Variability of the immunologic and clinical response in dystonic patients immunoresistant to botulinum toxin injections

Movement disorders of the mouth: a review of the common phenomenologies

Movement disorders of the mouth encompass a spectrum of hyperactive movements involving the muscles of the orofacial complex. They are rare conditions and are described in the literature primarily in case reports originating from neurologists, psychiatrists, and the dental community. The focus of this review is to provide a phenomenological description of different oral motor disorders including oromandibular dystonia, orofacial dyskinesia and orolingual tremor, and to offer management strategies for optimal treatment based on the current literature. A literature search of full text studies using PubMed/Medline and Cochrane library combined with a manual search of the reference lists was conducted until June 2021. Results from this search included meta-analyses, systematic reviews, reviews, clinical studies, case series, and case reports published by neurologists, psychiatrists, dentists and oral and maxillofacial surgeons. Data garnered from these sources were used to provide an overview of most commonly encountered movement disorders of the mouth, aiding physicians in recognizing these rare conditions and in initiating appropriate therapy.

Immunogenicity of botulinum toxin

Botulinum toxin treatment is the most common non-surgical cosmetic treatment. Although there are many available treatments using botulinum toxin, their effects are temporary and repeated injections are required. These frequent injections can trigger an immunological response. In addition, botulinum toxin acts as an antigen in the body; thus, its effect disappears progressively due to this immunological reaction, which may cause treatment failure. Active botulinum toxin consists of a core neurotoxin and complexing proteins, the exact effects of which remain unclear. However, the complexing proteins are closely related to the immune response and the formation of neutralizing antibodies. Since neutralizing antibodies can lead to treatment failure, their formation should be prevented. Furthermore, various methods of detecting neutralizing antibodies have been used to predict treatment failure.

Creating Lift in the Lower Face With Botulinum Toxin A Treatment: An Anatomical Overview With Videos and Case Studies Illustrating Patient Evaluation and Treatment

Background

Relaxation of depressor muscles in the lower face with botulinum toxin A (BoNT-A) can create a lifting effect and dramatically improve jawline contour and resting facial expression. Even with the recent increase in interest in lower face rejuvenation, BoNT-A is a relatively under-recognized tool for treatment of this area. When treating the lower face, an understanding of anatomy and the relationship between the facial muscles is especially important, as injection patterns must be customized for consistently positive outcomes.

Objectives

This study was aimed to provide basic knowledge of the activities of the muscles in the lower face and neck and to describe the basis for injecting BoNT-A to create lift in this area. Expert guidance for injection is also provided.

Methods

As part of a continuing medical education course on differentiating botulinum toxin products, a panel of 4 expert physician injectors participated in a live webinar to discuss the implications of increasing toxin use.

Results

The practical guidance in this manuscript is based on the most frequently requested information by audience members and the information considered critical for success by the authors. The authors outline the functional anatomy of the lower face most relevant for BoNT-A treatment and case studies as well as methods for patient evaluation and injection technique are also provided. Videos showing treatment planning and injection technique for the lower face and neck are included.

Conclusions

BoNT-A is an important nonsurgical tool for creating lift in the lower face.

Level of Evidence 5

Immunogenicity to Botulinum Toxin Type A: A Systematic Review With Meta-Analysis Across Therapeutic Indications

BACKGROUND

Botulinum toxin A (BTX-A) is commonly employed as a neuromodulator in several neurological diseases and aesthetic indications. Formation of neutralizing antibodies (NAbs) after BTX-A injections may be responsible for treatment failure.

OBJECTIVES

The authors sought to quantify the prevalence of NAbs following treatment with Abobotulinumtoxin A, Incobotulinumtoxin A, and Onabotulinumtoxin A for therapeutic indications.

METHODS

An electronic systematic search (2000-2020) of PubMed, Scopus, Web of Science, and Embase was conducted. Original studies reporting prevalence of NAbs were included. Data analysis was carried out through open meta-analysis softwares.

RESULTS

Forty-three studies involving 8833 patients were included in this meta-analysis. The incidence of NAbs was 1.8% (summary estimate = 0.018, 95% CI [0.012, 0.023]); a meta-regression analysis revealed that BTX-A duration was significantly associated with increased incidence of NAbs (P = 0.007). Patients with dystonia had the highest incidence (7.4%) of NAbs against BTX-A (summary estimate = 0.074, 95% CI = [0.045, 0.103], I2 = 93.%, P < 0.00) followed by patients with spasticity (6.7%) and urological indications (6.2%). Abobotulinumtoxin A was associated with the highest incidence of NAbs (7.4%) (summary estimate = 0.074, 95% CI = [0.053, 0.096], I2 = 97.24%, P < 0.00) by the Incobotulinumtoxin A and Onabotulinumtoxin A 0.3% (summary estimate <0.003%, 95% CI = [-0.001, 0.007], P < 0.003).

CONCLUSIONS

Although the overall incidence of NAbs following BTX-A injections is relatively low, patients with secondary nonresponse to BTX-A with no apparent causes should be investigated for NAbs. A consensus needs to be developed for the optimal management of such patients.

LEVEL OF EVIDENCE: 2

Transient Improvement after Switch to Low Doses of RimabotulinumtoxinB in Patients Resistant to AbobotulinumtoxinA

Botulinum toxin type B (BoNT/B) has been recommended as an alternative for patients who have become resistant to botulinum toxin type A (BoNT/A). This study aimed to compare the clinical effect, within a patient, of four injections with low doses of rimabotulinumtoxinB with the effect of the preceding abobotulinumtoxinA (aboBoNT/A) injections. In 17 patients with cervical dystonia (CD) who had become resistant to aboBoNT/A, the clinical effect of the first four rimabotulinumtoxinB (rimaBoNT/B) injections was compared to the effect of the first four aboBoNT/A injections using a global assessment scale and the TSUI score. After the first two BoNT/B injections, all 17 patients responded well and to a similar extent as to the first two BoNT/A injections, but with more side effects such as dry mouth and constipation. After the next BoNT/B injection, the improvement started to decline. The response to the fourth BoNT/B injection was significant (p < 0.048) lower than the fourth BoNT/A injection. Only three patients developed a complete secondary treatment failure (CSTF) and five patients a partial secondary treatment failure (PSTF) after four BoNT/B injections. In nine patients, the usual response persisted. With the use of low rimaBoNT/B doses, the induction of CSTF and PSTF to BoNT/B could not be avoided but was delayed in comparison to the use of higher doses. In contrast to aboBoNT/A injections, PSTF and CSTF occurred much earlier, although low doses of rimaBoNT/B had been applied.

