Localized myofascial pain responds better than referring myofascial pain to botulinum toxin injections

Does the Use of Botulinum Toxin in Treatment of Myofascial Pain Disorder of the Masseters and Temporalis Muscles Reduce Pain, Improve Function, or Enhance Quality of Life?

BACKGROUND

The efficacy of botulinum toxin for management of myofascial pain disorder (MPD) remains controversial.

PURPOSE

The purpose was to determine if the use of onabotulinumtoxinA (onabotA) in patients with MPD reduces pain, improves function, or enhances quality of life (QoL).

STUDY DESIGN, SETTING, AND SAMPLE

This is a multicenter, prospective, randomized, double-blinded, placebo-controlled clinical trial. Subjects with orofacial pain were screened for MPD as defined by the Diagnostic Criteria for Temporomandibular Disorders.

PREDICTOR VARIABLE

The primary predictor variable was MPD treatment with random assignment to onabotA or placebo (saline).

MAIN OUTCOME VARIABLE

The primary outcome variable was pain before treatment (T0) and at 1 month (T1) using a visual analog scale. Secondary outcome variables included pain at 2 months (T2) and 3 months (T3), maximal incisal opening (MIO), jaw function (jaw functional limitation scale), and QoL (Short Form 36) measured at T0, T1, T2, and T3.

COVARIATES

Covariates included subject demographics, prior treatments, and temporomandibular joint signs/symptoms.

ANALYSES

Descriptive and bivariate statistics included χ2 test, Fisher's exact test, or t-test.

RESULTS

Seventy five subjects with a mean age of 37 (±11) and 35 (±12) years in the onabotA and placebo groups, respectively (P = .6). Females represented 32 (86%) and 29 (76%), respectively (P = .3). Mean visual analog scale pain score in the onabotA group was 58 (±15), 39 (±24), 38 (±23), and 38 (±20) at T0, T1, T2, and T3, respectively; and the placebo group was 54 (±14), 40 (±23), 34 (±20), and 36 (±22) at T0, T1, T2, and T3, respectively. There was no statistically significant difference in pain between groups at any time point (P = .36). There was no statistically significant difference between groups in MIO (P = .124), jaw function (P = .236), or QoL domains (P > .05) at any time point. Within-group improvement in pain was seen in both groups (P < .005). Within-group improvement in jaw function was seen in the onabotA (P = .007) and placebo (P = .005) groups. There was no within-group improvement in MIO or QoL with either group (P > .05).

CONCLUSIONS

OnabotA and saline (placebo) injections both decrease pain and improve jaw function in subjects with MPD.

Diagnosis and Treatment of Myogenous Temporomandibular Disorders: A Clinical Update

Myogenous temporomandibular disorders (M-TMDs) are the most common chronic orofacial pain, affecting the masticatory muscles and, thus, jaw movement. While a concise diagnosis is crucial to formulate a rational treatment plan, the similarities in clinical presentations that M-TMDs share with other neuromuscular disorders affecting the temporomandibular joint (TMJ) could easily confuse physicians. In addition to the basics, such as thorough history taking and meticulous clinical examinations, different imaging techniques are useful adjuncts to facilitate the diagnostic process. This review presents an overview of the current understanding on a variety of diagnostic and treatment modalities for M-TMD patients. It is essential to highlight that there is not a single treatment for all, and the benefits of multidisciplinary strategies have been noted for the effective management of myogenous TMD pain. Treatment modalities ranging from conservative to minimally invasive options are discussed in this review.

Botulinum toxin A in dentistry and orofacial surgery: an evidence-based review - part 1: therapeutic applications

