Efficacy of botulinum toxin in treating myofascial pain in bruxers: a controlled placebo pilot study

Beyond Beauty: Onobotulinumtoxin A (BOTOX®) and the Management of Migraine Headaches

Based on the conducted anatomic studies at our institutions as well as clinical experience with migraine surgery, we have refined our onobotulinumtoxin A (BOTOX®) injection techniques. Pain management physicians are in unique position to be able to not only treat migraine patient, but also to be able to collaborate with neurologists and peripheral nerve surgeons in identifying the migraine trigger sites prior to surgical deactivation. The constellation of migraine symptoms that aid in identifying the migraine trigger sites, the potential pathophysiology of each trigger site, the effective methods of botulinumtoxin and nerve block injection for diagnostic and treatment purposes, as well as the pitfalls and potential complications, will be addressed and discussed in this paper.

Influence of botulinum toxin on rabbit jaw muscle activity and anatomy

INTRODUCTION

Muscles can adapt their fiber properties to accommodate to new conditions. We investigated the extent to which a decrease in muscle activation can cause an adaptation of fiber properties in synergistic and antagonistic jaw muscles.

METHODS

Three months after the injection of botulinum toxin type A in one masseter (anterior or posterior) muscle changes in fiber type composition and fiber cross-sectional areas in jaw muscles were studied at the microscopic level.

RESULTS

The injected masseter showed a steep increase in myosin type IIX fibers, whereas fast fibers decreased by about 50% in size. Depending on the injection site, both synergistic and antagonistic muscles showed a significant increase in the size of their fast IIA fibers, sometimes combined with an increased number of IIX fibers.

CONCLUSION

Silencing the activity in the masseter not only causes changes in the fibers of the injected muscle but also leads to changes in other jaw muscles.

Botulinum toxin treatment of secondary headaches and cranial neuralgias: a review of evidence

BACKGROUND

Recent scientific data support an effect of botulinum neurotoxin (BoNT) on pain and headache.

OBJECTIVE

We sought to conduct a systematic review of BoNT in the secondary headaches and cranial neuralgias.

METHODS

MEDLINE, EMBASE, Cochrane, ClinicalTrials.gov and reference lists were searched up to December 2010 to identify all relevant publications.

RESULTS

Only two papers were rated as highest evidence (Level 1). The absolute majority (30/38, 79%) of identified publications yield only low evidence (Level 4).

DISCUSSION

No treatment recommendations of Grade A or Grade B can be made based on available research. Grade C treatment recommendations in support of BoNT can be made for chronic headache attributed to whiplash injury, cephalalgic alopecia areata, headache and facial pain in blepharospasm, trigeminal neuralgia, occipital neuralgia and nummular headache. As a result of studies being troublingly inconsistent or inconclusive, only the weakest rank of recommendations (Grade D) can be made for using BoNT in medication overuse headache, cervicogenic headache, headache attributed to craniocervical dystonia, pain in masticatory hyperactivity and headache or facial pain attributed to temporomandibular disorder.

CONCLUSION

At present, BoNT cannot be firmly recommended as an evidence-based treatment in secondary headaches or cranial neuralgias.

Effectiveness of botulinum toxin type A treatment of neck pain related to nocturnal bruxism: a case report

OBJECTIVE

This case report describes a patient with nocturnal bruxism and related neck pain treated with botulinum toxin type A (BTX-A).

CLINICAL FEATURES

The patient was a 27-year-old man with nocturnal bruxism and difficulty in active mouth opening and chewing and neck pain at rest. His numeric pain score was 7 of 10. Surface electromyography of the temporalis and masseter muscles showed typical signs of hyperactivity, characterized by compound muscle action potential amplitude alterations.

INTERVENTION AND OUTCOME

After clinical evaluation, he was treated with BTX-A to reduce masseter and temporalis muscle hyperactivity. After 3 days of treatment with BTX-A, with each masseter muscle injected with a dose of about 40 mouse units with a dilution of 1 mL and with temporal muscle bilaterally injected with 25 mouse units with the same dilution, a decrease in bruxism symptoms was reported. Neck pain also decreased after the first treatment (visual analog scale of 2/10) and then resolved completely. After 4 weeks, electromyography showed the reduction of muscle hyperactivity with a decrease in the amplitude of the motor action potential. The same reduction in signs and symptoms was still present at assessment 3 months posttreatment.

CONCLUSION

These findings suggest that BTX-A may be a therapeutic option for the treatment of bruxism and related disorders.

Myositis ossificans traumatica of the temporalis muscle: a case report and diagnostic considerations

BACKGROUND

The present paper reported the case of a trauma-related myositis ossificans, with focus on considerations for a differential diagnosis process.

