Safety of high-dose botulinum toxin type A therapy for the treatment of pediatric spasticity

The Role of Botulinum Toxin Type-A in Spasticity: Research Trends from a Bibliometric Analysis

Botulinum toxin type-A (BoNT-A) has emerged as a key therapeutic agent for the management of spasticity. This paper presents a comprehensive bibliometric and visual analysis of research concerning BoNT-A treatment of spasticity to elucidate current trends and future directions in this research area. A search was conducted in the Web of Science database for articles focused on the use of BoNT-A in spasticity published between 2000 and 2022. We extracted various metrics, including counts of publications and contributions from different countries, institutions, authors, and journals. Analytical methods in CiteSpace were employed for the examination of co-citations, collaborations, and the co-occurrence of keywords. Our search yielded 1489 publications. Analysis revealed a consistent annual increase in research output. The United States, United Kingdom, and Italy were the leading contributors. The top institution in this research was Assistance Publique Hopitaux, Paris. The journal containing the highest number of relevant publications was Toxins. Key frequently occurring keywords were 'stroke', 'cerebral palsy', 'adult spasticity', and 'upper extremity'. This study identified 12 clusters of keywords and 15 clusters of co-cited references, indicating the main focus areas and emerging themes in this field. This study comprehensively analyzed and summarized trends in BoNT-A research in the field of spasticity over the past 22 years.

Safety of botulinum toxin injections in children less than one year old: A retrospective chart review

PURPOSE

Infants can have muscle hypertonia due to cerebral palsy, muscle strength imbalances due to brachial plexus palsy, refractory clubfoot, and torticollis. These muscle problems can cause significant development impairments. A child with severe sialorrhea and dysphagia from leukodystrophy can aspirate, causing respiratory problems. Botulinum toxin (BoNT) injections can improve these conditions but may lead to adverse effects from the toxin spreading to non-targeted muscles, potentially impacting breathing, swallowing, and overall strength. This is particularly concerning in infants. This study assessed the safety of BoNT injections in children less than one year of age.

METHODS

This was a retrospective cohort study.

RESULTS

Forty-seven patients (22 male, 25 female) received BoNT injections before one year of age (three to 12 months). Thirty-seven received one round of injections and 10 were injected on multiple occasions. Forty-five received onabotulinumtoxinA (15-100 units [U], 1.9-15.2 U/kg), one received abobotulinumtoxinA (70 U, 9.0 U/kg), and one received incobotulinumtoxinA (25 U, 3.5 U/kg). Lower extremities were treated in 15 patients, upper extremities in 38, the sternocleidomastoid in two, and the salivary glands in one. Forty-five patients had no reported complications. One experienced transient fever, vomiting, and diarrhea. The parent of another reported subjective weakness in one muscle.

CONCLUSION

BoNT injections in children less than one year of age appear to be safe.

Adverse effects following botulinum toxin A injections in children with cerebral palsy

The study aimed to analyze the adverse events associated with botulinum toxin A (BoNT-A) injections in children with cerebral palsy (CP). The literature search was completed using the Medline, PubMed, Google Scholar, Scopus, and Cochrane Library databases from the earliest date possible up to December 2021. Search terms included 'botulinum toxin', 'cerebral palsy', 'spasticity', 'adverse effects', 'side effects', 'undesirable effects', 'complications', 'lower limb', 'upper limb', and 'children' including combinations of index and free-text terms. Fifty-five studies were included in the study. Data on 6333 pediatric patients and more than 14 080 BoNT-A injections were collected. Respiratory symptoms and respiratory tract infections were the most frequently registered adverse events (AEs). Other common AEs included procedural/focal AEs, flu-like symptoms, and asthenia. Sentinel events including four cases of death were reported. AEs were more frequent and severe in high-dose patients; however, the capacity of BoNT-A to spread systemically remains unclear. Since severe adverse events are not common, further research is needed to collect more definitive clinical and homogeneous data to support the findings of the present research and clarify the safety profile of BoNT-A, especially regarding the incidence of respiratory issues and complications in GMFCS IV or V patients.

A consensus statement on the use of botulinum toxin in pediatric patients

Botulinum toxin has been used in medicine for the past 30 years. However, there continues to be controversy about the appropriate uses and dosing, especially in the pediatric population. A panel of nine pediatric physiatrists from different regions and previous training programs in the United States were nominated based on institutional reputation and botulinum toxin (BoNT) experience. Based on a review of the current literature, the goal was to provide the rationale for recommendations on the administration of BoNT in the pediatric population. The goal was not only to review safety, dosing, and injection techniques but also to develop a consensus on the appropriate uses in the pediatric population. In addition to upper and lower limb spasticity, the consensus also provides recommendations for congenital muscular torticollis, cervical dystonia, sialorrhea, and brachial plexus palsies.

Botulinum Neurotoxin Injections in Childhood Opisthotonus

Opisthotonus refers to abnormal axial extension and arching of the trunk produced by excessive contractions of the paraspinal muscles. In childhood, the abnormal posture is most often related to dystonia in the setting of hypoxic injury or a number of other acquired and genetic etiologies. The condition is often painful, interferes with ambulation and quality of life, and is challenging to treat. Therapeutic options include oral benzodiazepines, oral and intrathecal baclofen, botulinum neurotoxin injections, and deep brain stimulation. Management of opisthotonus within the pediatric population has not been systematically reviewed. Here, we describe a series of seven children who presented to our institution with opisthotonus in whom symptom relief was achieved following administration of botulinum neurotoxin injections.

Botulinum Toxin Type A injections for pediatric spasticity: Keeping our patients informed and practices safe

Serious adverse events (serious AEs) following the therapeutic use of Botulinum Toxin Type A (BoNT-A) are infrequent. Children with pediatric spasticity often have comorbidities that can cloud causation around an adverse event (AE). If a serious AE occurs, clear documentation of information sharing and informed consent as well as the provider-patient relationship are critical to minimizing litigation risks. Reviewing the litigation that has occurred following BoNT-A for pediatric spasticity can offer insight into how providers' perspectives regarding this intervention may differ from those of the public who might serve as jurists. This article offers suggestions for content sharing during the consent process to optimize patient understanding about potential adverse events.