Objective An evidence-based review on the safety and efficacy of botulinum toxin type-A (BoNTA) in orofacial conditions, focusing on the therapeutic applications and role of BoNTA as an adjuvant treatment.Data source and selection Data was collected using PubMed (Medline), Cochrane Library of Systematic Reviews and Cochrane Central Register of Controlled Trials electronic databases. Having satisfied the search parameters, 32 studies for therapeutic applications and 26 for BoNTA as an adjunctive treatment were included. The quality of relevant studies was assessed using the Best Evidence Topics (BETs) Critical Appraisal Tool.Data extraction The highest level of evidence (LOE) behind BoNTA safety and efficacy was for wound healing and scar management in the orofacial surgery context, where BoNTA was presented as an adjunctive modality. Level-I evidence was controversial for temporomandibular disorders and bruxism. However, it showed promising results for painful temporomandibular disorders of myogenic origin refractory to conservative therapies, and to decrease muscle contraction intensity in sleeping bruxism. There was only one level-II study for persistent recurrent aphthous stomatitis. Data showed limited level-III evidence for orofacial pain conditions (temporomandibular joint recurrent dislocation and pain, burning mouth syndrome or atypical odontalgia), oral cancer complications, or as an adjuvant to maxillofacial and orthognathic surgeries. Benefits of BoNTA in prosthodontics had weak level-IV evidence. No evidence was found among the periodontology field.Conclusion There is growing evidence to support the safety and efficacy of BoNTA in the investigated orofacial pathological conditions, with high levels of satisfaction from the patient and clinician perspective. However, there are some inconsistencies and limited high-quality evidence available. Well-designed controlled clinical trials are necessary to evaluate long-term safety, efficacy and cost-effectiveness before BoNTA is widely adopted with irrefutable evidence-based clinical guidelines.

Local myalgia compared to myofascial pain with referral according to the DC/TMD: Axis I and II results

BACKGROUND

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) categorized TMD muscle disorders into 3 subgroups: local myalgia, myofascial pain with spreading and myofascial pain with referral. However, the rationale for such division into subgroups and the pathogenesis and prognosis of muscle-related TMD are still poorly understood. The aim of this study was to explore the differences between local myalgia and myofascial pain with referral by means of a biopsychosocial model based on the DC/TMD.

METHODS

This retrospective study included all consecutive TMD patients who were diagnosed according to the DC/TMD in our institution between 2015 and 2018. The Axis I and II findings of patients diagnosed with local myalgia were compared to those of patients with myofascial pain with referral. A p value < 0.05 was considered statistically significant.

RESULTS

A total of 255 patients (61 men and 194 women, mean age 37.8 ± 15.34 years) were enrolled into the study, 114 in the local myalgia group and 83 in the myofascial pain with referral group. The levels of depression and nonspecific physical symptoms, headache attributed to TMD (HAattrTMD), and characteristic pain intensity (CPI) were significantly higher in the latter group. The significant differences for depression and nonspecific physical symptoms persisted after excluding patients diagnosed with HAattrTMD, however, the levels of significance were lower (p = 0.006 compared to p = 0.033 for depression total score, and p = 0.001 compared to p = 0.046 for nonspecific physical symptoms total score). CPI levels, extent of disability, and pain duration were similar for both groups when excluding for HAattrTMD.

CONCLUSION

The current study findings highlight the importance of differentiating between subgroups of myalgia according to the DC/TMD. The diagnosis of myofascial pain with referral may point to a significant Axis II component.

Temporomandibular Disorder Patients Benefit From Intramuscular Botulinum Toxin Type a Injections

PURPOSE

The aim of this study was to analyze the clinical outcome of the use of botulinum toxin type A (BTX) intramuscular injections to the head and neck, particularly the masticatory muscles of patients with temporomandibular disorder (TMD).

METHODS

The medical records of all patients who had received intramuscular BTX injections between 2005 and 2018 at Päijät-Häme Central Hospital, Lahti, Finland were analyzed retrospectively. Gender, age, previous medical history, number of injections, injection areas, and therapeutic results were collected and analyzed. The outcome was divided into three categories based on the patients' subjective reports: not beneficial, beneficial, and highly beneficial.

RESULTS

A total of 68 patients had received intramuscular BTX injections in our unit for TMD symptoms. Clinical effectiveness could be analyzed from 63 patients. Overall, 87% of them reported favorable outcomes. 8 (13%) reported BTX injections as not beneficial, 15 (24%) as beneficial, and 40 patients (63%) as highly beneficial.Most patients had already received conventional treatment with an occlusal splint (93%) combined with pain medication (60%) in the primary care units before they were referred to our hospital.There were 59 (83%) female patients, and they responded better to BTX therapy than the male patients: 91% versus 57% (P value = 0.04). Average age at the first BTX injection visit was 44.6 years (range 17.8-77.2). Most commonly (65%), BTX was divided bilaterally to the masseter and temporalis muscles.