CASE REPORT

A 50-year-old male with a severe painful limitation (12 mm) of jaw opening referred a trauma to the right temporomandibular joint (TMJ) area occurring about 40 days before. Posttraumatic TMJ ankylosis was ruled out on the basis of negative magnetic resonance and cone-beam computerized tomography findings, and the patient underwent treatment with arthrocentesis, botulinum toxin injections, and physiotherapy on the basis of two diagnostic hypotheses, viz., an anchored disk phenomenon or a myofibrotic contracture of the right masseter muscle due to prolonged myospasm. After 4 months, jaw opening was slightly increased to 23 mm, but limitation and pain persisted. A new CT was performed to investigate for the emerging clinical picture compatible with traumatic myositis ossificans of the right temporalis muscle. Once the diagnosis was confirmed, the patient underwent surgery for coronoidectomy. At the 6-month follow-up, mouth opening was increased to up to 35 mm and pain was absent.

DISCUSSION

It is fundamental that patients suspected of having uncommon clinical pictures leading to mouth opening restriction are promptly referred to specialized centers, where the differential diagnosis process should be based on a comprehensive assessment taking into account for the potential etiologic factors described in the literature.

Relação entre dor e atividade elétrica na presença de bruxismo

OBJETIVO: mensurar a atividade elétrica dos músculos masseter e temporal, verificar a graduação de dor à palpação e sua correlação com a atividade elétrica em sujeitos com bruxismo. MÉTODO: todos os sujeitos do estudo foram selecionados após avaliação por meio do instrumento Critérios de Diagnóstico em Pesquisa para Desordens Temporomandibulares (RDC/TMD) além de avaliação odontológica e fonoaudiológica. A atividade elétrica dos músculos mastigatórios foi avaliada por meio da eletromiografia de superfície nas situações de repouso, máxima intercuspidação e mastigação habitual ritmada. Para a coleta e análise dos sinais eletromiográficos foram usados os Software BioInspector®, 1.8 (Lynx®), e software AqDAnalysis®. 7.0 (Lynx®), respectivamente, quantificados em RMS (raiz quadrada média) e expressos em µV (microvolts). A análise estatística dos dados foi realizada por meio do Coeficiente de Spearman com significância de p<0,05. RESULTADOS: os resultados mostraram que o padrão eletromiográfico dos músculos estudados apresentou-se próximos aos níveis de normalidade, no repouso, máxima intercuspidação e na mastigação habitual ritmada. A maioria dos sujeitos apresentou queixa de algum tipo de dor, sendo mais evidenciado o grau severo e, principalmente, no músculo masseter. Não evidenciou-se correlação estatisticamente significante entre dor e atividade EMG, uma vez que esta última mostrou-se próxima aos níveis de normalidade. CONCLUSÃO: a análise dos resultados indicou que, apesar da presença da dor nos músculos mastigatórios, a maioria das correlações entre dor e EMG apresentou-se fraca e sem significância estatística, indicando que a dor não interferiu no desempenho da atividade elétrica dos músculos estudados nas situações avaliadas.

Efficacy of botulinum toxin type A for treatment of persistent myofascial TMD pain: a randomized, controlled, double-blind multicenter study

Evidence of an effect by botulinum toxins is still lacking for most pain conditions. In the present randomized, placebo-controlled, crossover multicenter study, the efficacy of botulinum toxin type A (BTX-A) was investigated in patients with persistent myofascial temporomandibular disorders (TMD). Twenty-one patients with myofascial TMD without adequate pain relief after conventional treatment participated. A total of 50 U of BTX-A or isotonic saline (control) was randomly injected into 3 standardized sites of the painful masseter muscles. Follow-up was performed after 1 and 3 months, followed by a 1-month washout period, after which crossover occurred. Pain intensity at rest was the primary outcome measure, while physical and emotional function, global improvement, side effects, and clinical measures were additional outcome measures. There was no main difference between drugs (ANOVA; P=.163), but there was a significant time effect (P<.001), so BTX-A reduced mean (SD) percent change of pain intensity by 30 (33%) after 1 month and by 23 (30%) after 3 months compared to 11 (40%) and 4 (33%) for saline. The number of patients who received a 30% pain reduction was not significantly larger for BTX-A than after saline at any follow-up visit. The number needed to treat was 11 after 1 month and 7 after 3 months. There were no significant changes after treatment in any other outcome measures, with the exception of pain on palpation, which decreased 3 months after saline injection (P<.05). These results do not indicate a clinical relevant effect of BTX-A in patients with persistent myofascial TMD pain.

