Employment of higher doses of botulinum toxin type A to reduce spasticity after stroke

Long-Term Management of Post-Stroke Spasticity with Botulinum Toxin: A Retrospective Study

Stroke-induced spasticity is a prevalent condition affecting stroke survivors, significantly impacting their quality of life. Botulinum Toxin A injections are widely used for its management, yet the long-term effects and optimal management strategies remain uncertain. This retrospective study analyzed medical records of 95 chronic stroke patients undergoing long-term BoNT-A treatment for spasticity. Demographic data, treatment duration, dosage variability, and dropout rates were assessed over a period ranging from 2 to 14 years. The study revealed a notable extension of the interval between BoNT-A injections throughout the treatment duration. Dropout rates peaked during the initial 5 years of treatment, perhaps due to perceived treatment ineffectiveness. Additionally, a trend of escalating dosage was observed across all groups, indicating a potential rise in the severity of spasticity or changes in treatment response over time. BoNT-A injections emerged as the predominant treatment choice for managing post-stroke spasticity. The delayed initiation of BoNT-A treatment underscores the need for heightened awareness among healthcare providers to recognize and manage spasticity promptly post-stroke. Patients' expectations and treatment goals should be clearly defined to optimize treatment adherence, while the observed escalation in dosage and treatment intervals emphasizes the dynamic nature of spasticity and underscores the importance of monitoring long-term treatment outcomes.

Botulinum toxin type A infiltration in spasticity and cervical dystonia. Muscle morphology: an overlooked factor

INTRODUCTION

Botulinum toxin type A is used to treat spasticity and dystonia. However, its relationship with muscle morphology has not been studied. The action mechanism of botulinum toxin is based on the inhibition of acetylcholine release. Therefore, larger doses of toxin would be needed to treat larger muscles. This study aims to establish whether there is a discrepancy between muscle morphology and the botulinum toxin doses administered.

METHODS

We dissected, and subsequently measured and weighed, muscles from the upper and lower limbs and the head of a fresh cadaver. We consulted the summary of product characteristics for botulinum toxin type A to establish the recommended doses for each muscle and calculated the number of units infiltrated per gramme of muscle.

RESULTS

Different muscles present considerable morphological variability, and the doses of botulinum toxin administered to each muscle are very similar. We observed great variability in the amount of botulinum toxin administered per gramme of muscle, ranging from 0.3 U/g in the biceps femoris to 14.6 U/g in the scalene muscles. The mean dose was 2.55 U/g. The doses administered for nearly all lower limb muscles were below this value.

CONCLUSIONS

There are significant differences in morphology between the muscles of the lower limbs, upper limbs, and head, but similar doses of botulinum toxin are administered to each muscle. These differences result in great variability in the number of units of botulinum toxin administered per gramme of muscle.

Stroke rehabilitation: from diagnosis to therapy

Stroke remains a significant global health burden, necessitating comprehensive and innovative approaches in rehabilitation to optimize recovery outcomes. This paper provides a thorough exploration of rehabilitation strategies in stroke management, focusing on diagnostic methods, acute management, and diverse modalities encompassing physical, occupational, speech, and cognitive therapies. Emphasizing the importance of early identification of rehabilitation needs and leveraging technological advancements, including neurostimulation techniques and assistive technologies, this manuscript highlights the challenges and opportunities in stroke rehabilitation. Additionally, it discusses future directions, such as personalized rehabilitation approaches, neuroplasticity concepts, and advancements in assistive technologies, which hold promise in reshaping the landscape of stroke rehabilitation. By delineating these multifaceted aspects, this manuscript aims to provide insights and directions for optimizing stroke rehabilitation practices and enhancing the quality of life for stroke survivors.

Safety and Real-World Dosing of OnabotulinumtoxinA for the Treatment of Adult Spasticity: Post Hoc Analysis of the Adult Spasticity International Registry Study

OBJECTIVE

The aim of the study is to evaluate the safety of onabotulinumtoxinA treatment for spasticity across dose ranges in real-world practice.

DESIGN

Adult Spasticity International Registry was a multicenter, prospective, observational study (NCT01930786) of onabotulinumtoxinA treatment for adult spasticity over 2 yrs. Adverse events, serious adverse events, treatment-related adverse events, and serious treatment-related adverse events were sorted into five categories (≤200, 201-400, 401-600, 601-800, ≥801 U) based on cumulative dose per session.

RESULTS

In 3103 treatment sessions ( T ), 730 patients received ≥1 dose of onabotulinumtoxinA. Dose categories included the following: ≤200 U ( n = 312, T = 811), 201-400 U ( n = 446, T = 1366), 401-600 U ( n = 244, T = 716), 601-800 U ( n = 69, T = 149), and ≥801 U ( n = 29, T = 61). Of these patients, 261 reported 827 adverse events, 94 reported 195 serious adverse events, 20 reported 23 treatment-related adverse events, and 2 patients treated with 201-400 U onabotulinumtoxinA reported 3 serious treatment-related adverse events. Treatment-related adverse events reported included ≤200 U (8/811, 0.9%), 201-400 U (7/1366, 0.5%), 401-600 U (6/716, 0.8%), 601-800 U (1/149, 0.7%), and ≥801 U (1/61, 1.6%).

