Serum antibody production to botulinum A toxin

Assessing Botulinum Toxin Effectiveness and Quality of Life in Axillary Hyperhidrosis: A One-Year Prospective Study

This study hypothesized that botulinum toxin (Botox) therapy would sustainably reduce sweat production in axillary hyperhidrosis patients over one year and significantly improve various quality-of-life aspects, including psychological well-being, social interactions, and daily functioning. The objectives were to quantitatively measure changes in sweat production and qualitatively assess the evolving impact on patients' quality of life over one year. Conducted prospectively at the Pius Brinzeu Clinical Emergency Hospital in Timisoara, Romania, this study complied with ethical standards and included adults with primary axillary hyperhidrosis unresponsive to conventional treatments. Participants underwent Botox injections and were evaluated at baseline, six months, and one year, using the Hyperhidrosis Disease Severity Scale (HDSS), WHOQOL-BREF, and the Dermatology Life Quality Index (DLQI), among other tools. Involving 81 patients, the study showed significant improvements in sweat production and quality-of-life metrics. Sweat production decreased from 0.81 g to 0.23 g per 15 min over one year (p < 0.001). HDSS scores reduced from 3.4 to 1.5, indicating a decrease in symptom severity (p < 0.001). The DLQI total score, assessing life quality impact, notably dropped from 19.9 to 6.9 (p < 0.001). Quality-of-life domains also showed significant improvements, especially in the social (from 65.3 to 73.4, p < 0.001) and environmental aspects (from 68.0 to 72.1, p < 0.001). Higher HDSS and sweat production were significantly associated with a lower quality of life on the DLQI (B coefficients of -4.1 and -2.5, respectively). Botulinum toxin therapy proved effective in reducing sweat production and improving the quality of life in axillary hyperhidrosis patients over a one-year period. These improvements were statistically significant in both physical and psychosocial domains. The study highlights the potential long-term benefits of Botox therapy for hyperhidrosis.

Botulinum toxin A treatment in facial palsy synkinesis: a systematic review and meta-analysis

BACKGROUND

Synkinesis is defined as involuntary movements accompanying by voluntary movements and can occur during the aftermath of peripheral facial palsy, causing functional, aesthetic and psychological problems in the patient. Botulinum toxin A (BTX-A) is frequently used as a safe and effective treatment; however, there is no standardized guideline for the use of BTX-A in synkinesis. The purpose of this article is to review and summarize studies about the BTX-A treatment of synkinesis in patients with a history of peripheral facial palsy; including given dosages, injection sites and time intervals between injections.

MATERIALS AND METHODS

A multi-database systematic literature search was performed in October 2020 using the following databases: Pubmed, Embase, Medline, and The Cochrane Library. Two authors rated the methodological quality of the included studies independently using the 'Newcastle-Ottawa Quality Assessment Scale' for non-randomised studies' (NOS).

RESULTS

Four-thousand-five-hundred-and-nineteen articles were found of which 34 studies met the inclusion criteria, in total comprising 1314 patients. Most studies were assessed to be of 'fair' to 'good' methodological quality. The Cohen's kappa (between author FJ and AS) was 0.78. Thirty-one studies investigated the reported dosage injected, 17 studies reported injection location and 17 studies investigated time intervals. A meta-analysis was performed for three studies comprising 106 patients, on the effects of BTX-A treatment on the Synkinesis Assessment Questionnaire (SAQ) scores. The mean difference was 11.599 (range 9.422-13.766), p < 0.01. However, due to inconsistent reporting of data of the included studies, no relationship with the dosage and location could be assessed.

CONCLUSIONS

Many treatment strategies for synkinesis exist, consisting of varying BTX-A brands, dosages, time intervals and different injection locations. Moreover, the individual complaints are very specific, which complicates creating a standardized chemodenervation treatment protocol. The BTX-A treatment of long-term synkinesis is very individual and further studies should focus on a patient-tailored treatment instead of trying to standardize treatment.

A Review of Tolerance and Safety Profiles of Long-Term Botulinum Neurotoxin Type A in Asian Patients with Hemifacial Spasm and Benign Essential Blepharospasm

This article reports the tolerance and long-term safety profiles of botulinum neurotoxin type A among Asian patients with benign essential blepharospasm (BEB) and hemifacial spasm (HFS). We performed a retrospective review of clinical documents and procedure records of consecutive BEB and HFS patients receiving onabotulinum toxin A (Botox) treatment in our clinic over the past 20 years. We reviewed the information of 105 patients diagnosed with BEB (n = 31) and HFS (n = 74). All of the patients were Asian. The mean age of disease onset was 59 (range 37-80) years old for BEB and 61 (range 31-83) for HFS. The mean follow up was 84 (range 12-240) months and the mean number of sessions per patient was 19 (range 1-61). The botulinum toxin dose per session increased significantly in both BEB (16.5 versus 21.6 units, p < .05) and HFS (22.6 versus 26.9 units, p < .05) patients after a mean of 18 sessions; however, the onset time, effective duration and subjective treatment outcome were similar over time in both BEB and HFS patients. At least one local complication was reported among 26% and 41% of patients with BEB and HFS respectively, with ptosis (32%) being most frequent.

Botulinum Toxin A: A Review of Potential Uses in Treatment of Female Urogenital and Pelvic Floor Disorders

Background: Botulinum toxin is an injectable neuromodulator that inhibits transmission between peripheral nerve endings and muscle fibers, resulting in muscle paralysis. Botulinum toxin type A is the most common form of botulinum toxin used in clinical practice.

Methods: In this review, we examine the mechanism of action, formulations, common clinical use in the genital-urinary tract, and potential clinical use in pelvic floor disorders of botulinum toxin type A.

Results: Several aspects of botulinum toxin A make it a favorable therapeutic tool, including its accessibility, its longevity, and its impermanence and reversibility of resultant chemodenervation in a relatively short and safe manner. Although botulinum toxin A has well-established efficacy in treating refractory overactive bladder and neurogenic detrusor overactivity, its use in pelvic floor disorders is still in its infancy.

Conclusion: The efficacy of botulinum toxin A for treating pelvic pain, voiding dysfunction, muscle pain and dysfunction, and certain colorectal-related pain issues shows promise but requires additional rigorous evaluation.

