Blepharospasm and hemifacial spasm. Randomized trial to determine the most appropriate location for botulinum toxin injections

The effect on blink frequency of a selective blue-filtering photochromic lens in patients with benign essential blepharospasm

Objective

The aim of this clinical study was to assess the impact of a non-invasive selective blue-filtering photochromic lens coating Crizal Prevencia on the treatment and response of benign essential blepharospasm (BEB).

Patients and methods

Twenty-four patients were recruited in the outpatient clinic of the Medical University of Vienna in a randomized, double-blind, cross-over study design. Blink frequencies were assessed in patients with BEB before and 14 days after intervention with either a filtering ophthalmic lens or a placebo lens, respectively. Outcome parameters include sub-group analysis of a blink frequency under six different conditions: three photopic conditions, one resting condition, one reading condition, and one video game condition.

Results

From 24 recruited patients, 15 patients were available for final analysis. Comparing the optical blue filtering lens to placebo, showed a reduced blink frequency in specific subtests, but not compared to baseline.

Discussion

In conclusion, optical filtering glasses might have a beneficial effect on BEB and provide a non-invasive therapeutic add-on option, in addition to botulinum neurotoxin therapy, for patients with BEB and should necessarily be further investigated in a multicenter setting, resulting in larger sample sizes to gain valid information about the effect of photochromic blue filter glasses in BEB.Clinical trial registration: https://drks.de/search/en/trial/DRKS00032135, DRKS00032135.

Botulinum toxin for motor disorders

Botulinum neurotoxins are a group of biological toxins produced by the gram-negative bacteria Clostridium botulinum. After intramuscular injection, they produce dose-related muscle relaxation, which has proven useful in the treatment of a large number of motor and movement disorders. In this chapter, we discuss the utility of botulinum toxin treatment in three major and common medical conditions related to the dysfunction of the motor system, namely dystonia, tremor, and spasticity. A summary of the existing literature is provided along with different techniques of injection including those recommended by the authors.

Therapeutic Approach to Botulinum Injections for Hemifacial Spasm, Synkinesis and Blepharospasm

The aim of this study was to show our therapeutic outcome of botulinum injection to the facial muscles and thereby to find the best therapeutic concept which should be embraced. The decision to treat the lower eyelid with 1-point or 2-points injection was randomly taken as there is no consensus regarding this debate. Injections of the lateral end of the upper eyelid were performed more laterally to the conventional injection point, just lateral to the conjunction of the upper and lower eyelids. Twenty-three patients (12 hemifacial spasm, 6 blepharospasm, 5 post facial palsy synkinesis) were enrolled. Data were retrieved from 112 visits between 2019 and 2022. Overall, 84.9% of the treatments had moderate or marked improvement. The most common side effect was facial weakness (11.8%). Neither ptosis nor diplopia were noted. Two-points regimen in the lower eyelid was associated with a lower risk of facial weakness (p = 0.01), compared to 1-point regimen, with a better therapeutic outcome as reflected by more favorable PGI-C scores (p = 0.04). Injection of the pretarsal segment of the upper eyelid, just onto or even lateral to the conjunction of the upper and lower eyelids, lowers the risk of ptosis.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson’s disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Iatrogenic corneal diseases or conditions

