Myofascial pain - A major player in musculoskeletal pain.

Myofascial pain is a soft tissue pain syndrome with local and referred musculoskeletal pain arising from trigger points. Myofascial pain and myofascial pain syndromes are among some of the most common acute and chronic pain conditions. Myofascial pain can exist independently of other pain generators or can coexist with or is secondary to other acute and chronic painful musculoskeletal conditions. Myofascial pain is most effectively treated with a multimodal treatment plan including injection therapy (known as trigger point injections, physical therapy, postural or ergonomic correction, and treatment of underlying musculoskeletal pain generators. The objectives of this review are to outline the prevalence of myofascial pain, describe the known pathophysiology of myofascial pain and trigger points, discuss the clinical presentation of myofascial pain, and present evidence-based best practices for pharmacologic, non-pharmacologic, and interventional treatments for myofascial pain.

Efficacy of trigger point injection therapy in noncardiac chest pain: A randomized controlled trial.

Objectives: This study aimed to compare the effects of trigger point injections and stretching exercises in patients with noncardiac chest pain (NCCP) associated with myofascial pain syndrome. Patients and methods: This prospective randomized controlled trial included 50 patients with noncardiac chest pain and trigger points in the pectoralis muscles between October 2019 and June 2020. The patients were randomly assigned to receive trigger point injections into the pectoralis muscles and exercise (n=25; 15 males, 10 females; mean age: 42.8±9.2 years; range, 25 to 57 years) or only perform exercise (n=25; 11 males, 14 females; mean age: 41.8±11.2 years; range, 18 to 60 years). The primary outcome was pain intensity at the first month and three months after the first treatment session, measured using the Visual Analog Scale from 0 to 100. The secondary outcome was the Nottingham Health Profile score. Results: Treatment with stretching exercises and trigger point injection resulted in significant pain reduction compared to stretching exercises alone, and the reduction was persistent at the three-month follow-up (p<0.001). A between-group comparison showed no significant difference in the Nottingham Health Profile (p=0.522). Complications related to the procedure or severe adverse events attributable to treatment were not reported. Conclusion: Trigger point injection combined with stretching exercises is an efficient treatment for noncardiac chest pain related to myofascial pain syndrome compared to exercise treatment alone.

Three Subtypes of Cutaneous Nerve Entrapment Syndrome: A Narrative Review.

Anterior, lateral, and posterior cutaneous nerve entrapment syndromes have been proposed as etiologies of trunk pain. However, while these syndromes are analogous, comprehensive reports contrasting the three subtypes are lacking. We therefore reviewed the literature on anterior, lateral, and posterior cutaneous nerve entrapment syndrome. We searched the PubMed and Cochrane Library databases twice for relevant articles published between March and September 2022. In addition to 16 letters, technical reports, and review articles, a further 62, 6, and 3 articles concerning anterior, lateral, and posterior cutaneous nerve entrapment syndromes, respectively, were included. These syndromes are usually diagnosed based solely on unique history and examination findings; however, the diagnostic process may be prolonged, and multiple re-evaluations are required. The most common first-line treatment is trigger point injection; however, the management of refractory cases remains unclear. Awareness of this disease should be expanded to medical departments other than general medicine.

Trigger Point Injections Versus Medical Management for Acute Myofascial Pain: A Systematic Review and Meta-Analysis.

Myofascial pain is a common problem resulting in musculoskeletal pain characterized by myofascial trigger points. These trigger points can cause substantial discomfort and functional limitations. This meta-analysis aims to assess the effectiveness and safety of trigger point injections versus medical management alone in treating acute onset myofascial pain. A thorough search was conducted across four databases, namely, PubMed, SCOPUS, Web of Science (WOS), and Cochrane Library, to identify randomized controlled trials that compared the effectiveness of trigger point injections versus medical management for the treatment of acute myofascial pain. The search encompassed articles published from the databases' inception until June 2023. The relevant data were extracted and analyzed using the standardized mean difference (SMD) and 95% confidence interval (CI). Of the 1151 records identified, four met the inclusion criteria for the systematic review, and all were included in the meta-analysis. The analysis of four randomized controlled trials (RCTs) showed that trigger point injections were effective in reducing pain scores compared to medical treatment (SMD = -2.09 (95% CI: -3.34 to -0.85, P = 0.001)). The data revealed a negative standardized mean difference, which was significant and consistent in favor of trigger point injections. Overall, these findings highlight the beneficial impact of trigger point injections in reducing acute myofascial pain when compared to isolated medical management.