Antibody-induced botulinum toxin treatment failure: A review and novel management approach

BACKGROUND

Botulinum neurotoxin A (BoNT/A) has been used for cosmetic indications for many decades. Consumption of BoNT/A usage has been markedly increased for a few years. Even new formulations of BoNT/A to decrease immunogenicity have been released, repeated treatment to maintain efficacy outcome is inevitable and could finally provoke immune response. In the past, prevalence of botulinum treatment failure (BTF) in cosmetic indication was rare leading to less medical concern. Current decade, case reports on BTF, especially antibody-induced botulinum toxin treatment failure (ABTF), have been increasingly revealed and risk factors associated with ABTF have been intensively studied.

AIMS

In this article, we will review antibody-induced botulinum toxin treatment failure (ABTF), risk-associated ABTF, prevalence and recent case reports of ABTF, and new approach to deal with ABTF.

METHODS

Literature search was conducted using PubMed. The relevant literatures published between January 2000 and May 2020 concerning BTF and ABTF including investigation for ABTF were included and analyzed.

RESULTS

Possible causes of BTF were summarized. ABTF could be a tip of iceberg of BTF, its prevalence, and currently, 10-year case reports of ABTF were published evidence. Risk factors and investigation methods for ABTF were also summarized. Based on previous studies and our experience, novel approach to management of ABTF was described.

CONCLUSION

Effective management of BTF is to explore causes of treatment failure. Antibodies against BoNT/A complex could be one of many possibilities. Laboratory in vitro tests could be alternative tools to decrease adverse effect and rebooting immune responses in BTF patients.

Immunogenicity Associated with Botulinum Toxin Treatment

Botulinum toxin (BoNT) has been used for the treatment of a variety of neurologic, medical and cosmetic conditions. Two serotypes, type A (BoNT-A) and type B (BoNT-B), are currently in clinical use. While considered safe and effective, their use has been rarely complicated by the development of antibodies that reduce or negate their therapeutic effect. The presence of antibodies has been attributed to shorter dosing intervals (and booster injections), higher doses per injection cycle, and higher amounts of antigenic protein. Other factors contributing to the immunogenicity of BoNT include properties of each serotype, such as formulation, manufacturing, and storage of the toxin. Some newer formulations with purified core neurotoxin devoid of accessory proteins may have lower overall immunogenicity. Several assays are available for the detection of antibodies, including both structural assays such as ELISA and mouse-based bioassays, but there is no consistent correlation between these antibodies and clinical response. Prevention and treatment of antibody-associated non-responsiveness is challenging and primarily involves the use of less immunogenic formulations of BoNT, waiting for the spontaneous disappearance of the neutralizing antibody, and switching to an immunologically alternate type of BoNT.

Anatomical Regional Targeted (ART) BOTOX Injection Technique: A Novel Paradigm for Migraines and Chronic Headaches

Supplemental Digital Content is available in the text.

Migraine headaches are a debilitating disease that causes significant socioeconomic problems. One of the speculated etiologies of the generation of migraines is peripheral nerve irritation at different trigger points. The use of Onabotulinum toxin A (BOTOX), although initially a novel approach, has now been determined to be a valid treatment for chronic headaches and migraines as described in the Phase III Research Evaluating Migraine Prophylaxis Therapy trials that prompted the approval by the Food and Drug Administration for treatment of chronic migraines. The injection paradigm established by this trial was one of a broad injection pattern across large muscle groups that did not always correspond to the anatomical locations of nerves. The senior author developed the Anatomical Regional Targeted BOTOX injection paradigm as an alternative to the current injection model. This technique targets both the anatomical location of nerves known to have causal effects with migraines and the region where the pain localizes, to provide relief across a wide distribution of the peripheral nerve. This article serves as a guide to the Anatomical Regional Targeted injection technique, which, to our knowledge, is the first comprehensive BOTOX injection paradigm described in the literature for treatment of migraines that targets nerves and nerve areas rather than purely muscle groups. This technique is based on the most up-to-date anatomical and scientific studies and large-volume migraine surgery experience.

Botulinum Toxin in Secondarily Nonresponsive Patients with Spasmodic Dysphonia

Chemodenervation with botulinum toxin (BoNT) has been effective and well tolerated for all types of dystonia for >30 years. We reviewed outcomes of our patients treated with BoNT serotype A (BoNT-A) for spasmodic dysphonia (SD) who became secondarily nonresponsive. We found that 8 of 1400 patients became nonresponsive to BoNT-A (0.57%), which is lower than the secondary nonresponse rate in other dystonias. After a cessation period, 4 of our patients resumed BoNT-A injections, and recurrence of immunoresistance was not seen in any of them. When compared with patients with other dystonias, patients with SD receive extremely low doses of BoNT. Small antigen challenge may explain the lower rate of immunoresistance and long-lasting efficacy after BoNT-A is restarted among secondary nonresponsive patients with SD.

Efficacy and safety of NABOTA in post-stroke upper limb spasticity: a phase 3 multicenter, double-blinded, randomized controlled trial

Botulinum toxin A is widely used in the clinics to reduce spasticity and improve upper limb function for post-stroke patients. Efficacy and safety of a new botulinum toxin type A, NABOTA (DWP450) in post-stroke upper limb spasticity was evaluated in comparison with Botox (onabotulinum toxin A). A total of 197 patients with post-stroke upper limb spasticity were included in this study and randomly assigned to NABOTA group (n=99) or Botox group (n=98). Wrist flexors with modified Ashworth Scale (MAS) grade 2 or greater, and elbow flexors, thumb flexors and finger flexors with MAS 1 or greater were injected with either drug. The primary outcome was the change of wrist flexor MAS between baseline and 4weeks post-injection. MAS of each injected muscle, Disability Assessment Scale (DAS), and Caregiver Burden Scale were also assessed at baseline and 4, 8, and 12weeks after the injection. Global Assessment Scale (GAS) was evaluated on the last visit at 12weeks. The change of MAS for wrist flexor between baseline and 4weeks post-injection was -1.44±0.72 in the NABOTA group and -1.46±0.77 in the Botox group. The difference of change between both groups was 0.0129 (95% confidence interval -0.2062-0.2319), within the non-inferiority margin of 0.45. Both groups showed significant improvements regarding MAS of all injected muscles, DAS, and Caregiver Burden Scale at all follow-up periods. There were no significant differences in all secondary outcome measures between the two groups. NABOTA demonstrated non-inferior efficacy and safety for improving upper limb spasticity in stroke patients compared to Botox.

