Botulinum toxin: dosing and dilution

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.

Safety and Efficacy of HU-014 in the Treatment of Post-Stroke Upper Limb Spasticity: A Phase I Pilot Study

Botulinum toxin type A (BTX-A) is widely used for treating post-stroke upper limb spasticity. We evaluated the safety and efficacy of HU-014 in treating post-stroke upper limb spasticity. Thirteen patients were administered with HU-014. The primary outcome was safety, including adverse events, vital signs, physical examination, laboratory tests, and antibody formation test. The secondary outcomes were changes in the Modified Ashworth Scale (MAS) score for wrist, elbow, and finger flexor; Disability Assessment Scale (DAS); Investigator's Global Assessment (IGA) and Subject's Global Assessment (SGA); Caregiver Burden Scale (CBS); and Columbia Suicide Severity Rating Scale (C-SSRS) at weeks 4, 8, and 12 from baseline. No notable safety-related issues were reported. MAS and DAS scores were significantly decreased from those at baseline at 4, 8, and 12 weeks (p < 0.05). At weeks 4, 8, and 12, the IGA and SGA scores were 5.85 ± 0.55, 5.69 ± 0.48, and 5.62 ± 0.65 and 5.46 ± 1.20, 5.85 ± 0.38, and 5.77 ± 0.73, respectively. CBS scores decreased at all timepoints and those for cutting fingernails significantly decreased at 8 and 12 weeks compared with baseline (p < 0.05). C-SSRS scores showed that suicidal ideation in all patients was "low" at all timepoints. HU-014 is a safe treatment that can improve post-stroke upper limb spasticity.

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.

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.

Botulinum toxin injection for chronic pelvic pain: A systematic review

INTRODUCTION

Botulinum toxin has proven therapeutic effects in alleviating pain in several myofascial disorders, with an expanding potential in chronic pelvic pain. The objective of this systematic review is to evaluate the efficacy and safety of botulinum toxin injection as an off-label treatment for female chronic pelvic pain.

MATERIAL AND METHODS

Using PRISMA guidelines, MEDLINE, EBM Reviews, PubMed, CINAHL, TRIP Database, EMBASE, Web of Science and gray literature were searched. Studies assessing the efficacy of botulinum toxin for chronic pelvic pain in adult females, with 10 or more women, published in English up to 13 January 2020, were included. All eligible studies were reviewed and data were extracted by two independent reviewers using a standardized form. Quality of evidence was graded using the Cochrane Risk of Bias 2 tool for randomized controlled trials and the Ottawa-Newcastle scale for observational studies.

RESULTS

In all, 491 records were screened. Seventeen articles were included in the final review: 5 randomized controlled trials and 12 observational studies. The quality of evidence ranged from low to high. There was a large degree of heterogeneity in study designs, and thus a meta-analysis was not feasible. All observational studies concluded that botulinum toxin was an effective treatment for chronic pelvic pain, with the greatest change in visual analog scale from 8.69 at baseline to 3.07 at 24 months post-injection. However, only one of the five randomized controlled trials found statistical significant differences favoring botulinum toxin in the reporting of the EQ-5D (botulinum 0.78 [0.69-1.00], control 0.69 [0.25-0.81], P = .03) and frequency of intercourse (botulinum 1 [1-1.75], placebo 1 [0-1], P = .025). The most common adverse effect was transient localized pain at injection site (6%-88%). No serious adverse events were reported.

CONCLUSIONS

Although observational studies were encouraging, there is insufficient high quality evidence to recommend botulinum toxin injection for chronic pelvic pain. However, it appears to be safe to use. Future studies of higher quality in its treatment efficacy are indicated.

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 injection, dilution confusion: The impact of toxin diffusion on clinical practice

Botulinum toxins (BoNT) are a standard of care for spasticity management of children with a variety of neuromuscular (NM) conditions. BoNT relaxes skeletal muscles by inhibiting the release of acetylcholine from the neuromuscular junction (NMJ). As part of their training physiatrist become proficient in the targeted injections of BoNT into affected skeletal musculature. While the pharmacology and pharmacokinetics of BoNT are well characterized, there is limited literature on the clinical impact that varying the volume of diluent that a toxin is reconstituted within. In theory, injection of a larger volume of dilute BoNT would allow for a larger spread affect reaching more distant NMJs; the reverse is also be true. Dilution volume of BoNT injections in children produces some unique situations due to their low weight, smaller muscle bulk, an increased relative risk of spread to surrounding structures, and novel differences in concentration of NMJ in immature muscle. Some of these factors may act as guiding principles that providers can use when adjusting from their standard BoNT dilutional practices. Although, there are recommended dosing strategies available each child's spasticity pattern represents a unique situation and providers must be allowed flexibility to think creatively about dilution strategies for BoNT injections.