Bruxismo do sono: possibilidades terapêuticas baseadas em evidências

INTRODUÇÃO: o bruxismo do sono (BS) é uma desordem de movimentos estereotipados e periódicos, associados ao ranger e/ou apertar de dentes durante o sono, decorrentes da contração rítmica dos músculos mastigatórios. Essa condição não é uma doença, porém quando exacerbada pode ocasionar desequilíbrio e alteração das estruturas orofaciais. Dessa forma, surge a necessidade de se obter terapêuticas efetivas e seguras para o controle e o manejo do paciente bruxômano. As alternativas de tratamento variam desde terapêuticas orodentais e farmacológicas até técnicas comportamentais-cognitivas. OBJETIVOS: através de uma revisão sistemática da literatura, tendo como bases de pesquisa a Medline, Cochrane, Embase, Pubmed, Lilacs e BBO, no período compreendido entre 1990 e 2008, e com enfoque em estudos clínicos randomizados e quasi-randomizados, revisões sistemáticas e meta-análises, esse trabalho teve como objetivo analisar e discutir métodos de tratamento para o BS. RESULTADOS: pela análise da literatura verifica-se que existe uma grande quantidade de opções terapêuticas para o BS, porém muitas das terapias não têm suporte científico que as sustente. Assim, a escolha terapêutica deve ser pautada em evidências científicas e no bom senso clínico, objetivando uma melhora na qualidade de vida do paciente bruxômano.

The role of botulinum toxin in management of pain: an evidence-based review

PURPOSE OF REVIEW

In the present review we discuss the role of botulinum neurotoxins (BoNTs) in the management of different pain conditions, with evidence-based data on the toxins' efficacy on pain and its mechanisms.

RECENT FINDINGS

Experimental in-vitro studies have reported promising results of a novel recombinant chimera of BoNT A and E that inhibits the calcitonin gene-related peptide exocytosis from brainstem sensory neurons. Animal studies in neuropathic pain rat models have reported an analgesic effect of BoNT A given after the neuropathic procedure and a bilateral antinociceptive effect to the unilateral noxious stimuli. There is a growing body of evidence that BoNTs are effective in myofascial pain syndrome, neuropathic pain, and joint pain. The pre-existing evidence that BoNTs are ineffective in migraine or other headache disorders has not yet been challenged. In other pain syndromes, studies published in the last review year have not contributed significantly in either demonstrating or invalidating the research that has so far proved inconclusive.

SUMMARY

The role of BoNTs in management of pain is not yet well established. Larger studies in neuropathic pain, joint pain, and myofascial pain syndrome are needed to fully ascertain the role for BoNT therapy in those areas.

The efficacy of botulinum toxin type A in managing chronic musculoskeletal pain: a systematic review and meta analysis

BACKGROUND

Botulinum toxin type A (BoNTA) is a neurotoxin that acts by inhibiting the release of neurotransmitters acetylcholine at neuromuscular junctions, thus reducing muscular contractions. Recent evidence suggests that BoNTA can reduce nociceptive activities of sensory neurons in animal models by inhibiting release of certain neuropeptides. Despite the therapeutic benefit of BoNTA in alleviating painful muscle spasms, its efficacy in other musculoskeletal pain conditions is less clear.

OBJECTIVE

We aim to examine the efficacy of BoNTA in reducing chronic musculoskeletal pain.

METHODS

Studies for inclusion in our report were identified using MEDLINE, EMBASE, PUBMED, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of relevant articles. Studies were considered eligible for inclusion if they were randomized controlled trials (RCTs), evaluating the efficacy of BoNTA injections in pain reduction. All studies were assessed and data were abstracted independently by paired reviewers. The outcome measures were baseline and final pain scores as assessed by the patients. The internal validity of trials was assessed with the Jadad scale. Disagreements were resolved through discussions.

MAIN RESULTS

Twenty-one studies were included in the systematic review and 15 of them were included in the final meta-analysis. There was a total of 706 patients in the meta-analysis, represented from trials of plantar fasciitis (n = 1), tennis elbow (n = 2), shoulder pain (n = 1), whiplash (n = 3), and myofascial pain (n = 8). Overall, there was a small to moderate pain reduction among BoNTA patients when compared to control (SMD = -0.27, 95% CI: -0.44 to -0.11). When the results were analyzed in subgroups, only tennis elbow (SMD = -0.44, 95% CI: -0.86 to -0.01) and plantar fasciitis (SMD = -1.04, 95% CI: -1.68 to -0.40) demonstrated significant pain relief. Although not in the meta-analysis, one back pain study also demonstrated positive results for BoNTA. Lastly, BoNTA was effective when used at ≥ 25 units per anatomical site or after a period ≥ 5 weeks.