CONCLUSIONS

BTX injections had good therapeutic outcomes for our TMD patients. However, most patients require multiple injection visits.

Restricted Mouth Opening in Head and Neck Cancer: Etiology, Prevention, and Treatment

Restricted mouth opening or trismus is often encountered in patients with head and neck cancer. The restriction may be the presenting sign of malignancy, a sequela of tumor site or growth, an adverse effect of oncologic treatment, or a first sign of tumoral recurrence. In general, any insult to the temporomandibular joint, masticatory muscles, or their neural innervation may cause limitation in mouth opening. The etiologies leading to trismus are as follows: myospasm secondary to tumor infiltration; reflectory myospasm; radiation-induced myositis and myofibrosis; temporomandibular joint involvement with tumor; unfavorable postsurgical scarring; muscle and joint atrophy secondary to immobilization; pain; jaw fracture and hardware failure; and infection. Preventive measures should be implemented before, during, and after treatment. These measures include identification of high-risk patients, utilization of dose-sculpting radiation techniques whenever possible, performing reconstruction at the same time of resective surgery whenever feasible, and initiating mobilization exercises as early as possible. When trismus develops, treatments are often challenging and disappointing. These include physical therapy, mouth opening appliances, drug therapy, and release surgery. All medical specialties dealing with head and neck cancer should be familiar with the diagnosis and prevention of trismus and make an effort to ensure patients are referred to the appropriate care when needed. Trismus should not be considered a trivial sequela of head and neck cancer.

Effect of botulinum toxin-A on pain and mouth opening following surgical intervention in oral submucous fibrosis - A controlled clinical trial

The purpose of this trial was to study the effect on pain and mouth opening of intramuscular injection of botulinum toxin-A into masticatory muscles following surgical intervention in oral submucous fibrosis (OSMF) cases. Injections of either botulinum toxin A (BTX-A) (study group) or normal saline (control group) were given 2 weeks prior to surgical intervention in OSMF patients, into the bilateral masseter and temporalis muscles. All patients were evaluated for pain and ease of active physiotherapy at 1 week and 1, 3, and 6 months after surgery using a numerical rating scale and appropriate questionnaires, with comparisons made between the study and control group patients. Electromyographic studies of the masticator muscles were also carried out in all patients before injection, and at 1 month and 6 months after injection. 20 OSMF patients were equally divided into study and control groups (n = 10 each). At 1, 3, and 6 months after surgery, the study group patients showed significantly greater decreases in pain (p-values of 0.007, 0.001, and 0.005, respectively) and greater ease in physiotherapy compared with the control group. EMG recordings of masticator muscles showed a transient drop in microvolt value in the study group 1 month after injection, unlike the control group recordings. It was concluded that preoperative BTX-A injection was a good addition to surgical therapy in the patient group.

Treatment and management of myofascial pain syndrome

Myofascial Pain Syndrome (MPS) is a regional pain disorder that affects every age-group and is characterized by the presence of trigger points (TrPs) within muscles or fascia. MPS is typically diagnosed via physical exam, and the general agreement for diagnostic criteria includes the presence of TrPs, pain upon palpation, a referred pain pattern, and a local twitch response. The prevalence of MPS among patients presenting to medical clinics due to pain ranges anywhere from 30 to 93%. This may be due to the lack of clear criteria and guidelines in diagnosing MPS. Despite the prevalence of MPS, its pathophysiology remains incompletely understood. There are many different ways to manage and treat MPS. Some include exercise, TrP injections, medications, and other alternative therapies. More research is needed to form uniformly-accepted diagnostic criteria and treatments.