CONCLUSIONS

In this post hoc analysis, most treatment sessions were performed with 201-400 U onabotulinumtoxinA. Patients treated with 201-400 U onabotulinumtoxinA had an adverse event profile consistent with onabotulinumtoxinA package inserts globally (e.g., United States, European Union, United Kingdom, Canada). No new safety signals were identified.

Improving Spasticity by Using Botulin Toxin: An Overview Focusing on Combined Approaches

Spasticity is a very common sign in the neurological field. It can be defined as "a motor disorder marked by a velocity-dependent increase in muscle tone or tonic stretch reflexes" associated with hypertonia. It leads to a high risk of limb deformities and pain that prejudices residual motor function, impairing quality of life". The treatment of spasticity depends on its severity and its location and, in general, it is based on rehabilitation, oral therapies (the gamma-aminobutyric acid b agonist baclofen) and injectable medications (i.e., botulin toxins, acting on polysynaptic reflex mechanisms). The botulin toxin type A (BoNT-A) injection has been effectively used to improve different types of spasticity. However, when BoNT-A is not sufficient, a combination of nonpharmacological approaches could be attempted. Therefore, additional intervention, such as conventional physical therapy by itself or further combined with robotic gait training, may be needed. Indeed, it has been shown that combination of BoNT-A and robotics has a positive effect on activity level and upper limb function in patients with stroke, including those in the chronic phase. The aim of this review is to evaluate the efficacy of pharmacological or nonpharmacological treatment in combination with BoNT-A injections on spasticity. The combined therapy of BoNT with conventional or adjunct activities or robot-assisted training, especially with end-effectors, is a valid tool to improve patients' performance and outcomes. The combined strategies might rise the toxin's effect, lowering its dosages of botulinum and reducing side effects and costs.

Extracorporeal Shockwave Treatment as Additional Therapy in Patients with Post-Stroke Spasticity of Upper Limb-A Narrative Review

Stroke is a severe injury of the central nervous system (CNS) and one of the leading causes of long-term disability and mortality. One of the main symptoms of neurological diseases is spasticity. This is defined as a motor condition characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks and resulting in the hyperexcitability of the stretch reflex. Rehabilitation after a stroke is focused on relearning lost skills and regaining independence. Many new methods in neurorehabilitation have been introduced. This review concentrates on the current evidence for extracorporeal shockwave therapy (ESWT) as a noninvasive alternative to treat spasticity. We present the effect of EWST and radial EWST interventions to post-stroke patients with spasticity in the upper limb. Our collected data suggest that different parameters of shockwaves can be used to achieve functional improvementsin the upper limb after a stroke. Our accumulated data imply that ESWT is safe and can be used for pain relief, reduced muscle tension, and an increased range of motion. According to many studies, complications after shockwave treatment are infrequent. Transient complications after shockwave therapy (ESWT) include redness, tingling, pain, and bruising. We reviewed clinical trials that present the possible benefits in upper-limb function after shockwave therapy for post-stroke patients. In this article, we used many database search engines, including PEDro. In the stroke rehabilitation literature, a key methodological problem is the design of double-blind studies, which very often are not feasible.

Botulinum Toxin-A High-Dosage Effect on Functional Outcome and Spasticity-Related Pain in Subjects with Stroke

Stroke patients can develop spasticity and spasticity-related pain (SRP). These disorders are frequent and can contribute to functional limitations and disabling conditions. Many reports have suggested that higher doses than initially recommended of BTX-A can be used effectively and safely, especially in the case of severe spasticity; however, whether the treatment produces any benefit on the functional outcome and SRP is unclear. Studies published between January 1989 and December 2022 were retrieved from MEDLINE/PubMed, Embase, and Cochrane Central Register. Only obabotulinumtoxinA (obaBTX-A), onabotulinumtoxinA, (onaBTX-A), and incobotulinumtoxinA (incoBTX-A) were considered. The term "high dosage" indicates ≥600 U. Nine studies met the inclusion criteria. Globally, 460 subjects were treated with BTX-A high dose, and 301 suffered from stroke. Studies had variable method designs, sample sizes, and aims. Only five (55.5%) reported data about the functional outcome after BTX-A injection. Functional measures were also variable, and the improvement was observed predominantly in the disability assessment scale (DAS). SRP pain was quantified by visual analog scale (VAS) and only three studies reported the BTX-A effect. There is no scientific evidence that this therapeutic strategy unequivocally improves the functionality of the limbs. Although no clear-cut evidence emerges, certain patients with spasticity might obtain goal-oriented improvement from high-dose BTX-A. Likewise, data are insufficient to recommend high BTX dosage in SRP.

Pooled Safety Analysis of IncobotulinumtoxinA in the Treatment of Neurological Disorders in Adults

The pooled incidences of treatment-emergent adverse events (TEAEs) were examined by indication using the integrated clinical database of Merz-sponsored, placebo-controlled, or repeat-dose studies of incobotulinumtoxinA in adults with cervical dystonia, blepharospasm, limb spasticity, sialorrhea, or essential tremor of the upper limb. Overall incidences of TEAEs, serious TEAEs, TEAEs leading to discontinuation, fatal TEAEs, TEAEs of special interest (TEAESIs; indicating possible toxin spread), and treatment-related (TR) events were determined for incobotulinumtoxinA and placebo after a single injection and for repeated dose cycles of incobotulinumtoxinA. The most frequent events after a single dose of incobotulinumtoxinA are summarized. After a single cycle, incidences of overall TEAEs were similar between incobotulinumtoxinA and the placebo in most indications, although between-indication differences were observed. Few TEAEs led to incobotulinumtoxinA discontinuation; there were no fatal TEAEs with incobotulinumtoxinA. In general, repeated cycles did not increase the incidence of any event. The most frequent TR-TEAEs were indication-dependent, including dysphagia for indications affecting the head or neck. The TR-TEAESIs across all indications were most commonly muscular weakness, dysphagia and dry mouth. Overall, the results of this pooled analysis support and extend the favorable safety and tolerability profile of incobotulinumtoxinA for the treatment of adult neurological disorders established by individual clinical studies.