Clinical Response to IncobotulinumtoxinA, after Demonstrated Loss of Clinical Response to OnabotulinumtoxinA and RimabotulininumtoxinB in a Patient with Musician's Dystonia

Botulinum toxin is a mainstay therapy for dystonia. Formulations available are three types of botulinumtoxinA and one type of botulinumtoxinB.¹ Antibodies can develop against the toxin, leading to treatment failure. IncobotulinumtoxinA (Xeomin; Merz Pharmaceuticals GmbH, Frankfurt, Germany) is differentiated from other types of botulinumtoxinA preparations by being free from complexing proteins, speculated to make the product less antigenic.².

Long-term efficacy and safety of botulinum toxin injections in dystonia

Local chemodenervation with botulinum toxin (BoNT) injections to relax abnormally contracting muscles has been shown to be an effective and well-tolerated treatment in a variety of movement disorders and other neurological and non-neurological disorders. Despite almost 30 years of therapeutic use, there are only few studies of patients treated with BoNT injections over long period of time. These published data clearly support the conclusion that BoNT not only provides safe and effective symptomatic relief of dystonia but also long-term benefit and possibly even favorably modifying the natural history of this disease. The adverse events associated with chronic, periodic exposure to BoNT injections are generally minor and self-limiting. With the chronic use of BoNT and an expanding list of therapeutic indications, there is a need to carefully examine the existing data on the long-term efficacy and safety of BoNT. In this review we will highlight some of the aspects of long-term effects of BoNT, including efficacy, safety, and immunogenicity.

Emerging opportunities for serotypes of botulinum neurotoxins

Background: Two decades ago, botulinum neurotoxin (BoNT) type A was introduced to the commercial market. Subsequently, the toxin was approved by the FDA to address several neurological syndromes, involving muscle, nerve, and gland hyperactivity. These syndromes have typically been associated with abnormalities in cholinergic transmission. Despite the multiplicity of botulinal serotypes (designated as types A through G), therapeutic preparations are currently only available for BoNT types A and B. However, other BoNT serotypes are under study for possible clinical use and new clinical indications; Objective: To review the current research on botulinum neurotoxin serotypes A-G, and to analyze potential applications within basic science and clinical settings; Conclusions: The increasing understanding of botulinal neurotoxin pathophysiology, including the neurotoxin’s effects on specific neuronal populations, will help us in tailoring treatments for specific diagnoses, symptoms and patients. Scientists and clinicians should be aware of the full range of available data involving neurotoxin subtypes A-G.

Human T-cell responses to botulinum neurotoxin. Responses in vitro of lymphocytes from patients with cervical dystonia and/or other movement disorders treated with BoNT/A or BoNT/B

We have previously reported that botulinum neurotoxin type A (BoNT/A)-specific T-cell responses occur in a majority of patients treated with botulinum neurotoxins (BoNT). In this study, we first determined if T-cell responses against BoNT/A and tetanus toxin (TeNT) differ between cervical dystonia (CD) patients and other movement disorder cases. Secondly, we have examined in CD cases the treatment parameters that may have an effect on the T-cell responses against BoNT/A. We found that T-cell responses to BoNT/A were significantly higher in patients with CD than in those with other movement disorders. An increase in TeNT T-cell response in CD was observed when compared to un-treated controls. CD patients who were injected with BoNT/B mounted higher responses to BoNT/A than patients treated with BoNT/A only. Frequent injections (more than 2.1/year) were associated with a significantly higher T-cell response to BoNT/A in CD. T cell responses to BoNT/A did not differ between CD patients who had clinically responsive and non-responsive status at the time of enrollment.

Neuronox versus BOTOX for spastic equinus gait in children with cerebral palsy: a randomized, double-blinded, controlled multicentre clinical trial

AIM

The aim of this study was to evaluate the efficacy and safety of a newly manufactured botulinum toxin, Neuronox, compared with BOTOX for the treatment of the spastic equinus gait in children with cerebral palsy.

METHOD

A total of 127 children with cerebral palsy, aged 2 to 10 years, who presented at three university hospitals with spastic equinus gait were assessed for eligibility to participate in this double-blinded, randomized, controlled trial. Of the 119 eligible participants (mean age 4.33 y; SD 2.07; 76 males and 43 females; 79 with diplegia and 40 with hemiplegia), 57 were classified as Gross Motor Function Classification System level I, 29 as level II, and 33 as level III. Participants were randomly assigned to receive an injection of Neuronox (n=60) or BOTOX (n=59) to the calf muscles at a dose of 4U/kg for those with hemiplegia and 6U/kg for those with diplegia. Assessments were performed at baseline (V1) and at 4 (V2), 12 (V3), and 24 (V4) weeks after the intervention. The primary outcome measure was response rate at V3, with a positive response being defined as at least a 2-point increase in the Physicians' Rating Scale (PRS) score. The non-inferiority margin was set as -20% for the difference in the response rate. The secondary outcome measures included PRS score, passive range of motion (PROM) of the ankle and knee, and Gross Motor Function Measure 88 (GMFM-88). Any adverse events were investigated for safety implications.