Pharmacologic Treatment Tools: Systemic Medications and Toxins, Opportunities, and Pitfalls

Treatment of pathologic muscle overactivity associated with upper motor neuron syndrome can be multifaceted. One of the initial decisions to be made when formulating an overarching treatment plan is selecting a combination of strategies that is most applicable. Strategies may include physical interventions, such as stretching or splinting modalities, or surgery, whereas pharmacotherapeutic strategies encompass oral/systemic medications as well as agents, such as toxins and alcohols, used for focal chemodenervation. This article reviews the oral/systemic therapies as well as toxins that are used focally. Although medication can also be administered via intrathecal pumps, this treatment approach is discussed elsewhere.

Heart Rate Variability modifications induced by high doses of incobotulinumtoxinA and onabotulinumtoxinA in hemiplegic chronic stroke patients: A single blind randomized controlled, crossover pilot study

BACKGROUND

Botulinum toxin type A is a valid and safe treatment for focal spasticity, with documented effects on both sympathetic and parasympathetic systems. Heart rate variability can provide detailed information about the control of the autonomic nervous system on cardiovascular activities. Previous studies in literature showed no significant changes in Heart Rate Variability with doses >600 U of incobotulinumtoxinA in chronic post stroke spastic patients; however, at present time, these results have not been confirmed with doses >600 U of onabotulinumtoxinA.

AIM

To evaluate changes in Heart Rate Variability induced by high doses (>600 U) of incobotulinumtoxinA or onabotulinumtoxinA in spastic stroke patients over a 1-year period.

DESIGN

single blind randomized controlled crossover study design.

SETTING

Rehabilitation Unit of the University Hospital in Novara.

POPULATION

10 stroke survivors with spastic hemiplegia (Modified Ashworth Scale ≥ 2) were recruited and randomly divided in two groups (A and B).

METHODS

In the first part of the study, patients in Group A were injected with incobotulinumtoxinA while patients in Group B with onabotulinumtoxinA; after 6 months, a crossover intervention was performed. All patients were blinded to Botulinum toxin type A type, and performed an ECG registration in the 24 h before injection (t0) and 10 days after treatment (t1), both in the first and in the second part of the study. Functional status was evaluated with Barthel Index, Motricity Index and Functional Ambulation Category scores.

RESULTS

Heart Rate Variability analysis showed no significant changes after each Botulinum toxin type A injection in both groups at any evaluation time. Moreover, no statistically significant differences were found regarding each variable between the two groups.

CONCLUSIONS

Our data show that high doses (>600 U) of incobotulinumtoxinA and onabotulinumtoxinA do not influence the cardiovascular activity of the autonomic nervous system in chronic hemiplegic spastic stroke survivors.

Recovery of rat muscle size but not function more than 1 year after a single botulinum toxin injection

INTRODUCTION

Neurotoxin injection is used to treat a wide variety of neuromuscular disorders. The purpose of this study was to measure the functional and structural properties of botulinum toxin-injected adult rat skeletal muscle over nearly the entire lifespan.

METHODS

Ten groups of animals were subjected to either neurotoxin injection [Botox, Type A (BT-A); Allergan, Irvine, California] or saline solution injection. Neurotoxin-injected animals (n = 90) were analyzed at different time-points: 1 week; 1 month; 3 months; 6 months; 12 months; or 18 months.

RESULTS

In spite of the recovery of structural features, such as muscle mass and fiber area, dorsiflexion torque production remained significantly depressed by 25%, even at 12 months after neurotoxin injection.

DISCUSSION

The data demonstrate that, after a single BT-A injection, although gross muscle morphology recovered over a 12-month time period, loss of contractile function did not recover. Muscle Nerve 57: 435-441, 2018.