[Correction of gait stereotype and reduction of the risk of falling in patients with equinovarus foot placement and central hemiparesis]

OBJECTIVE

To test a new approach to gait stereotype correction for patients with central hemiparesis with talipes equinovarus.

MATERIAL AND METHODS

The study was performed in a group of patients with formed talipes equinovarus and post-stroke hemiparesis. Footwear with orthopaedic elements was offered to the patients. Evaluation of spatial and temporal gait parameters was performed and the risk of falls was assessed.

RESULTS

In the process of work, data were obtained confirming the effectiveness of using specialized shoes for equinovarus foot placement. The risk of falling significantly decreased when walking; walking became more symmetrical due to an increase in the anterior extension of the paretic limb.

CONCLUSION

Application of this method does not decrease the tone in the paretic limb but optimises the gait stereotype, facilitates the increases of its velocity and decreases the risk of falling.

High Doses of Botulinum Toxin Type A for the Treatment of Post-Stroke Spasticity: Rationale for a Real Benefit for the Patients

In the past few years, there was a great interest in the use of higher doses of botulinum toxin type A, especially in case of upper and lower limb severe spasticity. To date, only one prospective, non-randomized, single-arm, multicenter, open-label, dose-titration study with the employment of incobotulinum toxin up to 800 U has been published, and the authors investigated safety and tolerability. Other researches showed efficacy in spasticity reduction, but there is a lack of evidence about the reasons to use high doses of botulinum toxin. This short communication highlights the benefits of higher doses for subjects with upper and lower limb spasticity.

An Observational Cross-Sectional Study of Gender and Disability as Determinants of Person-Centered Medicine in Botulinum Neurotoxin Treatment of Upper Motoneuron Syndrome

The motor behaviour of patients with Upper Motor Neuron Syndrome (UMNS) is characterised by spasticity. The first-line treatment for this clinical condition is Botulinum neurotoxin A (BoNTA), but the number and key locations of muscles which need to be treated is not much discussed in the literature. Cross-sectional analysis of outpatient cohort with UMNS spasticity, who were potential candidates for BoNTA treatment, was performed. Between November 2020 and November 2021, all consecutive adult patients eligible for BoNTA treatment were enrolled. The inclusion criteria encompass UMNS spasticity (onset being ≥6 months), with disabling muscles hypertonia. Patients underwent a clinical evaluation, a comprehensive assessment with the Modified Ashworth Scale, with the Modified Rankin Scale, and a patients’ perception-centred questionnaire. In total, 68 participants were enrolled in the study, among them 40 (58.8%) were male; mean age 57.9 ± 15.1. In women, BoNTA was more frequently required for adductor group muscles, independently from potential confounders (OR = 7.03, 95%CI: 1.90–25.97). According to the pattern of disability, patients with hemiparesis more frequently need to be treated in the upper limb, whereas the diplegia/double-hemiparesis group needed to be treated more frequently at the adductor and crux muscles compared to their counterparts. UMNS spasticity in women could require more attention to be paid to the treatment of adductor muscle spasticity, potentially because the dysfunction of those muscles could influence sphincteric management, required for perineal hygiene and/or sexual life.

BoNT-A for Post-Stroke Spasticity: Guidance on Unmet Clinical Needs from a Delphi Panel Approach

There is extensive literature supporting the efficacy of botulinum toxin (BoNT-A) for the treatment of post-stroke spasticity, however, there remain gaps in the routine management of patients with post-stroke spasticity. A panel of 21 Italian experts was selected to participate in this web-based survey Delphi process to provide guidance that can support clinicians in the decision-making process. There was a broad consensus among physicians that BoNT-A intervention should be administered as soon as the spasticity interferes with the patients' clinical condition. Patients monitoring is needed over time, a follow-up of 4-6 weeks is considered necessary. Furthermore, physicians agreed that treatment should be offered irrespective of the duration of the spasticity. The Delphi consensus also stressed the importance of patient-centered goals in order to satisfy the clinical needs of the patient regardless of time of onset or duration of spasticity. The findings arising from this Delphi process provide insights into the unmet needs in managing post-stroke spasticity from the clinician's perspective and provides guidance for physicians for the utilization of BoNT-A for the treatment of post-stroke spasticity in daily practice.