Intramuscular neural distribution of the obturator internus muscle regarding injective treatment.

INTRODUCTION: The obturator internus muscle is frequently targeted for injective treatments such as botulinum toxin injections in the management of pain syndromes. However, there are controversies over injective method delivering injection to the muscle. METHOD: A method called modified Sihler's method was used to stain the OI muscle in 16 specimens to reveal the intramuscular neural distribution of the muscle. RESULT: The greatest intramuscular neural distribution was located on the 2/10-4/10 of the muscle in the medial edge of the obturator foramen (0/0) to the greater trochanter of the femur (10/10). CONCLUSION: The result suggests that botulinum neurotoxin should be delivered in the intrapelvic portion of the obturator internus muscle. As most of the extrapelvic portion of the obturator muscle is composed of a tendinous portion, it should be considered unsuitable as an injection site by medical professionals.

Intramuscular neural distribution of the teres minor muscle using Sihler's stain: application to botulinum neurotoxin injection.

The aim of this study was to elucidate the intramuscular arborization of the teres minor muslce for effective botulinum neurotoxin injection. Twelve specimens from 6 adult Korean cadavers (3 males and 3 females, age ranging from 66 to 78 years) were used in the study. The reference line between the 2/3 point of the axillary border of the scapula (0/5), where the muscle originates ant the insertion point of the greater tubercle of the humerus (5/5). The most intramuscular neural distribution was located on 1/5-3/5 of the muscle. The tendinous portion was observed in the 3/5-5/5. The result suggests the botulinum neurotoxin should be delivered in the 1/5-3/5 area of the teres minor muscle.

Successful Nerve Block Therapy for Lateral Cutaneous Nerve Entrapment Syndrome (LACNES) Triggered by Exercise.

This report presents a case of a 59-year-old man who experienced pain in the left abdomen during abdominal exercises, which gradually improved. Pain recurred in the same area one year later and gradually worsened, rendering him unable to work. The strongest tender point, with a positive Carnett's sign, was noted on the flank. Ultrasonography revealed a 5 × 10 mm mass shadow in the internal oblique muscle. Trigger point injection at the same site was remarkably effective. Lateral cutaneous nerve entrapment syndrome caused by a crush injury due to abdominal exercises was diagnosed. Nerve block therapy provided effective pain relief.

Ultrasound-Guided Trigger Point Injections for the Treatment of Neck and Back Pain in the Emergency Department: A Randomized Trial.

OBJECTIVES: Patients frequently present to the emergency department (ED) with neck or back pain, which can be difficult to treat. We sought to compare ultrasound-guided trigger point injection (TPI) to standard medications for patients with neck or back pain. METHODS: We performed a single-center, open label, randomized controlled trial on ED patients with neck or back pain from myofascial pain syndrome comparing ultrasound-guided TPIs to those who received the combination of a nonsteroidal anti-inflammatory drug (NSAID) and a muscle relaxant (MR). The primary outcome of this study was the reduction in mean pain score at the time of ED disposition. RESULTS: In total, we analyzed 196 patients. At the time of ED disposition, patients in the TPI group had a mean reduction in their pain scores of 45.0 mm as compared to 49.9 mm in the NSAID plus MR group (difference: 4.9 [95% confidence interval (CI) -3.0 to 12.7], P = .22). At the first reassessment, patients in the TPI group had greater pain reduction by 10.7 mm (95% CI 3.1 to 18.4). The rate of rescue therapy use was higher in the NSAID plus MR group (difference: 17.5% [95% CI 4.4 to 36.2]). CONCLUSIONS: We found no difference in pain reduction at the time of ED disposition between patients randomized to the ultrasound-guided TPI group as compared to those who received an NSAID plus a MR. However, patients in the TPI group had greater pain reduction at the time of first reassessment and lower rates of rescue therapy use.

Importance of quadratus lumborum muscle trigger point injection and prolotherapy technique for lower back and buttock pain.