CONCLUSION

In our meta-analysis, BoNTA had a small to moderate analgesic effect in chronic musculoskeletal pain conditions. It was particularly effective in plantar fasciitis, tennis elbow, and back pain, but not in whiplash or shoulder pain patients. However, more evidence is required before definitive conclusions can be drawn. On the other hand, there is convincing evidence that BoNTA lacks strong analgesic effects in patients with myofascial pain syndrome. A general dose-dependent and temporal response with BoNTA injections was also observed.

Pathophysiology of TMD pain--basic mechanisms and their implications for pharmacotherapy

This article discusses the pathophysiology of temporomandibular disorders (TMD)-related pain and its treatment with analgesic drugs. Temporomandibular disorders are comprised of a group of conditions that result in temporomandibular joint pain (arthralgia, arthritis) and/or masticatory muscle pain (myofascial TMD). In at least some patients with TMD, a peripheral mechanism contributes to this pain. However, there is often a poor correlation between the severity of TMD-related pain complaints and evidence of definitive tissue pathology. This has led to the concept that pain in some patients with TMD may result from altered central nervous system pain processing and further that this altered pain processing may be attributable to specific genes that are heritable. Psychosocial stressors are also thought to contribute to the development of TMD-related pain, particularly masticatory muscle pain. Finally, substantially more women suffer from TMD than men. Although there are arguably multiple reasons for sex-related differences in the prevalence of TMD, one candidate for the increased occurrence of this disorder in women has been suggested to be the female sex hormone oestrogen. Analgesic drugs are an integral part of the primary treatment for TMD-related pain and dysfunction with more that 90% of treatment recommendations involving use of medications. The most commonly used agents include non-steroidal anti-inflammatory drugs, corticosteroids, muscle relaxants, anxiolytics, opiates and tricyclic antidepressants, however, evidence in support of the effectiveness of these drugs is lacking. Continued research into the pathophysiology of TMD-related pain and the effectiveness of analgesic treatments for this pain is required.

Effect of botulinum toxin injection on nocturnal bruxism: a randomized controlled trial

OBJECTIVE

To evaluate the effect of botulinum toxin type A on nocturnal bruxism.

DESIGN

Twelve subjects reporting nocturnal bruxism were recruited for a double-blind, randomized clinical trial. Six bruxers were injected with botulinum toxin in both masseters, and six with saline. Nocturnal electromyographic activity was recorded in the subject's natural sleeping environment from masseter and temporalis muscles before injection, and 4, 8, and 12 wks after injection and then used to calculate bruxism events. Bruxism symptoms were investigated using questionnaires.

RESULTS

Bruxism events in the masseter muscle decreased significantly in the botulinum toxin injection group (P = 0.027). In the temporalis muscle, bruxism events did not differ between groups or among times. Subjective bruxism symptoms decreased in both groups after injection (P < 0.001).

CONCLUSIONS

Our results suggest that botulinum toxin injection reduced the number of bruxism events, most likely mediated its effect through a decrease in muscle activity rather than the central nervous system. We controlled for placebo effects by randomizing the interventions between groups, obtaining subjective and objective outcome measures, using the temporalis muscle as a control, and collecting data at three postinjection times. Our controlled study supports the use of botulinum toxin injection as an effective treatment for nocturnal bruxism.

The therapeutic use of botulinum toxin in cervical and maxillofacial conditions

DATA SOURCES

Medline, Cochrane Library and bibliographies of identified articles.

STUDY SELECTION

Studies of high methodological quality (systematic reviews or randomised controlled trials; RCT) were selected if considered use of botulinum toxin (BTX) either prophylactically or therapeutically, as an adjunct to dental implant therapy for temporomandibular disorders or for other maxillofacial conditions such as bruxism, masseteric hypertrophy, oromandibular dystonia or cervical dystonia.

DATA EXTRACTION AND SYNTHESIS

Only studies with high levels of evidence were evaluated. Four RCT met the search criteria in the area of cervical dystonia and chronic facial pain.

RESULTS

No RCT were identified that evaluated dental implant therapy along with use of BTX. Four RCT did meet the search criteria in the area of cervical dystonia and chronic facial pain. People who had cervical dystonia exhibited significant improvements in baseline functional, pain and global assessments compared with placebo, whereas individuals with chronic facial pain improved significantly compared with placebo in terms of pain.

CONCLUSIONS

During the period of study, no references were found evaluating use of BTX in dental implantology. Nevertheless, it appears relatively safe and effective in treating cervical dystonia and chronic facial pain associated with masticatory hyperactivity.