The Use of Botulinum Toxin for Treatment of Spasticity

Spasticity is one component of the upper motor neuron (UMN) syndrome resulting from a multitude of neurologic conditions, such as stroke, brain injury, spinal cord injury, multiple sclerosis, and cerebral palsy. It is clinically recognized as a phenomenon of velocity-dependent increase in resistance, i.e., hypertonia. Recent advances in the pathophysiology of spasticity improve our understanding of mechanisms underlying this complex phenomenon and its relations to other components of UMN syndrome (weakness and disordered motor control), as well as the resultant clinical problems. This theoretical framework provides a foundation to set up treatment goals and to guide goal-oriented clinical assessment and treatment. Among a spectrum of treatment options, botulinum toxin (BoNT) therapy is the preferred treatment for focal spasticity. The evidence is very robust that BoNT therapy effectively reduces spasticity; however, it does not improve voluntary movement. In this chapter, we highlight a few issues on how to achieve the best clinical outcomes of BoNT therapy, such as dosing, dilution, guidance techniques, adjunctive therapies, early treatment, repeated injections, and central effects, as well as the ways to improve motor function in selected subgroups of patients with spasticity. We also discuss the reasons of poor responses to BoNT therapy and when not to use BoNT therapy.

Focal arm weakness following intradetrusor botulinum toxin administration in spinal cord injury: Report of two cases

Context: Outpatient Spinal Cord Injury follow-up practice Findings: We present two cases of individuals with tetraplegia who experienced proximal arm weakness temporally related to the administration of intradetrusor onabotulinumtoxinA without other systemic effects. This arm weakness lasted approximately three months in both cases, whereas the effect of the toxin on the bladder lasted for over six months. In one of the cases, the pattern of proximal arm weakness after intravesicular botulinum toxin injection recurred after repeat injection. Conclusion: These cases represent a previously unreported phenomenon of proximal focal weakness associated with the use of intradetrusor chemodenervation. Possible mechanisms for these cases are discussed.

High Dosage of Botulinum Toxin Type A in Adult Subjects with Spasticity Following Acquired Central Nervous System Damage: Where Are We at?

Spasticity is a common disabling disorder in adult subjects suffering from stroke, brain injury, multiple sclerosis (MS) and spinal cord injury (SCI). Spasticity may be a disabling symptom in people during rehabilitation and botulinum toxin type A (BTX-A) has become the first-line therapy for the local form. High BTX-A doses are often used in clinical practice. Advantages and limitations are debated and the evidence is unclear. Therefore, we analysed the efficacy, safety and evidence for BTX-A high doses. Studies published from January 1989 to February 2020 were retrieved from MEDLINE/PubMed, Embase, Cochrane Central Register. Only obabotulinumtoxinA (obaBTX-A), onabotulinumtoxinA (onaBTX-A), and incobotulinumtoxinA (incoBTX-A) were considered. The term “high dosage” indicated ≥ 600 U. Thirteen studies met the inclusion criteria. Studies had variable method designs, sample sizes and aims, with only two randomised controlled trials. IncoBTX-A and onaBTX-A were injected in three and eight studies, respectively. BTX-A high doses were used predominantly in treating post-stroke spasticity. No studies were retrieved regarding treating spasticity in MS and SCI. Dosage of BTX-A up to 840 U resulted efficacious and safety without no serious adverse events (AEs). Evidence is insufficient to recommend high BTX-A use in clinical practice, but in selected patients, the benefits of high dose BTX-A may be clinically acceptable.

Botulinum toxin type A ameliorates adjuvant-arthritis pain by inhibiting microglial activation-mediated neuroinflammation and intracellular molecular signaling

Chronic inflammatory pain is a serious clinical problem caused by inflammation of the joints and degenerative diseases and greatly affects patients' quality of life. Persistent pain states are thought to result from the central sensitization of nociceptive pathways in the spinal dorsal horn. Spinal microglia-mediated neuroinflammation plays a pivotal role in the development and maintenance of the central sensitization of chronic inflammatory pain. Botulinum toxin type A (BoNT/A) was recently reported to have analgesic and anti-inflammatory effects. However, the precise mechanism underlying its analgesic effect remains unclear. Although several studies have reported that BoNT/A could regulate neuroflammation, the reduction of neuroinflammation regulated by BoNT/A in chronic inflammatory pain in experimentally induced arthritis has not been reported. The aim of this study was to investigate whether BoNT/A could alleviate adjuvant-arthritis pain via modulating microglia-mediated neuroinflammation and intracellular molecular pathway. The pain behavioral tests were performed before and after CFA immunization as well as after BoNT/A injection. Western blotting and immunofluorescence staining were used to assess the changes of microglial activation markers (ionized calcium binding adaptor molecule 1, IBA-1) and phosphorylation of P38MAPK (P-p38MAPK) in the lumbar spinal cord. TNF-αand P2X4R gene expression were studied by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that (1) the activation of spinal microglia can be continued till 21 days after CFA injection, which suggested its role in the development and maintenance of chronic inflammatory pain. (2) The intra-articular administration of a single effective dose of BoNT/A (5U/10 U) on day 21 after CFA injection significantly reduced nociceptive behaviors and decreased protein overexpression and immunoreactivity for IBA-1 and P-p38MAPK in CFA induced rat. Simultaneously, BoNT/A (5 U) also inhibited the increase in TNF-α mRNA and P2X4R mRNA expression induced by CFA injection. These results suggested that BoNT/A is a potential therapeutic agent for relieving the neuroinflammation that occurs in chronic inflammatory pain by inhibiting the activation of microglial cells and the release of microglia-derived TNF-α. This effect is likely mediated by inhibiting the activation of the P2X4R-P38MAPK signaling pathways in spinal microglial cells.