Any prescribed or self-administered therapy carries inherent risks of secondary adverse events. While the volume of treatments being administered through healthcare systems has been increasing, scientific advancements in our understanding of the mechanisms of pharmaceutical side effects and complications from procedures now allow us to reduce the risk of non-intentional damage to ocular health. This review summarizes the most common and leading causes of iatrogenic visual impairment, corneal diseases, and conditions that present in a general ophthalmologic practice, including a comprehensive analysis of their pathophysiology and recommendations for management and prophylaxis.Iatrogenic corneal diseases and conditions can arise from topical drugs, contact lens use, eye surgeries and procedures, systemic drugs, non-ophthalmological events, and cosmetic procedures. Topical and systemic drugs may disturb tear film homeostasis or result in ocular surface deposits. The use of ill-fitted contact lenses can trigger eye discomfort and poor hygiene conditions that can predispose to severe infections. Procedures to the eye may result in a variety of anatomical and functional complications that ophthalmologists should be aware of how to avoid or at least be prepared to manage if they occur. Even non-ophthalmological events such as non-invasive ventilation, radiation therapies and, immune-based conditions, or cosmetic procedures such as eyelash growth and fillers, can result in unwanted damage to the ocular surface.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Blepharospasm is the second most common form of focal dystonia. It is a disabling disorder, characterised by chronic, intermittent or persistent, involuntary eyelid closure, due to spasmodic contractions of the orbicularis oculi muscles. Currently, botulinum toxin type A (BtA) is considered the first line of therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with blepharospasm.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of included articles, and conference proceedings. We ran all elements of the search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with blepharospasm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We did not carry out any prespecified subgroup analyses. The primary efficacy outcome was improvement on any validated symptomatic rating scale. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included three RCTs, assessed at low to moderate overall risk of bias, which randomised 313 participants with blepharospasm. Two studies excluded participants with poorer prior responses to BtA treatment, therefore, they included an enriched population with a higher probability of benefiting from this therapy. All trials were industry-funded. All RCTs evaluated the effect of a single BtA treatment session. BtA resulted in a moderate to large improvement in blepharospasm-specific severity, with a reduction of 0.93 points on the Jankovic Rating Scale (JRS) severity subscale at four to six weeks after injection (95% confidence interval (CI) 0.61 to 1.25; I² = 9%) compared to placebo. BtA was also resulted in a moderate to large improvement in blepharospasm-specific disability and blepharospasm-specific involuntary movements at four to six weeks after injection (disability: 0.69 JRS disability subscale points, 95% CI 0.18 to 1.19; I² = 74%; blepharospasm-specific involuntary movements: standardised mean difference (SMD) 0.79, 0.31 to 1.27; I² = 58%) compared to placebo. BtA did not show a risk of adverse events (risk ratio (RR) 1.18, 95% CI 0.87 to 1.60; I² = 0%). However, BtA increased the risk of vision complaints and eyelid ptosis (vision complaints: RR 5.73, 95% CI 1.79 to 18.36; I² = 51%; eyelid ptosis: RR 4.02, 95% CI 1.61 to 10.00; I² = 39%). There was no distinction between BtA and placebo in the number of participants who dropped out of the trial. A single trial estimated the duration of effects to be 10.6 weeks (range 6.1 to 19.1). We found no evidence supporting the existence of a clear dose-response relationship with BtA. We found no data reporting the impact of BtA on health-related quality of life, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain that a single BtA treatment resulted in a clinically relevant reduction of blepharospasm-specific severity and disability, and have low certainty that it is well tolerated, when compared with placebo. There is low-certainty evidence that people treated with BtA are not at an increased risk of developing adverse events, though BtA treatment likely increases the risk of visual complaints and eyelid ptosis. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, or the impact on quality of life.

Botulinum toxin type A therapy for hemifacial spasm

BACKGROUND

This is an update of a Cochrane Review, first published in 2005. Hemifacial spasm (HFS) is characterised by unilateral, involuntary contractions of the muscles innervated by the facial nerve. It is a chronic disorder, and spontaneous recovery is very rare. The two treatments routinely available are microvascular decompression and intramuscular injections with botulinum toxin type A (BtA).

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with HFS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, reference lists of articles, and conference proceedings in July 2020. We ran the electronic database search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with HFS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records. We planned to select included studies, extract data using a paper pro forma, and evaluate the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We planned to perform meta-analyses. The primary efficacy outcome was HFS-specific improvement. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We found no parallel-group randomised controlled trials comparing BtA and placebo in HFS.

AUTHORS' CONCLUSIONS

We did not find any randomised trials that evaluated the efficacy and safety of botulinum toxin type A in people with hemifacial spasm, so we are unable to draw any conclusions. Observational data show a strong association between BtA treatment and symptom improvement, and a favourable safety profile. While it is unlikely that future placebo-controlled RCTs will evaluate absolute efficacy and safety, they should address relevant questions for both people with HFS (such as long-term effects, quality of life, and other patient-reported outcomes), and clinicians (such as relative effectiveness of different BtA formulations and schemes of treatment) to better guide clinical practice.).

Botulinum toxin for benign essential blepharospasm: A systematic review and an algorithmic approach

BACKGROUND

Currently, there is no standardised approach for benign essential blepharospasm treatment with botulinum toxin, and controversies still exist regarding this subject.

OBJECTIVE

The objective of this systematic review is to summarise and compare all the published data regarding benign essential blepharospasm treatment with botulinum toxin.

METHODS

On October 3, 2018, an online search of the Medline database was conducted. All articles with a detailed description of their botulinum toxin injection technique for benign essential blepharospasm were included in this review.

RESULTS

Five studies were selected for inclusion with a total of 854 patients. Four of the included studies used onabotulinumtoxin A and one study used abobotulinumtoxin A. All studies injected the pretarsal orbicularis occuli muscle. The preseptal orbicularis occuli was injected in four studies, and the preorbital muscle in three studies. The most commonly used method of evaluation was the Jankovic Rating Scale. Adverse events were transient, and dose related. Ptosis was more frequently encountered with the preseptal orbicularis injections.