RESULTS

The response rate of the Neuronox group at V3 was not inferior to that of the BOTOX group (90% lower limit=-11.58%). There were significant improvements in PRS, PROM of ankle dorsiflexion, and GMFM scores at V2, V3, and V4 in both groups. The changes in PRS score were not statistically different between the two groups in serial evaluation (p=0.96). PROM of the ankle dorsiflexion increased without any significant difference between the two groups, either overall (p=0.56) or at each visit (V2, p=0.32; V3, p=0.66; V4, p=0.90). The increase in GMFM score in serial measurements were not significantly different between the two groups (p=0.16), whereas it was larger in the BOTOX group than in the Neuronox group at V2 and V4 (p=0.03 and 0.05 respectively). The frequency of adverse events was not significantly different between the two groups (p=0.97), and drug-related complications of Neuronox treatment were not addressed.

INTERPRETATION

The outcomes of Neuronox, based on PRS, proved to be as effective and safe as those of BOTOX for the treatment of spasticity in individuals with cerebral palsy.

Evolution of dose and response to botulinum toxin A in cervical dystonia: a multicenter study

Botulinum neurotoxin (BoNT) is an effective treatment for cervical dystonia (CD). Long-term changes of several variables, including the dose of BoNT, in these patients is largely unknown. We reviewed the clinical charts of 275 patients with CD treated with BoNT type A (BoNT-A) for at least 5 years since 1989 at ten tertiary centers. The mean dose of BoNT-A per session during the first 5 years of treatment was calculated and the appearance of resistance was noted. The dose of BoNT-A for the whole group showed a significant trend to increase over time (year 1: 180 ± 65 U; year 5: 203 ± 63 U; ANOVA: p < 0.0001). However, when we studied the evolution of the dose of BoNT-A for those patients (n = 49) first injected after 2000 (introduction of current BOTOX preparation in our country), there was no significant increase in dose (year 1: 181.8 ± 75 U; year 5: 181.7 ± 75 U; ANOVA p: ns). A total of 19 patients became secondary nonresponders; all but one of these patients began BoNT-A treatment before 2000. In summary, there is a statistically significant increase of mean dose of BoNT-A per session over time, and this could be explained by the appearance of secondary nonresponders. On the other hand, those patients initially treated after 2000 did not show any statistically significant increase in dose for 5 years. This could be explained by better experience and techniques, fewer immunogenic problems with the current BoNT-A, and also less variability of the dose per vial.

Review and update of involuntary facial movement disorders presenting in the ophthalmological setting

We review the existing literature on the involuntary facial movement disorders-benign essential blepharospasm, apraxia of eyelid opening, hemifacial spasm, and aberrant facial nerve regeneration. The etiology of idiopathic blepharospasm, a disorder of the central nervous system, and hemifacial spasm, a condition involving the facial nerve of the peripheral nervous system, is markedly different. We discuss established methods of managing patients and highlight new approaches.

Focal hand dystonia: effectiveness of a home program of fitness and learning-based sensorimotor and memory training

STUDY DESIGN

This was a pre post test design.

INTRODUCTION

Retraining the brain is one approach to remediate movement dysfunction resulting from task specific focal hand dystonia (FHD(TSP)).

PURPOSE

Document change in task specific performance (TSP) for patients with FHD(TSP) after 8 weeks of comprehensive home training (fitness activities, task practice, learning based memory and sensorimotor training).

METHODS

Thirteen subjects were admitted and evaluated at baseline, immediately and 6 months post treatment for task specific performance, functional independence, sensory discrimination, fine motor speed and strength. In Phase I, 10 subjects were randomly assigned to home training alone or supervised practice prior to initiating the home training. In phase II, 2 subjects crossed over and 3 new subjects were added (18 hands). The intent to treat model was followed. Outcomes were summarized by median, effect size, and proportion improving with nonparametric analysis for significance.

RESULTS

Immediately post-intervention, TSP, sensory discrimination, and fine motor speed improved 60-80% (p<0.00l respectively). Functional independence and strength improved by 50%. Eleven subjects (16 hands) were re-evaluated at 6 months; all but one subject reported a return to work. Task-specific performance was scored 84-90%. Supervised practice was associated with greater compliance and greater gains in performance.

CONCLUSIONS

Progressive task practice plus learning based memory and sensorimotor training can improve TSP in patients with FHD(TSP). Compliance with home training is enhanced when initiated with supervised practice.

Long-term treatment with botulinum toxin type A in cervical dystonia has low immunogenicity by mouse protection assay

To evaluate the immunogenicity of botulinum toxin type A (BoNTA; BOTOX) in cervical dystonia (CD). Subjects diagnosed with CD for > or =1 year and previously naïve to BoNTs were treated with BoNTA in a prospective, open-label, multicenter study. Serum samples were analyzed for BoNTA neutralizing antibodies using the Mouse Protection Assay (MPA). Clinical resistance was assessed with a test injection of 20 U BoNTA placed unilaterally into the frontalis (Frontalis Antibody Test; FTAT) or corrugator muscle (Unilateral Brow Injection; UBI). Efficacy was assessed and adverse events were recorded. Of 326 subjects enrolled, 251 (77%) completed the study. Subjects received a median of 9 BoNTA treatments (mean dose per session ranged from 148.4 to 213.0 U over a mean of 2.5 years [range: 3.2 months-4.2 years]). Only 4 of 326 subjects (1.2%) tested positive for antibodies in the MPA; three of these subjects stopped responding clinically to BoNTA (of whom one also showed clinical resistance in the FTAT) and one continued to respond. Consistent improvements in the signs/symptoms of CD were noted. The most frequent treatment-related adverse events were mild to moderate weakness, dysphagia, neck pain, and injection-site pain. The current formulation of BoNTA rarely causes neutralizing antibody formation in CD subjects treated < or =4 years.

Orofacial movement disorders

This article reviews three poorly recognized yet relatively common presentations of hyperactive orofacial movement disorders: oromandibular dystonia, orofacial dyskinesia, and drug-induced extrapyramidal syndrome reactions. Orofacial movement disorders are often misdiagnosed as temporomandibular disorders, hence understanding these conditions is pertinent for the practitioner treating orofacial pain. Aspects of epidemiology, etiology, pathophysiology, clinical presentation, and diagnosis are discussed along with treatment considerations for these orofacial movement disorders.