Detection of Botulinum Toxin Muscle Effect in Humans Using Magnetic Resonance Imaging: A Qualitative Case Series

BACKGROUND

Although important for dosing and dilution, there are few data describing botulinum toxin (BT) movement in human muscle.

OBJECTIVE

To better understand BT movement within human muscle.

DESIGN

Proof-of-concept study with descriptive case series.

SETTING

Outpatient academic practice.

PARTICIPANTS

Five subjects with stroke who were BT naive with a mean age of 60.4 ± 14 years and time poststroke of 4.6 ± 3.7 years.

METHODS

Three standardized injections were given to the lateral gastrocnemius muscle (LGM): 2 contained 25 units (U) of onabotulinumtoxinA (Botox) in 0.25 mL of saline solution and the third 0.25 mL of saline solution only. The tibialis anterior muscle (TAM) was not injected in any subject. A leg magnetic resonance image was obtained at baseline, 2 months, and 3 months later with a 3.0 Tesla Siemens scanner. Three muscles, the LGM, lateral soleus muscle (LSM), and TAM, were manually outlined on the T2 mapping sequence at each time point. A histogram of T2 relaxation times (T2-RT) for all voxels at baseline was used to calculate a mean and standard deviation (SD) T2-RT for each muscle. Botulinum toxin muscle effect (BTME) at 2 months and 3 months was defined as a subject- and muscle-specific T2-RT voxel threshold ≥3 SD above the baseline mean at or near BT injection sites.

MAIN OUTCOME MEASURES

BTME volume for each leg magnetic resonance imaging slice at 3 time points and 3 muscles for all subjects.

RESULTS

One subject missed the 3-month scan, leaving 18 potential observations of BTME. Little to no BTME effect was seen in the noninjected TAM. A BTME was detected in the LGM in 13 of 18 possible observations, and no effect was detected in 5 observations. Possible BTME effect was seen in the LSM in 3 subjects due to either diffusion through fascia or needle misplacement. Volume of BTME, as defined here, appeared to be substantially greater than the 0.25-mL injection volume.

CONCLUSIONS

This descriptive case series is among the first attempts to quantify BTME within human muscle. Our findings are preliminary and are limited by a few inconsistencies. However, we conclude that use of magnetic resonance imaging to detect the volume of BTME is feasible and may assist researchers in modeling the spread and diffusion of BT within human muscle.

LEVEL OF EVIDENCE

IV.

In-vivo comparison of the neurotoxic potencies of incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA

Three botulinum neurotoxin type A (BoNT/A) products, incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA, all manufactured by different methods, are employed in clinical practice. Comparing the three BoNT/A products is difficult because their concentrations and volumes differ and the precise dose equivalence ratio is not known. We aimed to compare the neurotoxic potencies by a systematic analysis of injected volume and dose. The potency of BoNT in inducing hind limb paresis was assessed by analyzing the wheel-running performance of mice. To standardize the volume, the effect of an identical dose of incobotulinumtoxinA dissolved in different volumes of saline (15, 10, 5, and 2μl) was studied in four groups of mice (n=13-15). The potencies of the BoNT products were then compared by injecting identical volumes (10μl) containing different doses into both hind leg muscles. Mice injected with incobotulinumtoxinA showed a volume-dependent reduction in wheel-running, with larger volumes inducing more intense paresis. A standardized volume containing the same number of mouse units of the BoNT/A products produced different degrees of paresis. The conversion ratio of incobotulinumtoxinA and onabotulinumtoxinA is estimated to be between 1:0.75 and 1:0.5. OnabotulinumtoxinA displayed a two-fold greater potency than abobotulinumtoxinA. Doses of onabotulinumtoxinA and abobotulinumtoxinA that produce an identical severity of pareses even result in the same duration of pareses. This wheel-running assay allows one to compare the neurotoxic potency of different volumes and doses of the BoNT products in vivo. Our results argue against common clinical practice because incobotulinumtoxinA and onabotulinumtoxinA are not readily interchangeable and a two-fold dose of abobotulinumtoxinA is needed to induce an effect identical to onabotulinumtoxinA. In addition, this emphasizes that the duration of BoNT-induced effect is the same as long as equipotent doses of BoNT are injected.

