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

Short- medium- and long-term effects of botulinum toxin on upper limb spasticity in children with cerebral palsy: A meta-analysis of randomized controlled trials

BACKGROUND

Botulinum toxin (BTX) is an effective management method for spasticity in children with cerebral palsy (CP), but the short- medium- and long-term effects remain unclear.

OBJECTIVE

The primary objective was to quantify the effects of BTX injections on upper limb spasticity over time in children with CP. The secondary objective was to evaluate efficacy according to the International Classification of Functioning, Disability, and Health-Children & Youth version framework.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials that included control/comparison groups treated with a placebo or other treatments. We searched CINAHL, Embase, PubMed, Scopus, Web of Science, and PsycINFO from their inception to April 2024. The pooled mean difference (MD) or standard mean difference (SMD) with 95 % CI was calculated using a random effects model at the short-term (up to 3 months), medium-term (3 to 6 months), and long-term (over 6 months).

RESULTS

A total of 658 children with CP aged 1.8 to 19 years old in 12 eligible trials were involved. The primary outcome of the Melbourne Assessment percentile showed a significant increase in the medium- (MD = 2.63, 95 % CI 0.22 to 5.04, I² = 0 %) and long-term (MD = 4.72, 95 % CI 0.93 to 8.51, I² = 0 %) in favor of BTX. Pooled effects also showed that BTX significantly improved Modified Ashworth Scale scores in the short- (MD = -0.44, 95 % CI -0.88 to -0.01, I² = 88 %) and medium-term (MD = -0.20, 95 % CI -0.28 to -0.13, I² = 0 %), and individual goals and bimanual performance up to 6-months. No significantly higher risk of adverse events was observed with BTX.

CONCLUSIONS AND IMPLICATIONS

BTX injections sustainably improved the quality of affected upper limb function and temporarily improved individual goals and bimanual performance in children with CP. Our findings cautiously support a time interval of 3 to 6 months between BTX injections in the upper limbs of children with CP.

TRIAL REGISTRATION

This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (Registration ID: CRD42022323672).

Utilization of shear wave elastography to quantify and predict response to upper extremity botulinum toxin injections in patients with cerebral palsy: A pilot study

OBJECTIVE

Shear wave elastography (SWE) was used to quantify change in upper extremity muscle stiffness in patients with unilateral spastic cerebral palsy (USCP) following botulinum toxin A (BTX-A) therapy. We hypothesized that SWE measures would decrease following ultrasound-guided BTX-A injection, and correlate with functional improvement.

METHODS

SWE measures of BTX-A treated muscles were recorded immediately pre-injection, and at 1-, 3- and 6-months post-injection. At the same timepoints, functional assessment was performed using the Modified Ashworth Scale (MAS), and passive and active range of motion (PROM and AROM) measures. Correlation of SWE with MAS, PROM and AROM, as well as the relationship between change in SWE and change in MAS, PROM and AROM was determined using Spearman's rank correlation coefficient and generalized estimating equation modeling.

RESULTS

16 muscles were injected and longitudinally assessed. SWE and MAS scores decreased following BTX-A injection (p = 0.030 and 0.004, respectively), reflecting decreased quantitative and qualitative muscle stiffness. Decreased SWE reached statistical significance at 1- and 3-months, and 1-, 3- and 6-months for MAS. When comparing relative change in SWE to relative change in AROM, larger change in SWE strongly correlated with positive change in AROM (p-value range:<0.001-0.057). BTX-A responders also demonstrated lower baseline SWE (1.4 m/s) vs. non-responders (1.9 m/s), p = 0.035.

CONCLUSION

Ultrasound-guided BTX-A injections in patients with USCP resulted in decreased quantitative and qualitative muscle stiffness. Strong correlation between change in SWE and AROM, as well as the significant difference in baseline SWE for BTX-A responders and non-responders, suggests SWE may provide a useful tool to predict and monitor BTX-A response.

Physical characteristics and upper-limb treatment with botulinum neurotoxin A in children with cerebral palsy: A population-based study

AIM

To describe the use of upper-limb botulinum neurotoxin A (BoNT-A) treatment in a population-based sample of children with cerebral palsy (CP), by investigating whether factors may be related to a first upper-limb BoNT-A treatment and whether passive range of motion (ROM) is related to a first BoNT-A treatment after adjustment for confounders.