Bupivacaine-induced myotoxicity and its effect on botulinum toxin paresis

PURPOSE

To determine the effect of the coinjection of bupivacaine with botulinum toxin type A on the degree of muscular paralysis. Enhancement of paralysis could allow a decreased dose of neurotoxin treatment, thus reducing the risk for neutralizing antibody formation.

METHODS

Prospective, randomized, double-blind study. Sixteen consecutive patients undergoing treatment of glabellar furrows received botulinum toxin A reconstituted with bupivacaine 0.75% to one corrugator muscle and botulinum toxin A reconstituted with nonpreserved normal saline to the contralateral muscle. Patients were evaluated on days 0 (injection day), 3, 7, 30, 60, and 90. Patients also completed a questionnaire each visit regarding their assessment of paralysis, asymmetry, and adverse effects.

RESULTS

At 1 week after botulinum toxin A injection, 68.8% of the patients showed greater weakness on the bupivacaine-reconstituted side as opposed to 25.0% of patients showing greater weakness on the saline-reconstituted side. At 1 and 3 months, there was no statistical difference in weakness between the saline and the bupivacaine sides. The survey revealed that 56% of the patients had greater pain on the saline side, 31% on the bupivacaine side, and equal pain in 13%.

CONCLUSIONS

Reconstituting botulinum toxin A with bupivacaine is safe, does not limit efficacy, and does not reduce the degree or relative duration of muscular paralysis. Reconstituting botulinum toxin A with bupivacaine results in faster onset of paresis, possibly due to a synergistic effect of bupivacaine induced myotoxicity. Utilizing bupivacaine may result in less pain for patients.

Presynaptic neurotoxins with enzymatic activities

Toxins that alter neurotransmitter release from nerve terminals are of considerable scientific and clinical importance. Many advances were recently made in the understanding of their molecular mechanisms of action and use in human therapy. Here, we focus on presynaptic neurotoxins, which are very potent inhibitors of the neurotransmitter release because they are endowed with specific enzymatic activities: (1) clostridial neurotoxins with a metallo-proteolytic activity and (2) snake presynaptic neurotoxins with a phospholipase A2 activity.

Neuromuscular paralysis and recovery in mice injected with botulinum neurotoxins A and C

Botulinum neurotoxin type A (BoNT/A) is commonly used in human therapy. This treatment may induce immunoresistance and preliminary evaluation of other botulinum neurotoxin serotypes suggested botulinum neurotoxin type C (BoNT/C) to be a good alternative to BoNT/A. Here, we have further characterized the biological activities of BoNT/C using a variety of experimental approaches. Muscle paralysis and time of recovery of mouse hind limb injected with BoNT/A or BoNT/C were assayed with the Digit Abduction Scoring assay. The extent and duration of paralysis were similar with the two toxin serotypes. Extensor digitorum longus or tibialis anterior muscles were dissected at times of complete paralysis and of complete recovery. Muscle weight and force were significantly reduced in mice injected with BoNT/A and BoNT/C, and some atrophy persisted for a long time. In BoNT/C-treated junctions, nerve terminal sprouting was prominent, indicating that the capacity to extend the field of innervation is not hampered by BoNT/C. BoNT/C induced a marked decrease in the frequency of miniature endplate potentials and in the amplitude of endplate potentials. 3,4-diaminopyridine reversed the effect of BoNT/C by increasing the amplitude of synchronized endplate potentials. The present study shows an extensive similarity in the biological activities of BoNT/A and BoNT/C, further supporting the suggestion that BoNT/C is a valid alternative to BoNT/A.

Botulinum Toxin (Botox) to Enhance Facial Macroesthetics: A Literature Review

Dental implants have emerged as a predictable treatment option for partial edentulism. Their ability to preserve bone and soft tissue yields highly esthetic results in the long term. Increasingly, patients are demanding not only enhancements to their dental (micro) esthetics but also to their overall facial (macro) esthetics. Dynamic wrinkles (caused by hyperfunctional muscles) in the perioral, glabellar, and forehead regions can cause a patient's expressions to be misinterpreted as angry, anxious, fearful, or fatigued. An emerging treatment option to address these issues is the use of a paralyzing material such as botulinum toxin A (Botox) to decrease the appearance of the wrinkles, which yields a more esthetic and youthful facial appearance. Botox is a deadly poison that is produced by the bacterium Clostridium botulinum and causes muscle paralysis by inhibiting acetylcholine release at the neuromuscular junction. When used in areas of hyperfunctional muscles, a transient partial paralysis occurs that diminishes the appearances of wrinkles, Therefore, wrinkles not attributable to hyperfunctional muscles (eg, wrinkles caused by aging, gravity, photodamage, trauma, and scarring) will not be amenable to treatment with the toxin. As a result, proper case selection is essential. A thorough understanding of the indications, techniques, dosages, and complications and their management is imperative to achieve a satisfactory result. This article will review the pathogenesis of facial wrinkles as well as the history, techniques, clinical controversies, and other important considerations for successful treatment of facial wrinkles with Botox.

Secondary nonresponsiveness to botulinum toxin A in cervical dystonia: the role of electromyogram-guided injections, botulinum toxin A antibody assay, and the extensor digitorum brevis test

We studied 20 patients with cervical dystonia who had started to respond poorly to botulinum toxin A (BTXA) injections after an initial good response. All patients had extensor digitorum brevis (EDB) tests performed in addition to BTXA immunoprecipition assay (IPA) and mouse bioassay (MBA) antibody testing. The patients were reexamined and then treated with carefully placed electromyogram (EMG)-guided BTXA. Nine patients had a good clinical response to EMG-guided injections and all of these patients showed an obvious decrement on the EDB test. All were BTXA blocking antibodies (Abs)-negative via IPA and MBA (apart from one patient who had low BTXA antibodies titers using IPA but no antibodies by MBA). In the other 11 patients, there was a poor clinical response to EMG-guided BTXA injections. Seven of these 11 had small EDB decrement and BTXA antibodies using IPA, suggesting resistance to BTXA. Of the remaining four patients, two had obvious EDB decrement and low antibody titers via IPA (one of them had no antibodies via MBA), while the other two patients showed obvious decrement on the EDB test and no antibodies via IPA. This study shows that the EDB test correlates better with the clinical response than the antibody assays and that EDB decrement does not always correlate quantitatively with the BTXA antibody titers. In patients with secondary nonresponsiveness, it is recommended that an EDB test is the initial investigation of choice. In those patients where the EDB test does not demonstrate resistance to BTXA, a reexamination of the patients and carefully placed injections under EMG guidance may improve results.