Use of Botulinum Toxin in Orofacial Clinical Practice

Introduction: Botulinum neurotoxin (BoNT) is a potent biological toxin and powerful therapeutic tool for a growing number of clinical orofacial applications. BoNT relaxes striated muscle by inhibiting acetylcholine’s release from presynaptic nerve terminals, blocking the neuromuscular junction. It also has an antinociceptive effect on sensory nerve endings, where BoNT and acetylcholine are transported axonally to the central nervous system. In dentistry, controlled clinical trials have demonstrated BoNT’s efficiency in pathologies such as bruxism, facial paralysis, temporomandibular joint (TMJ) disorders, neuropathic pain, sialorrhea, dystonia and more. Aim: This study’s aim was to conduct a systematic literature review to assess the most recent high-level clinical evidence for BoNT’s efficacy and for various protocols (the toxin used, dilution, dosage and infiltration sites) used in several orofacial pathologies. Materials and methods: We systematically searched the MedLine database for research papers published from 2014 to 2019 with randomly allocated studies on humans. The search included the following pathologies: bruxism, dislocation of the TMJ, orofacial dystonia, myofascial pain, salivary gland disease, orofacial spasm, facial paralysis, sialorrhea, Frey syndrome and trigeminal neuralgia. Results: We found 228 articles, of which only 20 met the inclusion criteria: bruxism (four articles), orofacial dystonia (two articles), myofascial pain (one article), salivary gland disease (one article), orofacial spasm (two articles), facial paralysis (three articles), sialorrhea (four articles) or trigeminal neuralgia (three articles). Discussion: The clinical trials assessed showed variations in the dosage, application sites and musculature treated. Thus, applying BoNT can reduce symptoms related to motor muscular activity in the studied pathologies efficiently enough to satisfy patients. We did not identify the onset of any important side effects in the literature reviewed. We conclude that treatment with BoNT seems a safe and effective treatment for the reviewed pathologies.

Botulinum toxin type A applications for masticatory myofascial pain and trigeminal neuralgia: what is the evidence regarding adverse effects?

OBJECTIVES

The objective of the study was to conduct a systematic review of literature assessing botulinum toxin type A (BoNT-A) safety and adverse effects in the treatment of myofascial pain (MFP) and trigeminal neuralgia (TN).

MATERIALS AND METHODS

The search for articles by two specific researchers involved the PubMed, EMBASE, Web of Science, and Scopus databases. Specific terms were used, and no publication time and language restrictions were applied. Clinical trials that investigated the effects of BoNT-A among participants with myofascial pain in masticatory muscles or trigeminal neuralgia were considered eligible for this systematic review. Data for each study were extracted and analyzed according to a PICO-like structured reading.

RESULTS

The search strategy provided 436 citations. After analysis, 16 citations were included, seven for MFP and nine for TN. In all studies, BoNT-A was well tolerated and improved pain. The most common adverse effects were temporary regional weakness, tenderness over the injection sites, and minor discomfort during chewing. Most studies reported a spontaneous resolution of adverse effect.

CONCLUSIONS

It can be concluded that BoNT-A treatment is well tolerated, since minor adverse effects were the most frequently reported; however, it is recommended that future studies aim to assess the safety and possible adverse effects of multiples applications or high doses of this treatment.

CLINICAL RELEVANCE

BoNT-A has been increasingly diffused in dentistry, being used for the management of masticatory myofascial pain and trigeminal neuralgia. Nonetheless, there is no consensus about its efficacy and adverse effects that could occur when this treatment is applied.

The use of botulinum toxin-a in the treatment of muscular temporomandibular joint disorders

INTRODUCTION

Botulinum toxin has been used mainly in the treatment of muscular temporomandibular joint disorders (TMD) and hyperactivity of the masticatory muscles. It is used also as a therapeutic option to relieve pain and help in functional recovery from dental, oral and maxillofacial surgery. The aim of our study was to investigate the efficacy of botulinum toxin injection in the treatment of muscular TMD.

MATERIALS AND METHODS

Of the 200 temporomandibular joint patients who applied for treatment, 25 patients with muscular dysfunction of the origin were included in the study. This patient group received drug, drug - physical therapy, occlusal splint therapy and botulinum toxin. These treatments were performed step by step. Botulinum toxin was applied, in accordance with reflex measurement in electromyography guidelines to nine patients whose results were not success from the other treatments had not been successful. Measurements were taken of bite force, pain and mouth openness.

RESULTS

Sixteen patients were treated with drug-physical therapy-occlusal splint therapy, and botulinum toxin treatment was found to be successful in the case of nine patients. No side effects were observed at six months follow-up.

CONCLUSION

Botulinum toxin injection for the treatment of muscular temporomandibular joint disorder is a viable treatment option in the case of patients who do not respond to conservative treatment methods.