CONCLUSION

Botulinum toxin injection for benign essential blepharospasm is a non-invasive and safe procedure. The pretarsal muscle should be considered as the key component when treating benign essential blepharospasm with botulinum toxin. We developed an algorithmic approach to the treatment of benign essential blepharospasm with botulinum toxin. However, further randomised controlled trials are warranted.

Chemodenervation for the Treatment of Facial Dystonia: A Report by the American Academy of Ophthalmology

PURPOSE

To review the medical literature on the outcomes and complications of various Food and Drug Administration-approved botulinum toxins for benign essential blepharospasm (BEB) and hemifacial spasm (HFS).

METHODS

Literature searches were last conducted in February 2017 in PubMed for articles published in English and in the Cochrane Library database without language limitations; studies published before 2000 were excluded. The combined searches yielded 127 citations. Of these, 13 articles were deemed appropriate for inclusion in this assessment, and the panel methodologist assigned ratings to them according to the level of evidence.

RESULTS

A combined total of 1523 patients (1143 with BEB and 380 with HFS) were included in the 13 studies. Five studies provided level I evidence, 2 studies provided level II evidence, and 6 studies provided level III evidence. Pretarsal injections were more efficacious than preseptal injections (96% vs. 86%, respectively). Pretarsal injections also resulted in a higher response rate on clinical scales (P < 0.05) and a longer duration of maximum response for both HFS and BEB. Patients with HFS require lower overall doses of onabotulinumtoxinA than patients with BEB for a similar duration of effect. Adverse events were dose related, and they occurred more frequently in patients who were given more units.

CONCLUSIONS

Level I evidence supports the efficacy of Botox (Allergan Corp., Irvine, CA), Meditoxin, and Xeomin (Merz Pharmaceuticals, Frankfurt am Main, Germany) for the treatment of BEB. Meditoxin and Botox have equivalent effectiveness and incidence of adverse events for BEB and HFS. Dysport (Ipsen Biopharmaceuticals, Inc, Paris, France) seems to have efficacy similar to Botox and Meditoxin for BEB and HFS, but any definitive conclusions from the 2 level II studies in this review are limited by differences in the methodologies used. Higher doses of Botox and Dysport result in more adverse events. Repeated treatments using Botox seem to maintain efficacy for treatment of facial dystonias over a follow-up period of at least 10 years, based on level III evidence.

TFOS DEWS II iatrogenic report

Dry eye can be caused by a variety of iatrogenic interventions. The increasing number of patients looking for eye care or cosmetic procedures involving the eyes, together with a better understanding of the pathophysiological mechanisms of dry eye disease (DED), have led to the need for a specific report about iatrogenic dry eye within the TFOS DEWS II. Topical medications can cause DED due to their allergic, toxic and immuno-inflammatory effects on the ocular surface. Preservatives, such as benzalkonium chloride, may further aggravate DED. A variety of systemic drugs can also induce DED secondary to multiple mechanisms. Moreover, the use of contact lens induces or is associated with DED. However, one of the most emblematic situations is DED caused by surgical procedures such as corneal refractive surgery as in laser-assisted in situ keratomileusis (LASIK) and keratoplasty due to mechanisms intrinsic to the procedure (i.e. corneal nerve cutting) or even by the use of postoperative topical drugs. Cataract surgery, lid surgeries, botulinum toxin application and cosmetic procedures are also considered risk factors to iatrogenic DED, which can cause patient dissatisfaction, visual disturbance and poor surgical outcomes. This report also presents future directions to address iatrogenic DED, including the need for more in-depth epidemiological studies about the risk factors, development of less toxic medications and preservatives, as well as new techniques for less invasive eye surgeries. Novel research into detection of early dry eye prior to surgeries, efforts to establish appropriate therapeutics and a greater attempt to regulate and oversee medications, preservatives and procedures should be considered.

Comparison of Two Botulinum Neurotoxin A Injection Patterns with or without the Medial Lower Eyelid in the Treatment of Blepharospasm

The aim of this study was to evaluate the efficacy of two botulinum toxin A (BoNT-A) injection patterns with or without the medial lower eyelid (MLE) in treating benign essential blepharospasm (BEB) and influencing lacrimal drainage. Two different injection patterns of BoNT-A were randomly applied to 98 eyes of 49 BEB patients: MLE Group received a full injection pattern of 5 sites and non-MLE Group received a MLE waived injection pattern of 4 sites. Tear breakup time (BUT), Schirmer I test, lagophthalmos height, and lower lid tear meniscus height (TMH) were measured and Jankovic Rating Scale (JRS) was surveyed before injection and at 1 week, 1 month, and 3 months after injection. The symptom of BEB was relieved in both groups as suggested by JRS scores at all time points after injection, and MLE Group came up with a better JRS score at 3 months. The increases of Schirmer I test value and TMH in MLE Group were higher than those in non-MLE Group at 1 week after injection. This study shows that the MLE-involved full injection pattern is a better choice for patients with BEB. It has longer-lasting effects in relieving BEB symptoms and better efficacy in reducing lacrimal drainage. Clinical Trials registration number is NCT02327728.