Clinical use of non-A botulinum toxins: botulinum toxin type C and botulinum toxin type F

Botulinum neurotoxin (BoNT) serotype A is commonly used in the treatment of focal dystonia, but some patients are primarily or become secondarily resistant to it. Consequently, other serotypes have to be used when immuno-resistance is proven. In the literature, patients with focal dystonia have been treated with BoNT serotype F with clinical benefit but with short lasting effects. Recently, BoNT serotype C has been used with positive clinical outcome. An update on the clinical use of BoNT serotype F and BoNT serotype C is provided.

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.

Long-term botulinum toxin efficacy, safety, and immunogenicity

To determine the long-term efficacy of botulinum toxin (BTX) treatments, we analyzed longitudinal follow-up data on 45 patients (32 women; mean age, 68.8 years) currently followed in the Baylor College of Medicine Movement Disorders Clinic, who have received BTX treatments continuously for at least 12 years (mean 15.8 +/- 1.5 years). Their mean response rating after the last injection, based one a previously described scale 0-to-4 scale (0 = no effect; 4 = marked improvement) was 3.7 +/- 0.6 and the mean total duration of response was 15.4 +/- 3.4 weeks. Although the latency and total duration of the response to treatment have not changed over time, the peak duration of response (P < 0.005) and dose per visit (P < 0.0001) have increased since the initial visit. Furthermore, global rating (P < 0.02) and peak effect (P < 0.05) have improved. In total, 20 adverse events occurred in 16 of 45 (35.6%) patients after their initial visit and 11 adverse events in 10 of 45 (22.2%) patients at their most recent injection visit. Antibody (Ab) testing was carried out in 22 patients due to nonresponsiveness; blocking Abs were confirmed by the mouse protection assay in 4 of 22 (18%) patients. Of the Ab-negative patients, 16 resumed responsiveness after dose adjustments and 2 persisted as nonrespondents. Except for 1 patient, the 4 Ab-positive and the 2 clinical nonresponders are being treated with BTX-B. This longest reported follow-up of BTX injections confirms the long-term efficacy and safety of this treatment.

Clinical presentation and management of antibody-induced failure of botulinum toxin therapy

Therapy with botulinum toxin (BT) can fail due to numerous reasons, including failure due to formation of antibodies against BT (BT-AB, AB-TF). AB-TF is a secondary therapy failure, i.e. it occurs during the course of an ongoing BT therapy. It can be subjective or objective, temporary or permanent, and partial or complete. Complete AB-TF is usually preceded by injection series with partial AB-TF in which the therapeutic effect is reduced in its intensity and duration. AB-TF usually occurs within 2 or 3 years after initiation of BT therapy. After 4 years it is rare. BT-AB are neutralising or blocking by definition, i.e. they are directly interfering with BT's biological mechanism of action. Non-neutralizing or non-blocking antibodies occur. BT-AB can be detected by the mouse diaphragm assay, the mouse protection assay, and by patient-based tests such as the sternocleidomastoid test, the extensor digitorum brevis test, and the frowning test. Enzyme-linked immunosorbent assays (ELISA) have a low specificity and a low sensitivity for detection of BT-AB. BT-AB titres drop spontaneously after cessation of BT therapy but latencies are too long to be compatible with an effective BT therapy. BT dosage increase can be successful to overcome AB-TF when AB-TF is partial and when BT-AB titres are low. Usage of alternative BT type A preparations fail to overcome AB-TF. Alternative BT types, such as BT type B and BT type F, are initially successful in AB-TF, but stimulate formation of antibodies against the alternative BT types after few applications. BT-AB reduction with immunosuppressants and inactivation of BT-AB by intravenous immunoglobuline application has not yet been achieved. Extraction of BT-AB by plasmapheresis and immunoadsorption is possible but is associated with substantial logistic problems. Prevention of BT-AB formation, therefore, is of paramount importance. Identified risk factors for BT-AB formation must be taken into account when BT therapy is planned. The most interesting perspective seems to be the development of new BT preparations with reduced antigenicity.

Complications with the use of botulinum toxin

This article discusses complications with the use of botulinum toxin. The following topics are explored: conditions caused by muscle spasms, resistance to botulinum toxin, cosmetic use of botulinum toxin, complications in treating hyperhidrosis, treatment of migraine headaches, and informed consent.

Treatment of cervical dystonia with botulinum toxin

Cervical dystonia (CD) is the most common form of dystonia encountered in a movement disorders clinic. The treatment of this focal dystonia has improved markedly with the advent on botulinum toxin (BTX) injections, which has now become the treatment of choice. Initial studies, even double-blind controlled trials, failed to show robust effect, largely as a result of poor design, often using fixed dosage and site of administration. When the BTX treatment is customized to the needs of the individual patients and the most involved muscles are targeted, the effects can be quite dramatic and the improvement usually lasts 3 to 4 months. Experience and improved skills can largely prevent the adverse effects such as dysphagia and neck weakness. Although there is no evidence that BTX slows the progression of the disease, as a result of early intervention with BTX, many of the long-term complications of CD, such as contractures and radiculopathy, have been largely eliminated.