The effectiveness and safety of extracorporeal shock wave therapy (ESWT) on spasticity after upper motor neuron injury: A protocol of systematic review and meta-analysis

BACKGROUND

Spasticity is one of the manifestations of motor dysfunction in upper motor neuron syndrome, which is characterized by increased muscle tone. Spasticity seriously affects the motor function and activity of daily life of patients. Some studies have shown that extracorporeal shock wave therapy (ESWT) can relieve spasticity in recent years. However, the effectiveness and safety of ESWT on spasticity after motor neuron injury have not been confirmed. The purpose of this systematic review (SR) is to evaluate the effectiveness and safety of ESWT on spasticity after upper motor neuron injury.

METHODS

We will search China National Knowledge Infrastructure (CNKI), the Chinese Science and Technology Periodical Database (VIP), Wan Fang Data, China Biology Medicine (CBM), PubMed, Embase, The Cochrane Library, and Web of Science systematically from their inception dates through October 2019 to obtain randomized controlled trials (RCTs) using ESWT to relieve spasticity in patients after upper motor neuron injury. The primary outcome will be the Modified Ashworth Scale (MAS). Secondary outcomes will include Composite Spasticity Scale (CSS), Spasm Frequency Scale, Modified Tardieu Scale (MTS), electrophysiological study (ratio of maximum H reflex to maximum M response, root mean square value, integrated electromyogram, co-contraction ratio, etc.), or other spasticity-related outcomes. In addition, adverse events will also be assessed as safety measurement. Study selection, data extraction, and quality assessment will be performed independently by 2 reviewers. Assessment of risk of bias and data synthesis will be performed using Review Manager software (RevMan, version 5.3.5) and R (version 3.6.1) software.

RESULTS

We will synthesize current studies to evaluate the effectiveness and safety of ESWT on spasticity after upper motor neuron injury.

CONCLUSION

Our study will provide evidence of ESWT on spasticity after upper motor neuron injury.

ETHICS AND DISSEMINATION

The ethical approval is not required since SR is based on published studies. The results of this SR will be published in a peer-reviewed scientific journal according to the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) guidelines.

PROSPERO REGISTRATION NUMBER

CRD42019131059.

Contemporary Review and Case Report of Botulinum Resistance in Facial Synkinesis

BACKGROUND

Botulinum resistance poses significant treatment challenges for both patients and healthcare practitioners. We first present a case highlighting botulinum resistance in a patient who failed to respond to alternative formulations but who responded remarkably to incobotulinum toxinA, an identical toxin free of complexing proteins. Secondly, we provide a treatment algorithm and a review of the literature detailing clinical and immunochemical botulinum resistance.

RESULTS

Patients with botulinum resistance show a predisposition to failure on subsequent injections and possess a propensity toward neutralizing and nonneutralizing antibody development. The mechanisms of resistance are not entirely understood but thought to be secondary to an immunologic response. Risk factors for resistance include higher botulinum doses, more frequent injections, and high total lifetime dosage. Patients may still respond to other botulinum formulations or subtypes; however, this effect may be temporary.

CONCLUSION

This case report describes a patient who responded to incobotulinum toxinA after failing treatment with the identical toxin compounded with buffer proteins, ultimately supporting the possibility of immune-mediated resistance to the surrounding proteins and not the toxin itself. Often, impending treatment resistance is preceded by a poor or limited clinical response. Antibody testing is not indicated because it is neither sensitive nor specific and does not change clinical practice. Initially, higher doses of botulinum may overcome resistance without increasing treatment frequency, and side effects are far less common in those with clinical resistance. If higher dosages fail to produce a response, alternative botulinum formulations or subtypes can be considered. Laryngoscope, 129:2269-2273, 2019.

Positive Effects of Extracorporeal Shock Wave Therapy on Spasticity in Poststroke Patients: A Meta-Analysis

BACKGROUND

Spasticity is a common and serious complication following a stroke, and many clinical research have been conducted to evaluate the effect of extracorporeal shock wave therapy (ESWT) on muscle spasticity in poststroke patients. This meta-analysis aimed to evaluate the therapeutic effect on decreasing spasticity caused by a stroke immediately and 4 weeks after the application of shock wave therapy.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library databases for relevant studies through November 2016 using the following item: (Hypertonia OR Spasticity) and (Shock Wave or ESWT) and (Stroke). The outcomes were evaluated by Modified Ashworth Scale (MAS) grades and pooled by Stata 12.0 (Stata Corp, College Station, TX, USA).

RESULTS

Six studies consisting of 9 groups were included in this meta-analysis. The MAS grades immediately after ESWT were significantly improved compared with the baseline values (standardized mean difference [SMD], -1.57; 95% confidence intervals [CIs], -2.20, -.94). Similarly, the MAS grades judged at 4 weeks after ESWT were also showed to be significantly lower than the baseline values (SMD, -1.93; 95% CIs, -2.71, -1.15).

CONCLUSIONS

ESWT for the spasticity of patients after a stroke is effective, as measured by MAS grades. Moreover, no serious side effects were observed in any patients after shock wave therapy. Nevertheless, our current study with some limitations such as the limited sample size only provided limited quality of evidence; confirmation from a further systematic review or meta-analysis with large-scale, well-designed randomized control trials is required.

Comparative Study of Efficacy and Safety of Botulinum Toxin a Injections and Subcutaneous Curettage in the Treatment of Axillary Hyperhidrosis

BACKGROUND

Primary focal axillary hyperhidrosis is a chronic distressing disorder affecting both the sexes. When the condition is refractory to conservative management, we should go for more promising therapies like intradermal botulinum toxin A (BtxA) injections in the axilla, and surgical therapies like subcutaneous curettage of sweat glands.

AIMS AND OBJECTIVES

The aim of this study is to compare the efficacy, safety and duration of action of intradermal BtxA injections in one axilla and subcutaneous curettage of sweat glands in the other axilla of the same patient with axillary hyperhidrosis.

MATERIALS AND METHODS

Twenty patients (40 axillae) received intradermal BtxA injections on the right side (20 axillae) and underwent tumescent subcutaneous curettage of sweat glands on the left side (20 axillae). Sweat production rate was measured using gravimetry analyses at baseline and at 3 months after the procedure. Subjective analyses were done using hyperhidrosis disease severity scale (HDSS) score at baseline, at 3^rd and 6^th month after the procedure.

RESULTS

At 3 months post-treatment, the resting sweat rate in the toxin group improved by 80.32% versus 79.79% in the subcutaneous curettage method (P = 0.21). Exercise-induced sweat rate in the toxin group improved by 88.76% versus 88.8% in the subcutaneous curettage group (P = 0.9). There was a significant difference in the HDSS score after treatment with both the modalities. There were no adverse events with BtxA treatment compared to very minor adverse events with the surgical method.