A pragmatic approach to Botulinum Toxin safety

Botulinum Toxin (BoNT) is widely used to treat hypertonia in pediatric patients. Although serious adverse events (AEs) occur infrequently, they can lead to significant patient morbidity and mortality. This paper will discuss potential safety risks that may affect outcomes, medical comorbidities, medication dosing, targeting techniques, and muscle morphology. It is the responsibility of the physician to discuss risks and benefits regarding the use of BoNT and mitigate risks of AEs while maximizing the effectiveness of the medication.

Case of iatrogenic botulism after botulinotherapy in clinical practice

Injections of botulinum toxin are widely used in different medical fields, namely neurology, urology, stomatology, cosmetology, gastroenterology etc. Preparations of botulinum toxin type A (BTA) prevent the release of acetylcholine at the endings of motor nerves leading to the long-term muscle relaxation. It has been acknowledged that treatment with BTA has very good safety profile and tolerability. Extremely rare but severe complication of botulinotherapy (BT) is a condition, which is associated with generalized muscle Weakness, swallowing difficulty, respiratory arrest, and may lead to the lethal outcomes in the solitary cases. Such disorders, which present like botulism, are known as botulism-like syndrome and iatrogenic botulism. We report a clinical case of such complication in the paper. The probability of the development of such rare but severe complications necessitates certain awareness and vigilance among clinicians performing BT.

Comparison of efficacy and toxicity between botulinum toxin subtypes A1 and A2 in cynomolgus macaques

Botulinum toxin type A (subtype A1) is used as therapeutic agent for some neurological disorders causing spasticity. The toxin products have an upper dosage limit, and their adverse events, such as side effects of diffusion following high-dose administration, have become serious issues. Therefore, a preparation with greater therapeutic efficacy at lower dosages and less diffusion in the body is desired. We have attempted to produce neurotoxin derived from subtype A2 (A2NTX), which has a different amino acid sequence from that of neurotoxin derived from subtype A1. In this study, to investigate whether A2NTX is applicable for treatment, we compared the muscle relaxation effects and the toxicity between A1LL and A2NTX in adult cynomolgus macaques. In the isometric muscle contraction test elicited by 30 Hz tetanus stimulation, the contractions observed in the 0.4 U/site A1LL-treated group were similar in value to those in the 0.13 U/site A2NTX-treated group. In the toxicity test, the 12 and 24 U/kg A1LL- and A2NTX-treated groups all exhibited similar signs of toxicity regarding symptoms, rate of weight loss, and decrease in the length of the right lower leg perimeter. Thus, A2NTX demonstrated approximately 3.0-times higher muscle relaxation activity than A1LL, and their toxicity was equivalent. This study suggested that A2NTX products are more suitable for the treatment of neurological disorders.

Three new case reports of Arteriovenous malformation-related Amyotrophic Lateral Sclerosis

Despite recent advances in genetics, in most cases of Amyotrophic Lateral Sclerosis (ALS) no etiological factor can be identified. Cerebral Arteriovenous Malformations (AVMs) have been associated with ALS development in a few studies, but the nature of this connection is unclear. We report here 3 additional cases of young adults, who had undergone repeated embolizations for complex AVMs, and who then developed, after many years, ALS symptoms and signs. In two of these cases Vascular Endothelial Growth Factor (VEGF) levels were found to be extremely high, in contrast to previous reports. Our 3 cases, together with the previously reported ones, suggest that a subgroup of patients with AVMs, with a particular profile of a complex nidus with repeated embolization procedures, are at increased risk of developing ALS. The reason for this association is unclear, but may relate to dysregulation of secreted vascular factors, as suggested by our VEGF results, or more broadly to the neurovascular hypothesis of ALS. Alternatively, a transneuronal type of neurodegeneration may be involved.

Long-Term Safety and Efficacy of Botulinum Toxin A Treatment in Adolescent Patients with Axillary Bromhidrosis

BACKGROUND

For adolescent bromhidrosis, the long-term safety and efficacy of botulinum toxin type A (BTX-A) treatment are not clear to date.

PATIENTS AND METHODS

From June 2011 to July 2016, 62 adolescent patients with primary axillary bromhidrosis were recruited and 50 U of BTX-A was administered in each axilla. Repetitive injections were performed when the malodor returned.

RESULTS

The average follow-up was 2.64 years. There were no reported local or systemic adverse effects. After the first BTX-A injection, 61.3% of patients (38/62) maintained the duration of more than 4 weeks. Of these patients, 21 patients underwent two sessions, 8 patients underwent three sessions, and 4 patients underwent four sessions. Twenty-four of sixty-two (38.7%) of patients had the duration of < 4 weeks. The second injection with the same dose was immediately administered, and the resulting duration increased to 9 weeks. Nineteen patients received the third injection with 100 U per underarm, and the resulting duration was extended up to 16 weeks. Overall, 82% of patients (51/62) ranked the BTX-A treatment to be very good or good.

CONCLUSION

For adolescent axillary bromhidrosis, BTX-A injection is safe and effective over a long-term follow-up. The duration of efficacy is variable, and the dosage should be fine-tuned based on the individual response.

LEVEL OF EVIDENCE IV

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[Treatment of spasticity after traumatic brain injury in children: the role of botulinum toxin therapy]

Traumatic brain injury (TBI) is one of the main reasons of death and disability in children and adolescents in Russia and abroad. Spasticity is a frequent outcome of the TBI that influences on the rehabilitation prognosis, degree of movement disorders and quality of life after trauma. Early spasticity correction and complex rehabilitation lead to the optimal recovery and prevent secondary complications. This review presents the current data about the prognostic role of the spasticity in children after TBI, methods of its correction and their scientific evidence. Limitations and challenges of per-oral antispastic agents are described especially for the patients with local spasticity. Attention is focused on the methods of treatment of local hypertonus, in particular botulinum toxin A (BTA) injections proved to be effective in adults with acquired brain injury. The article summarizes the results of international investigations, systematic reviews and consensus statements about the efficacy and safety of botulinum toxin treatment in children after the TBI. The authors describe an algorithm of the optimal patient selection and goal setting for BTA injections in children with acquired brain injury.