Different types of botulinum toxin in humans

In humans, botulinum neurotoxin (BoNT) serotype A (BoNT/A) is a useful therapeutic tool, but different BoNT serotypes may be useful when a specific immune resistance related to BoNT/A is proved. BoNT serotype F (BoNT/F) was injected into human muscles but its effects are shorter compared to BoNT/A, whereas BoNT serotype B (BoNT/B) is effective in humans only if injected at very high doses. BoNT serotype C (BoNT/C) has a general profile of action similar to BoNT/A. Nevertheless, a comparison between these different BoNTs in human has not yet been reported. To establish the general profile of these different BoNTs in humans and the spread in near and untreated muscles we conducted an electrophysiological evaluation in 12 healthy volunteers by injecting BoNT/A (BOTOX 15MU), BoNT/B (NeuroBloc 1500MU), BoNT/F (15MU), BoNT/C (15MU) and a saline solution (placebo) in the abductor digiti minimi muscle (ADM) in a double-blind manner. The compound muscle action potential (CMAP) amplitude variation, before and at 2, 4, 6 and 8 weeks after the injections, was evaluated in the ADM, the fourth dorsal interosseus, the first dorsal interosseus and the abductor pollicis brevis APB. We detected an earlier recovery for BoNT/F when compared to the other BoNTs. No significant differences in the local or distant BoNT spread was observed among the different serotypes. We conclude that in humans, BoNT/B and BoNT/C have a general profile similar to BoNT/A and as such these serotypes could be alternative therapies to BoNT/A. BoNT/F might be useful when only a short duration of neuromuscular blockade is required.

Contraindications and complications with the use of botulinum toxin

Cosmetic use of BTX has skyrocketed in recent years, especially since the approval of BTX-A for treatment of glabellar lines. Complications and adverse reactions can easily arise, particularly for the novice injector. This paper provides insights from an experienced physician on how to avoid these complications, and how to treat them when and if they occur. The main cosmetic uses for BTX are analyzed for possible complications and adverse events. Injection techniques are discussed. Comparisons between BTX-A and BTX-B are given to point out the need for different injection techniques based on the product being used. Treatment recommendations for the Glabella, Brow, Crow's Feet, Upper Lip Wrinkling/Lines, Depressor Anguli Oris, Nasolabial Folds, Mentalis, Neck and Hyperhidrosis are discussed, as well as systemic complications. It is important for the injecting physician to be familiar with these potential complications, even though the use of BTX has been safe and generally well tolerated, because it will lead to even greater success with the use of BTX.

Injectable neuromuscular blockade in the treatment of spasticity and movement disorders

Neuromuscular blockade via injection of alcohol, phenol, or botulinum toxin reduces the tone of overactive muscles in order to restore the appropriate balance between agonists and antagonists. Such a restoration allows improved stretch and increased resting length and can reduce the likelihood of contracture. Alcohol or phenol, injected onto the motor nerve, denatures proteins and promotes axonal degeneration. The onset of action is within hours, whereas the duration of action is variable, ranging from 2 weeks to 6 months and beyond. The advantages of alcohol or phenol chemodenervation lie in their low cost and lack of antigenicity. The disadvantages include the technical difficulty of the injections and significant risk for pain as a result of treatment. Botulinum toxins, purified forms of Clostridium botulinum exotoxins, are injected directly into muscle, where they cleave one or more vesicle fusion proteins, thus blocking release of acetylcholine at the neuromuscular junction. Three commercial products--two of serotype A and one of B--are available. Each differs in its unit potency, side effects, and duration of action. On average, botulinum toxin has a clinical onset of action approximately 12 to 72 hours after injection, with a peak effect at 1 to 3 weeks. Effects then plateau for 1 to 2 months, with patients often requiring reinjection approximately every 3 months. Side effects may include local discomfort at the site of the injection and excessive weakness of the injected or nearby muscles, although more distant effects may occur. Antibody formation is a significant clinical concern and eventually obviates treatment benefit in approximately 5% of patients. Switching serotypes may be effective, at least temporarily. Consensus dosing guidelines have been developed and are presented within. Numerous studies have suggested that botulinum toxin has a role in the care of children with spasticity or dystonia related to cerebral palsy, and may improve equinus, gait, upper extremity use, comfort, and care. Evidence of functional improvement remains equivocal in the severely impaired child; however, there is evidence for improvement in less impaired children. The optimal candidate for injectable neuromuscular blockade is one who has a limited number of muscles that need treatment, who does not have fixed contracture, and who retains selective motor control. The ultimate goal of treatment for the hypertonic child is to maximize function, comfort, and independence. Hypertonia is only one aspect of the upper motoneuron syndrome, which includes both positive and negative symptoms. The treatment program, in which chemodenervation is only one tool, requires a multidisciplinary evaluation and individualized plan to address the whole patient.

Quantitative changes in botulinum toxin a treatment over time in patients with essential blepharospasm and idiopathic hemifacial spasm

PURPOSE

To evaluate the quantitative changes in botulinum toxin A (BTA) treatment required over time to achieve relief for 3 to 4 months in patients with essential blepharospasm (EBS) and idiopathic hemifacial spasm (IHFS).

DESIGN

Interventional case series.

METHODS

In this retrospective longitudinal study in an institutional ophthalmologic outpatient clinic, data were retrieved from patient files and a comparison between patients with EBS and IHFS was performed. The patient population consisted of 27 patients, 17 with EBS and 10 with IHFS, who were treated for the first time with BTA injections and were followed up for 4 to 6 consecutive years. All patients initially received 12 or more courses of treatment with a lower dose (<or=20 U) and were then switched to a higher dose (>20 U). The main outcome measures were the shift in the dose-response relationship between the lower and higher doses and were analyzed with respect to four variables: average number of treatments, dosage, duration of therapy, and interval of symptomatic relief.

RESULTS

In the EBS group the mean dose for each patient changed from 16.0 +/- 1.4 U (lower dose) to 24.2 +/- 1.4 U (higher dose). The shift occurred after a mean of 8.8 +/- 2.9 treatments per patient given for a mean of 33.5 +/- 13.3 months. The mean interval of relief was longer with the lower dose than with the higher dose (4.0 +/- 1.4 months vs 3.2 +/- 1.0 months, respectively). In the IHFS group, the mean dose / patient changed from 16.8 +/- 1.2 U to 25.0 +/- 1.8 U, and the switch occurred after a mean of 6.5 +/- 2.3 treatments given over a mean period of 23.8 +/- 6.6 months. The mean duration of treatment with the lower dose was shorter than with the higher dose. The interval of relief was similar for both dose ranges (3.8 +/- 10 months and 4.1 +/- 1.3 months, respectively). The IHFS group switched to the higher dose earlier, by both number and duration of treatments, than the EBS group. Only minor and transient side effects of treatment were observed in both groups.