CONCLUSION

Both intradermal BtxA injections and tumescent subcutaneous curettage of sweat glands had a significant decrease in the sweat rates with no significant difference between the two modalities. Hence, in resource poor settings where affordability of BtxA injection is a constraint, subcutaneous curettage of sweat glands can be preferred which has been found equally effective with no or minimal adverse events.

Effects of Extracorporeal Shock Wave Therapy on Spasticity in Patients after Brain Injury: A Meta-analysis

[Purpose] The purpose of this meta-analysis was to assess the effects of extracorporeal shock wave therapy (ESWT) on reducing spasticity immediately and 4 weeks after application of ESWT. [Subjects and Methods] We searched PubMed, TCL, Embase, and Scopus from their inception dates through June 2013. The key words "muscle hypertonia OR spasticity" were used for spasticity, and the key words "shock wave OR ESWT" were used for ESWT. Five studies were ultimately included in the meta-analysis. [Results] The Modified Ashworth Scale (MAS) grade was significantly improved immediately after ESWT compared with the baseline values (standardized mean difference [SMD], -0.792; 95% confidence interval [CI], -1.001 to -0.583). The MAS grade at four weeks after ESWT was also significantly improved compared with the baseline values (SMD, -0.735; 95% CI, -0.951 to -0.519). [Conclusion] ESWT has a significant effect on improving spasticity. Further standardization of treatment protocols including treatment intervals and intensities needs to be established and long-term follow up studies are needed.

Type A botulinum neurotoxin complex proteins differentially modulate host response of neuronal cells

Type A Botulinum neurotoxin (BoNT/A), the most potent poison known to mankind, is produced by Clostridium botulinum type A as a complex with neurotoxin-associated proteins (NAPs). Currently BoNT/A in purified and complex forms are both available in therapeutic and cosmetic applications to treat neuromuscular disorders. Whereas Xeomin(®) (incobotulinumtoxin A, Merz Pharmaceuticals, Germany) is free from complexing proteins, Botox(®) (onabotulinumtoxin A, Allergan, USA) contains NAPs, which by themselves have no known role in the intracellular biochemical process involved in the blockade of neurotransmitter release. Since the fate and possible interactions of NAPs with patient tissues after intramuscular injection are not known, it was the aim of this study to evaluate the binding of BoNT/A and/or the respective NAPs to cells derived from neuronal and non-neuronal human tissues, and to further explore neuronal cell responses to different components of BoNT/A. BoNT/A alone, the complete BoNT/A complex, and the NAPs alone, all bind to neuronal SH-SY5Y cells. The BoNT/A complex and NAPs additionally bind to RMS13 skeletal muscle cells, TIB-152 lymphoblasts, Detroit 551 fibroblasts besides the SH-SY5Y cells. However, no binding to these non-neuronal cells was observed with pure BoNT/A. Although BoNT/A, both in its purified and complex forms, bind to SH-SY5Y, the intracellular responses of the SH-SY5Y cells to these BoNT/A components are not clearly understood. Examination of inflammatory cytokine released from SH-SY5Y cells revealed that BoNT/A did not increase the release of inflammatory cytokines, whereas exposure to NAPs significantly increased release of IL-6, and MCP-1, and exposure to BoNT/A complex significantly increased release of IL-6, MCP-1, IL-8, TNF-α, and RANTES vs. control, suggesting that different components of BoNT/A complex induce significantly differential host response in human neuronal cells. Results suggest that host response to different compositions of BoNT/A based therapeutics may play important role in local and systemic symptoms in patients.

Efficacy and safety of serial injections of botulinum toxin A in children with spastic cerebral palsy

BACKGROUND

Botulinum toxin A (BTX-A) has been successfully used as a treatment for children with spastic cerebral palsy; however, the effect of BTX-A on reducing spasticity only lasts a few months, thus serial injections are required. The present study was to evaluate the efficacy and safety of serial injections of BTX-A in children with spastic cerebral palsy.

METHODS

Fifty-two pediatric patients with spastic cerebral palsy, 2-12 years of age (mean age, 4.79 ± 2.70), were retrospectively analyzed. Muscle tone was assessed with the Modified Ashworth Scale, and gait was assessed with the Physician Rating Scale. Assessments were undertaken at baseline, 3 months, and 6 months after serial injections of BTX-A.

RESULTS

The beneficial effects of BTX-A occurred 1 week after the injection, whereas the adverse side-effects appeared within 1 week and lasted <2 weeks. BTX-A significantly improved muscle tone and gait 3 and 6 months after its serial injections compared to baseline (P <0.05).

CONCLUSIONS

Serial injections of BTX-A are effective and safe for children with spastic cerebral palsy. The sideeffects of serial injections of BTX-A are mild and selflimited.

Immunogenicity of botulinum toxins

Botulinum neurotoxins are formulated biologic pharmaceuticals used therapeutically to treat a wide variety of chronic conditions, with varying governmental approvals by country. Some of these disorders include cervical dystonia, post-stroke spasticity, blepharospasm, migraine, and hyperhidrosis. Botulinum neurotoxins also have varying governmental approvals for cosmetic applications. As botulinum neurotoxin therapy is often continued over many years, some patients may develop detectable antibodies that may or may not affect their biological activity. Although botulinum neurotoxins are considered "lower risk" biologics since antibodies that may develop are not likely to cross react with endogenous proteins, it is possible that patients may lose their therapeutic response. Various factors impact the immunogenicity of botulinum neurotoxins, including product-related factors such as the manufacturing process, the antigenic protein load, and the presence of accessory proteins, as well as treatment-related factors such as the overall toxin dose, booster injections, and prior vaccination or exposure. Detection of antibodies by laboratory tests does not necessarily predict the clinical success or failure of treatment. Overall, botulinum neurotoxin type A products exhibit low clinically detectable levels of antibodies when compared with other approved biologic products. This review provides an overview of all current botulinum neurotoxin products available commercially, with respect to the development of neutralizing antibodies and clinical response.