Botulinum toxin injections for the treatment of hemifacial spasm over 16 years

The aim of this study was to investigate the efficacy and side effects of botulinum toxin (BTX) in the treatment of hemifacial spasm (HFS). We also focused on the divergence between different injection techniques and commercial forms. We retrospectively evaluated 470 sessions of BTX injections administered to 68 patients with HFS. The initial time of improvement, duration and degree of improvement, and frequency and duration of adverse effects were analysed. Pretarsal and preseptal injections and Botox (Allergan, Irvine, CA, USA) and Dysport (Ipsen Biopharmaceuticals, Paris, France) brands were compared in terms of efficacy and side effects, accompanied by a review of papers which reported BTX treatment of HFS. An average of 34.5 units was used per patient. The first improvement was felt after 8 days and lasted for 14.8 weeks. Patients experienced a 73.7% improvement. In 79.7% of injections, no adverse effect was reported, in 4.9% erythema, ecchymosis, and swelling in the injection area, in 3.6% facial asymmetry, in 3.4% ptosis, in 3.2% diplopia, and in 2.3% difficulty of eye closure was detected. Patients reported 75% improvement on average after 314 sessions of pretarsal injections and 72.7% improvement after 156 sessions of preseptal injections (p=0.001). The efficacy and side effects of Botox and Dysport were similar. BTX is an effective and safe treatment option for HFS. No difference was determined between Botox and Dysport, and pretarsal injection is better than preseptal injection regarding the reported degree of improvement.

Efficacy of botulinum toxin in benign essential Blepharospasm: Desirable & undesirable effects

Objective: To study the efficacy, desirable and undesirable effects of locally injectable preparation of botulinum toxin in patients suffering from Benign Essential Blepharospasm (BEB).

Methods: It was a prospective study carried out from October 2006 till November 2012 at a private set up, “Dr Shakaib’s Eye Clinic”, in Islamabad. Follow up of Seventeen patients of BEB has been done over six years period after injecting botulinum toxin. The patients had been explained about the study and informed consent was taken. After taking all the standard precautions for botulinum toxin injection, 5 to 7 (mean 6) sites for injecting 1.5 to 2.0 IU of the toxin were selected depending upon the severity and duration of the problem. These patients were requested to attend the clinic regularly, initially after three days and then weekly for two weeks, followed by every month for three months and then at three monthly intervals for up to six years.

Results: The useful effects of the injection appeared in all the patients within 48 hours. There were minor side effects like irritation in the eyes and heaviness in the brow region. One (5.88 %) patient developed mild ptosis, which subsided over two weeks. Four (23.52 %) patients felt almost cured after three to four repetitions of injections. The useful effect of the injection lasted for about three months in all the patients.

Conclusion: Botulinum toxin is a useful remedy for Benign Essential Blepharospasm (BEB), although the effects are short term and repeated applications are required which is quite costly for the patient.

Difficulties with differentiating botulinum toxin treatment effects in essential blepharospasm

Blepharospasm is a focal dystonia in which the extraocular muscles contract repetitively, leading to excessive blinking and forced eyelid closure. Botulinum toxin type A (BoNTA) is the primary symptomatic treatment for blepharospasm and its effects have been evaluated using numerous rating scales. The main scales in use today were initially used to determine whether BoNTA treatment was superior to placebo, and most controlled trials have confirmed this. More recently, these scales have been used to determine whether there are efficacy differences between different BoNTs in blepharospasm. However, although the scales used in these trials are able to differentiate the effects of BoNT from placebo, they may not be sensitive enough to differentiate between BoNTs. Most of the scales include only four possible points for each item, which would necessitate a 25% greater improvement in one group than the other to detect any differences. Current scales are also relatively insensitive to patients with mild disability who may experience mainly psychosocial problems related to their blepharospasm. Clinical trials comparing BoNTs that include substantial numbers of mildly affected patients may be unlikely to find differences because the scales do not adequately measure mild symptoms. Additional challenges with evaluating blepharospasm include the lack of precision and objectivity of current measures, symptom variability, the need to evaluate aspects of the disorder that are most important to patients, and the different types of blepharospasm. Although no single scale may be able to capture all relevant aspects of blepharospasm, more sensitive and patient-centered scales are needed.