Botulinum Neurotoxin-A Injected Intrastriatally into Hemiparkinsonian Rats Improves the Initiation Time for Left and Right Forelimbs in Both Forehand and Backhand Directions

Forelimb stepping is a widely used test for the assessment of forelimb akinesia in hemiparkinsonian (hemi-PD) rats. The initiation time (IT) is considered the most sensitive parameter in the stepping test procedure. Here we propose a novel, reliable, and simple method for the measurement of IT of both forelimbs in both forehand and backhand directions in rats. Evaluating the same videos taken for quantifying adjusting steps, IT measurements were done without additional experiments. This is in contrast to the classical approach introduced by Olsson et al. (1995), in which separate experiments are necessary. We successfully applied our approach to hemi-PD rats intrastriatally treated with botulinum neurotoxin-A (BoNT-A). In naïve rats, an IT of about 0.62 s was found, and in right-sided hemi-PD rats the IT of the left forepaw increased to about 3.62 s. These hemi-PD rats showed, however, reduced ITs of the impaired left forepaws 1 month and the second time 7 months after induction of hemi-PD via the injection of 1 ng BoNT-A into the ipsilateral striatum, depending on post BoNT-A survival time. The method described offers the possibility of a precise and animal-friendly evaluation of IT in rats, including the beneficial effect of BoNT-A treatment in hemi-PD rats.

Efficacy and Safety of Botulinum Toxin Type A in Spasticity Caused by Spinal Cord Injury: A Randomized, Controlled Trial

Background

Baclofen is approved by the US FDA to treat spasticity, but its sustained use may cause drug addiction. The objective of this study was to compare the efficacy and safety of botulinum toxin type A versus baclofen in spasticity.

Material/Methods

A total of 336 patients who had spasticity caused by spinal cord injury were enrolled in a randomized (in 1: 1: 1: ratio) for placebo, controlled trial. Patients had received baclofen (BA group, n=112), local intramuscular injection of 500 U Botulinum toxin type A (BTI group, n=112), or physical therapies alone (placebo group, n=112). Modified Ashworth scale (mAS) score, disability assessment scale (DAS) score, modified medical research council (mMRC) score, the Barthel Index (BI) score, and treatment-emergent adverse effects were evaluated during the follow-up period. Wilcoxon test or one-way ANOVA/Tukey post hoc tests were performed at 95% of confidence level.

Results

Baclofen (1.504±0.045 vs. 1.53±0.06, p=0.003, q=4.068) and botulinum toxin type A (1.49±0.09 vs. 1.528±0.15, p=0.0224, q=3.5541) had improved mAS scores after 2 weeks. Baclofen had a more strongly improved DAS score than botulinum toxin type A at 4 (p=0.0496, q=3.48) and 6 (p<0.0001, q=6.48) weeks. Baclofen and botulinum toxin type A had consistently improved BI scores. Baclofen caused asthenia and sleepiness, while botulinum toxin type A caused bronchitis and elevated blood pressure.

Conclusions

Botulinum toxin type A may be an effective therapeutic option for spasticity caused by spinal cord injury.

Quantifying and Reducing Retained Botulinum Toxin Postinjection

BACKGROUND

Retained botulinum toxin solution may be visible in vials and syringe tips after mixing and presumed complete injections, leaving patients without the full prescribed dose.

OBJECTIVE

To quantify the mean amount of retained toxin within vials, syringes, and needles following spasticity injections (phase 1) and to design/test a targeted intervention for reduced retained toxin (phase 2).

DESIGN

Prospective cohort quality assurance study.

SETTING

Outpatient spasticity program in a rehabilitation facility.

PARTICIPANTS

Nine physicians specializing in physical medicine and rehabilitation, performing successive mixing and injections for spasticity with onabotulinumtoxinA or incobotulinumtoxinA.

METHODS

After initial review (phase 1), recommendations were made (phase 2) including not inverting the vial to withdraw medication unless needed, favoring 2-mL dilutions when possible, and decapping of vials for more complete medication withdrawal.

MAIN OUTCOME MEASUREMENTS

Retained volume of toxin solution that was not injected and estimated retained units of toxin.

RESULTS

A total of 157 vials of botulinum toxin A were tested. Of the 82 initial, phase 1, preintervention vials (8200 units), 5.5% (∼452 units) of toxin solution was retained following mixing and injections. One and 3-mL syringe tips contained a mean of 3.32 and 1.44 units of toxin respectively. Within vials, saline dilutions with 2 mL contained less mean retained toxin (1.89 vs 3.31 units) relative to 1-mL dilution. Awareness of monitoring significantly decreased retained solution in vials (0.035 mL vs 0.069 mL for naïve group, P = .002). Phase 2, postintervention testing of 75 vials demonstrated that withdrawing toxin from the inferior edge from a non-inverted vial reduced the retained toxin by 32.8% (P < .001). Decapping the vial further reduced the mean retained toxin to 0.42 units per vial (81.9% reduction, P < .001).

CONCLUSIONS

A potentially clinically significant amount of botulinum toxin solution is retained following mixing and injections. Implementation of guidelines significantly decreased wasted botulinum toxin.

LEVEL OF EVIDENCE

III.