Immunogenicity of botulinum toxins

Botulinum neurotoxins are formulated biologic pharmaceuticals used therapeutically to treat a wide variety of chronic conditions, with varying governmental approvals by country. Some of these disorders include cervical dystonia, post-stroke spasticity, blepharospasm, migraine, and hyperhidrosis. Botulinum neurotoxins also have varying governmental approvals for cosmetic applications. As botulinum neurotoxin therapy is often continued over many years, some patients may develop detectable antibodies that may or may not affect their biological activity. Although botulinum neurotoxins are considered "lower risk" biologics since antibodies that may develop are not likely to cross react with endogenous proteins, it is possible that patients may lose their therapeutic response. Various factors impact the immunogenicity of botulinum neurotoxins, including product-related factors such as the manufacturing process, the antigenic protein load, and the presence of accessory proteins, as well as treatment-related factors such as the overall toxin dose, booster injections, and prior vaccination or exposure. Detection of antibodies by laboratory tests does not necessarily predict the clinical success or failure of treatment. Overall, botulinum neurotoxin type A products exhibit low clinically detectable levels of antibodies when compared with other approved biologic products. This review provides an overview of all current botulinum neurotoxin products available commercially, with respect to the development of neutralizing antibodies and clinical response.

Long-term efficacy of botulinum toxin A for treatment of blepharospasm, hemifacial spasm, and spastic entropion: a multicentre study using two drug-dose escalation indexes

PURPOSE

To investigate the long-term effectiveness and safety of botulinum neurotoxin A (BoNT-A) treatment in patients with blepharospasm (BEB), hemifacial spasm (HFS), and entropion (EN) and to use for the first time two modified indexes, 'botulin toxin escalation index-U' (BEI-U) and 'botulin toxin escalation index percentage' (BEI-%), in the dose-escalation evaluation.

METHODS

All patients in this multicentre study were followed for at least 10 years and main outcomes were clinical efficacy, duration of relief, BEI-U and BEI-%, and frequency of adverse events.

RESULTS

BEB, HFS, and EN patients received a mean BoNT-A dose with a significant inter-group difference (P<0.0005, respectively). The mean (+/-SD) effect duration was statistically different (P=0.009) among three patient groups. Regarding the BoNT-A escalation indexes, the mean (+/-SD) values of BEI-U and BEI-% were statistically different (P=0.035 and 0.047, respectively) among the three groups. In BEB patients, the BEI-% was significantly increased in younger compared with older patients (P=0.008). The most frequent adverse events were upper lid ptosis, diplopia, ecchymosis, and localized bruising.

CONCLUSIONS

This long-term multicentre study supports a high efficacy and good safety profile of BoNT-A for treatment of BEB, HFS, and EN. The BEI indexes indicate a significantly greater BoNT-A-dose escalation for BEB patients compared with HFS or EN patients and a significantly greater BEI-% in younger vsolder BEB patients. These results confirm a greater efficacy in the elderly and provide a framework for long-term studies with a more flexible and reliable evaluation of drug-dose escalation.

Use of high-dose botulinum A toxin in benign essential blepharospasm: is too high too much?

BACKGROUND

Botulinum toxin (Botox) is the mainstay treatment for benign essential blepharospasm. Current treatment practice appears restricted by several reports demonstrating adverse effects and resistance to high-frequency, higher-dose therapy. This study aimed to explore whether high-dose, high-frequency treatments could be used without developing secondary resistance and without significant side-effects in patients refractory to conventional Botox doses.

METHODS

From a cohort of 120 patients being treated with Botox therapy for benign essential blepharospasm and idiopathic hemifacial spasm, case notes from six patients were retrospectively examined. In these patients, therapy had exceeded the recommended 50 units per side for a duration greater than 12 months and at less than 3 monthly intervals. Patterns in subjective severity grading and percentage of improvement as well as reported side-effects were analysed.

RESULTS

All patients described greater than 60% improvement and 0-2 severity grading over a 3- to 15-year period with no evidence of secondary resistance. Side-effects were minor, transient and less frequently reported at higher doses.

CONCLUSION

In a select group of patients, Botox therapy can be used effectively at doses higher than recommended over long periods with minimal side-effects and little evidence of secondary resistance.

Blepharospasm and hemifacial spasm: a protocol for titration of botulinum toxin dose to the individual patient and for the management of refractory cases

PURPOSE

To evaluate a protocol for the treatment of facial dystonias.

METHOD

A retrospective noncomparative interventional case series of all patients who attended a specialised tertiary referral clinic between January 2000 and January 2003. At the start of treatment, patients were seen and treated at weekly intervals until their symptoms were controlled or they developed complications. The sum of the weekly doses was taken as the individual patient dose and then given at 3-4 monthly intervals as required for the individual patient. Refractory cases of spasm underwent orbicularis muscle reduction. Pretarsal spasm was treated with pretarsal botulinum toxin. If the spasm was relieved but the patient could not open their eyelids, a trial of ptosis props was undertaken and the toxin injections continued, before considering a brow suspension. If patients could not see because of a spastic Bell's phenomenon, they were given centrally acting systemic medication.

RESULTS

Of 182 new patients, 63 (35%) required two or more sets of injections to titrate their optimum dose of toxin. Symptoms improved in 169 patients (93%). Of a total 332 new patients and follow-up patients, 47 (14%) underwent surgery during their management, 36 protractor myectomy, and 13 brow suspension. Protractor myectomy improved symptoms in 23 (64%). Brow suspension improved symptoms in 12 patients (92%).

CONCLUSIONS

The dose of botulinum toxin can be titrated to the individual patient, and the refractory cases managed satisfactorily if a logical protocol is followed.

Myotoxic effects of the skeletal muscle-specific immunotoxin, ricin-mAb35, on orbicularis oculi muscle after eyelid injections in rabbits

PURPOSE

The authors recently demonstrated that a single injection of the immunotoxin ricin-mAb35 has potent and long-lasting myotoxic effects in extraocular muscles. The myotoxicity of injected ricin-mAb35 was tested in the eyelids of rabbits to determine its potential for use in the treatment of benign essential blepharospasm and other dystonias.

METHODS

The immunotoxin ricin-mAb35 was injected in one eyelid of adult rabbits. After 1 week, 1 month, or 6 months, the rabbits were euthanized, and the eyelids were prepared for histologic examination of inflammatory cell infiltrate with immunohistochemical localization of cd11b and myosin heavy chain isoform expression. Muscle loss was quantified by analysis of muscle fiber cross-sectional area and total myofiber number.