METHOD

Data from five regions in Sweden, in the national registry and follow-up programme for CP (CPUP), were collected for children with spastic or dyskinetic CP assessed between 2000 and 2017. CP subtypes, functional classification levels, and traffic-light-based passive ROM categories were investigated. Data were analysed with logistic regression (odds ratios).

RESULTS

Of a total of 496 children (317 males, 179 females; median 2 years, interquartile range 1-5 years, range 1-15 years at first measurement occasion), 22% (n = 108) had received upper-limb BoNT-A treatment, 45% of whom by 1 to 3 years of age. Those classified in Manual Ability Classification System levels IV and V showed the highest crude odds ratio for a first upper-limb BoNT-A treatment. Children with full passive ROM with tightness at the end of the movement range were most likely to receive an upper-limb BoNT-A treatment, also after adjustment for confounders. Thumb and forearm muscles were the most targeted at the first upper-limb BoNT-A treatment.

INTERPRETATION

Full passive ROM with tightness at the end of the movement range increases the likelihood of a first upper-limb BoNT-A treatment. This new traffic-light category is an aspect to consider in the dialogue about upper-limb BoNT-A.

WHAT THIS PAPER ADDS

Among children receiving upper-limb botulinum neurotoxin A (BoNT-A), 45% had their first treatment before the age of 4 years. Thumb and forearm muscles were the most treated with BoNT-A, finger flexor muscles the least. Full passive range of motion with tightness was related to first upper-limb BoNT-A treatment.

Upper Limb Onabotulinumtoxin A Injections in Children Under 2 Years with Cerebral Palsy: A Retrospective Chart Review

Aim: To report on the safety of using Onabotulinumtoxin A (OnaA) in the upper limb(s) of children <2 years of age with cerebral palsy and to describe a proactive clinical model of care in the management of upper limb impairment in children with cerebral palsy. Methods and procedures: Retrospective chart audit of 65 infants aged 13-23 months (mean 18.69) who received upper limb OnaA injections. Administration procedures, trends in muscle selection, and adverse events were examined. Results: Adverse events were reported in 6 (4%) of the 65 children. Across the study period, muscles that control thumb and forearm movements were most commonly injected. The number of OnaA injections to subscapularis and flexor digitorum profundus increased over this period. Conclusions and implications: OnaA is a safe treatment option for the short-term management of focal upper limb muscle overactivity in children under 2 years of age with cerebral palsy. In line with existing evidence, OnaA should always be considered as an adjunct to evidence-based therapy.

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.

Analgesic effect of botulinum toxin in children with cerebral palsy: A systematic review

This review aims to determine the analgesic efficacy of botulinum toxin (BTX) for the management of pain in children with cerebral palsy (CP). During July and August 2020, a systematic literature search was performed using a mixture of subject headings and free text. The eligibility criteria for inclusion in the review were: (1) interventional studies, (2) participants: children aged 0-18 with CP, (3) participants were treated with BTX, (4) an outcome measure of pain or satisfaction with pain management, and (5) published in an English-language peer-reviewed journal. Eleven studies met the eligibility criteria; nine studies explored analgesic effects of BTX for hypertonia related pain and two for postoperative pain. The studies were of level II to level IV evidence. We identified one high-quality study, which provides level II evidence, and two observational studies that supported BTX therapy for muscle hypertonia related pain in non-ambulant children with CP (GMFCS levels IV and V). For children in GMFCS levels I to III, the evidence for the analgesic effects of BTX was contradictory possibly due to the heterogeneity of the studies and/or weak study design. Mixed evidence for the use of BTX to reduce pain after hip surgery was found likely due to differences in the surgical method, injection protocols, and outcome measures.

Upper-extremity Spasticity-reducing Treatment in Adjunct to Movement Training and Orthoses in Children with Cerebral Palsy at Gross Motor Function- and Manual Ability Classification System Levels IV-V: A Descriptive Study

Covering a 20-year period of work with children with severe cerebral palsy (CP) within a Swedish habilitation service, changes in passive wrist extension with fingers extended (PWE-FE) and current hand function are described and compared between children receiving systematic upper-extremity treatment with botulinum neurotoxin type A and intervention programs from before 7 years of age (Group 1, n = 7), those whom for various reasons did not undergo this treatment (Group 2, n = 10), and those not having the option to receive treatment until later during childhood/adolescence (Group 3, n = 8). Group 3 showed more critical and less normal PWE-FE values for both wrists, and poorer hand function scores, particularly compared with Group 1. Findings cautiously suggest that repeated upper-extremity spasticity-reducing treatment and movement training/orthoses from an early age may help prevent critical loss of passive range of motion of the wrist joint flexion/extension and promote hand function development in children with severe CP.