Botulinum Toxin Treatment for Limb Spasticity in Childhood Cerebral Palsy

CP is the most common cause of chronic disability in childhood occurring in 2–2.5/1000 births. It is a severe disorder and a significant number of patients present cognitive delay and difficulty in walking. The use of botulinum toxin (BTX) has become a popular treatment for CP especially for spastic and dystonic muscles while avoiding deformity and pain. Moreover, the combination of physiotherapy, casting, orthotics and injection of BTX may delay or decrease the need for surgical intervention while reserving single-event, multi-level surgery for fixed musculotendinous contractures and bony deformities in older children. This report highlights the utility of BTX in the treatment of cerebral palsy in children. We include techniques for administration, side effects, and possible resistance as well as specific use in the upper and lower limbs muscles.

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.

Differential characteristics of incobotulinumtoxinA and its use in the management of glabellar frown lines

Objectives

This review examines the pharmacologic and clinical characteristics of incobotulinumtoxinA (Xeomin^®/Xeomeen^®/Bocouture^®/XEOMIN Cosmetic™; botulinum toxin type A [150 kDa]), which is free from complexing proteins, and discusses its efficacy and safety in the treatment of glabellar frown lines. Differences between incobotulinumtoxinA and other commercially available botulinum neurotoxin type A (BoNT/A) products that have been approved by the European Medicines Agency, US Food and Drug Administration, and other regulatory agencies for this indication are also discussed.

Findings

IncobotulinumtoxinA differs from other commercially available BoNT/A preparations, in that it is free from complexing proteins and contains only active neurotoxin, minimizing foreign protein load. IncobotulinumtoxinA is commonly used at a 1:1 dose ratio with onabotulinumtoxinA and displays comparable efficacy and safety; furthermore, it is associated with early onset and long duration of effect, and high levels of subject satisfaction. In terms of practical considerations, incobotulinumtoxinA does not require cold storage and demonstrates low spread, enabling precise treatment and good tolerability.

Conclusion

IncobotulinumtoxinA is an efficacious and well-tolerated treatment for glabellar frown lines. It differs from other BoNT/A preparations, in that it is free from complexing proteins and contains only active neurotoxin, which is relevant clinically, as this reduces the foreign protein load and minimizes the risk of neutralizing antibody production. In practical terms, incobotulinumtoxinA has a long shelf-life, remaining stable without the need for refrigeration, and due to its limited spread is a precise localized treatment.

Abo-, inco-, ona-, and rima-botulinum toxins in clinical therapy: a primer

Botulinum neurotoxin (BoNT) is an acetylcholine release inhibitor and a neuromuscular-blocking agent used for the treatment of a variety of medical and cosmetic indications. Currently, in the United States, there are four BoNT formulations licensed for use: abobotulinumtoxinA, incobotulinumtoxinA, onabotulinumtoxinA, and rimabotulinumtoxinB. These revised name designations were established to reinforce the understanding that each BoNT product has an individual potency and is not interchangeable with any other BoNT product. The therapeutic use of BoNTs is expanding and new formulations are on the horizon. This article is a primer that describes distinctions among currently available, licensed BoNT formulations. Toxin pharmacology, product characteristics, storage, handling, preparation, and dosages will be reviewed. In addition, issues related to dose equivalency ratios, immunogenicity, potency, and toxin spread will be discussed. Therapeutic indications and safety are discussed briefly. Knowledge of the available and licensed BoNT formulations and the ability to make distinctions in toxin pharmacology, product characteristics, and indications are vital for product selection, preparation, drug information, avoidance of drug errors, quality assurance, and patient safety.

Effectiveness and safety of botulinum toxin type a in children with musculoskeletal conditions: what is the current state of evidence?

