascial Trigger Points in the Masseter Muscle. J Oral Maxillofac Surg 2021;79:88.e1-9. [Crossref] [PubMed]
19. Haviv Y, Rettman A, Aframian D, et al. Myofascial pain: an open study on the pharmacotherapeutic response to stepped treatment with tricyclic antidepressants and gabapentin. J Oral Facial Pain Headache 2015;29:144-51. [Crossref] [PubMed]
20. de Leeuw R, Klasser GD. Orofacial Pain: Guidelines for Assessment, Diagnosis, and Management (AAOP The American Academy of Orofacial Pain). 6th ed. Chicago: Quintessence Publishing Co, Inc; 2018.
21. Nouged E, Dajani J, Ku B, et al. Local Anesthetic Injections for the Short-Term Treatment of Head and Neck Myofascial Pain Syndrome: A Systematic Review with Meta-Analysis. J Oral Facial Pain Headache 2019;33:183-198. [Crossref] [PubMed]
22. Bonica JJ. The Management of Pain. 2nd ed. Philadelphia: Lea & Febiger; 1990.
23. Cheshire WP, Abashian SW, Mann DJ. Botulinum toxin in the treatment of myofascial pain syndrome. Pain 1994;59:65-69. [Crossref] [PubMed]
24. Esenyel M, Caglar N, Aldemir T. Treatment of myofascial pain. Am J Phys Med Rehabil 2000;79:48-52. [Crossref] [PubMed]
25. Flor H, Birbaumer N. Comparison of the efficacy of electromyographic biofeedback, cognitive-behavioral therapy, and conservative medical interventions in the treatment of chronic musculoskeletal pain. J Consult Clin Psychol 1993;61:653-8. [Crossref] [PubMed]
26. Hong CZ. Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response. Am J Phys Med Rehabil 1994;73:256-63. [Crossref] [PubMed]
27. Janzen VD, Scudds R. Sphenopalatine blocks in the treatment of pain in fibromyalgia and myofascial pain syndrome. Laryngoscope 1997;107:1420-2. [Crossref] [PubMed]
28. Scudds RA, Janzen V, Delaney G, et al. The use of topical 4% lidocaine in spheno-palatine ganglion blocks for the treatment of chronic muscle pain syndromes: a randomized, controlled trial. Pain 1995;62:69-77. [Crossref] [PubMed]
29. David Simons JT, Lois Simons. Myofascial Pain and Dysfunction. The Trigger Point Manual. Baltimore: Williams & Wilkins Co.; 1999.
30. G A. Efficacy of Dry Needling Versus Transcutaneous Electrical Nerve Stimulation in Patients With Neck Pain Due to Myofascial Trigger Points: A Randomized Controlled Trial. Cureus 2023;15:e36473. [PubMed]
31. Hoseininejad Z, Kouhzad Mohammadi H, Azadeh H, et al. Comparison of immediate and delayed effects of superficial and deep dry needling in patients with upper trapezius myofascial trigger points. J Bodyw Mov Ther 2023;33:106-11. [Crossref] [PubMed]
32. Money S. Pathophysiology of Trigger Points in Myofascial Pain Syndrome. J Pain Palliat Care Pharmacother 2017;31:158-9. [Crossref] [PubMed]
33. Perreault T, Dunning J, Butts R. The local twitch response during trigger point dry needling: Is it necessary for successful outcomes? J Bodyw Mov Ther 2017;21:940-7. [Crossref] [PubMed]
34. Cao QW, Peng BG, Wang L, et al. Expert consensus on the diagnosis and treatment of myofascial pain syndrome. World J Clin Cases 2021;9:2077-89. [Crossref] [PubMed]
35. Hakim IK, Takamjani IE, Sarrafzadeh J, et al. The effect of dry needling on the active trigger point of upper trapezius muscle: Eliciting local twitch response on long-term clinical outcomes. J Back Musculoskelet Rehabil 2019;32:717-24. [Crossref] [PubMed]
36. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. J Craniomandib Disord 1992;6:301-55. [PubMed]
37. Fitzcharles MA, Cohen SP, Clauw DJ, et al. Chronic primary musculoskeletal pain: a new concept of nonstructural regional pain. Pain Rep 2022;7:e1024. [Crossref] [PubMed]
38. Vulfsons S, Ratmansky M, Kalichman L. Trigger point needling: techniques and outcome. Curr Pain Headache Rep 2012;16:407-12. [Crossref] [PubMed]
39. Al-Moraissi EA, Alradom J, Aladashi O, et al. Needling therapies in the management of myofascial pain of the masticatory muscles: A network meta-analysis of randomised clinical trials. J Oral Rehabil 2020;47:910-22. [Crossref] [PubMed]
40. Arias-Buría JL, Monroy-Acevedo Á, Fernández-de-Las-Peñas C, et al. Effects of dry needling of active trigger points in the scalene muscles in individuals with mechanical neck pain: a randomized clinical trial. Acupunct Med 2020;38:380-7. [Crossref] [PubMed]