Clinical Management of Dystonia in Childhood

Dystonia is one of the most frequent movement disorders in childhood. It can impede normal motor development and cause significant motor disability. The diagnostic evaluation of childhood dystonia is challenging due to the phenotypic variability and heterogeneous etiologies. Evidence to guide the diagnostic evaluation and treatment is limited. Assessment is primarily directed by clinical history and distinctive examination findings. Neuroimaging is typically necessary to evaluate for acquired or complex inherited dystonias. A trial of levodopa can be both diagnostic and therapeutic in children with dopa-responsive dystonia. However, for the majority of children with early-onset dystonia, treatment is symptomatic with varying efficacy. There is a paucity of therapeutic trials for childhood dystonia and most treatment recommendations are consensus or expert opinion driven. This review summarizes the available evidence and guidelines on the diagnostic evaluation and pharmacological treatment of childhood-onset dystonia and provides practical frameworks to approach both issues based on best evidence.

Establishing a Multidisciplinary Approach to the Management of Neurologic Disease Affecting the Urinary Tract

Neurologic diseases often affect the urinary tract and may be congential or acquired. The progressive nature of many neurologic diseases necessitates routine surveillance and treatment with a multidisciplinary approach. Urologic treatments may interact with pharmacologic or procedural interventions planned by other specialists, mandating close coordination of care and communication among providers. Primary care and nursing often can serve as the quarterbacks of the multidisciplinary team by identifying when a slowly progressive condition warrants further investigation and management by specialists.

Novel Use of Botulinum Toxin to Ameliorate Arthrofibrosis: An Experimental Study in Rabbits

This study aimed to investigate the effects of intra-articular botulinum toxin in preventing arthrofibrosis. Arthrofibrosis was induced in both stifle joints of 20 rabbits by transecting the anterior cruciate ligament under intramuscular anesthesia with ketamine and xylazine. Intra-articular toxin at a dose of 0.6 ml (50 unit) and physiologic saline solution (0.6 ml) were injected into the right and left stifle joints, respectively, 3 times with a 1-week interval between each injection. The rabbits were euthanized in the 12th week via high dose anesthesia to remove the stifle joint. The severity of adhesions was assessed, applying a universal scoring system. Also the stifle joints were histologically evaluated for fibrosis. With regards to severity of adhesion a significant reduction in the adhesion score was observed in the toxin-treated group in comparison to untreated controls with mean ± SE values of 0.2 ± 0.1 and 2.4 ± 0.2, respectively ( p < 0.01). The histological evaluation showed no significant fibroblast in the toxin-treated group versus dense fibers with mature fibroblasts in the control group. Our results suggest that botulinum toxin demonstrated efficacy in preventing adhesion after knee surgery and all the parameters monitored showed consistent statistically significant improvement.

A novel use for botulinum toxin A in the management of ileostomy and urostomy leaks

PURPOSE

To assess the efficacy of Botulinum toxin A (BoNT-A) in the treatment of patients with hypercontractile stomas resulting in repeated pouching system failures and leaks.

DESIGN

Prospective case series.

SUBJECTS AND SETTING

Ten consecutive patients who presented to the outpatient stoma clinic with actively contractile stomas that shortened spasmodically resulting in leaks were offered treatment with BoNT-A if treatment with other measures had been unsuccessful.

METHODS

Following an observed reduction in the peristalsic shortening of a stoma after intradermal injection of BoNT-A for hyperhidrosis, we conducted a prospective case series of 10 patients with pouch adhesive failures attributed to spasmodic shortening of the stoma. Ten patients, 3 with urostomies and 7 with ileostomies, were offered BoNT-A injection. The first was treated cautiously with 15 units of BoNT-A injected into the muscularis layer, followed by an additional 25 units injected 1 month later. Subsequent patients received doses varying from 50 to 100 units. Ongoing treatments ranged 50 to 100 units every 3 to 6 months.

RESULTS

Seventy percent (n = 7) of patients reported a useful reduction in leakage and pouching system seal failures. In these 7 patients, the frequency of pouch changes changed from an average of 2.18 to 0.44 per day (over all 10 patients this was a change from an average of 2.35 per day to 1.16 per day). No adverse side effects were reported.

CONCLUSION

Findings from this clinical case series suggest that BoNT-A may be a promising treatment in the management of patients with leaks caused by actively contracting stomas.

Botulinum toxin in the management of facial paralysis

PURPOSE OF REVIEW

Complete flaccid facial paralysis, as well as the synkinetic and hyperkinetic sequelae of partial recovery, has significant impact on quality of life. Patients suffer from functional deficiencies, cosmetic deformity, discomfort and social consequences leading to emotional distress. Despite an extensive and sophisticated array of available interventions for facial reanimation, most patients have persistent issues that require consistent follow-up. In long-term management, botulinum toxin (BT) injection remains a critical tool in the treatment of the facial paralysis patient, particularly in the case of synkinesis, hyperkinesis and imbalance. We review the recent scientific literature and highlight key principles and developments in the use of BT in the management of facial paralysis, including less common applications for acute facial paralysis, hyperlacrimation and pseudoptosis.

RECENT FINDINGS

We reviewed the literature for the latest advances in the use of BT in facial paralysis, including applications and technique, as well as measurement tools and adjunct exercises. We also share our experience in treating our own patient population.

SUMMARY

BT continues to be a well tolerated and effective tool in the long-term management of facial paralysis, specifically in treating synkinesis, imbalance and hyperkinesis, as well as hyperlacrimation and pseudoptosis. Consistent measurement tools and adjunct neuromuscular retraining are crucial in the successful deployment of BT. Controversy exists as to whether BT should be used to manage facial paralysis during the acute phase, and whether BT application to the nonparalyzed face can improve long-term recovery in the paralyzed side.