Children with musculoskeletal conditions experience muscle weakness, difficulty walking and limitations in physical activities. Standard treatment includes physiotherapy, casting, and surgery. The use of botulinum toxins appears as a promising treatment on its own, but usually as an adjunct to other treatment modalities and as an alternative to surgery. The objectives were to establish the evidence on the effectiveness, safety and functional outcome of BTX-A in children with musculoskeletal conditions. A literature search using five electronic databases identified 24 studies that met our inclusion criteria. Two randomized clinical trials were included; most studies were case studies with small sample sizes and no control group. Improvements in gait pattern, function, range of motion, reduction of co-contractions, and avoidance of surgical procedures were found following BTX-A injections. Adverse events were not reported in 10 studies, minor adverse events were reported in 13 children and there were no severe adverse events. Additional doses appear safe. BTX-A is a promising treatment adjunct in improving functional outcomes in children with musculoskeletal conditions. Future studies including larger samples, longer follow-up periods and a comparison group are required to provide evidence on the effectiveness and safety of this drug in children with musculoskeletal conditions.

Determining the technical and clinical factors associated with pain for children undergoing botulinum toxin injections under nitrous oxide and anesthetic cream

AIMS

To determine technical and clinical factors associated with pain when using an analgesic protocol with 50% nitrous oxide/oxygen and anesthetic cream (lidocaine and prilocaine, Emla(®)) for children with cerebral palsy undergoing botulinum toxin injections.

METHODS

Monocentric prospective study including 50 children newly injected with a mean age of 6.6 years (± 4.32, range 1-18) and 199 injected muscles. Pain was evaluated using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS). The following variables were noted: gender, age, weight, Gross Motor Function Classification System, type of cerebral palsy (hemiplegic, diplegic, tetraplegic), muscles injected and severe cognitive impairment. The procedure was broken down into three phases for the purpose of pain evaluation: puncture, muscle localization using electrostimulation and injection of botulinum toxin.

RESULTS

The mean CHEOPS score was 8.16 (± 3.5) and 38% of scores were above the therapeutic threshold of 9. The injection phase was significantly more painful (6.77 ± 3.30) than the puncture (4.88 ± 2.03) and localization (5.46 ± 2.68) phases. The adductor muscles were less painful than other muscles. Children with more severe cognitive impairment seemed to perceive higher levels of pain than the others. Other clinical factors were not associated with pain score.

CONCLUSION

Clinical characteristics seem not strongly correlated to the success or failure of the 50% nitrous oxide/oxygen-Emla(®) protocol and this pain treatment protocol does not prevent equally all phases of botulinum toxin injections. Future research on the products and its dilution might help to reduce pain level.

The efficacy of botulinum toxin type A in managing chronic musculoskeletal pain: a systematic review and meta analysis

BACKGROUND

Botulinum toxin type A (BoNTA) is a neurotoxin that acts by inhibiting the release of neurotransmitters acetylcholine at neuromuscular junctions, thus reducing muscular contractions. Recent evidence suggests that BoNTA can reduce nociceptive activities of sensory neurons in animal models by inhibiting release of certain neuropeptides. Despite the therapeutic benefit of BoNTA in alleviating painful muscle spasms, its efficacy in other musculoskeletal pain conditions is less clear.

OBJECTIVE

We aim to examine the efficacy of BoNTA in reducing chronic musculoskeletal pain.

METHODS

Studies for inclusion in our report were identified using MEDLINE, EMBASE, PUBMED, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of relevant articles. Studies were considered eligible for inclusion if they were randomized controlled trials (RCTs), evaluating the efficacy of BoNTA injections in pain reduction. All studies were assessed and data were abstracted independently by paired reviewers. The outcome measures were baseline and final pain scores as assessed by the patients. The internal validity of trials was assessed with the Jadad scale. Disagreements were resolved through discussions.

MAIN RESULTS

Twenty-one studies were included in the systematic review and 15 of them were included in the final meta-analysis. There was a total of 706 patients in the meta-analysis, represented from trials of plantar fasciitis (n = 1), tennis elbow (n = 2), shoulder pain (n = 1), whiplash (n = 3), and myofascial pain (n = 8). Overall, there was a small to moderate pain reduction among BoNTA patients when compared to control (SMD = -0.27, 95% CI: -0.44 to -0.11). When the results were analyzed in subgroups, only tennis elbow (SMD = -0.44, 95% CI: -0.86 to -0.01) and plantar fasciitis (SMD = -1.04, 95% CI: -1.68 to -0.40) demonstrated significant pain relief. Although not in the meta-analysis, one back pain study also demonstrated positive results for BoNTA. Lastly, BoNTA was effective when used at ≥ 25 units per anatomical site or after a period ≥ 5 weeks.