Benefits and Risks of Non-Approved Injection Regimens for Botulinum Toxins in Spasticity

Spasticity with muscle paresis and loss of dexterity is a common feature of upper motor neuron syndrome due to injuries or the pyramidal tract in several neurological conditions. Botulinum toxin type A has been considered the gold standard treatment for spasticity and movement disorders, with efficacy, reversibility, and low prevalence of complications. During the last 30 years, thousands of studies of its use have been performed, but few guidelines are available. Therefore, there is great variability in both the doses and intervals of administration and the approaches taken by clinicians with considerable experience in spasticity and movement disorder treatment. In the present review article, we provide a short overview of the benefits and risks of non-approved injection regimens and doses for botulinum toxins, focusing on the treatment of post-stroke spasticity, where there is great interest in the potential for increasing the number of treatment/years and the dose of botulinum toxin treatment for subjects with upper and lower limb spasticity. However, many doubts exist regarding antibody development and possible adverse effects.

Towards flexible and tailored botulinum neurotoxin dosing regimens for focal dystonia and spasticity - Insights from recent studies

Botulinum neurotoxin (BoNT) is an effective, well-tolerated, and well-established option for the treatment of dystonic and spastic movement disorders. However, a single approach does not suit all patients, even within one disease indication. The degree of flexibility in treatment protocols is determined by individual product licenses, which often lag behind real-world clinical experience. A number of patient/practitioner surveys conducted recently have highlighted a desire for greater flexibility than that currently approved, both in BoNT doses and in the intervals between consecutive doses. New evidence arising from research conducted during the last few years has opened new avenues for tailoring BoNT treatment to patients' needs. Data suggest that escalating incobotulinumtoxinA doses enables treatment of a greater number of spasticity patterns than current dose limitations allow, without compromising safety or tolerability. Similarly, in patients with cervical dystonia (CD), repeated injections of incobotulinumtoxinA at intervals as early as 6 weeks after a previous treatment, based on individual patient need, were effective and well tolerated. Here, the BoNT doses and dosing intervals currently indicated in the USA and European Union are reviewed, together with the use of BoNT for the treatment of spasticity, CD, and blepharospasm. Opportunities for tailored BoNT therapy are also discussed.

Effective Site for the Application of Extracorporeal Shock-Wave Therapy on Spasticity in Chronic Stroke: Muscle Belly or Myotendinous Junction

OBJECTIVE

To compare the effect of extracorporeal shock-wave therapy (ESWT) applied at the muscle belly and myotendinous junction on spasticity in the upper and lower limbs of chronic stroke patients.

METHODS

Of the 151 patients, a total of 80 patients with stroke-induced spasticity on the elbow flexor and 44 patients on the knee flexor were enrolled for a prospective, randomized clinical trial. The patients were divided into control, muscle belly, and myotendinous junction groups, and a total of three ESWT sessions (0.068-0.093 mJ/mm², 1,500 shots) were conducted at one per week. A Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS) were collected at the baseline and at 1 week after each session.

RESULTS

After interventions, the MAS and MTS of both the belly and the junction groups showed positive effects from the ESWT on spasticity in the elbow and knee flexors, but the control group did not. The results also tended to improve after each session until the entire intervention was completed. However, there was no significant difference between the belly and junction groups.

CONCLUSION

ESWT could be effective for treating chronic spasticity after stroke when applied to muscle belly or myotendinous junction.

Botulinum neurotoxin C mutants reveal different effects of syntaxin or SNAP-25 proteolysis on neuromuscular transmission

Botulinum neurotoxin serotype C (BoNT/C) is a neuroparalytic toxin associated with outbreaks of animal botulism, particularly in birds, and is the only BoNT known to cleave two different SNARE proteins, SNAP-25 and syntaxin. BoNT/C was shown to be a good substitute for BoNT/A1 in human dystonia therapy because of its long lasting effects and absence of neuromuscular damage. Two triple mutants of BoNT/C, namely BoNT/C S51T/R52N/N53P (BoNT/C α-51) and BoNT/C L200W/M221W/I226W (BoNT/C α-3W), were recently reported to selectively cleave syntaxin and have been used here to evaluate the individual contribution of SNAP-25 and syntaxin cleavage to the effect of BoNT/C in vivo. Although BoNT/C α-51 and BoNT/C α-3W toxins cleave syntaxin with similar efficiency, we unexpectedly found also cleavage of SNAP-25, although to a lesser extent than wild type BoNT/C. Interestingly, the BoNT/C mutants exhibit reduced lethality compared to wild type toxin, a result that correlated with their residual activity against SNAP-25. In spite of this, a local injection of BoNT/C α-51 persistently impairs neuromuscular junction activity. This is due to an initial phase in which SNAP-25 cleavage causes a complete blockade of neurotransmission, and to a second phase of incomplete impairment ascribable to syntaxin cleavage. Together, these results indicate that neuroparalysis of BoNT/C at the neuromuscular junction is due to SNAP-25 cleavage, while the proteolysis of syntaxin provides a substantial, but incomplete, neuromuscular impairment. In light of this evidence, we discuss a possible clinical use of BoNT/C α-51 as a botulinum neurotoxin endowed with a wide safety margin and a long lasting effect.