Botulinum Toxin in the Treatment of Pediatric Upper Limb Spasticity

Botulinum neurotoxin (BoNT) is one of the mainstays in the treatment of pediatric spasticity and dystonia. When considering initiation of BoNT treatment for spasticity, treatment goals and responses to prior conservative measures such as passive range of motion exercises, splinting, and other medication trials should be reviewed. As a general rule, children should be engaged in therapy services around the time of the injections and have a robust home program in place. When managing spasticity in children with BoNT injections, the practitioner should be well versed in functional anatomy with specialized training in injection techniques. Localization techniques in addition to anatomical landmarks are recommended for improved efficacy and include limited electromyography, electrical stimulation, and/or ultrasound guidance. A follow-up visit for the purpose of reassessment during the peak effect of the drug is advised. It is known that BoNT is effective at reducing spasticity and improving range of motion, but it remains to be determined to what degree this translates into improved function, activity, and participation.

Comparison of Efficacy and Side Effects of Oral Baclofen Versus Tizanidine Therapy with Adjuvant Botulinum Toxin Type A in Children With Cerebral Palsy and Spastic Equinus Foot Deformity

This retrospective study aimed to compare the therapeutic response, including side effects, for oral baclofen versus oral tizanidine therapy with adjuvant botulinum toxin type A in a group of 64 pediatric patients diagnosed with static encephalopathy and spastic equinus foot deformity. Following botulinum toxin A treatment, clinical improvement led to the gradual reduction of baclofen or tizanidine dosing to one-third of the former dose. Gross Motor Functional Measure and Caregiver Health Questionnaire scores were markedly elevated post-botulinum toxin A treatment, with scores for the tizanidine (Gross Motor Functional Measure: 74.45 ± 3.72; Caregiver Health Questionnaire: 72.43 ± 4.29) group significantly higher than for the baclofen group (Gross Motor Functional Measure: 68.23 ± 2.66; Caregiver Health Questionnaire: 67.53 ± 2.67, P < .001). These findings suggest that the combined use of botulinum toxin A and a low dose of tizanidine in treating children with cerebral palsy appears to be more effective and has fewer side effects versus baclofen with adjuvant botulinum toxin A.

Questionnaire about the adverse events and side effects following botulinum toxin A treatment in patients with cerebral palsy

Botulinum toxin A (BoNT-A) injections for treatment of spasticity in patients with cerebral palsy (CP) have been used for about two decades. The treatment is considered safe but a low frequency of adverse events (AE) has been reported. A good method to report AEs is necessary to verify the safety of the treatment. We decided to use an active surveillance of treatment-induced harm using a questionnaire we created. We studied the incidence of reported AEs and side effects in patients with CP treated with BoNT-A. We investigated the relationship between the incidence of AEs or side effects and gender, age, weight, total dose, dose per body weight, Gross Motor Function Classification System (GMFCS) and number of treated body parts. Seventy-four patients with CP participated in our study. In 54 (51%) of 105 BoNT-A treatments performed in 45 (61%) patients, there were 95 AEs and side effects reported, out of which 50 were generalized and/or focal distant. Severe AEs occurred in three patients (4%), and their BoNT-A treatment was discontinued. Consecutive collection of the AE and side-effect incidence using our questionnaire can increase the safety of BoNT-A treatment in patients with CP.

Botulinum Toxin in Pediatric Neurology: Switching Lanes From Death to Life

Botulinum neurotoxins are natural molecules produced by anaerobic spore-forming bacteria called Clostradium boltulinum. The toxin has a peculiar mechanism of action by preventing the release of acetylcholine from the presynaptic membrane. Consequently, it has been used in the treatment of various neurological conditions related to muscle hyperactivity and/or spasticity. Also, it has an impact on the autonomic nervous system by acting on smooth muscle, leading to its use in the management of pain syndromes. The use of botulinum toxin in children separate from adults has received very little attention in the literature. This review presents the current data on the use of botulinum neurotoxin to treat various neurological disorders in children.

High doses of onabotulinumtoxinA in post-stroke spasticity: a retrospective analysis

We retrospectively evaluated the efficacy and safety of high doses of onabotulinumtoxinA (from 600 to 800 units) in 26 patients affected by upper and/or lower limb post-stroke spasticity. They were assessed before, 30 and 90 days after treatment. We observed a significant muscle tone reduction and a significant functional improvement (assessed with the Disability Assessment Scale). No adverse events were reported. In our retrospective analysis the treatment with high doses of onabotulinumtoxinA showed to be effective and safe.

Comparison of Systemic Toxicity between Botulinum Toxin Subtypes A1 and A2 in Mice and Rats

The adverse events caused by botulinum toxin type A (subtype A1) product, thought to be after-effects of toxin diffusion after high-dose administration, have become serious issues. A preparation showing less diffusion in the body than existing drugs has been sought. We have attempted to produce neurotoxin derived from subtype A2 (A2NTX) with an amino acid sequence different from that of neurotoxin derived from subtype A1 (A1NTX). In this study, to investigate whether A2NTX has the potential to resolve these issues, we compared the safety of A2NTX, a progenitor toxin derived from subtype A1 (A1 progenitor toxin) and A1NTX employing the intramuscular lethal dose 50% (im LD50) in mice and rats and the compound muscle action potential (CMAP) in rats. Mouse im LD50 values for A1 progenitor toxin and A2NTX were 93 and 166 U/kg, respectively, and the rat im LD50 values were 117 and 153 U/kg, respectively. In the rat CMAP test, the dose on the contralateral side, which caused a 50% reduction in the CMAP amplitude, that is, CMAP-TD50 , was calculated as 19.0, 16.6 and 28.7 U/kg for A1 progenitor toxin, A1NTX and A2NTX, respectively. The results indicate that A2NTX is safer than A1 progenitor toxin and A1NTX.