CONCLUSIONS

Botulinum toxin A is an effective and safe treatment for EBS and IHFS. The dose in our study was increased over time by 50% to achieve 3 to 4 months of symptomatic relief with minimal complications.

Treatment of dystonia

Therapeutic strategies in the treatment of dystonia consist primarily of pharmacologic, surgical, and supportive approaches. Many recent advances have been made in the treatment of dystonia with newer medications, availability of different botulinum toxins, and surgical procedures. However, these treatment modalities all have limiting factors and varying levels of efficacy. Studies range from case reports and open-label trials to double-blind placebo-controlled trials. More research and larger studies are needed to explore these newer medications and surgical techniques for both primary focal and generalized dystonia. Studies in functional outcome and quality of life further support the importance of discovering safe and effective means to treat dystonia. An algorithmic approach may be useful to guide the physician along the various treatment choices.

Botulinum neurotoxin serotypes A and C do not affect motor units survival in humans: an electrophysiological study by motor units counting

OBJECTIVES

Botulinum neurotoxin serotype A (BoNT/A) is a valid therapy for dystonia but repeated BoNT/A injections may induce a clinical immuno-resistance that could be overcome by using other BoNT serotypes. In vitro experiments and our preliminary investigations in vivo, indicate that botulinum neurotoxin serotype C (BoNT/C) could be an effective alternative to BoNT/A. Moreover, in cultured neurons 'in vitro' BoNT/C has been reported to be more toxic than BoNT/A.

METHODS

To verify this possibility, we compare the effect of BoNT/C and BoNT/A on the motor units count in humans by using the electrophysiological motor unit number estimation (MUNE) technique ('multiple point nerve stimulation'). Preliminarily, BoNT/C and BoNT/A dosage was calibrated in a mouse hemidiaphragm neuromuscular junction preparation. Subsequently, 8 volunteers were treated with 3IU of BoNT/C in the extensor digitorum brevis muscle of one foot and 3IU of BoNT/A in the contralateral one. Other 4 subjects were similarly injected at higher doses (10IU of BoNT/C or BoNT/A) to detect a possible dose-toxic effect.

RESULTS

In both groups, no statistically significant variations in MUNE counting or single motor unit potential size were detected after 4 months from injections, when it was evident a recovery from the BoNTs blockade.

CONCLUSIONS

We conclude that BoNT/C, similarly to BoNT/A, is safe and effective in humans and it could be proposed for a clinical use.

Botulinum toxin type A (BOTOX) for treatment of migraine

An open-label study and 2 double-blind, placebo-controlled studies have provided supporting evidence of botulinum toxin type A (BTX-A) as an effective, well-tolerated treatment for migraine. Observed durations of benefit were consistent with known properties of BTX-A. Findings suggest that response may vary by features of preinjection headaches, such as migraine frequency. The precise mechanism by which BTX-A provides pain relief is hypothesized to be related not only to acetylcholine inhibition but also to a blocking action on the parasympathetic nervous system. Additional studies that control factors likely to be related to response may lead to better understanding of the BTX-A effect on migraine and an optimal treatment protocol.

Complications and adverse reactions with the use of botulinum toxin

Botulinum toxins are the causative agents of the severe food-borne illness botulism. With lethal doses approximating 10(-9) g/kg body weight, these neurotoxins represent some of the most toxic naturally occurring substances. Regardless, botulinum toxin is considered a safe therapy for inappropriate muscle spasms with adverse effects being typically self-limited. This article deals with some of the complications that have occurred with these treatments. The greatest concern with the use of BOTOX is probably the formation of blocking antibodies leading to nonresponse of subsequent treatment. Prevalence of resistance is less than 5%. Most complications associated with its aesthetic use are few and anecdotal. Nevertheless, the common problems and pitfalls associated with aesthetic treatment of the various areas of the face and neck with botulinum toxin are discussed. Also included are recommendations as to how to avoid these very undesirable, yet common, problems.

Botulinum toxin B: a review of its therapeutic potential in the management of cervical dystonia

Botulinum toxins are well known as the causative agents of human botulism food poisoning. However, in the past two decades they have become an important therapeutic mainstay in the treatment of dystonias including cervical dystonia, a neurological disorder characterised by involuntary contractions of the cervical and/or shoulder muscles. The toxins inhibit acetylcholine release from neuromuscular junctions, producing muscle weakness when injected into dystonic muscles. Data from three double-blind, randomised, placebo-controlled trials demonstrate that botulinum toxin B effectively reduces the severity, disability and pain of cervical dystonia. In two of the trials, mean Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at week 4 (primary efficacy measure) after botulinum toxin B 10 000U was reduced by 11.7 (25%) or 11 (21%) compared with baseline. These changes were significantly greater than those obtained with placebo [4.3 (10%) or 2 (4%)] and were generally similar in patients who were responsive or resistant to botulinum toxin A. Statistically significant benefits compared with placebo were also evident for a range of other efficacy parameters including TWSTRS-Severity, -Pain and -Disability subscales, patient- assessed pain and patient-/physician-assessed global improvement ratings. In another trial, the percentage of patients with botulinum toxin A-resistant or -responsive cervical dystonia who had a > or =20% improvement in the TWSTRS-Total score between baseline and week 4 was significantly higher with botulinum toxin B 2500 to 10 000U (58 to 77%) than with placebo (27%). Overall, botulinum toxin B was generally well tolerated. The most frequently reported treatment-related adverse events were dry mouth and dysphagia. Most adverse events in patients receiving botulinum toxin B were mild or moderate; no serious adverse events or laboratory abnormalities were associated with the use of botulinum toxin B and, where reported, no patients discontinued from any of the clinical trials as a result of adverse events.

CONCLUSIONS

Botulinum toxin B has shown clinical efficacy in patients with cervical dystonia at doses up to 10 000U and is generally well tolerated. Its efficacy extends to patients who are resistant to botulinum toxin A. Although the potential for secondary resistance to botulinum toxin B remains unclear, it may occur less than with botulinum toxin A because methods for manufacturing commercially available botulinum toxin B do not include lyophilisation and the product does not require reconstitution before use. As injection with botulinum toxin is generally considered the treatment of choice for patients with cervical dystonia, botulinum toxin B should be considered a potential treatment option in this setting.