The effect of omitting botulinum toxin from the lower eyelid in blepharospasm treatment

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.

The therapeutic usage of botulinum toxin (Botox) in non-cosmetic head and neck conditions - An evidence based review

Botulinum toxin (Botox) is an exotoxin produced from Clostridium botulinum. It blocks the release of acetylcholine from the cholinergic nerve end plates resulting in inactivity of the muscles or glands innervated. The efficacy of Botox in facial aesthetics is well established; however, recent literature has highlighted its utilization in multiple non-cosmetic medical and surgical conditions. The present article reviews the current evidence pertaining to Botox use in the non-cosmetic head and neck conditions. A literature search was conducted using MEDLINE, EMBASE, ISI Web of Science and the Cochrane databases limited to English Language articles published from January 1980 to December 2014. The findings showed that there is level 1 evidence supporting the efficacy of Botox in the treatment of laryngeal dystonia, headache, cervical dystonia, masticatory myalgia, sialorrhoea, temporomandibular joint disorders, bruxism, blepharospasm, hemifacial spasm and rhinitis. For chronic neck pain there is level 1 evidence to show that Botox is ineffective. Level 2 evidence exists for vocal tics and trigeminal. For stuttering, facial nerve paresis, Frey's syndrome and oromandibular dystonia the evidence is level 4. Thus, there is compelling evidence in the published literature to demonstrate the beneficial role of Botox in a wide range of non-cosmetic conditions pertaining to the head and neck (mainly level 1 evidence). With more and more research, the range of clinical applications and number of individuals getting Botox will doubtlessly increase. Botox appears to justify its title as 'the poison that heals'.

An evidence-based review of botulinum toxin (Botox) applications in non-cosmetic head and neck conditions

Botulinum toxin (Botox) is an exotoxin produced from Clostridium botulinum. It works by blocking the release of acetylcholine from the cholinergic nerve end plates leading to inactivity of the muscles or glands innervated. Botox is best known for its beneficial role in facial aesthetics but recent literature has highlighted its usage in multiple non-cosmetic medical and surgical conditions. This article reviews the current evidence pertaining to Botox use in the head and neck. A literature review was conducted using The Cochrane Controlled Trials Register, Medline and EMBASE databases limited to English Language articles published from 1980 to 2012. The findings suggest that there is level 1 evidence supporting the efficacy of Botox in the treatment of spasmodic dysphonia, essential voice tremor, headache, cervical dystonia, masticatory myalgia, sialorrhoea, temporomandibular joint disorders, bruxism, blepharospasm, hemifacial spasm and rhinitis. For chronic neck pain there is level 1 evidence to show that Botox is ineffective. Level 2 evidence exists for vocal tics, trigeminal neuralgia, dysphagia and post-laryngectomy oesophageal speech. For stuttering, 'first bite syndrome', facial nerve paresis, Frey's syndrome, oromandibular dystonia and palatal/stapedial myoclonus the evidence is level 4. Thus, the literature highlights a therapeutic role for Botox in a wide range of non-cosmetic conditions pertaining to the head and neck (mainly level 1 evidence). With ongoing research, the spectrum of clinical applications and number of people receiving Botox will no doubt increase. Botox appears to justify its title as 'the poison that heals'.

Uses of Botulinum Toxin a in Ophthalmology

Introduction:

Botox® (serotype A) is currently available and used to treat various ophthalmological conditions. The aim of our study was to review the current indications, side-effects and updates on the clinical use of botulinum toxin- A (Btx-A) in the field of ophthalmology.

Methods:

A literature search using the keywords “Botulinum Toxin”, “Botulinum Toxin A”, “Botox” and “Ophthalmology” was performed using Pubmed. Articles describing the use of botulinum toxin A were selected and reviewed.

Results:

The uses of Btx-A in ophthalmology can be broadly classified into four categories: eyelid, strabismus, cosmetic and others. In the eyelid, it can be used to treat blepharospasm, hemifacial spasm, apraxia of lid opening or induce ptosis in lid retraction and exposure keratopathy. In strabismus management, it can be injected into overacting muscles to realign the eyes. For cosmesis, it can be used to relax facial muscles to reduce wrinkles while other indications include treatment of chronic dry eye, lacrimal hypersecretion and pain relief in acute angle closure attack. Complications of the injection include local effects like ecchymosis, pain or infection and spillover effects like ptosis, diplopia, lagophthalmos, mid facial weakness and dry eyes.

Conclusion:

The clinical application of botulinum toxin A in ophthalmology is extensive. When considering its application in clinical practice, one should be mindful of the indications, risks and benefits of the procedure. When properly delivered, its potential as an efficacious, minimally-invasive treatment modality can be maximised in patient management.

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.

Botulinum toxin in the treatment of blepharospasm and hemifacial spasm

Blepharospasm and hemifacial spasm are the two most common craniofacial movement disorders. Blepharospasm is a syndrome characterized by excessive or continuous eye closure related to overactivity of the orbicularis oculi and adjacent muscles bilaterally. Hemifacial spasm is a peripherally-induced movement disorder typically caused by vascular compression of cranial nerve VII (CN VII) leading to involuntary unilateral contractions of muscles used in facial expression. Treatment options for both conditions include medications, botulinum toxin, and various surgical interventions. This article summarizes the existing medical literature which indicates that botulinum toxin is the treatment of choice for blepharospasm and hemifacial spasm.