Rationale for using botulinum toxin A as an adjunct to upper limb rehabilitation in children with cerebral palsy

Cerebral palsy describes a group of disorders of movement and posture that result from disturbances in the developing brain. Although the brain lesion is nonprogressive, the secondary physical symptoms change with time and growth. If left untreated, symptoms may result in the development of physical impairment and impede independent performance of daily tasks. Intramuscular injection of botulinum neurotoxin A is a relatively safe and effective adjunct to upper limb therapy. Botulinum neurotoxin A primarily aims to reduce muscle overactivity, thereby reducing the development of increased muscle stiffness that can lead to permanent changes. With a specific focus on the physiological action of botulinum neurotoxin A, this article describes the secondary symptoms of cerebral palsy and their different contributions. To highlight research directions and future implications for clinical practice, this article also documents the recent scientific evidence for upper limb botulinum neurotoxin A and proposes a preventive clinical model that aims to mitigate the effects of increasing upper limb impairment.

Onabotulinumtoxin A injections: a safety review of children with clubfoot under 2 years of age at BC Children's Hospital

BACKGROUND

Pediatric indications for Onabotulinumtoxin A extend beyond treatment of skeletal muscle conditions. Each of the indications for Onabotulinumtoxin A use have adverse events reported in the past. The aim of this study was to review dverse events in children less than 2 years of age who were treated with Onabotulinumtoxin A injections as part of equinus foot deformity, in the setting of clubfoot at British Columbia's Children Hospital.

METHODS

A retrospective review of all clubfoot patients at British Columbia's Children Hospital, less than 2 years of age, who received a Onabotulinumtoxin A injection for equinus correction, between September 2000 and December 2012 was conducted. Data collected included demographics, clinical diagnosis, treatment history, ankle range of motion and any adverse event noted by the clubfoot team or reported by the families.

RESULTS

A total of 239 eligible subjects (361 feet) had received 523 Onabotulinumtoxin A injections before the age of 2 years. There was only one adverse event reported out of the 523 Onabotulinumtoxin A injections (adverse events rate of 0.19%) given at British Columbia's Children Hospital. However, this adverse event was not found related to the Onabotulinumtoxin A injection.

CONCLUSIONS

Onabotulinumtoxin A appears to be safe with respect to the adverse events, for use in children under 2 years of age with the diagnosis of clubfoot when dosed at 10 units per kilogram. However, the dose of Onabotulinumtoxin A and underlying diagnosis should always be kept in mind.

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.

Safety of botulinum toxin A in children and adolescents with cerebral palsy in a pragmatic setting

This retrospective study aimed to examine the safety of botulinum toxin A (BoNT-A) treatment in a paediatric multidisciplinary cerebral palsy clinic. In a sample of 454 patients who had 1515 BoNT-A sessions, data on adverse events were available in 356 patients and 1382 sessions; 51 non-fatal adverse events were reported (3.3% of the total injections number, 8.7% of the patients). On five occasions, the adverse reactions observed in GMFCS V children were attributed to the sedation used (rectal midazolam plus pethidine; buccal midazolam) and resulted in prolongation of hospitalization. Of the reactions attributed to the toxin, 23 involved an excessive reduction of the muscle tone either of the injected limb(s) or generalized; others included local pain, restlessness, lethargy with pallor, disturbance in swallowing and speech production, seizures, strabismus, excessive sweating, constipation, vomiting, a flu-like syndrome and emerging hypertonus in adjacent muscles. Their incidence was associated with GMFCS level and with the presence of epilepsy (Odds ratio (OR) = 2.74 - p = 0.016 and OR = 2.35 - p = 0.046, respectively) but not with BoNT-A dose (either total or per kilogram). In conclusion, treatment with BoNT-A was safe; adverse reactions were mostly mild even for severely affected patients. Their appearance did not necessitate major changes in our practice.

The effects of electrical stimulation exercise on muscles injected with botulinum toxin type-A (botox)

Botulinum toxin type A (BTX-A) is a frequently used treatment modality for a variety of neuromuscular disorders. It acts by preventing acetylcholine release at the motor nerve endings, inducing muscle paralysis. Although considered safe, studies suggest that BTX-A injections create adverse effects on target and non-target muscles. We speculate that these adverse effects are reduced by direct electrical stimulation (ES) exercising of muscles. The aims were to determine the effects of ES exercise on strength, mass, and contractile material in BTX-A injected muscles, and to investigate if BTX-A injections affect non-target muscles. Seventeen New Zealand White (NZW) rabbits were divided into three groups: (1) Control group received saline injections; (2) BTX-A group received monthly BTX-A (3.5 U/kg) injections into the quadriceps for six months and (3) BTX-A+ES group received monthly BTX-A injections and ES exercise three times a week for six months. Outcome measures included knee extensor torque, muscle mass, and contractile material percentage area in injected and contralateral, non-injected quadriceps. Glycogen depletion and direct muscle stimulation were used to assess possible muscle inhibition in non-injected quadriceps. ES exercise partially prevented muscle weakness, atrophy, and contractile material loss in injected muscles, and mostly prevented muscle degeneration in contralateral, non-injected muscles. Non-injected muscles of BTX-A+ES group showed higher force with direct muscle compared to nerve stimulation, and retained glycogen following the depletion protocol, suggesting that BTX-A inhibited activation in non-target muscles. We conclude that ES exercise provides some protection from degeneration to target and non-target muscles during BTX-A treatments.

Botulinum toxin-A use in paediatric hypertonia: Canadian practice patterns

BACKGROUND

This study aims to assess current practices of Canadian physicians providing botulinum toxin-A (BoNT-A) treatments for children with hypertonia and to contrast these with international "best practice" recommendations, in order to identify practice variability and opportunities for knowledge translation.

METHODS

Thirteen Canadian physicians assembled to develop and analyze results of a cross-sectional electronic survey, sent to 50 physicians across Canada.