RESULTS

Within the first week after a single injection of ricin-mAb35, some edema developed, which resolved by the second week. Otherwise, the eyelids were normal in appearance. A short-lived inflammatory response was seen at 1 week, but this resolved 1 month after treatment. One week after injection, there was a significant decrease in the total number of orbicularis oculi myofibers in the ricin-mAb35-treated eyelids. This myofiber loss remained significant 1 month later and was maintained 6 months after the initial injection.

CONCLUSIONS

Direct injection of the immunotoxin ricin-mAb35 resulted in significant, acute muscle loss in the orbicularis oculi of rabbits that was maintained for up to 6 months. Physiologic studies are needed to demonstrate concomitant loss of muscle strength, but these results suggest that ricin-mAb35 injection holds promise as a muscle-weakening agent in the eyelid.

The basic science of botulinum toxin

Understanding the basic science of botulinum toxin should serve as a fundamental first step for clinical therapy. This article endeavors to cover many aspects of basic research that also have clinical import. The two principal toxins of the clostridial family, Clostridium tetani and C botulinum, are described in detail. The five clinical manifestations of botulism poisoning are also outlined, and structural aspects and the mechanism of action of botulinum toxin are then presented. Finally, the immunologic and pharmacologic principles that define the various serotypes of botulinum toxin are set forth.

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.

Orbicularis oculi muscle graft augmentation after protractor myectomy in blepharospasm

PURPOSE

To evaluate the effectiveness of free orbicularis oculi muscle grafts in correcting volume deficit deformities after protractor myectomy in patients with essential blepharospasm.

METHODS

Prospective case series. During the 13-month period from October 2000 through November 2001, all patients with essential blepharospasm undergoing primary eyelid protractor myectomy received an orbicularis oculi muscle graft to replace the volume deficit deformity created by the myectomy. Only patients who had at least 6 months of postoperative follow-up were included in the analysis.

RESULTS

Forty-six patients underwent primary eyelid protractor myectomy and had a free orbicularis oculi muscle graft for volume replacement. All patients had significant functional improvement of their eyelid spasms after the myectomy. Of the 38 patients who underwent upper eyelid myectomy, 3 patients were overcorrected and no patients were undercorrected with the orbicularis muscle graft. Two of the overcorrected patients underwent surgical debulking of their muscle grafts. Of the 8 patients who underwent lower eyelid myectomy, no patients were overcorrected and 1 patient was undercorrected. None of the patients were observed to have any spasms, contractions, or other signs of muscular activity or aberrant innervation of the muscle graft.

CONCLUSIONS

The orbicularis oculi muscle graft is a useful adjunct to protractor myectomy in improving the aesthetic outcomes for blepharospasm patients. Our study demonstrates the viability of the orbicularis oculi muscle graft and may lead to future applications of the graft in facial aesthetics.

Immunologic characterization of spasmodic dysphonia patients who develop resistance to botulinum toxin

The immune status of six spasmodic dysphonia patients who became resistant to botulinum toxin was compared to that of a series of patients who remained responsive. The two groups were similar in terms of age, sex, and cumulative dose of toxin. Five of the resistant patients had a significant titer of anti-botulinum toxin IgG antibodies, as determined by enzyme-linked immunosorbent assay (ELISA). These same five resistant patients had a circulating titer of anti-heavy chain antibodies, but only three of these patients had a circulating titer of anti-light chain antibodies, as determined by Western blotting. By contrast, none of the responsive patients had antibodies against the holotoxin or its two chains. Interestingly, two of the resistant patients also had a low circulating titer of anti-botulinum toxin IgA antibodies. None of the responsive patients was IgA-positive. The cumulative dose of botulinum toxin administered to resistant patients was lower than that customarily associated with emergence of immunity in dystonia patients.

Treatment of blepharospasm with botulinum neurotoxin type A: long-term results

PURPOSE

To describe the long-term efficacy and side effects of treatment of blepharospasm with botulinum neurotoxin type A (Botox).

METHODS

A total of 178 patients with blepharospasm were treated by injections of botulinum toxin in the Eye Clinic of the University of Naples from 1980 to 2001. The severity of spasm for each patient was graded on a four-point scale. Duration of improvement was assessed and reported in months.

RESULTS

Of 178 cases, 10 were lost to follow-up; of the remaining patients, 93% reported improvement after treatments. The mean duration of improvement was 3.6 months. Twelve patients (76%) who underwent more than 14 treatments maintained stable relief. Three patients (1.7%) had a total remission of spasms. Side-effects were local; none of the 168 patients experienced any systemic or toxic reaction.

CONCLUSIONS

Botulinum toxin therapy for blepharospasm can provide long-lasting relief and reduction of spasms in the majority of patients. This therapy has the advantages of being safe, simple, and repeatable.

Separation of the components of type A botulinum neurotoxin complex by electrophoresis

Clostridium botulinum neurotoxins (BoNTs) are the most toxic substances known. They exert potent neuroparalysis on vertebrates. C. botulinum produces seven serotypes of neurotoxin (A-G). BoNT/A, found in bacterial cultures of C. botulinum type A, is produced as a complex with a group of neurotoxin associated proteins (NAPs). Botulinum neurotoxin complex is the only known example of a protein complex where a group of proteins (NAPs) protect another protein (BoNT) against the acidity and proteases of the stomach. Here, we used sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for separation and identification of the constituent proteins of BoNT/A complex. A range of homogenous and gradient SDS-PAGE gels was used to resolve the BoNT/A complex. These gels were run under constant voltage and constant current conditions. The molecular weight and relative amount of each protein band were determined. On a 12.5% homogenous SDS-PAGE under reducing conditions, seven protein bands were identified with average molecular weights of 118, 106, 90, 56, 36, 23 and 17 kDa. The relative amounts of these seven proteins were determined densitometrically as 10, 6, 13, 27, 22, 13 and 8%, respectively. The separation and identification of BoNT/A complex will help in understanding the molecular structure and function of BoNT/A NAPs and their interaction with the toxin, in the toxico-infection process of the botulism diseased state. In particular, the stoichiometry of the individual components is established for a typical preparation of BoNT/A complex. Furthermore, the studies reported here identify the most favorable conditions for the baseline resolution of BoNT/A NAPs proteins for other workers in this field.