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.

Ocular Effects of Cosmetic Products and Procedures

Cosmetic products and procedures can produce adverse effects on the ocular surface, ranging from mild discomfort to vision-threatening conditions. Complications of skin and eye products can be related to allergy or toxicity, often attributable to perfumes. Complications of blepharoplasty may be associated with overcorrection, scarring, or uneven contour of the lid margins, conditions that can cause significant ocular surface disease until they are corrected. Ocular surface effects of botulinum toxin injection include dry eye syndromes and also epiphora. More serious complications occur (rarely) and are dose- and location-related. Adverse effects of micropigmentation procedures involve pathological processes or, simply, poor cosmetic results. In certain youth cultures, special-effect contact lenses and even decorative conjunctival implants have gained popularity, presenting a wide variety of dangers, often attributable to poor education about care and hygiene.

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 for Aberrant Facial Nerve Regeneration: Double-Blind, Placebo-Controlled Trial Using Subjective Endpoints

BACKGROUND

Aberrant facial nerve regeneration syndrome is systematically studied by constructing a subjective questionnaire organized into pertinent domains (impairment of quality of life, social interactions, perception of self-appearance, visual function, and perception of problem severity) and by physical assessment of degree of involuntary palpebral fissure closure during routine facial movements using videotaping and a physicians' grading scale.

METHODS

The videotape measurements of corneal light reflex to upper lid margin distance and vertical palpebral distance were made during adynamic and active facial expression. Thirty-six patients were studied (six in an open-label pilot study design and 30 in a multicenter, double-blind, placebo-controlled trial). Botulinum toxin type A injections consistently suppressed the degree of involuntary eyelid movement associated with smiling, chewing, and puckering by each measurement and in both study designs.

RESULTS

In all subjective morbidity domains, improvement was demonstrated in the double-blind study design (quality of life, p < 0.05; social interaction, p < 0.001; personal appearance, p < 0.001; peripheral visual impairment, p < 0.01; and perception of severity, p < 0.05). Correlation between degrees of physical impairment was significant but low comparing degree of subjective impairment to direct videotaped measurements. Correlation was more significant comparing subjective scores to the physicians' grading scale assessment of degree of physical impairment.

CONCLUSIONS

Impairment in quality of life, social interactions, and self-assessment of appearance closely reflected the nature of the morbidity associated with palpebral fissure asymmetry associated with aberrant facial nerve regeneration. The physicians' grading scale best reflected subjective morbidity over direct videotaped measurements.

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.

Intramuscular injection of 125I-botulinum neurotoxin-complex versus 125I-botulinum-free neurotoxin: time course of tissue distribution

The diffusion from the site of intramuscular injection of 900 kDa botulinum neurotoxin-hemagglutinin complex (BoNT/A-complex) and 150 kDa free-botulinum neurotoxin (free-BoNT/A) was compared. Radioiodinated compounds were injected into the gastrocnemius muscle of rats (70Units (U) 125I-BoNT/A-complex, 67 or 344 U free-125I-BoNT/A, or free-125I-iodide) and the eyelids of rabbits (24 U 125I-BoNT/A-complex or 108 U free-125I-BoNT/A), and measured in various tissues at different time points. There were no detectable systemic effects or generalized botulinum neurotoxin toxicity in either rats or rabbits, indicating that most of the toxin, whether as 125I-BoNT/A-complex or free-125I-BoNT/A, remained at the injection site. In rats, 125I-BoNT/A-complex and free-125I-BoNT/A diffused in a pattern that was grossly similar. Almost no radioactivity was recovered from the brain. Radioactivity recovered from distant tissues (thyroid, skin, and contralateral muscle) was primarily attributable to either low molecular weight 125I-containing peptides or 125I-iodide. After injection into rabbit eyelids, neither 125I-BoNT/A-complex nor free-125I-BoNT/A spread to distant structures, including the eye. The results indicate that most of the neurotoxin does not diffuse from the injection site, whether in free or complexed form, and this may reduce the potential for systemic effects.

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.

Differential section of the seventh nerve as a tertiary procedure for the treatment of benign essential blepharospasm

PURPOSE

To examine the efficacy of differential section of the seventh nerve in treatment of patients with blepharospasm refractory to botulinum toxin and eyelid protractor myectomy.

METHODS

A retrospective noncomparative interventional case series consisting of a cohort of 228 patients with benign essential blepharospasm followed from 1987 to 1997 in a university ophthalmic plastic surgery referral practice. Patients were treated with botulinum toxin injections, eyelid protractor myectomy, and differential section of the seventh nerve in stepwise fashion as needed for symptomatic control.