RESULTS

Seventy-eight percent (39/50) of physicians completed the survey. The most frequently identified assessment tools were Gross Motor Function Classification System, Modified Tardieu Scale and neurological examination. Goal-setting tools were infrequently utilized. Common indications for BoNT-A injections and the muscles injected were identified. Significant variability was identified in using BoNT-A for hip displacement associated with hypertonia. The most frequent adverse event reported was localized weakness; 54% reporting this "occasionally" and 15% "frequently". Generalized weakness, fatigue, ptosis, diplopia, dysphagia, aspiration, respiratory distress, dysphonia and urinary incontinence were reported rarely or never. For dosage, 52% identified 16 Units/kg body weight of Botox® as maximum. A majority (64%) reported a maximum 400 Units for injection at one time. For localization, electrical stimulation and ultrasound were used infrequently (38% and 19% respectively). Distraction was the most frequently used pain-management technique (64%).

CONCLUSIONS

Canadian physicians generally adhere to international best practices when using BoNT-A to treat paediatric hypertonia. Two knowledge-translation opportunities were identified: use of individualized goal setting prior to BoNT-A and enhancing localization techniques. Physicians reported a good safety profile of BoNT-A in children.

Management of children with multiple sclerosis

Pediatric onset multiple sclerosis (MS) may be seen in 2-5% of patients with MS. It is characterized by high disease burden. As such, early treatment with preventative therapies should be considered. Although randomized controlled trials have not been conducted on therapies for pediatric MS, there is a growing body of literature suggesting safety of first-line agents approved for use in adult MS, including interferons and glatiramer acetate. The use of second-line therapies, such as natalizumab, cyclophosphamide, and mitoxantrone has been described in a small number of pediatric MS cases. These case series suggest benefit of these agents after limited follow-up. Little information on long-term effects of therapies such as cyclophosphamide, mitoxantrone, or natalizumab is available for this population, although concerns of increased risk for opportunistic infections (progressive multifocal leukoencephalopathy with natalizumab) and secondary hematologic cancers (with mitoxantrone) exist. Finally, although fatigue, motor, cognitive, and psychosocial difficulties are common in this population, no trials have been conducted on pharmacologic or non-pharmacologic interventions for the management of these problems. Therapies for spasticity, including baclofen (including the baclofen pump), diazepam, and botulinum toxin have been evaluated in children with cerebral palsy and may be used safely in children. Psychiatric intervention is often necessary for affective disorders. Interventions for fatigue have not been studied, although evidence in the adult MS literature suggests possible benefit of exercise and modafinil. This article provides a practical guide to the diagnosis and treatment of multiple sclerosis in pediatric patients.

Spread of botulinum neurotoxin type a at standard doses is inherent to the successful treatment of spastic equinus foot in cerebral palsy: short-term neurophysiological and clinical study

To evaluate whether botulinum toxin type A at standard doses spreads to antagonist leg muscles in dynamic equinus foot, we studied 18 ambulatory children with hemiplegic cerebral palsy. The gastrocnemius muscle on the affected side was injected with botulinum toxin type A (Dysport) (mean ± standard deviation, 14.3 ± 0.9 U/kg). Compound muscle action potential areas were assessed in the lateral gastrocnemius and tibialis anterior muscles on the treated and untreated sides before botulinum toxin type A injections and on days 10 and 30 after injections. In all patients, compound muscle action potential areas recorded from both the muscles on the treated side decreased from preinjection values at day 10 (P < .05) and 30 (P < .002). After injection, ankle spasticity had diminished (P < .05), equinus foot excursion increased (P < .05), and functional gait improved (P < .05). This study shows that botulinum toxin type A spreads from foot flexors to antagonist extensors and suggests that spread may be partly responsible for improving gait in children with cerebral palsy.

Botulinum toxin type A treatment in children with cerebral palsy: evaluation of treatment success or failure by means of goal attainment scaling

BACKGROUND

There is considerable variability in the amount of response to BTX-A treatment between and within patients with cerebral palsy (CP).

AIMS

The purpose of this retrospective cohort study was to evaluate the clinical responsiveness of Botulinum toxin type A (BTX-A) treatment in children with CP and specifically delineate features of treatment success and failure.

METHODS

Four hundred and thirty-eight children (251 boys, 187 girls; mean age 8 years 2 months, SD 4 years) were included into the study. Goal Attainment Scaling (GAS) was used to classify and evaluate treatment efficacy. Two study groups were defined: one group with an excellent response (GAS≥60.0) and one group with a lack of response (GAS≤40.0) to BTX-A.

RESULTS

Seventy-five patients (17.1%) had an excellent response and treatment was found to be unsuccessful for 31 patients (7.1%). Children with a lack of response to BTX-A were significantly older compared to children with a high responsiveness (p=0.0013). In the latter group, more children received multi-level injections and fewer children had injections in proximal parts of the lower limb compared to the low responsiveness group (p=0.0024). Moreover, there was a significant difference in the use of different types of casts between both study groups (p=0.0263).

CONCLUSION

Age, level of treatment and casting seem to be crucial features of BTX-A treatment success or failure in children with CP.

Endoscopic intrapyloric injection of botulinum toxin A in the treatment of children with gastroparesis: a retrospective, open-label study

BACKGROUND

Botulinum toxin A has been used in children to treat spastic disorders and recently for GI conditions. Open-label studies in adults with gastroparesis have reported an improvement in symptoms and gastric emptying after endoscopic intrapyloric botulinum injections (IPBIs), although placebo-controlled trials have shown conflicting results. Only a single case report of IPBI is available in children.

OBJECTIVE

To determine the long-term clinical outcomes and predictive factors for IPBI response in children with gastroparesis refractory to medical therapy.

DESIGN

Retrospective review.

SETTING

Single tertiary care center.

PATIENTS

Children with refractory gastroparesis symptoms undergoing IPBIs.

INTERVENTIONS

IPBIs.

MAIN OUTCOME MEASUREMENTS

Clinical improvement and predictive factors for response.

RESULTS

A total of 70 injections were given to 47 patients (mean age 9.98 ± 6.5 years; 23 female patients) with follow-up in 45 patients. IPBI failed in 15 patients and was successful in 30 patients. The median duration of response to the first IPBI was 3.0 months (95% CI, 1.2-4.8). A total of 29 patients received a single IPBI, and 18 received multiple IPBIs. Older age and vomiting predicted response to initial IPBI, and male sex predicted response to repeat IPBI. Only 1 patient reported exacerbation of vomiting after IPBI resolving within a week.