CONCLUSION

In our meta-analysis, BoNTA had a small to moderate analgesic effect in chronic musculoskeletal pain conditions. It was particularly effective in plantar fasciitis, tennis elbow, and back pain, but not in whiplash or shoulder pain patients. However, more evidence is required before definitive conclusions can be drawn. On the other hand, there is convincing evidence that BoNTA lacks strong analgesic effects in patients with myofascial pain syndrome. A general dose-dependent and temporal response with BoNTA injections was also observed.

Botulinum toxin (Dysport) treatment of the spastic gastrocnemius muscle in children with cerebral palsy: a randomized trial comparing two injection volumes

OBJECTIVE

To compare the effect of equivalent doses in two different volumes of botulinum toxin type A (Dysport) on gastrocnemius spasticity.

DESIGN

Single-blind, randomized, controlled trial.

SETTING

Hospital rehabilitation department.

SUBJECTS

Twenty-two children with spastic diplegic or quadriplegic cerebral palsy.

INTERVENTION

High (500 U/5 mL) and low (500 U/1 mL)-volume preparations of Dysport were injected into the gastrocnemius muscles, each child randomly receiving one preparation in the right and the other in the left leg.

MAIN MEASURES

Dynamic ankle joint range of motion (ROM), passive ROM of the ankle joint, modified Ashworth Scale scores, and the areas of the compound muscle action potential assessed before treatment and at four and eight weeks post treatment.

RESULTS

Both legs improved significantly. The mean (SD) improvements between baseline and the end of follow-up were 19.7 (10.83) degrees for dynamic ROM, 8.4 (9.19) degrees for passive ROM, -1.3 (0.6) for modified Ashworth Scale scores, and -9.4 (11.41) mV-ms for compound muscle action potential in the high-volume group; and 13.5 (10.45) degrees for dynamic ROM, 7.4 (7.88) for passive ROM, -0.9 (0.5) for modified Ashworth Scale scores, and -5.9 (7.50) mV-ms for areas of compound muscle action potential in the low-volume group. The high-volume preparation yielded significantly greater improvement in dynamic ROM (P<0.001), muscle tone (P < 0.001), and lower compound muscle action potential area (P = 0.006).

CONCLUSIONS

A high-volume preparation of Dysport is more effective than a low volume in reducing spasticity in the gastrocnemius muscle.

Dynamic splinting after treatment with botulinum toxin type-A: a randomized controlled pilot study

INTRODUCTION

Over 1.5 million Americans are diagnosed with a stroke each year, and excessive flexion or extension (hypertonia) of upper extremity joints are common secondary conditions. The purpose of this study was to compare the efficacy of botulinum toxin type-A and manual therapy, with the adjunct treatment of dynamic splinting on range of motion, spasticity, and elbow flexor hypertonia, in a randomized trial.

METHODS

Thirty-six subjects were recruited for this pilot study and all exhibited hypertonia in elbow flexion. Six patients were excluded due to noncompliance. Testing was done with pre/post active range of motion in elbow extension, and the Modified Ashworth Scale (extension) for spasticity. All patients received the current standard of care: botulinum toxin type-A injections and manual therapy. Experimental patients were randomly assigned adjunct treatment with Elbow Extension Dynasplint.

RESULTS

Thirty patients completed the study (mean age [SD] 52+/-17 years). The percentage of change in active range of motion in elbow extension was greater for the experimental than for control subjects (33.5% vs. 18.7%). The Modified Ashworth Scale (extension) scores showed comparable changes of a mean 9.3% improvement for experimental versus 8.6% for the control subjects.

CONCLUSION

This study confirmed the efficacy of botulinum toxin type-A in tone management and occupational therapy in contracture reduction. It also showed the value of dynamic splinting in maintaining gains in range of motion.

Botulinum toxin: description of injection techniques and examination of controversies surrounding toxin diffusion

The benefits derived from botulinum toxin (BTX) injections may be negated by unintentional weakness of adjacent uninjected muscles. Such weakness may be the result of inaccurate targeting, or diffusion of BTX to surrounding muscles. Several techniques, using electromyographic, endoscopic or imaging guidance are purported to increase the accuracy of targeting. Diffusion of BTX is thought to be influenced by factors such as dose, concentration, injectate volume, number of injections, site and rate of injection, needle gauge, muscle size, muscular fascia, distance of needle tip from the neuromuscular junction, and protein content of the BTX formulation. This article describes techniques that aim to increase the accuracy of BTX injections and examines the controversies surrounding diffusion of BTX following injection.