The seven established Botulinum Neurotoxins serotypes (BoNT/A to G) and the many BoNT subtypes, the causative agents of botulism, are the most poisonous substances known (lethal doses in the low ng/kg range). Due to their toxicological properties, BoNTs are Janus-faced toxins: potent pathogenic factors and potential bioterrorism agents as well as safe and efficacious therapeutics. BoNTs exert their neuroparalytic action by cleaving SNARE proteins, either SNAP-25 or synaptobrevin/VAMP, which mediate neurotransmitter release at the neuromuscular junction; BoNT/C is the only serotype shown to cleave SNAP-25 and syntaxin-1 in vitro. Our study shows for the first time that this parallel cleavage also occurs in vivo. By using mutated toxins reported to be syntaxin-selective, we found that SNAP-25 proteolysis at the neuromuscular junction is the key determinant of BoNT/C lethality as it completely blocks nerve-muscle transmission. Conversely, syntaxin-1 cleavage only attenuates nerve terminal activity without inactivating the synapse, leading to only a partial decrease of neuromuscular functionality. As a result, the BoNT/C mutants have dramatically reduced lethality, but still modulate neuromuscular junction activity upon intramuscular injection. This aspect is particularly relevant considering the possible use of syntaxin-specific BoNT/C derivatives to improve the present clinical utilization of BoNTs.

Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology

The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects. Novel BoNTs are being discovered owing to next generation sequencing, but their biologic and pharmacological properties remain largely unknown. The molecular structure of the large protein complexes that the toxin forms with accessory proteins, which are included in some BoNT type A1 and B1 pharmacological preparations, have been determined. By far the largest effort has been dedicated to the testing and validation of BoNTs as therapeutic agents in an ever increasing number of applications, including pain therapy. BoNT type A1 has been also exploited in a variety of cosmetic treatments, alone or in combination with other agents, and this specific market has reached the size of the one dedicated to the treatment of medical syndromes. The pharmacological properties and mode of action of BoNTs have shed light on general principles of neuronal transport and protein-protein interactions and are stimulating basic science studies. Moreover, the wide array of BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed with specific properties suggest novel uses in therapeutics with increasing disease/symptom specifity. These recent developments are reviewed here to provide an updated picture of the biologic mechanism of action of BoNTs, of their increasing use in pharmacology and in cosmetics, and of their toxicology.

Botulinum toxin type A reduces TRPV1 expression in the dorsal root ganglion in rats with adjuvant-arthritis pain

Arthritis pain affects people's long-term health, and recent studies have demonstrated that transient receptor potential vanilloid type 1 (TRPV1) plays a crucial role in arthritis pain. In addition, Pre-clinical evidence indicated that botulinum toxin type A (BoNT/A) has antinociceptive effect. The present study investigated the causality between the antinociceptive effects of BoNT/A and the expression of TRPV1 in dorsal root ganglion (DRG) in rats with adjuvant-arthritis pain. The results showed that BoNT/A significantly reduced adjuvant-arthritis nociceptive behaviors in a dose-dependent manner. Furthermore, the BoNT/A cleaved synaptosomal-associated protein of 25 kDa (cl-SNAP-25) was detected in the DRG using immunofluorescence after intra-articular administration. Although BoNT/A significantly reduced the protein levels of TRPV1, there were no significant changes in the mRNA levels of TRPV1 between CFA and BoNT/A (1U, 3U, 10U) group after BoNT/A retrograde axonal transport into the DRG with quantitative RT-PCR. This research provides evidence that the antinociceptive mechanism of BoNT/A might be mediated by reduction of TRPV1 expression through inhibition of its plasma membrane trafficking after intra-articular administration.

Safety and efficacy of incobotulinumtoxinA doses up to 800 U in limb spasticity: The TOWER study

Objective:

To evaluate safety (primary objective) and efficacy of increasing doses (400 U up to 800 U) of incobotulinumtoxinA (Xeomin, Merz Pharmaceuticals GmbH) for patients with limb spasticity.

Methods:

In this prospective, single-arm, dose-titration study (NCT01603459), patients (18–80 years) with spasticity due to cerebral causes, who were clinically deemed to require total doses of 800 U incobotulinumtoxinA, received 3 consecutive injection cycles (ICs) with 400 U, 600 U, and 600–800 U incobotulinumtoxinA, respectively, each followed by 12–16 weeks' observation. Outcomes included adverse events (AEs), antibody testing, Resistance to Passive Movement Scale (REPAS; based on the Ashworth Scale), and Goal Attainment Scale.

Results:

In total, 155 patients were enrolled. IncobotulinumtoxinA dose escalation did not lead to an increased incidence of treatment-related AEs (IC1: 4.5%; IC2: 5.3%; IC3: 2.9%). No treatment-related serious AEs occurred. The most frequent AEs overall were falls (7.7%), nasopharyngitis, arthralgia, and diarrhea (6.5% each). Five patients (3.2%) discontinued due to AEs. No patient developed secondary nonresponse due to neutralizing antibodies. Mean (SD) REPAS score improvements from each injection to 4 weeks postinjection increased throughout the study (IC1: −4.6 [3.9]; IC2: −5.9 [4.2]; IC3: −7.1 [4.8]; p < 0.0001 for all). The proportion of patients achieving ≥3 (of 4) treatment goals also increased (IC1: 25.2%; IC2: 50.7%; IC3: 68.6%).

Conclusion:

Escalating incobotulinumtoxinA doses (400 U up to 800 U) did not compromise safety or tolerability, enabled treatment in a greater number of muscles/spasticity patterns, and was associated with increased treatment efficacy, improved muscle tone, and goal attainment.

ClinicalTrials.gov identifier:

NCT01603459.

Classification of evidence:

This study provides Class IV evidence that, for patients with limb spasticity, escalating incobotulinumtoxinA doses (400 U up to 800 U) increases treatment efficacy without compromising safety or tolerability.