Characterization of Differences in the Time Course of Reflex and Voluntary Responses Following Botulinum Toxin Injections in Chronic Stroke Survivors

Spasticity is a major impairment that can occur following a hemispheric stroke and is often treated with injections of botulinum toxin, a neurotoxin that impairs transmission at the neuromuscular junction. Hyperreflexia is a defining feature of spasticity. Our main objective here was to quantify the time course of changes in the deep tendon reflex (DTR) responses and voluntary activation capacity following BT injection as well as to track changes in a clinical assessment of spasticity. Four chronic stroke survivors, scheduled to receive BT in their Biceps Brachii(BB) as part of their clinical care plan, were recruited for repeated testing sessions over the course of 4 months post injection. Both surface BB EMG reflex response to bicipital tendon taps as well as signals of applied tendon tap forces were recorded before and up to 18 weeks post-BT. Voluntary force and biceps EMG signals were also recorded during maximum voluntary (isometric) contractions (MVC) at each testing session. Our results show major reductions (up to 75%) in voluntary sEMG and force arising between 11 to 35 days post-BT-injection. The stretch reflex gain declined two weeks after the maximal reductions in voluntary EMG and force. Paradoxically, there was a short-term increase in stretch reflex gain, in three out of four participants, approximately 11-35 days post BT. The time course of recovery of voluntary MVC and reflex responses varied considerably with a longer recovery time for the reflex responses.

Effect of botulinum toxin type-A in spasticity and functional outcome of upper limbs in cerebral palsy

INTRODUCTION

Spasticity has been considered to be a main contributor to both the impairment of function as well as posture in children with cerebral palsy (CP). Patterns of upper limb motor involvement in CP vary with resultant limitations in daily independence, participation, and quality of life. Botulinum Toxin-A (BTX-A) is a potent neurotoxin which acts by preventing the release of acetylcholine (Ach) from presynaptic axon at motor end plate reducing focal spasticity. With literature established role of BTX-A available for lower limb spasticity in CP, the purpose of this study was to present an objective analysis of the effect of a single i.m. injection of BTX-A in reduction of spasticity in the upper limb as well as functional outcome in children (4-12yrs) with spastic CP.

METHODS

A total of 28 patients (30 upper limbs) of spastic CP with minimum follow up of 6months were included in the study. Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS) were used to measure the spasticity. Surface landmarks were used to give I.m. Botox in selected spastic muscles followed by targeted rehabilitation. Functional outcomes were measured by MACS (Manual Ability Classification System) and Canadian Occupational Performance Measure (COPM) before treatment, at 3 and 6 months follow up.

RESULTS

Pronator teres was the most frequently injected muscle followed by FCU and Adductor pollicis. MAS scores at all joints and MTS scores at forearm deteriorated between 3 and 6 months. However, MACS and COPM showed sustained improvement at 3months and 6months with statistically significant change.

CONCLUSION

I.m. BTX-A injected using anatomical landmarks had significant improvement in both clinical and functional outcome measures. We noticed significant improvement in MACS and COPM at 6 months despite return of local spasticity. It is safe and effective for spasticity of upper limbs in cerebral palsy and capable of improving function without major side effects. MACS & COPM are easy to use, less time consuming & easily adjusted to local needs. Randomized control trials with long follow up are required in future with special focus on dosing and timing, scoring system for functional outcome as per regional needs and issue for antibody formation for repeat injections of BTX-A.

Development of a Pediatric Goal-Centered Upper Limb Spasticity Home Exercise Therapy Program for Use in a Phase-III Trial of Abobotulinumtoxina (Dysport®)

AIMS

To create a standardized home exercise therapy program that could be implemented by international sites to provide a consistent level of therapeutic intervention for pediatric patients participating in an ongoing Phase-III, randomized, controlled trial of repeat abobotulinumtoxinA injections for pediatric upper limb spasticity (NCT02106351).

METHODS

Physical therapists, occupational therapists, and medical doctors worked collaboratively to design an exercise therapy program to be implemented in the home setting. In this article, we describe the development process and the finalized program that is currently being used in the Phase-III trial.