Safety and efficacy of botox injection in alleviating post-operative pain and improving quality of life in lower extremity limb lengthening and deformity correction

BACKGROUND

Distraction osteogenesis is the standard treatment for the management of lower limb length discrepancy of more than 3 cm and bone loss secondary to congenital anomalies, trauma or infection. This technique consists of an osteotomy of the bone to be lengthened, application of an external fixator, followed by gradual and controlled distraction of the bone ends. Although limb lengthening using the Ilizarov distraction osteogenesis principle yields excellent results in most cases, the technique has numerous problems and is not well tolerated by many children. The objective of the current study is to determine if Botulinum Toxin A (BTX-A), which is known to possess both analgesic and paralytic actions, can be used to alleviate post-operative pain and improve the functional outcome of children undergoing distraction osteogenesis.

METHODS/DESIGN

The study design consists of a multi centre, randomized, double-blinded, placebo-controlled trial. Patients between ages 5-21 years requiring limb lengthening or deformity correction using distraction will be recruited from 6 different sites (Shriners Hospital for Children in Montreal, Honolulu, Philadelphia and Portland as well as DuPont Hospital for Children in Wilmington, Delaware and Hospital for Sick Children in Toronto, Ont). Approximately 150 subjects will be recruited over 2 years and will be randomized to either receive 10 units per Kg of BTX-A or normal saline (control group) intraoperatively following the surgery. Functional outcome effects will be assessed using pain scores, medication dosages, range of motion, flexibility, strength, mobility function and quality of life of the patient. IRB approval was obtained from all sites and adverse reactions will be monitored vigorously and reported to IRB, FDA and Health Canada.

DISCUSSION

BTX-A injection has been widely used world wide with no major side effects reported. However, to the best of our knowledge, this is the first time BTX-A is being used under the context of limb lengthening and deformity correction.

TRIAL REGISTRATION

NCT00412035.

Botulinum toxin a, evidence-based exercise therapy, and constraint-induced movement therapy for upper-limb hemiparesis attributable to stroke: a preliminary study

OBJECTIVE

To determine whether the combination of botulinum toxin A (BTX-A) treatment for the upper limb and a 4-wk course of exercise therapy could improve motor function sufficiently to allow those with poststroke hemiparesis and spasticity to achieve the minimal motor criteria (MMC) to be enrolled in constraint-induced movement therapy (CIMT), and to determine the feasibility of enrolling participants into CIMT if they meet MMC after treatment with a combination of BTX-A plus exercise therapy.

DESIGN

Twelve individuals received BTX-A and exercise therapy for 1 hr/day, three times per week, for 4 wks. Those who met MMC were enrolled in 2 wks of CIMT, and the rest received a home exercise program. Outcome measures included the Ashworth Scale, Wolf Motor Function Test (WMFT), the Motor Activity Log (MAL), the Box and Blocks Test (BBT), and the upper-extremity subtest of the Fugl-Meyer Assessment of Motor Function (FM-UE).

RESULTS

Ashworth Scale scores declined from a mean score of 2.0-1.2 (P = 0.01). Four of 12 subjects were able to achieve MMC (P = 0.026). CIMT participants improved in the BBT, the MAL, and the WMFT compared with their own baseline. Gains achieved during CIMT receded by week 24 as spasticity returned.

CONCLUSION

BTX-A plus exercise therapy shows potential to improve function for those with severe hand paresis and spasticity after stroke. Those who meet MMC may initially realize further modest gains through CIMT. However, gains are likely to recede as spasticity returns. Adding medications or modifying the therapy protocol to include activities such as functional neuromuscular stimulation or robotic training may yield a more potent effect.