Background: Low back pain is a heterogeneous disease. Myofascial pain and enthesopathy of the quadratus lumborum muscle are important causes of lower back and/or buttock pain. However, a concrete, safe, and effective injection technique for the treatment of trigger points and enthesopathy in the quadratus lumborum muscle has not yet been developed. Objectives: We aimed to evaluate the importance of the quadratus lumborum muscle and introduce an effective landmark-based blind injection technique for treating quadratus lumborum trigger points and enthesopathy. Methods: Adult patients (n = 17) with lower back and/or buttock pain were placed in the lateral decubitus position. Next, we delicately palpated the quadratus lumborum muscle to accurately locate its lesions, including trigger points, taut bands, and tendon lesions, after five key landmarks had been identified. A newly designed 60-90-mm, 28G thin hypodermic needle was inserted at the tender points. The needle was typically advanced until its tip touched the transverse process to treat myofascial trigger points and tendon lesions in the iliolumbar and lumbocostal fibers, excluding superficial trigger points of the iliocostal fibers. Subsequently, lidocaine (0.5%) or a mixture of lidocaine (0.5%) and dextrose (12.5-15%) was injected. Results: The pretreatment visual analog scale score for all 17 patients decreased from ≥4-8/10 (mean 5.588) to 0-1/10 (mean 0.294) after completion of all treatments. The total number of treatments was one to four in acute and subacute cases and two to eight in chronic cases. The mean follow-up period was 73.5 days (treatment period: range, 4 to 43 days + at least 60 days of follow-up). Conclusions: Herein, we describe for the first time a landmark-based integrated injection technique for the treatment of trigger points and myofascial pain in the quadratus lumborum; this technique is safe, effective, and can be used with or without steroids, fluoroscopy, or ultrasound guidance.

Subacute postoperative myofascial pain diagnosed and treated successfully by ultrasound: a case after laparoscopic hepatectomy.

BACKGROUND: Myofascial pain syndrome is one of the causes of prolonged postoperative pain after abdominal surgery. However, diagnosis and treatment of myofascial pain syndrome, especially its myofascial trigger point (MTrP), have not been well established. CASE PRESENTATION: A 55-year-old man experienced severe subacute abdominal pain after laparoscopic hepatectomy despite aggressive postoperative pain management. He had a positive Carnett's sign, indicating abdominal wall pain, 2 weeks after the surgery. Ultrasonography showed a hyperechoic spot surrounded by a hypoechoic area in the inner abdominal oblique muscle under the palpable spot that fulfills the criteria of MTrP. The echogenic MTrP disappeared after repetitive ultrasound-guided trigger point injections (USG TPIs) with pain relief. CONCLUSIONS: Our present case indicates that diagnosing myofascial pain by visualizing the echogenic MTrPs in the abdominal muscles, and subsequent USG TPIs, might provide an accurate maneuver for diagnosis and treatment of subacute myofascial pain after abdominal surgery.

Guidance to trigger point injection for treating myofascial pain syndrome: Intramuscular neural distribution of the quadratus lumborum.

Postural habits and repetitive motion contribute toward the progress of myofascial pain by affecting overload on specific muscles, the quadratus lumborum (QL) muscle being the most frequently involved. The therapy of myofascial pain syndrome includes the release of myofascial pain syndrome using injective agents such as botulinum neurotoxin, lidocaine, steroids, and normal saline. However, an optimal injection point has not been established for the QL muscle. This study aimed to propose an optimal injection point for this muscle by studying its intramuscular neural distribution using the whole mount staining method. A modified Sihler's procedure was completed on 15 QL muscles to visualize the intramuscular arborization areas in terms of the inferior border of the 12th rib, the transverse processes of L1-L4, and the iliac crest. The intramuscular neural distribution of the QL had the densely arborized areas in the three lateral portions of L3-L4 and L4-L5 and the medial portion between L4 and L5.

Trigger Point Injections.

Myofascial pain and myofascial pain syndromes are among some of the most common acute and chronic pain conditions. Many interventional procedures can be performed in both an acute and chronic pain setting to address myofascial pain syndromes. Trigger point injections can be performed with or without imaging guidance such as fluoroscopy and ultrasound; however, the use of imaging in years past has been recommended to improve patient outcome and safety. Injections can be performed using no injectate (dry needling), or can involve the administration of local anesthetics, botulinum toxin, or corticosteroids.

Evaluation of the efficacy of Superior Cluneal Nerve Block in low back pain: A prospective observational study.