RESULTS

The final program is presented as a "toolbox" for therapists, and includes a standardized step-wise process for choosing the most appropriate exercises and functional activities to achieve the agreed treatment goals of each abobotulinumtoxinA injection. The core toolbox includes: a clear protocol for clinicians, information sheets, signature of commitment forms, exercise score charts, and the library of exercises and functional activities that therapists choose from to aid the patient in achieving their treatment goals.

CONCLUSIONS

Implementation of this home therapy program provides a standardized background of good practice against which to test the efficacy of abobotulinumtoxinA. Preliminary data show that the program is readily accepted by patients and their families.

The Future of Upper Extremity Spasticity Management

Surgical management of upper limb spasticity has traditionally tackled the downstream effects at the muscle, tendon, and joint levels. Because this approach does not address the underlying pathologic condition within the nerve, surgical outcomes have been marked by unsatisfactory relapse over time. Future management may focus on reestablishing a normal neuronal impulse pathway to the dysfunctional musculotendinous unit. By severing the faulty γ-neuronal circuit at the C7 level, spasticity may be reduced. Transfer of the contralateral C7 nerve root to the injured C7 nerve root may open the potential for simultaneously restoring extension and improving reach and grasp functions.

A Variant of the Autophagy-Related 5 Gene Is Associated with Child Cerebral Palsy

Cerebral palsy (CP) is a major cause of childhood disability in developed and developing countries, but the pathogenic mechanisms of CP development remain largely unknown. Autophagy is a highly conserved cellular self-digestion of damaged organelles and dysfunctional macromolecules. Growing evidence suggests that autophagy-related gene 5 (ATG5)-dependent autophagy is involved in neural development, neuronal differentiation, and neurological degenerative diseases. The aim of this study was to analyze ATG5 protein expression and gene polymorphisms in Chinese patients with CP and to evaluate the importance of ATG5 in the development of CP. Five polymorphisms from different regions of the ATG5 gene (rs510432, rs3804338, rs573775, rs2299863, and rs6568431) were analyzed in 715 CP patients and 658 controls using MassARRAY. Of these, 58 patients and 56 controls were selected for measurement of plasma ATG5 level using ELISA. The relevance of disease-associated SNPs was evaluated using the SHEsis program. We identified a significant association between rs6568431 and CP (OR = 1.388, 95% CI = 1.173~1.643, P_allele = 0.0005, P_genotype = 0.0015). Subgroup analysis showed a highly significant association of rs6568431 with spastic CP (n = 468, OR = 1.511, 95% CI = 1.251~1.824, P_allele = 8.50e^-005, P_genotype = 1.57e^-004) and spastic quadriplegia (OR = 1.927, 95% CI = 1.533~2.421, P_allele = 7.35e^-008, P_genotype = 3.24e^-009). Furthermore, mean plasma ATG5 levels were lower in CP patients than in controls, and individuals carrying the AA genotype of rs6568431 that was positively associated with CP had lower plasma ATG5 levels (P < 0.05). This study demonstrated an association of an ATG5 gene variant and low level of ATG5 protein with CP, and stronger associations with severe clinical manifestations were identified. Our results provide novel evidence for a role of ATG5 in CP and shed light on the molecular mechanisms underlying this neurodevelopmental disorder.

Is Botulinum Toxin Type A a Valuable Adjunct During Femoral Lengthening? A Randomized Trial

BACKGROUND

Reduced joint ROM and distraction-induced pain are common complaints of patients who have undergone gradual femoral lengthening. Attempts to reduce the effects of lengthening on joint motion have included the use of botulinum toxin to reduce the muscle forces that restrict motion. The benefits of this approach during femoral lengthening, however, have not been conclusively established.

QUESTIONS/PURPOSES

We wished to evaluate the effects of botulinum toxin type A (BtX-A) injection in the anterior thigh muscles during femoral distraction osteogenesis on adjacent joint ROM and distraction-induced pain. We asked: (1) Does injection of BtX-A in the quadriceps muscles lead to improved knee and hip motion during femoral lengthening? (2) Does injection of BtX-A reduce pain during femoral lengthening?