Botulinum toxin in poststroke spasticity

Poststroke hemiparesis, together with abnormal muscle tone, is a major cause of morbidity and disability. Although most hemiparetic patients are able to reach different ambulatory levels with rehabilitation efforts, upper and lower limb spasticity can impede activities of daily living, personal hygiene, ambulation and, in some cases, functional improvement. The goals of spasticity management include increasing mobility and range of motion, attaining better hygiene, improving splint wear and other functional activities. Conservative measures, such as positioning, stretching and exercise are essential in spasticity management, but alone often are inadequate to effectively control it. Oral antispastic medications often provide limited effects with short duration and frequent unwanted systemic side effects, such as weakness, sedation and dry mouth. Therefore, neuromuscular blockade by local injections have become the first choice for the treatment of focal spasticity, particularly in stroke patients. Botulinum toxin (BTX), being one of the most potent biological toxins, acts by blocking neuromuscular transmission via inhibiting acetylcholine release. Currently, focal spasticity is being treated successfully with BTX via injecting in the spastic muscles. Two antigenically distinct serotypes of BTX are available on the market as type A and B. Clinical studies of BTX used for spastic hemiplegic patients are reviewed in this article in two major categories, upper and lower limb applications. This review addresses efficacy in terms of outcome measures, such as muscle tone reduction and functional outcome, as well as safety issues. Application modifications of dose, dilutions, site of injections and combination therapies with BTX injections are also discussed.

Botulinum toxin type A injection for management of upper limb spasticity in children with cerebral palsy: a literature review

The aim of this article was to present a review of the research literature on the outcome of botulinum toxin type A (BTX-A) injection for management of upper limb spasticity in children with cerebral palsy (CP). We searched the electronic databases of MEDLINE, CINAHL and PUBMED for all published studies with full-length English text available. For each study, the quality of the methods and the strength of evidence were assessed by 2 independent reviewers based on the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) guidelines. Four studies of level I, 8 studies of level IV and 4 studies of level V were identified. Due to the limited number of studies with high quality evidence and inconsistent results among studies, we were unable to support or refute the usefulness of BTX-A injection for management of upper limb spasticity in children with CP. Moreover, we identified several variables that may affect the outcome of injection, such as timing of age, dosage, dilution volumes, localization techniques of target muscles and participant characteristics. In summary, we have presented a review the literature and a discussion of the considerable uncertainty and variation associated with the clinical use of BTX-A injection for management of upper limb spasticity in children with CP.

Management of spasticity in adults: practical application of botulinum toxin

Spasticity, characterized by increased muscle tone, exaggerated stretch reflexes, and abnormal limb posture, is a common sequel of central nervous system pathology. Historically, medicinal treatments have been of limited efficacy. This review discusses the clinical features of spasticity, the functional and pathological consequences, and treatment. It reviews the most common patterns of spasticity encountered in the upper and lower limbs and focuses on focal treatment of spastic muscles with the three commercially available botulinum toxins Botox, Dysport, and Myobloc/NeuroBloc. It addresses practical details such as muscle selection and identification, drug dilution, and doses.

Management of childhood spasticity: a neurosurgical perspective

The management of childhood spasticity requires a multidisciplinary effort. With input from pediatricians, physical and occupational therapists, neurologists, orthotists, orthopedic surgeons, neurological surgeons, and other healthcare personnel, effective treatment for spasticity can be initiated and maintained that can lead to meaningful improvements in quality of life for vast numbers of children. Neurosurgical treatment of spasticity will continue to evolve and be refined as procedures and techniques are appropriately evaluated with reliable and validated outcome measures.

Multiple Sclerosis and Spasticity

Spasticity is a common impairment in MS. It can result in significant medical complications and is associated with increased disability. Treatment strategies include skilled rehabilitation strategies, neuromuscular blocks, oral agents, intrathecal management, and surgery. Rehabilitation strategies are central, whereas other strategies are added based on the level of impairment and functional loss. Treatment strategies for spasticity management are far from optimal and are complicated in MS as a result of lesions in the brain and the spinal cord. Pharmaceutical management in MS is complicated by the numerous secondary impairments in MS and its associated polypharmacy.Head-to-head studies of the various agents are rare. The studies that exist are small and do not point to any one strategy over another. Although management is difficult, it is essential for the health, functional status, and well-being of the individual who has MS. Providers must use well-developed clinical skills to arrive at optimal individualized treatment programs and monitor them frequently. For spasticity that is unresponsive, referral to a MS Center with a spasticity program is ideal.