LIMITATIONS

The open-label and retrospective nature of the study.

CONCLUSION

IPBI is safe and may be effective in the management of children with symptoms of gastroparesis. Subgroups identifying who responded to the first IPBI include older patients and those presenting with vomiting, whereas male patients responded better to repeat IPBIs.

Therapeutic use of botulinum toxin in neurorehabilitation

The botulinum toxins (BTX), type A and type B by blocking vesicle acetylcholine release at neuro-muscular and neuro-secretory junctions can result efficacious therapeutic agents for the treatment of numerous disorders in patients requiring neuro-rehabilitative intervention. Its use for the reduction of focal spasticity following stroke, brain injury, and cerebral palsy is provided. Although the reduction of spasticity is widely demonstrated with BTX type A injection, its impact on the improvement of dexterity and functional outcome remains controversial. The use of BTX for the rehabilitation of children with obstetrical brachial plexus palsy and in treating sialorrhea which can complicate the course of some severe neurological diseases such as amyotrophic lateral sclerosis and Parkinson's disease is also addressed. Adverse events and neutralizing antibodies formation after repeated BTX injections can occur. Since impaired neurological persons can have complex disabling feature, BTX treatment should be viewed as adjunct measure to other rehabilitative strategies that are based on the individual's residual ability and competence and targeted to achieve the best functional recovery. BTX therapy has high cost and transient effect, but its benefits outweigh these disadvantages. Future studies must clarify if this agent alone or adjunctive to other rehabilitative procedures works best on functional outcome.

A French observational study of botulinum toxin use in the management of children with cerebral palsy: BOTULOSCOPE

BACKGROUND

Dystonia and spasticity are common symptoms in children with Cerebral Palsy (CP), whose management is a challenge to overcome in order to enable the harmonized development of motor function during growth.

AIM

To describe botulinum toxin A (BTX-A) use and efficacy as a treatment of focal spasticity in CP children in France.

METHODS

This prospective observational study included 282 CP children mostly administered according to French standards with BTX-A in lower limbs. Realistic therapeutic objectives were set with parents and children together before treatment initiation and assessed using the Visual Analogue Scale (VAS). Child management was recorded and the efficacy of injections was assessed during a 12-month follow-up period by physicians (Modified Ashworth Scale, joint range of motion, Physician Rating Scale, Gillette Functional Assessment Questionnaire and Gross Motor Function Measure-66) and by patients/parents (Visual Analogue Scale).

RESULTS

BTX-A treatment was administered in different muscle localizations at once and at doses higher than those recommended by the French Health Authorities. Children were treated in parallel by physiotherapy, casts and ortheses. Injections reduced spasticity and improved joint range of motion, gait pattern and movement capacity. Pain was reduced after injections. BTX-A administration was safe: no botulism-like case was reported. The log of injected children who were not included in the study suggested that a large population could benefit from BTX-A management.

CONCLUSIONS

We showed here the major input of BTX-A injections in the management of spasticity in CP children. The results are in favor of the use of BTX-A as conservative safe and efficient treatment of spasticity in children, which enables functional improvement as well as pain relief.

Adverse events and health status following botulinum toxin type A injections in children with cerebral palsy

AIM

The aim of this study was to assess changes in health status before and after, as well as adverse events after, botulinum toxin type A (BoNT-A) injections in children with cerebral palsy (CP).

METHOD

A total of 334 children (190 male; 144 female) aged 1y 6mo to 19y 4mo (mean 9y 2mo, SD 4y) with CP who were undergoing BoNT-A injections (596 injection courses in total) were clinically audited over a 16-month period. Of the 334 children, 62 were classified at Gross Motor Function Classification System (GMFCS) level I, 52 of whom had unilateral CP and 10 of whom had bilateral CP. Eighty-six children were classified at GMFCS level II, 39 of whom had unilateral CP and 47 of whom had bilateral CP. Forty-four children were classified at GMFCS level III, two of whom had unilateral CP and 42 of whom had bilateral CP. Sixty-six of the 334 children were classified at GMFCS level IV and 76 as level V. All the children classified as level IV or V had bilateral involvement. The health status of the children in the month before and a prospective audit of health status and adverse events in the month after BoNT-A injections were examined in order to assess the effects of the toxin.

RESULTS

The data gathered for the month before administration of BoNT-A indicated that children with CP had significant background morbidities. After injection of BoNT-A, adverse events occurred in 23.2% of children. All adverse events were temporary and there were no deaths.

INTERPRETATION

The results of this audit indicate that there is insufficient evidence to warrant restriction of the administration of BoNT-A in children with CP at any GMFCS level in our service.

Systemic weakness after therapeutic injections of botulinum toxin a: a case series and review of the literature

The use of intramuscular injections of Botulinum neurotoxin A (BoNT-A) is common in the treatment of hypertonicity and movement disorders. Although most side effects are mild, systemic effects, manifested by generalized weakness distant from the site of injection, have been reported. Previously reported occurrences are discussed, and 3 new cases of patients, who developed systemic weakness after administration of BoNT-A (Botox), despite having tolerated similar injections on several previous occasions, are presented. A review of the literature and reported cases indicate that risk of developing systemic effects does not seem to be related to dose based on body weight. It may be more likely that risk for systemic effects is related to total injection dose and injection frequency. The results of our 3 patients would indicate that injections of greater than 600 units of Botox with follow-up injections occurring every 3 months may lead to an increased risk. We would recommend careful consideration of reinjection frequency if injections of greater than 600 units of Botox are given. Reduction in systemic side effects may occur if reinjection frequency occurs in intervals of 4 months or greater in these individuals.