Considering the immune response to botulinum toxin

The immune system is unable to determine whether material it encounters is deleterious, benign, or even beneficial to the organism. This presents a significant challenge when protein-based biological therapies, such as botulinum toxin, are administered to patients. Many factors combine to influence the likelihood and the magnitude of an immune response if a response is elicited. Those factors intrinsic to antigens that heighten their immunogenicity include nonhuman origin, larger molecules, and aggregated forms of the protein. Extrinsic factors also must be considered, such as the presence of adjuvants in the formulation, either intended or unintended; increasing amounts of antigen within specific dosing ranges; frequent dosing; and, finally, the genetic predisposition of the patient. Once present, not all immune responses preclude the biological therapy from being clinically effective. Only antibodies that bind botulinum toxin in a manner that neutralizes its biological activity will attenuate its effect on the neuromuscular junction. The majority of anti-toxin antibodies do not affect its function. Finally, although crossreactivity has been reported among the seven botulinum toxin serotypes, non-neutralizing antibodies are present that recognize regions of similarity among the serotypes. No cross-neutralizing antibodies have been described in patients administered any of the toxin serotypes.

Sudomotor testing predicts the presence of neutralizing botulinum A toxin antibodies

The increasing number of patients being treated with botulinum toxin A complex (BoNT/A) has led to a higher incidence of neutralizing anti-BoNT/A antibodies (ABAs). Because BoNT/A is known to inhibit sweating, here we report sudometry as a possibility for predicting the presence of ABA. Sixteen patients suffering from spasmodic torticollis were selected: in 2 patients, BoNT/A treatment continued to be effective, in 9 patients, the treatment effect was impaired, and in 5 patients, secondary treatment failure developed. BoNT/A (100 mouse units, Dysport; Ipsen Pharma, Berkshire, United Kingdom) was injected subcutaneously into the lateral calves. Sweating was visualized with iodine starch staining. In addition, quantitative sudomotor axon reflex testing was performed at the injection site. Individual ABA titers were determined with a mouse bioassay. Results of sudometry significantly correlated with the BoNT/A treatment success. The quantitative sudomotor axon reflex testing was 0.58 +/- 0.63 fraction of the normal mean in patients with treatment failure, 0.18 +/- 0.13 fraction of the normal mean in those who responded partially, and 0 in responders (p < 0.01). Accordingly, the areas of the anhidrotic skin after subcutaneous injections were 4.5 +/- 10.3 cm(2), 32.7 +/- 16.5 cm(2), and 62 cm(2) (p < 0.01). Discrimination analysis indicated that the presence of ABA (6 ABA-positive and 10 ABA-negative) could be predicted correctly in all patients from the results of sudometry. Therefore, sudometry is a useful tool for identifying patients with neutralizing ABAs and might be helpful for identifying reasons for BoNT/A treatment failure.

Cervical dystonia pathophysiology and treatment options

Dystonia is a syndrome of sustained involuntary muscle contractions, frequently causing twisting and repetitive movements or abnormal posturing. Cervical dystonia (CD) is a form of dystonia that involves neck muscles. However, CD is not the only cause of neck rotation. Torticollis may be caused by orthopaedic, musculofibrotic, infectious and other neurological conditions that affect the anatomy of the neck, and structural causes. It is estimated that there are between 60,000 and 90,000 patients with CD in the US. The majority of the patients present with a combination of neck rotation (rotatory torticollis or rotatocollis), flexion (anterocollis), extension (retrocollis), head tilt (laterocollis) or a lateral or sagittal shift. Neck posturing may be either tonic, clonic or tremulous, and may result in permanent and fixed contractures. Sensory tricks ('geste antagonistique') often temporarily ameliorate dystonic movements and postures. Commonly used sensory tricks by patients with CD include touching the chin, back of the head or top of the head. Patients with CD are classified according to aetiology into two groups: primary CD (idiopathic--may be genetic or sporadic) or secondary CD (symptomatic). Patients with primary CD have no evidence by history, physical examination or laboratory studies (except primary dystonia gene) of any secondary cause for the dystonic symptoms. CD is a part of either generalised or focal dystonic syndrome which may have a genetic basis, with an identifiable genetic association. Secondary or symptomatic CD may be caused by central or peripheral trauma, exposure to dopamine receptor antagonists (tardive), neurodegenerative disease, and other conditions associated with abnormal functioning of the basal ganglia. In the majority of patients with CD, the aetiology is not identifiable and the disorder is often classified as primary. Unless the aetiological investigation reveals a specific therapeutic intervention, therapy for CD is symptomatic. It includes supportive therapy and counselling, physical therapy, pharmacotherapy, chemodenervation [botulinum toxin (BTX), phenol, alcohol], and central and peripheral surgical therapy. The most widely used and accepted therapy for CD is local intramuscular injections of BTX-type A. Currently, both BTX type A and type B are commercially available, and type F has undergone testing. Pharmacotherapy, including anticholinergics, dopaminergic depleting and blocking agents, and other muscle relaxants can be used alone or in combination with other therapeutic interventions. Surgery is usually reserved for patients with CD in whom other forms of treatment have failed.

Botulinum toxin for blepharospasm and hemifacial spasm: stability of duration of effect and dosage over time

BACKGROUND

Patients often ask whether the relief they experience with botulinum A toxin will diminish with time, resulting in the need for an increased dosage and more frequent administration. We performed a retrospective study to examine these questions.

METHODS

We reviewed the charts of 28 patients (17 with benign essential blepharospasm and 11 with hemifacial spasm) seen between 1989 and 1994 by one ophthalmologist at the botulinum clinic at a university-affiliated hospital in Edmonton. All patients had had at least 6 botulinum A toxin treatments; 17 had had 12 or more treatments, and 7 had had 20 or more treatments. A follow-up data collection form was used to record duration of effect, dosage and side effects. We analysed the data on duration of effect and dosage versus treatment number for individual patients and for the overall group using linear regression analysis.

RESULTS

There was no clinically or statistically significant change in duration of effect over time (mean slope 0.024 [95% confidence interval (CI) -0.218 to 0.266]). A positive mean slope of 0.677 (95% CI 0.252 to 1.102) was observed for the change in dosage over time. This trend was most likely related to the practitioner's habit of using half the normal maintenance dosage for the initial injection. When we eliminated the data for the first injection and recalculated the dosage requirement over time, the mean slope for the change in dosage was 0.321 (95% CI -0.084 to 0.726), confirming stable dosage requirements over time.

INTERPRETATION

The results suggest that patients can be reassured that duration of benefit and dosage requirements will likely remain stable over time for at least their first 20 treatments.

Botulinum toxin A for axillary hyperhidrosis (excessive sweating)

BACKGROUND

Treatment of primary focal hyperhidrosis is often unsatisfactory. Botulinum toxin A can stop excessive sweating by blocking the release of acetylcholine, which mediates sympathetic neurotransmission in the sweat glands.