41. Lehn C, Chipman C, Augustine S, et al. Trigger Point Injection for Low Back Pain. Am Fam Physician 2023;108:85-6. [PubMed]
42. Khoshnazar SS, Farpour HR, Shahriarirad R. A comparison between effectiveness of gluteal trigger point and epidural steroid injection in lumbosacral canal stenosis patients: a randomized clinical trial. Br J Neurosurg 2023;37:1117-23. [Crossref] [PubMed]
43. Kalladka M, Thondebhavi M, Ananthan S, et al. Myofascial pain with referral from the anterior digastric muscle mimicking a toothache in the mandibular anterior teeth: a case report. Quintessence Int 2020;51:56-62. [PubMed]
44. Kaga M, Ueda T. Effectiveness of Hydro-Dissection of the Piriformis Muscle Plus Low-Dose Local Anesthetic Injection for Piriformis Syndrome: A Report of 2 Cases. Am J Case Rep 2022;23:e935346. [Crossref] [PubMed]
45. Quek SY, Subramanian G, Patel J, et al. Efficacy of regional nerve block in management of myofascial pain of masseteric origin. Cranio 2015;33:285-90. [Crossref] [PubMed]
46. Robbins MS, Kuruvilla D, Blumenfeld A, et al. Trigger point injections for headache disorders: expert consensus methodology and narrative review. Headache 2014;54:1441-59. [Crossref] [PubMed]
47. Mitidieri AMS, Baltazar MCDV, da Silva APM, et al. Ashi Acupuncture Versus Local Anesthetic Trigger Point Injections in the Treatment of Abdominal Myofascial Pain Syndrome: A Randomized Clinical Trial. Pain Physician 2020;23:507-18. [PubMed]
48. Hsieh YL, Kao MJ, Kuan TS, et al. Dry needling to a key myofascial trigger point may reduce the irritability of satellite MTrPs. Am J Phys Med Rehabil 2007;86:397-403. [Crossref] [PubMed]
49. Gupta P, Singh V, Sethi S, et al. A Comparative Study of Trigger Point Therapy with Local Anaesthetic (0.5% Bupivacaine) Versus Combined Trigger Point Injection Therapy and Levosulpiride in the Management of Myofascial Pain Syndrome in the Orofacial Region. J Maxillofac Oral Surg 2016;15:376-83. [Crossref] [PubMed]
50. Simons DG, Travell JG, Simons LS. Myofascial Pain and Dysfunction: The Trigger Point Manual. 3rd ed. Philadelphia, PA: Williams & Wilkins; 2019.
51. Dommerholt J, de las Penas CF. Trigger Point Dry Needling An Evidence and Clinical-Based Approach. 2nd ed. London: Churchill Livingstone Elsevier; 2019.
52. Ashkenazi A, Blumenfeld A, Napchan U, et al. Peripheral nerve blocks and trigger point injections in headache management - a systematic review and suggestions for future research. Headache 2010;50:943-52. [Crossref] [PubMed]
53. Yoon SH, Rah UW, Sheen SS, et al. Comparison of 3 needle sizes for trigger point injection in myofascial pain syndrome of upper- and middle-trapezius muscle: a randomized controlled trial. Arch Phys Med Rehabil 2009;90:1332-9. [Crossref] [PubMed]
54. Taylor A, McLeod G. Basic pharmacology of local anaesthetics. BJA Educ 2020;20:34-41. [Crossref] [PubMed]
55. Becker DE, Reed KL. Essentials of local anesthetic pharmacology. Anesth Prog 2006;53:98-108; quiz 109-10. [Crossref] [PubMed]
56. Cherobin ACFP, Tavares GT. Safety of local anesthetics. An Bras Dermatol 2020;95:82-90. [Crossref] [PubMed]
57. Cagnie B, Dewitte V, Barbe T, et al. Physiologic effects of dry needling. Curr Pain Headache Rep 2013;17:348. [Crossref] [PubMed]
58. Dib-Zakkour J, Flores-Fraile J, Montero-Martin J, et al. Evaluation of the Effectiveness of Dry Needling in the Treatment of Myogenous Temporomandibular Joint Disorders. Medicina (Kaunas) 2022;58:256. [Crossref] [PubMed]
59. Nowak Z, Chęciński M, Nitecka-Buchta A, et al. Intramuscular Injections and Dry Needling within Masticatory Muscles in Management of Myofascial Pain. Systematic Review of Clinical Trials. Int J Environ Res Public Health 2021;18:9552. [Crossref] [PubMed]
60. Gerwin RD. The Taut Band and Other Mysteries of the Trigger Point: An Examination of the Mechanisms Relevant to the Development and Maintenance of the Trigger Point. Journal of Musculoskeletal Pain 2008;16:115-21. [Crossref]
61. Ge HY, Fernández-de-Las-Peñas C, Yue SW. Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation. Chin Med 2011;6:13. [Crossref] [PubMed]