Efficacy and safety of purified botulinum toxin type A (Dysport) for the treatment of benign essential blepharospasm: a randomized, placebo-controlled, phase II trial

The majority of studies on the effects of botulinum toxin in blepharospasm patients have been small or unblinded. Our large-scale, multicenter, randomized clinical trial on the efficacy and safety of botulinum toxin (Dysport; 40, 80, and 120 units/eye) versus placebo in bilateral benign essential blepharospasm (BEB) supported the high efficacy and good safety profile of Dysport, with improvement in functional impairment, reduced frequency and intensity of facial spasms, and fewer withdrawals through lack of efficacy in the active treatment group compared with controls. The best balance of sustained efficacy and favorable safety profile was provided by 80 units of Dysport/eye in this study.

Efficacy of Botulinum Toxin Type A After Topical Anesthesia

PURPOSE

To determine whether the use of topical anesthesia has an impact on botulinum toxin type A (BTX-A) efficacy.

METHODS

Forty patients (20 receiving BTX-A for facial cosmetic rhytid reduction and 20 for benign essential blepharospasm) were evaluated in a double-blind, randomized, triple-crossover study at 2.5- to 4.5-month intervals. The discomfort and efficacy of BTX-A injections after betacaine application to half the face (random assignment) were compared against the discomfort and efficacy of a placebo ointment on the other half of the face. This was followed by cryoanalgesia to the entire face.

RESULTS

Patients ranged from 27 to 81 years of age (mean, 53 years), and 34 were female. Of the 120 total injection comparisons, a better BTX-A effect on one side of the face was reliably identified by 80% and 77% of blepharospasm and cosmetic patients, respectively, with the placebo-treated side providing better BTX-A effect approximately 90% of the time (p < 0.001). Patients reported a more painful side during injection in just 18 of the 120 trials, and only 1 of 40 patients believed the administration of analgesia was worth the trouble.

CONCLUSIONS

Pretreatment with topical betacaine followed by skin cooling seems to have a deleterious impact on BTX-A effect without a significantly beneficial patient-perceived reduction in injection discomfort.

Treatment of dystonia

Dystonia may be a sign or symptom, that is comprised of complex abnormal and dynamic movements of different etiologies. A specific cause is identified in approximately 28% of patients, which only occasionally results in specific treatment. In most cases, treatment is symptomatic and designed to relieve involuntary movements, improve posture and function and reduce associated pain. Therapeutic options are dictated by clinical assessment of the topography of dystonia, severity of abnormal movements, functional impairment and progression of disease and consists of pharmacological, surgical and supportive approaches. Several advances have been made in treatment with newer medications, availability of different forms of botulinum toxin and globus pallidus deep brain stimulation (DBS). For patients with childhood-onset dystonia, the majority of whom later develop generalized dystonia, oral medication is the mainstay of therapy. Recently, DBS has emerged as an effective alternative therapy. Botulinum toxin is usually the treatment of choice for those with adult-onset primary dystonia in which dystonia usually remains focal. In patients with secondary dystonia, treatment is challenging and efficacy is typically incomplete and partially limited by side effects. Despite these treatment options, many patients with dystonia experience only partial benefit and continue to suffer significant disability. Therefore, more research is needed to better understand the underlying cause and pathophysiology of dystonia and to explore newer medications and surgical techniques for its treatment.

Botulinum toxin therapy of hemifacial spasm: comparing different therapeutic preparations

Hemifacial spasm (HFS) is characterized by involuntary irregular clonic or tonic movements of the muscles innervated by cranial nerve VII on one side of the face, and is most often a result of vascular compression of the facial nerve at the root exit zone (Muscle and Nerve 1998;21:1740). Disability associated with this disorder ranges from social embarrassment to interference with vision resulting from involuntary eye closure. Treatment of HFS most often involves botulinum toxin injections, but may also include medications and surgery. We describe treatment with the three types of botulinum toxin currently commercially available--Botox, Dysport and Myobloc/NeuroBloc.

Botulinum toxin in blepharospasm and oromandibular dystonia: comparing different botulinum toxin preparations

Amongst all regions of the body, the craniocervical region is the one most frequently affected by dystonia. Whilst blepharospasm--involuntary bilateral eye closure--is produced by spasmodic contractions of the orbicularis oculi muscles, oromandibular dystonia may cause jaw closure with trismus and bruxism, or involuntary jaw opening or deviation, interfering with speaking and chewing. Both forms of dystonia can be effectively treated with botulinum toxin injection. This article summarizes injection techniques in both forms of dystonia and compares doses, potency and efficacy of different commercially available toxins, including Botox, Dysport, Xeomin and Myobloc/NeuroBloc.