METHODS

We conducted a multicenter trial of botulinum toxin A in 145 patients with axillary hyperhidrosis. The patients had rates of sweat production greater than 50 mg per minute and had had primary axillary hyperhidrosis that was unresponsive to topical therapy with aluminum chloride for more than one year. In each patient, botulinum toxin A (200 U) was injected into one axilla, and placebo was injected into the other in a randomized, double-blind manner. (The units of the botulinum toxin A preparation used in this study are not identical to those of other preparations.) Two weeks later, after the treatments were revealed, the axilla that had received placebo was injected with 100 U of botulinum toxin A. Changes in the rates of sweat production were measured by gravimetry.

RESULTS

At base line, the mean (+/-SD) rate of sweat production was 192+/-136 mg per minute. Two weeks after the first injections the mean rate of sweat production in the axilla that received botulinum toxin A was 24+/-27 mg per minute, as compared with 144+/-113 mg per minute in the axilla that received placebo (P< 0.001). Injection of 100 U into the axilla that had been treated with placebo reduced the mean rate of sweat production in that axilla to 32+/-39 mg per minute (P<0.001). Twenty-four weeks after the injection of 100 U, the rates of sweat production (in the 136 patients in whom the rates were measured at that time) were still lower than base-line values, at 67+/-66 mg per minute in the axilla that received 200 U and 65+/-64 mg per minute in the axilla that received placebo and 100 U of the toxin. Treatment was well tolerated; 98 percent of the patients said they would recommend this therapy to others.

CONCLUSIONS

Intradermal injection of botulinum toxin A is an effective and safe therapy for severe axillary hyperhidrosis.

Post-stroke spasticity management with repeated botulinum toxin injections in the upper limb

OBJECTIVE

Although the botulinum toxin A (BTX-A) treatment has proved effective in spasticity management, no information is available with regard to the effects of repeated injections over time.

DESIGN

To evaluate the effects of BTX-A on moderate or severe upper limb spasticity, an exploratory investigation was performed on 28 stroke patients treated for 2 yr or longer and observed for 3 yr. Every 3 to 5 mo, each patient received BTX-A injections in upper limb muscles. The assessment, performed before and 1 mo after each injection for a median of 28 mo, included technical and functional objectives and the burden of care. The former were evaluated by using the modified Ashworth Scale for spasticity and the goniometric measurement of rest position and range of motion; functional objectives were evaluated by means of the Frenchay Arm Test and a patient/caregiver goals assessment scale.

RESULTS

BTX-A treatment was followed by an improvement in all technical outcome measures. Motor dexterity scores improved in only 8 of 28 patients, vs. daily living activities, which increased in all subjects. Although the average dosage injected per session did not change, intervals between injections became longer. No relationship between either spasticity onset or residual motoricity and response to treatment could be found.

CONCLUSIONS

This investigation is relevant clinically because repeated BTX-A injections show unchanging effectiveness in the management of focal spasticity after stroke.

Comparison of mouse bioassay and immunoprecipitation assay for botulinum toxin antibodies

OBJECTIVE

To compare a recently developed immunoprecipitation assay (IPA) to the mouse protection bioassay (MPB), currently considered the "gold standard", for detecting antibodies against botulinum toxin A (BTX-A) and to correlate these assay results with clinical responses to BTX-A injections.

METHODS

MPB and IPA assays were performed on serum samples from 83 patients (38 non-responders, 45 responders) who received BTX-A injections. Six non-responders had serum tested on two separate occasions. Some patients also received a "test" injection into either the right eyebrow (n=29) or right frontalis (n=19).

RESULTS

All patients antibody positive (Ab+) by MPB were also Ab+ by IPA, whereas an additional 19 patients (17 with reduced or no clinical response) who were MPB Ab- were Ab+, with low titres, by IPA. Two of these 19 patients (non-responders) were initially MPB Ab- but later became MPB Ab+. Similar to previous studies, the sensitivity for the MPB was low; 50% for clinical, 38% for eyebrow, and 30% for frontalis responses whereas the IPA sensitivity was much higher at 84% for clinical (p<0.001), 77% for eyebrow (p=0.111, NS) and 90% for frontalis responses (p<0.02). The IPA specificity was 89% for clinical, 81% for eyebrow, and 89% for frontalis responses, whereas the MPB specificity was 100% for all three response types, which were all non-significant differences.

CONCLUSIONS

Both assays had high specificity although the sensitivity of the IPA was higher than the MPB. In addition, the IPA seems to display positivity earlier than the MPB, and as such, it may prognosticate future non-responsiveness. Eyebrow and frontalis "test" injections correlated well with clinical and immunological results and are useful in the assessment of BTX non-responders.

Association of adhesive macromolecules with terminal sprouts at the neuromuscular junction after botulinum treatment

Small quantities of botulinum toxin (BTX) are useful in the treatment of certain movement disorders, such as laryngeal spasmodic dysphonia, blepharospasm, and cervical dystonia. However, the corrective paralytic effects of BTX are only temporary, in part because of the formation of remodeled neuromuscular junctions. Here, we questioned whether various factors within and near the neuromuscular junction could contribute to the remodeling seen after BTX treatment. BTX was injected subcutaneously in the region of the levator auris longus muscle. At 1-week intervals, levator auris longus muscles were removed and examined histochemically. As previously described, BTX treatment results in a progressive elongation of end plates. The neural cell adhesion molecule was not associated with the elongated end plates but was associated with the BTX-induced nerve sprouts after long intervals (3 to 4 weeks). Similarly, after BTX, laminin-1 (composed of alpha 1, beta 1, and gamma 1 chains) reactivity was associated with the nerve sprouts, but not with the end plates. Laminin beta 2 reactivity at the end plate dispersed somewhat within 1 week but remained diffusely associated with the elongating end plates for up to 5 weeks. Together these results suggest that neural cell adhesion molecule and laminins may participate in the sprouting observed after BTX treatment and that alterations in laminin beta 2 expression may participate in initial loss of contacts.