Effect of electrical stimulation as an adjunct to botulinum toxin type A in the treatment of adult spasticity: a systematic review

OBJECTIVE

To investigate whether electrical stimulation (ES) as an adjunct to BTX-A boosts botulinum activity and whether the combined therapeutic procedure is more effective than BTX-A alone in reducing spasticity in adult subjects.

DATA SOURCES

A search was conducted in PubMed, EMBASE, Cochrane Central Register, and CINAHL from January 1966 to January 2016.

STUDY SELECTION

Only randomized controlled studies (RCT) involving the combination of BTX-A and ES were considered. RCTs were excluded if BTX plus ES was investigated in animals or healthy subjects; certain techniques were used as an adjunct to BTX-A, but ES was not used; BTX-A or ES were compared but were not used in combination. ES was divided into neuromuscular stimulation (NMS), functional electrical stimulation (FES), and transcutaneous electrical nerve stimulation (TENS). Two authors independently screened all search results and reviewed study characteristics using the Physiotherapy Evidence Database (PEDro) scale.

RESULTS

Fifteen RCTs were pinpointed and nine studies were included. Trials varied in methodological quality, size, and outcome measures used. ES was used in the form of NMS and FES in seven and two studies, respectively. No study investigating BTX-A plus TENS was found. BTX-A plus ES produced significant reduction in spasticity on the Ashworth Scale (AS) and on the modified AS in seven studies, but only four showed high quality on the PEDro scale. Significant reduction in compound muscular action potential (CMAP) amplitude was detected after BTX-A plus ES in two studies.

CONCLUSIONS

ES as an adjunctive therapy to BTX-A may boost BTX-A action in reducing adult spasticity, but ES variability makes it difficult to recommend the combined therapy in clinical practice. Implications for rehabilitation Electrical stimulation (ES) as adjunct to botulinum toxin type A (BTX-A) injections may boost neurotoxin action in treating adult spasticity. Given the variability of ES characteristics and the paucity of high-quality trials, it is difficult to support definitively the use of BTX-A plus ES to potentiate BTX-A effect in clinical practice. A vast array of rehabilitation interventions combined with BTX-A have been provided in reducing spasticity, but the present evidence is not sufficient to recommend any combined therapeutic strategy.

Spotlight on botulinum toxin and its potential in the treatment of stroke-related spasticity

Poststroke spasticity affects up to one-half of stroke patients and has debilitating effects, contributing to diminished activities of daily living, quality of life, pain, and functional impairments. Botulinum toxin (BoNT) is proven to be safe and effective in the treatment of focal poststroke spasticity. The aim of this review is to highlight BoNT and its potential in the treatment of upper and lower limb poststroke spasticity. We review evidence for the efficacy of BoNT type A and B formulations and address considerations of optimal injection technique, patient and caregiver satisfaction, and potential adverse effects of BoNT.

Safety and efficacy of incobotulinumtoxinA as a potential treatment for poststroke spasticity

Spasticity is a common disabling symptom for several neurological conditions. Botulinum toxin type A injection represents the gold standard treatment for focal spasticity after stroke showing efficacy, reversibility, and low prevalence of complications. In recent years, incobotulinumtoxinA, a new Botulinum toxin type A free of complexing proteins, has been used for treating several movement disorders with safety and efficacy. IncobotulinumtoxinA is currently approved for treating spasticity of the upper limb in stroke survivors, even if several studies described the use also in lower limb muscles. In the present review article, we examine the safety and effectiveness of incobotulinumtoxinA for the treatment of spasticity after stroke.

Electromyographic control of botulinum toxin a injections in the upper extremities in patients with spasticity of various etiology

AIM

The study was aimed at studying the efficacy of botulinum toxin A injections combined with EMG-control of the injections in patients with upper limb spasticity of various etiology for decreasing muscle tone and improving the passive limb function as well as at assessing the possibility of a botulinum toxin dose reduction under combination of these methods.

MATERIAL AND METHODS

61 patients with upper limb spasticity of different etiology were evaluated. The main group consisted of 29 patients who were injected with abobotulinum, the botulinum toxin A (500 U per vial), under EMG-control. The control group consisted of 32 patients who received BTA injections without EMG-control. A repeated BTA injection was performed on the 4th month of the study. Patients in both groups received standard rehabilitation therapy. The spasticity pattern was determined using the Arm Spasticity Pattern (ASP) scale. Evaluation of the treatment efficacy was performed using the modified Ashworth scale to determine upper limb spasticity and the modified Barthel Index scale to assess the quality of life as well as the Disability Assessment Scale (DAS) and Clinical Global Impression (CGI) scale.

RESULTS

The main spasticity patterns were as follows: the type III was in 13 (44.8%) and 17 (53.1%) patients, the type I was in 9 (31.0%) and 9 (28.1%) patients, and the type VI was in 7 (24.2%) and 6 (18.8%) patients of the main and control groups, respectively. One month after BTA treatment, a significant improvement was observed in both groups, but the improvement in the main group was more pronounced compared to that in the control group (р<0.05). This difference persisted for the whole treatment period (р<0.05). The DAS score demonstrated improvement in both groups, but only patients of the main group had a statistically significant improvement in putting the arm through a sleeve (р<0.05). EMG-control enabled a reduction in the BTA dose by 50-300 U.

CONCLUSION

BTA injections under EMG-control in upper limb spasticity patients may improve the treatment efficacy.