INTRODUCTION: Superior cluneal nerve (SCN) entrapment giving rise to low back pain (LBP) remains undiagnosed many times; in this clinical study authors have evaluated therapeutic role of lidocaine injection of SCN for low back pain relief in patients with SCN entrapment. METHODS: The present study was a prospective, observational study; 25 patients with unilateral LBP over the iliac crest and buttock for more than six months not responding to conservative measures were included in this clinical trial. SCN lidocaine injection was done under fluoroscopy guidance; patients having more than 50% reduction in numeric rating scale (NRS) score, for at least 2 h following SCN injection, were enrolled in the study and followed for 6 months. The primary outcome measure was severity of LBP, measured by NRS score. Secondary outcome measures were percentage pain relief; Oswestry Disability Index (ODI) score, reduction of analgesic usage, DSM-IV score for psychological assessment. All these assessments were done prior to the procedure and at 2 weeks, 1, 3 and 6 months after the procedure. RESULTS: A significant reduction in the NRS scores was observed at 2 weeks, 1, 3 and 6 months after SCN lidocaine injection as compared to the baseline (P value < 0.05); authors also observed a significant pain relief and significantly reduced ODI scores, analgesic consumption and DSM scores compared to the baseline values (P value < 0.05). CONCLUSION: A single SCN lidocaine injection provided significant pain relief in LBP patients with SCN entrapment for a period of 6 months.

Intramuscular Neural Distribution of the Serratus Anterior Muscle: Regarding Botulinum Neurotoxin Injection for Treating Myofascial Pain Syndrome.

The serratus anterior muscle is commonly involved in myofascial pain syndrome and is treated with many different injective methods. Currently, there is no definite injection point for the muscle. This study provides a suggestion for injection points for the serratus anterior muscle considering the intramuscular neural distribution using the whole-mount staining method. A modified Sihler method was applied to the serratus anterior muscles (15 specimens). The intramuscular arborization areas were identified in terms of the anterior (100%), middle (50%), and posterior axillary line (0%), and from the first to the ninth ribs. The intramuscular neural distribution for the serratus anterior muscle had the largest arborization patterns in the fifth to the ninth rib portion of between 50% and 70%, and the first to the fourth rib portion had between 20% and 40%. These intramuscular neural distribution-based injection sites are in relation to the external anatomical line for the frequently injected muscles to facilitate the efficiency of botulinum neurotoxin injections. Lastly, the intramuscular neural distribution of serratus anterior muscle should be considered in order to practice more accurately without the harmful side effects of trigger-point injections and botulinum neurotoxin injections.

Ultrasound-guided 3-in-1 trigger point injection for treating myofascial pain syndrome in muscles of the lateral scapular area: a case report.

BACKGROUND: Myofascial pain syndrome (MPS) is a common cause of musculoskeletal pain. MPS in the muscles of the lateral scapula frequently develops due to poor sitting posture (rounded shoulders and cervical kyphosis) in the office as well as long working hours. Herein, we introduce the use of the trigger point injection (TPI) technique in three muscles (i.e., the deltoid, infraspinatus, and teres major muscles) with the same sonographic view for the purpose of treating MPS in the lateral scapular area. CASE DESCRIPTION: A 48-year-old woman presented to our hospital complaining of dull pain in the right lateral scapular area that had persisted for 4 months. The numeric rating scale (NRS) pain score was 5. After confirming taut bands and tenderness in the muscles of the right lateral scapular area, we diagnosed the patient with MPS within the deltoid, infraspinatus, and teres major muscles. Under ultrasound (US) guidance, a mixed solution of 1 mL of 2% lidocaine and 2 mL of normal saline was injected layer by layer into the three muscles within the same sonographic view. At the 1-month follow-up (F/U) visit, the patient reported only slight initial pain (NRS score, 1). CONCLUSIONS: Thus, we recommend our US-guided 3-in-1 technique for performing TPI to treat MPS in the muscles of the lateral scapular area.

Combined effectiveness of extracorporeal radial shockwave therapy and ultrasound-guided trigger point injection of lidocaine in upper trapezius myofascial pain syndrome.

OBJECTIVE: Myofascial pain syndrome (MPS) is a major musculoskeletal problem and a leading cause of disability worldwide. Extracorporeal shockwave therapy (ESWT) and trigger point injection (TPI) have shown positive results for MPS but no previous study has investigated the combined effects of radial shockwave and trigger point injection of lidocaine for upper trapezius myofascial pain syndrome. METHOD: For this purpose, forty-five participants were randomly divided into shockwave (n = 15), shockwave with ultrasound-guided trigger point injection (combined; n = 15), and control (standard care; n = 15) groups. Participants were assessed at baseline, one week and four weeks by using the visual analog scale, neck disability index, electromyography, infrared thermography, and sonoelastography. RESULTS: Compared with control group, both shockwave and combined groups showed a statistically significant reduction in pain (P<0.01), functional disability (P<0.01), skin temperature (P<0.01), and elastic stiffness, with greater reduction in the combined group (P<0.01) than shockwave group (P<0.05) at four weeks. However, no significant difference was found in electrical activity between the groups (P>0.05). The combined group also showed significant differences in pain (P<0.05) and elastic stiffness (P<0.01) compared with shockwave group at four weeks. CONCLUSION: Our study revealed that extracorporeal radial shockwave therapy combined with trigger point injection of lidocaine was more effective for decreasing pain and elastic stiffness in upper trapezius myofascial pain syndrome at four weeks.