Botulinum toxin injections for pediatric patients with hereditary spastic paraparesis

Limited information is available on the use of botulinum toxin type A injections for children with hereditary spastic paraplegia. This report includes 12 children with hereditary spastic paraplegia (mean age 4.8 +/- 2.5 years) who underwent 1 to 6 sessions of botulinum toxin A injections to the hamstrings, adductors and gastrocnemius muscles. Patients showed both improved muscle tone (mean 1.9 +/- 0.5 vs 1.18 +/- 0.33, P < .001, Ashworth Scale) and motor function (75.3 +/- 11.9 vs 77.7 +/- 11, P < .001, Gross Motor Function Measure). The effect lasted for a mean of 6.6 +/- 3.6 months. During the study period (mean 2.8 +/- 1.8 years), the preinjection Gross Motor Function Measure increased (69.2 +/- 14.7 vs 78.3 +/- 13.5, P = .005), whereas the Ashworth Scale remained stable, suggesting a prolonged effect of botulinum toxin A on motor function. The authors conclude that botulinum toxin A injections to lower limbs of pediatric patients with hereditary spastic paraplegia result in prolonged functional improvement despite the progressive nature of the disease.

The use of botulinum toxin A in children with cerebral palsy, with a focus on the lower limb

PURPOSE

The purpose of this review is to clarify the role of botulinum toxin serotype A (BTX-A) in the treatment of children with cerebral palsy (CP), with a special focus on the lower limb.

BACKGROUND

The treatment of spasticity is central in the clinical management of children with CP. BTX-A blocks the release of acetylcholine at the motor end plate, causing a temporary muscular denervation and, in an indirect way, a reduced spasticity. Children with increased tone develop secondary problems over time, such as muscle contractures and bony deformities, which impair their function and which need orthopaedic surgery. However in these younger children, delaying surgery is crucial because the results of early surgical interventions are less predictable and have a higher risk of failure and relapse. As BTX-A treatment reduces tone in a selective way, it allows a better motor control and muscle balance across joints, resulting in an improved range of motion and potential to strengthen antagonist muscles, when started at a young age. The effects are even more obvious when the correct BTX-A application is combined with other conservative therapies, such as physiotherapy, orthotic management and casts. There is now clear evidence that the consequences of persistent increased muscle tone can be limited by applying an integrated multi-level BTX-A treatment approach. Nevertheless, important challenges such as patient selection, defining appropriate individual goals, timing, dosing and dilution, accuracy of injection technique and how to measure outcomes will be questioned. Therefore, "reflection is more important than injection" remains an actual statement.

Botulinum toxin A as an adjunct to treatment in the management of the upper limb in children with spastic cerebral palsy (UPDATE)

BACKGROUND

Cerebral palsy (CP) is "a group of permanent disorders of the development of movement and posture causing activity limitation(s) that are attributed to non-progressive disturbance that occurred in the developing fetal or infant brain" (Rosenbaum 2007, p.9). The spastic motor type is the most common form of CP. Therapeutic management may include splinting/casting, passive stretching, facilitation of posture/movement, spasticity-reducing medication and surgery. Botulinum toxin-A (BoNT-A) is now used as an adjunct to these techniques in an attempt to reduce spasticity, improve range of movement and function.

OBJECTIVES

To assess the effectiveness of injections of BoNT-A or BoNT-A and occupational therapy in the treatment of the upper limb in children with CP.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register/CENTRAL (The Cochrane Library, Issue 3, 2008), MEDLINE (1966 to August Week 1 2008), EMBASE (1980 to 2008 Week 28) and CINAHL (1982 to August Week 1 2008).

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing BoNT-A injection or BoNT-A injection and occupational therapy in the upper limb(s) with other types of treatment (including no treatment or placebo) in children with CP.

DATA COLLECTION AND ANALYSIS

Two authors using standardised forms extracted the data independently. Each trial was assessed for internal validity and rated for quality using the PEDro scale. Data were extracted and entered into RevMan 5.0.15.

MAIN RESULTS

Ten trials met the inclusion criteria. PEDro quality ratings ranged from 6/10 to 10/10. Concentration of BoNT-A ranged from 50U/1.0ml to 200U/1.0ml saline with doses of 0.5U to 16U/kg body weight and total doses of 220 to 410 Units (Botox(R)).A combination of BoNT-A and occupational therapy is more effective than occupational therapy alone in reducing impairment, improving activity level outcomes and goal achievement, but not for improving quality of life or perceived self-competence. When compared with placebo or no treatment, there is moderate evidence that BoNT-A alone is not effective.

AUTHORS' CONCLUSIONS

This systematic review found high level evidence supporting the use of BoNT-A as an adjunct to managing the upper limb in children with spastic CP. BoNT-A should not be used in isolation but should be accompanied by planned occupational therapy.Further research is essential to identify children most likely to respond to BoNT-A injections, monitor longitudinal outcomes, determine timing and effect of repeated injections and the most effective dosage, dilution and volume schedules. The most effective adjunct therapies including frequency and intensity of delivery also requires investigation.

The updated European Consensus 2009 on the use of Botulinum toxin for children with cerebral palsy

An interdisciplinary European group of clinical experts in the field of movement disorders and experienced Botulinum toxin users has updated the consensus for the use of Botulinum toxin in the treatment of children with cerebral palsy (CP). A problem-orientated approach was used focussing on both published and practice-based evidence. In part I of the consensus the authors have tabulated the supporting evidence to produce a concise but comprehensive information base, pooling data and experience from 36 institutions in 9 European countries which involves more than 10,000 patients and over 45,000 treatment sessions during a period of more than 280 treatment years. In part II of the consensus the Gross Motor Function Measure (GMFM) and Gross Motor Function Classification System (GMFCS) based Motor Development Curves have been expanded to provide a graphical framework on how to treat the motor disorders in children with CP. This graph is named "CP(Graph) Treatment Modalities - Gross Motor Function" and is intended to facilitate communication between parents, therapists and medical doctors concerning (1) achievable motor function, (2) realistic goal-setting and (3) treatment perspectives for children with CP. The updated European consensus 2009 summarises the current understanding regarding an integrated, multidisciplinary treatment approach using Botulinum toxin for the treatment of children with CP.