62. Hägg GM. Static work loads and occupational myalgia a new explanation model. 1991.
63. Zhang Y, Ge HY, Yue SW, et al. Attenuated skin blood flow response to nociceptive stimulation of latent myofascial trigger points. Arch Phys Med Rehabil 2009;90:325-32. [Crossref] [PubMed]
64. Yeh SW, Hong CH, Shih MC, et al. Low-Level Laser Therapy for Fibromyalgia: A Systematic Review and Meta-Analysis. Pain Physician 2019;22:241-54. [PubMed]
65. Osborne NJ, Gatt IT. Management of shoulder injuries using dry needling in elite volleyball players. Acupunct Med 2010;28:42-5. [Crossref] [PubMed]
66. Tough EA, White AR, Cummings TM, et al. Acupuncture and dry needling in the management of myofascial trigger point pain: a systematic review and meta-analysis of randomised controlled trials. Eur J Pain 2009;13:3-10. [Crossref] [PubMed]
67. Melzack R, Stillwell DM, Fox EJ. Trigger points and acupuncture points for pain: correlations and implications. Pain 1977;3:3-23. [Crossref] [PubMed]
68. Speed CA. Injection therapies for soft-tissue disorders. Best Pract Res Clin Rheumatol 2003;17:167-81. [Crossref] [PubMed]
69. Gonzalez-Perez LM, Infante-Cossio P, Granados-Nunez M, et al. Deep dry needling of trigger points located in the lateral pterygoid muscle: Efficacy and safety of treatment for management of myofascial pain and temporomandibular dysfunction. Med Oral Patol Oral Cir Bucal 2015;20:e326-33. [Crossref] [PubMed]
70. Lopez-Martos R, Gonzalez-Perez LM, Ruiz-Canela-Mendez P, et al. Randomized, double-blind study comparing percutaneous electrolysis and dry needling for the management of temporomandibular myofascial pain. Med Oral Patol Oral Cir Bucal 2018;23:e454-62. [Crossref] [PubMed]
71. Muñoz M, Dommerholt J, Pérez-Palomares S, et al. Dry Needling and Antithrombotic Drugs. Pain Res Manag 2022;2022:1363477. [Crossref] [PubMed]
72. Navarro-Santana MJ, Sanchez-Infante J, Gómez-Chiguano GF, et al. Dry Needling Versus Trigger Point Injection for Neck Pain Symptoms Associated with Myofascial Trigger Points: A Systematic Review and Meta-Analysis. Pain Med 2022;23:515-25. [Crossref] [PubMed]
73. Smith P, Mosscrop D, Davies S, et al. The efficacy of acupuncture in the treatment of temporomandibular joint myofascial pain: a randomised controlled trial. J Dent 2007;35:259-67. [Crossref] [PubMed]
74. Unverzagt C, Berglund K, Thomas JJ. Dry needling for myofascial trigger point pain: a clinical commentary. Int J Sports Phys Ther 2015;10:402-18. [PubMed]
75. American Physical Therapy Association. Physical Therapists & The Performance of Dry Needling: An Educational Resource Paper. Alexandria, VA, USA: APTA Department of Practice and APTA State Government Affairs; 2012:140.
76. Hammi C, Schroeder JD, Yeung B. Trigger Point Injection. 2024. StatPearls Publishing LLC.; 2022.
77. Martín-Pintado-Zugasti A, Fernández-Carnero J, León-Hernández JV, et al. Postneedling Soreness and Tenderness After Different Dosages of Dry Needling of an Active Myofascial Trigger Point in Patients With Neck Pain: A Randomized Controlled Trial. PM R 2018;10:1311-20. [Crossref] [PubMed]
78. Martín-Pintado-Zugasti A, Mayoral Del Moral O, Gerwin RD, et al. Post-needling soreness after myofascial trigger point dry needling: Current status and future research. J Bodyw Mov Ther 2018;22:941-6. [Crossref] [PubMed]
79. Martín-Pintado-Zugasti A, Rodríguez-Fernández ÁL, Fernandez-Carnero J. Postneedling soreness after deep dry needling of a latent myofascial trigger point in the upper trapezius muscle: Characteristics, sex differences and associated factors. J Back Musculoskelet Rehabil 2016;29:301-8. [Crossref] [PubMed]
80. Boyce D, Wempe H, Campbell C, et al. Adverse events associated with therapeutic dry needling. Int J Sports Phys Ther 2020;15:103-13. [Crossref] [PubMed]
81. DiLorenzo L, Traballesi M, Morelli D, et al. Hemiparetic Shoulder Pain Syndrome Treated with Deep Dry Needling During Early Rehabilitation: A Prospective, Open-Label, Randomized Investigation. Journal of Musculoskeletal Pain 2004;12:25-34. [Crossref]
82. Martín-Pintado-Zugasti A, Pecos-Martin D, Rodríguez-Fernández ÁL, et al. Ischemic Compression After Dry Needling of a Latent Myofascial Trigger Point Reduces Postneedling Soreness Intensity and Duration. PM R 2015;7:1026-34. [Crossref] [PubMed]