Dry Needling Versus Trigger Point Injection for Neck Pain Symptoms Associated with Myofascial Trigger Points: A Systematic Review and Meta-Analysis.

OBJECTIVE: To examine the effects of dry needling against trigger point (TrP) injections (wet needling) applied to TrPs associated with neck pain. METHODS: Electronic databases were searched for randomized clinical trials in which dry needling was compared with TrP injections (wet needling) applied to neck muscles and in which outcomes on pain or pain-related disability were collected. Secondary outcomes consisted of pressure pain thresholds, cervical mobility, and psychological factors. The Cochrane Risk of Bias tool, the Physiotherapy Evidence Database score, and the Grading of Recommendations Assessment, Development, and Evaluation approach were used. RESULTS: Six trials were included. TrP injection reduced pain intensity (mean difference [MD ] -2.13, 95% confidence interval [CI] -3.22 to -1.03) with a large effect size (standardized mean difference [SMD] -1.46, 95% CI -2.27 to -0.65) as compared with dry needling. No differences between TrP injection and dry needling were found for pain-related disability (MD 0.9, 95% CI -3.09 to 4.89), pressure pain thresholds (MD 25.78 kPa, 95% CI -6.43 to 57.99 kPa), cervical lateral-flexion (MD 2.02°, 95% CI -0.19° to 4.24°), or depression (SMD -0.22, 95% CI -0.85 to 0.41). The risk of bias was low, but the heterogenicity and imprecision of results downgraded the evidence level. CONCLUSION: Low evidence suggests a superior effect of TrP injection (wet needling) for decreasing pain of cervical muscle TrPs in the short term as compared with dry needling. No significant effects on other outcomes (very low-quality evidence) were observed. LEVEL OF EVIDENCE: Therapy, level 1a.

The Immediate Effect of Trigger Point Injection With Local Anesthetic Affects the Subsequent Course of Pain in Myofascial Pain Syndrome in Patients With Incurable Cancer by Setting Expectations as a Mediator.

A trigger point injection (TPI) with local anesthetic in myofascial pain syndrome (MPS) often has the immediate effect of a decrease in pain. It is unknown whether the immediate effect of a decrease in pain affects the subsequent course of pain. It is also unknown whether expectations of a decrease in pain mediate such effects. We aimed to clarify how the effect of a decrease in pain immediately after TPI with local anesthetic affected the subsequent course of pain, and whether it increased expectations of a decrease in pain. This was a prospective, single-center, observational clinical trial. Patients with incurable cancer who visited the palliative care department and received TPI with local anesthetic for MPS were prospectively examined. We evaluated whether the immediate effect of a TPI with local anesthetic affects the subsequent course of pain in MPS by setting expectations as a mediator, using path analysis. From 2018 to 2020, 205 patients with incurable cancer received TPI for MPS. Of these, 58.1% of patients reported an immediate effect of decreased pain. Compared with the non-immediate effect group, the immediate effect group had higher expectations of a decrease in pain, and the higher expectation was maintained at 7 days (p < 0.001). The percentage of patients with pain reduction at 7 days after TPI was 88.2% in the immediate effect group and 39.5% in the non-immediate effect group (p < 0.001). The immediate effect of decreased pain had the greatest influence on pain reduction at 7 days, both directly (ß = 0.194) and indirectly through increased expectations (ß = 0.293), as revealed by path analysis. The effect of a decrease in pain immediately after TPI with local anesthetic affected the subsequent course of MPS pain in patients with incurable cancer by setting expectations as a mediator. There were limitations to the discussion of these findings because this was an observational study.

Bilateral supraclavicular abscesses following trigger point injections.

A 54-year-old-woman presented to the emergency department with worsening bilateral shoulder pain six days after trigger point injections in the bilateral supraclavicular areas for chronic pain. A computed tomography scan of the neck revealed bilateral irregular rim enhancing fluid collections. Image-guided percutaneous drainage resulted in marked improvement and near complete resolution by 17 days post-drainage. This case demonstrates the need for early detection of soft-tissue infection and abscess formation related to interventional pain procedures to avoid potentially life-threatening complications, such as Staphylococcus aureus bacteremia.