Botulinum toxin type A therapy for hemifacial spasm

BACKGROUND

Hemifacial spasm is characterised by unilateral involuntary contractions of muscles innervated by the facial nerve. The usual cause is a vessel touching the facial nerve near its origin from the brain stem. Although it is a benign condition it can cause significant cosmetic and functional disability. It is a chronic disease and spontaneous recovery is very rare. The two treatments routinely available are microvascular decompression and Botulinum Toxin type A (BtA) muscular injections.

OBJECTIVES

To determine whether botulinum toxin (BtA) is an effective and safe treatment for hemifacial spasm.

SEARCH STRATEGY

We searched the Cochrane Movement Disorders Group trials register, the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2004), MEDLINE (1977 to December 2003), EMBASE (1977 to December 2003), and reference lists of articles. We also contacted drug manufacturers and researchers in the field.

SELECTION CRITERIA

Randomised studies comparing BtA with placebo in people with hemifacial spasm.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

We found only one small randomised, placebo-controlled trial involving 11 people. It was a crossover trial during which patients underwent four sets of injections, comparing placebo with three different doses of BtA - formulation Botox(r) (low dose: one-half of the intermediate dose; intermediate dose; and high dose: twice the intermediate dose), and one of placebo. In this trial BtA was superior to placebo.

AUTHORS' CONCLUSIONS

The findings of this single eligible trial support the results of large, open, case-control studies showing a benefit rate between 76 and 100%. This effect size probably makes it very difficult to perform new large placebo controlled trials for hemifacial spasm. Despite the paucity of good quality controlled data, all the studies available suggest that BtA is effective and safe for treating hemifacial spasm. Future trials should explore technical factors such as the optimum treatment intervals, different injection techniques, doses, Bt types and formulations. Other issues include service delivery, quality of life, long-term efficacy, safety, and immunogenicity. BtA should be compared with surgical microvascular decompression.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

Blepharospasm is a focal dystonia characterized by chronic intermittent or persistent involuntary eyelid closure due to spasmodic contractions of the orbicularis oculi muscles. Other facial and neck muscles are also frequently involved. Most cases are idiopathic and blepharospasm is generally a life-long disorder. Its severity can range from repeated frequent blinking to persistent forceful closure of the eyelids with functional blindness. Botulinum toxin type A (BtA) is the current first line therapy.

OBJECTIVES

To determine whether botulinum toxin (BtA) is an effective and safe treatment for blepharospasm.

SEARCH STRATEGY

We identified studies for inclusion in the review using the Cochrane Movement Disorders Group trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, handsearches of the Movement Disorders Journal and abstracts of international congresses on movement disorders and botulinum toxin, communication with other researchers in the field, reference lists of papers found using above search strategies, and contact with authors and drug manufacturers.

SELECTION CRITERIA

Studies were eligible for inclusion in the review if they evaluated the efficacy of BtA for the treatment of blepharospasm. They must have been randomised and placebo-controlled.

DATA COLLECTION AND ANALYSIS

We used a paper pro-forma to collect data from the included studies using double extraction by two independent reviewers. The two reviewers separately assessed each trial for internal validity and they settled differences between them by discussion. The outcome measures used included adverse events, improvement in symptomatic rating scales, subjective evaluation by patients and clinicians, and changes in quality of life assessments.

MAIN RESULTS

We found few controlled trials. They were of short duration and enrolled small numbers of patients. Because of their poor internal validity, the characteristics of the populations studied, and the types of interventions and outcomes, none of the trials fitted our criteria for inclusion. However, all these trials found BtA to be superior to placebo as did large case-control and cohort studies, which reported that around 90% of patients benefited.

AUTHORS' CONCLUSIONS

There are no high quality, randomised, controlled efficacy data to support the use of Bt for blepharospasm. Despite this, other studies suggest that BtA is highly effective and safe for treating blepharospasm and support its use. The effect size (90% of patients benefit) seen in open studies makes it very difficult and probably unethical to perform new placebo-controlled trials of efficacy of BtA for blepharospasm. Future trials should explore technical factors such as the optimum treatment intervals, different injection techniques, doses, Bt types and formulations. Other issues include service delivery, quality of life, long-term efficacy, safety, and immunogenicity.