METHODS

A single-center, double-blind, randomized placebo-controlled trial was conducted. Forty-four patients (88 femurs) undergoing bilateral femoral lengthening for familial short stature were included in the study. BtX-A (200 IU) was injected intraoperatively in the quadriceps muscles of one thigh. An equal volume of sterile normal saline was injected in the other thigh as a control. Selection of the limb receiving the toxin was randomized. Clinical evaluation included a VAS score for pain measurement, ROM evaluation of the hips and knees, and measurement of thigh circumference. Side-to-side differences were analyzed throughout the entire consolidation phase. No patients were lost to followup, leaving 44 patients (88 femurs). The mean followup was 26 months (range, 14-40 months). The distraction rate and final length of gain were similar between treated and control limbs. A priori power analysis suggested that 44 legs were required in each group to achieve statistical significance of 0.05 with 90% power to detect a 50% difference in treatment effect between treatment and control groups.

RESULTS

There were no differences in hip ROM, knee ROM, or maximal thigh circumference between the two lower extremities at any time during the study period. VAS scores were no different between the patients who received BtX-A and those who received saline.

CONCLUSIONS

Local injection of 200 IU BtX-A in the quadriceps muscles does not appear to reduce distraction-induced pain nor enhance ROM in the hip or knee during femoral lengthening. Additional studies are needed to evaluate the effect of larger doses or different injection methods. Based on our findings, we do not recommend routine use of botulinum injections during limb lengthening and believe any further use of this drug should only be in the context of a controlled trial.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Quantitative evaluation for spasticity of calf muscle after botulinum toxin injection in patients with cerebral palsy: a pilot study

Background

Cerebral palsy (CP) is the most common pediatric disease to cause motor disability. Two common symptoms in CP are spasticity and contracture. If this occurred in the ankle plantar flexors of children with CP, it will impair their gait and active daily living profoundly. Most children with CP receive botulinum toxin type A (BoNT-A) injection to reduce muscle tone, but a knowledge gap exists in the understanding of changes of neural and non-neural components of spasticity after injection. The purpose of this study was to determine if our device for quantitative modified Tardieu approach (QMTA) is a valid method to assess spasticity of calf muscles after botulinum toxin injection.

Methods

In this study, we intended to develop a device for quantitative measurement of spasticity in calf muscles based on the modified Tardieu scale (MTS) and techniques of biomedical engineering. Our QMTA measures the angular displacement and resistance of stretched joint with a device that is light, portable and can be operated similar to conventional approaches for MTS. The static (R2), dynamic (R1) and R2-R1 angles derived from the reactive signals collected by the miniature sensors are used to represent the non-neural and neural components of stretched spastic muscles. Four children with CP were recruited to assess the change in spasticity in their gastrocnemius muscles before and 4 weeks after BoNT-A injection.

Results

A simulated ankle model validated the performance of our device in measuring joint displacement and estimating the angle of catch. Data from our participants with CP showed that R2 and R2-R1 improved significantly after BoNT-A administration. It indicates both neural and non-neural components of the spastic gastrocnemius muscles improved at four weeks after BoNT-A injection in children with CP.

Conclusion

Our device for QMTA can objectively measure the changes in spasticity of the gastrocnemius muscle in children with cerebral palsy after BoNT-A injection.

Evaluating Functional Outcomes of Botulinum Toxin Type A Injection Combined with Occupational Therapy in the Upper Limbs of Children with Cerebral Palsy: A 9-Month Follow-Up from the Perspectives of Both Child and Caregiver

Objective

To assess the effectiveness of combining botulinum toxin type A (BoNT-A) with functional occupational therapy (OT) at 9-month follow-up in children with cerebral palsy (CP) with bilateral upper limb impairments from the perspectives of both child and caregiver.

Methods

Twelve children with CP and their caregivers were assessed across 5 time points over 9 months based on the ICF after BoNT-A injection and functional OT in this open-label study.

Results

Significant differences were found across the 5 time points (p < .05) for both grasp and visual-motor integration with small effects (effect sizes = 0.12–0.24) and the self-care capability and performance of social function (p < .05). However, based on the effect sizes (0.02–0.14), no significant effects were found at the 4 post-test time points. Small effects were found on the psychological domain (effect sizes = 0.25–0.37) and environmental domains (effect size = 0.27) at follow-ups.

Conclusion

Combining a BoNT-A injection with OT not only reduced the muscle tone and increased ROM but also improved the upper limb function and self-care capability in children with CP. More importantly, these effects persisted for up to 9 months. Functional OT extends the effectiveness of a BoNT-A injection.