RESULTS

Thirty-four patients (15% of total) underwent eyelid protractor myectomy during this period. Eyelid protractor myectomy failed to control blepharospasm in 7 (21%) of these 34 patients, who then underwent differential section of the seventh nerve an average of 2 years after myectomy. Patients were followed up for an average of 36 months, with a success rate of 42% (3 of 7). The remaining 4 patients had repeat differential section of the seventh nerve with a 50% success rate, which brought the overall success rate from differential section of the seventh nerve to 71%. Lower eyelid ectropion requiring surgical repair complicated 27% of differential section of the seventh nerve procedures.

CONCLUSIONS

Differential section of the seventh nerve is a reasonable alternative in the treatment of patients who have persistent disability despite treatment with botulinum toxin injections and eyelid protractor myectomy.

Botulinum-A toxin in the treatment of craniocervical muscle spasms: short- and long-term, local and systemic effects

Botulinum toxin has become the initial treatment of choice for the management of essential blepharospasm, hemifacial spasm and other craniocervical dystonias. Numerous studies have confirmed a 90% to 95% response rate. Although a number of common side effects have been reported, the occurrence and incidence of rare local complications remains poorly understood. More importantly, the acute and chronic distant effects of botulinum toxin have not been clearly elucidated. A better understanding of such effects is essential if clinicians are to appropriately advise patients on the use of this therapeutic modality. This article is based on the Duke University experience in the management of over 500 patients with craniocervical spasm disorders, combined with a review of the published literature. These disorders include essential blepharospasm, oromandibular dystonia, hemifacial spasm, and torticollis. The incidence of side effects following more than 6000 treatments with botulinum toxin is presented. Pertinent research relating to the causes of these complications is also reviewed. The most common complications of treatment with botulinum toxin are related to acute local effects resulting from chemodenervation. The most important clinical effect in this group is weakening of the levator muscle resulting in ptosis, and the corneal consequences of lagophthalmos. The latter includes exposure keratitis, dry eyes, blurred vision, and hypersecretion epiphora. Less common local effects include facial numbness, diplopia, and ectropion. Some distant effects are being observed with increasing frequency. These include pruritus, dysphagia, nausea, and a flu-like syndrome. Most significant, however, are the rare reports of generalized weakness and the documentation of EMG abnormalities distant to the site of toxin injection. This has been seen with injections for both blepharospasm and torticollis. Until further studies on the long-term distant complications of botulinum toxin are available, it is recommended that patients receive as few life-time doses of toxin as possible, consistent with adequate management of their spasms. The practice of reinjecting patients routinely every three months, or at the first return of mild spasms should be discouraged.

Histologic assessment of dose-related diffusion and muscle fiber response after therapeutic botulinum A toxin injections

Fiber diameter variability, acetylcholinesterase staining properties, and average fiber diameter were determined 5 weeks after varying doses of botulinum A toxin were administered into albino rabbit longissimus dorsi muscle. The average fiber diameter within the muscle appeared to be a function of the dose of botulinum toxin injected. Fiber diameter variability correlated with the dose of botulinum toxin administered. Both fiber diameter variability and acetylcholinesterase spread characteristics showed a distinct diffusion gradient over a defined field within a muscle. At lower doses (1 IU), collapse of the diffusion gradient occurred over a 15-30-mm segment of muscle. At higher doses (5-10 IU), diffusion of botulinum A toxin effect occurred throughout the entire muscle with no apparent end point. This study demonstrated that botulinum A toxin produces a gradient of denervation in a given muscle and that both the magnitude of denervation and the extent of the gradient are dose dependent. Furthermore, both muscle fiber diameter variability and acetylcholinesterase staining were useful as measures of chemodenervation.

Botulinum a toxin for spasmodic torticollis: multiple vs single injection points per muscle

Eighty-six injections in 49 patients with adult onset spasmodic torticollis were evaluated for efficacy with respect to single point per muscle versus multiple point per muscle injection techniques. Parameters of the syndrome assessed were pain, posture deformity, range of cervical motion, disfigurement, cervical muscle hypertrophy, activity limitation, and degree of involuntary movement. The multiple point per muscle injection strategy appeared superior to the single injection per muscle technique with respect to pain (p less than 0.002, chi-square), posture deformity (p less than 0.001), range of motion (p less than 0.001), and improvement in activity endurance (p less than 0.001). No significant differences were noted with respect to cervical muscle hypertrophy or degree of involuntary movements, although the injections were considered beneficial in both groups to these syndrome components.

Botulinum A toxin (Oculinum) in ophthalmology

Botulinum A toxin has been used to treat strabismus and a variety of spasmodic neuromuscular diseases. Botulinum toxin treatment of strabismus is not as definitive and stable as the traditional surgical approach, but it has been found most useful in postoperative overcorrection, small deviations, sensory deviations, and acute sixth nerve palsy. This toxin has been effective in the treatment of essential blepharospasm and hemifacial spasm, for which it produces temporary relief of symptoms. In addition, this treatment has been applied to lower lid entropion, myokymia, aberrant regeneration of the seventh nerve, lid retraction, corneal exposure, nystagmus, spasmodic torticollis, and adductor spastic dysphonia.