Botulinum toxin type A in the management of masseter muscle hypertrophy

PURPOSE

We sought to evaluate the response of 6 patients with masseter muscle hypertrophy to botulinum toxin type A therapy.

PATIENTS AND METHODS

Six patients with unilateral or bilateral masseter muscle hypertrophy received intramuscular injection of the botulinum toxin type A. The functional and cosmetic results were evaluated as well as recurrence.

RESULTS

In all patients, satisfactory regression of the masseter muscle hypertrophy occurred and mild muscular pain was relieved. Recurrence was observed in 2 cases.

CONCLUSIONS

The use of botulinum toxin type A in masseter muscle hypertrophy therapy was shown to be a successful and safe treatment method. This procedure to control parafunctional activities involving the masticatory muscles of patients appears to be useful.

Comparison of the therapeutic indexes of different molecular forms of botulinum toxin type A

Botulinum toxin is produced by Clostridium botulinum in three different molecular-weight forms: LL toxin, 900 kDa; L toxin, 500 kDa; and M toxin, 300 kDa. We isolated the M toxin, then compared its muscle-weakening efficacy with those of L+LL toxin and BOTOX both in vitro and in vivo. The twitch tension of the mouse isolated phrenic nerve-hemidiaphragm was used for the in vitro study. For the in vivo study, grip strength was measured in the toxin-injected legs. Undesirable muscle weakening was evaluated by grip-strength measurement in the contralateral leg. Concentration-response curves for effects on the phrenic nerve-hemidiaphragm showed that M toxin was 10 times more potent than L+LL toxin. The therapeutic index in vivo was 3- to 5-times higher for M toxin than for L+LL toxin or BOTOX, indicating a greater separation for M toxin between doses with local efficacy and systemic toxicity. These findings indicate that the M toxin preparation may have a better pharmacological profile than the conventional preparation.

Botox: beyond wrinkles

First used and approved over a decade ago for the treatment of strabismus (or misaligned eyes), botulinum toxin (BTX) has demonstrated efficacy in blepharospasm, hemifacial spasm, spastic lower eyelid entropion, and a number of other disorders seen in the traditional medical environment that are characterized by abnormal muscle contraction. Moreover, other conditions-notably some pain and gastrointestinal disorders-have responded to BTX injections.

Botulinum toxins in neurological disease

Botulinum toxins are among the most potent neurotoxins known to humans. In the past 25 years, botulinum toxin has emerged as both a potential weapon of bioterrorism and as a powerful therapeutic agent, with growing applications in neurological and non-neurological disease. Botulinum toxin is unique in its ability to target peripheral cholinergic neurons, preventing the release of acetylcholine through the enzymatic cleavage of proteins involved in membrane fusion, without prominent central nervous system effects. There are seven serotypes of the toxin, each with a specific activity at the molecular level. Currently, serotypes A (in two preparations) and B are available for clinical use, and have been shown to be safe and effective for the treatment of dystonia, spasticity, and other disorders in which muscle overactivity gives rise to symptoms. This review focuses on the pharmacology, electrophysiology, immunology, and application of botulinum toxin in selected neurological disorders.

The management of oromandibular motor disorders and facial spasms with injections of botulinum toxin

Although much work is yet to be done in this area, nine general conclusions can be derived: 1. Local site-of-injection side effects from botulinum toxin injections are rare, assuming proper technique is used. 2. The two most common medication-related side effects from botulinum toxin orofacial injections are alterations in salivary consistency and inadvertent weakness of the swallowing, speech, and facial muscles. These complications are injection site-specific (eg, more common with lateral pterygoid injections and palatal and tongue muscle injections) and dose-dependent problems. These problems are bothersome but are not contraindications for the therapy if it is needed. 3. The data presented in this article are mostly case series-based and open trial-based information that is promising, but randomized, blinded, controlled trials are needed to establish the true efficacy of this method for the orofacial motor and pain disorders. 4. The novice should begin with injection of muscles he or she can inject with low risk of incorrect placement. The hard-to-find muscles should be avoided when starting out. The novice clinician should inject and dissect a few cadavers to improve injection technique. 5. The general latency for botulinum toxin type A is 1 week, its duration is 2 to 3 months, and it is recommended that injection be done no more than once every 12 weeks to avoid development of antibodies against the toxin. 6. Depending on the target muscle, injection dose is 10 to 50 U of Botox type A per site with a total dose of 200 U in the masticatory system. More than this can be used (400 U maximum) if other sites in the head and neck are included in the injection protocol. 7. Regarding injecting painful muscles that do not exhibit palpable muscle hardness or EMG-determined spasticity or observable involuntary movements but have chronic myofascial trigger points or the patient localizes them as the site of their chronic daily headache pain, botulinum toxin injections might be helpful used in this manner, but conclusive data for this controversial application of botulinum toxin are still missing. 8. Hemifacial spasm has the largest number of open-label, clinical trials, some of which have a 10-year follow-up. The conclusions reached by all of these reports is that treatment of hemifacial spasm with repeated injections of botulinum toxin has been highly successful and that the dose and relative effect of the injections are stable over time. 9. Although EMG-guided injection may be useful, EMG is neither practical nor needed in most situations for orofacial injections because most of the orofacial muscles are easily palpable muscles or have definitive bony landmarks to help with the localization process.