Pharmacologic characterization of botulinum toxin for basic science and medicine

The use of Botulinum neurotoxin (BoNT) is increasing in both clinical and basic science. Clinically, intramuscular injection of nanogram quantities of BoNT is fast becoming the treatment of choice for a spectrum of disorders including movement disorders such as torticollis, blepharospasm, Meige Disease, and hemifacial spasm (Borodic et al., 1991, 1994a; Jankovic and Brin, 1991; Clarke, 1992). Neuroscientists are using BoNTs as tools to develop a better understanding of the mechanisms underlying the neurotransmitter release process. Consequently, our ability to accurately and reliably quantify the biologic activity of botulinum toxin has become more important than ever. The accurate measurement of the pharmacologic activity of BoNTs has become somewhat problematic with the most significant problems occurring with the clinical use of the toxins. The biologic activity of BoNTs has been measured using a variety of techniques including assessment of whole animal responses to in vitro effects on neurotransmitter release. The purpose of this review is to examine the approaches employed to characterize, quantify and investigate the actions of the BoNTs and to provide a guide to aid investigators in determining which of these methods is most appropriate for their particular application or use.

Botulinum toxin for spasticity and athetosis in children with cerebral palsy

Botulinum toxin A has been used therapeutically in humans for a variety of conditions since 1980. Over the past few years, it has been used more frequently for spasticity management. We describe the use of botulinum toxin for spasticity or athetosis management in three children with cerebral palsy. Two of these children had severe spasticity or athetosis that was unresponsive to other forms of treatment. The injection of botulinum toxin decreased pain and improved ease of care in these two children. Another child with left hemiparetic cerebral palsy underwent injection of botulinum toxin into upper and lower limb muscles to improve function. In this patient, the injections were combined with other forms of treatment. In this patient spasticity was decreased and function was increased temporarily. The use of botulinum toxin in general is discussed and related to these three cases.

The use of botulinum A toxin to ameliorate facial kinetic frown lines

PURPOSE

External photography and subjective response were used to evaluate the use of botulinum A toxin to diminish glabellar kinetic folds.

METHODS

Eleven patients with glabellar folds and midline forehead wrinkling received one to four injections of 0.1 ml of 100 U/1 ml botulinum A toxin. The injections were given into the procerus or corrugator muscles or both. The number of injections corresponded to the wrinkle lines in each patient. The patients were examined and photographed just before the injections and at 7 to 10 days after the injections. Treatment efficacy was judged by photographic evaluation and by the patient's subjective evaluation of the effect of the treatment.

RESULTS

Photographic evaluation showed objective improvement in the glabellar wrinkling in 6 of 11 patients in relaxed facial position and in all 11 patients during contraction of the periocular mulscles. Ten of the 11 patients reported satisfaction with their cosmetic results and indicated that they would choose to have the procedure done again.

CONCLUSIONS

The results of this study suggest that botulinum A toxin is a safe and effective treatment for glabellar folds.

Botulinum-A toxin as a treatment of detrusor-sphincter dyssynergia: a prospective study in 24 spinal cord injury patients

PURPOSE

The paralytic effect of botulinum-A toxin injections on the external urethral sphincter was investigated prospectively in patients with neurogenic voiding disorders.

MATERIALS AND METHODS

Transurethral versus transperineal botulinum-A toxin injections were performed in 24 spinal cord injury male patients with detrusor-sphincter dyssynergia and the respective efficacy was compared.

RESULTS

In 21 of 24 patients detrusor-sphincter dyssynergia was significantly improved with a concomitant decrease in post-void residual volumes in most cases. Botulinum-A toxin effects lasted 3 to 9 months, making reinjections necessary.

CONCLUSIONS

Although costly, botulinum-A toxin injections, which aim at suppressing detrusor-sphincter dyssynergia but not bladder neck dyssynergia, appear to be a valid alternative for patients who do not desire surgery or are unable to perform self-catheterization.

Botulinum toxin F in the treatment of torticollis clinically resistant to botulinum toxin A

Two reports have shown a Japanese preparation of botulinum toxin type F (BTX-F) to be an effective alternative for patients with torticollis who develop clinical resistance to botulinum toxin type A (BTX-A). A group of patients with torticollis, comprising five secondary non-responders and one primary non-responder, were treated with a preparation of BTX-F produced in the UK (Speywood Pharmaceuticals). A low dose of BTX-F (220 mouse units (MU) in total) was given into clinically affected neck muscles, followed six weeks later by an injection of a total of 520 MU. Antibodies to BTX-A (mouse protection assay) were present in all secondary non-responders but not in the primary non-responder. No patients developed atrophy after injection of Dysport BTX-A (40 MU) into the left extensor digitorum brevis muscle whereas pronounced atrophy occurred in all patients after injection of 40 MU of BTX-F into the right extensor digitorum brevis muscle. Three patients improved subjectively after treatment with 220 MU BTX-F and five (all secondary non-responders) after the subsequent dose of 520 MU (two considerably), with reduced Tsui scores, but group scores were only significantly changed after the higher dose. The primary non-responder remained unchanged after both doses of BTX-F. One patient reported mild dysphagia with 520 MU BTX-F. Mean duration of improvement with 520 MU BTX-F was five (range 4-6)weeks. Thus BTX-F provides benefit for BTX-A non-responders with few side effects but for a shorter period than BTX-A, possibly due to relative underdosing. As with BTX-A, biological sensitivity to BTX-F does not necessarily predict a clinical response.

Long-term changes in duration of relief with botulinum toxin treatment of essential blepharospasm and hemifacial spasm

PURPOSE

To determine long-term changes in duration of relief with serial treatments of botulinum A toxin (BAT) used to treat benign essential blepharospasm and hemifacial spasm, in view of conflicting reports as to whether BAT has an increasing, decreasing, or an unchanging duration of effect over a long period of treatment.

METHODS

Thirty-two patients with facial dyskinesia (20 with essential blepharospasm, 12 with hemifacial spasm) were followed between 5 and 9 years through a mean of 18 (range, 12-32) BAT treatments with prospective documentation of intervals of relief from symptoms. Repeated measures and linear regression analyses were used to determine trends in each group.

RESULTS

Marked inter- and intrapatient variability was found in the length of effect of BAT. Statistical analysis showed no significant changes in mean duration of relief within each group (P = 0.65 for essential blepharospasm, 0.36 for hemifacial spasm). There was a trend to slow decline in the interval of relief, especially in patients with an initial duration of effect greater than 150 days. No relation was found between duration of relief and age or sex of patient or grade and duration of disease before initial treatment.

CONCLUSION

In the long term, the mean duration of relief from symptoms with BAT changes little over a period of serial treatments. Short-term fluctuations in the length of therapeutic effect did not indicate the development of a resistance to treatment.