Botulinum toxin type B (MYOBLOC) versus botulinum toxin type A (BOTOX) frontalis study: rate of onset and radius of diffusion

BACKGROUND

Botulinum toxin types A and B can improve the appearance of facial wrinkles. Differences in the time until onset and the degree of diffusion have been observed anecdotally, but no direct comparative studies have been done.

OBJECTIVE

To compare the rate of onset and the radius of diffusion of botulinum toxin types A and B in the rhytides of the forehead.

METHODS

Adults with symmetrical moderate to severe forehead wrinkles at full contracture received botulinum toxin type A (BOTOX; 5 U) on one side of the forehead and type B (MYOBLOC; 500 U) on the other side. Photographs taken at rest and full frontalis contracture were analyzed by computer, and a time-lapse motion picture was created. Radius of diffusion and time until full effect were measured.

RESULTS

Botulinum toxin type B had a slightly faster onset of action than type A. All patients responded to type B quickly, whereas some had a delayed response to type A. A greater radius of diffusion was consistently observed with botulinum toxin type B, as measured by the greater area of wrinkle reduction at the doses used.

CONCLUSIONS

In this comparative study of patients with symmetrical forehead wrinkles, botulinum toxin type B produced a greater area of diffusion and a more rapid onset of action than type A.

Botulinum toxin-induced paralysis of frontotemporal muscles improves seizure focus localization

BACKGROUND

Scalp EEG localization of epileptic foci may be obscured by electromyographic (EMG) artifact produced by ictal contraction of cranial muscles. Injection of botulinum toxin type A (BTX-A) into frontotemporal scalp muscles reduces EMG activity. Initial scalp video-EEG monitoring in three patients suggested partial seizures, but definitive lateralization or localization was precluded by EMG artifact.

METHODS

EMG-guided BTX-A injection to bilateral frontotemporal muscles was performed. When artifact persisted, BTX-A administration was selectively repeated. Patients subsequently underwent scalp video-EEG monitoring 1 week later.

RESULTS

All patients had reduction of EMG artifact during subsequent scalp video-EEG monitoring. No patient had adverse effects after BTX-A administration. All three patients had localization to either frontal or temporal lobes and definitive lateralization. Two of the three patients were able to proceed to invasive placement of frontotemporal subdural grid electrodes based on the BTX-A scalp video-EEG localization, and the third patient was determined to have a multifocal seizure disorder.

CONCLUSIONS

Paralysis of frontotemporal scalp muscle after BTX-A administration reduces EMG artifact and may improve localization and lateralization of a seizure focus, providing a noninvasive technique for advancement toward epilepsy surgery.

Focal dystonia: the role of botulinum toxin

Botulinum toxin (BTX) has been found to be effective in a wide range of focal dystonias. Debate surrounds the selection of injection sites. In general, localization is satisfactory by clinical examination, but poor response, requiring localization of deep muscles, may necessitate use of electromyography for localization. Delineation of optimal doses of BTX is a work in progress; as studies have tended to show efficacy at lower doses than used in the past, the trend is to use lower doses. This is important, because development of antibodies to BTX, the main reason for secondary resistance to this treatment, is more frequent with larger doses and shorter inter-injection intervals. Although the mechanism of denervation of the neuromuscular injunction by BTX is relatively well understood, secondary changes at the level of the basal ganglia, thalamus, and cortex, and their role in response to BTX, need further exploration.

[Surgical treatment of blepharospasm. Report of 2 patients]

Essential blepharospasm can be approached by several types of treatment: clinical in which the most important is the botulinum toxin with advantages and limitations; and some options of surgical treatment. The surgical technique described by Gillum and Anderson offers an alternative to patients resistant to the clinical treatment or with secondary complications. Two cases are analysed. Myectomy of all accessible orbicularis oculi, procerus and corrugator superciliaris muscle associated with blepharoplastic surgery and frontal lifting was indicated due to poor answer to clinical treatment. The results were satisfactory and both patients returned to their normal activities.