Long-term effect of repeated injections of botulinum toxin in children with cerebral palsy: a prospective study

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

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

Virtual Reality-Incorporated Horse Riding Simulator to Improve Motor Function and Balance in Children with Cerebral Palsy: A Pilot Study

The horse riding simulator (HRS) reportedly has a beneficial effect on motor function and balance in children with cerebral palsy (CP). However, by itself, the HRS is not a sufficient source of challenge and motivation for children. To address this issue, we combined the HRS with virtual reality (VR) to promote somatosensory stimulation and motivation. Sixteen children (ages: 5–17 years) with CP and presenting Gross Motor Function Classification System (GMFCS) levels I–IV were enrolled in the study. Using a head-mounted display and controllers, interventions were carried out over 30-min periods (two rides lasting 12 min each, along with a six-min rest period) twice a week over a period of eight weeks (16 sessions in aggregate). The Pediatric Balance Scale (PBS), Gross Motor Function measure (GMFM)-88, and GMFM-66 scores of each participant were measured before and after the interventions. Statistically significant improvements were observed in the PBS, GMFM-66, the total GMFM-88 scores, and those corresponding to dimensions D and E of GMFM-88 after the intervention (p < 0.05). This study demonstrates that VR-incorporated HRS is effective in improving motor function and balance in children with CP and that its incorporation in conventional PT programs could yield beneficial results.

Repeated onabotulinum neurotoxin A injections for drooling in children with neurodisability

AIM

To evaluate the effect of repeated onabotulinum neurotoxin A injections for the treatment of drooling in children with neurodisabilities.

METHOD

This was a retrospective cohort study, in which the first, second, and third onabotulinum neurotoxin A injection were compared within children treated between 2000 and 2020. Primary outcomes included drooling quotient, visual analogue scale (VAS), and treatment success defined as ≥50% reduction in drooling quotient and/or VAS 8 weeks after treatment. Each outcome was obtained at baseline and 8 weeks posttreatment.

RESULTS

Seventy-seven children were included (mean age at first injection: 8y 3mo, SD 3y 7mo, range 3-17y; 44 males, 33 females; 51.9% with cerebral palsy, 45.5% wheelchair-bound). The objective (drooling quotient) and subjective (VAS) effect after the second injection was lower compared to the first injection. The third injection showed less objective and significantly less subjective effect compared to the first injection. An overall success rate of 74.0%, 41.6%, and 45.8% were found for the first, second, and third injection respectively.

INTERPRETATION

Although onabotulinum neurotoxin A remained effective throughout the entire treatment course, there is less effect of subsequent onabotulinum neurotoxin A injections compared to the first. Although there might be a loss of effect after repeated injections, there is continued improvement for most children. What this paper adds Repeated injections show a diminished treatment effect after the second injection. A continued improvement is seen in most patients.

Effect of Long-Term Repeated Interval Rehabilitation on the Gross Motor Function Measure in Children with Cerebral Palsy

BACKGROUND

The efficacy of interventions for cerebral palsy (CP) has been frequently investigated with inconclusive results and motor function measured by the Gross Motor Function Measure (GMFM-66) is common.

OBJECTIVE

In this observational analysis, we quantify the GMFM-66 change scores of the second and third year of a multimodal rehabilitation program (interval rehabilitation including home-based, vibration-assisted training) in children with CP.

METHODS

The study was a retrospective analysis of children with CP (2-13 years) participating for a second (n = 262) and third year (n = 86) in the rehabilitation program with GMFM-66 scores at start (M0), after 4 months (M4) of intensive training, and after 8 months of follow-up (M12). A method was previously developed to differentiate between possible treatment effects and expected development under standard of care for GMFM-66 scores using Cohen's d effect size (ES; size of difference).

RESULTS

After the treatment phase of 4 months (M4) in the second year, 125 of 262 children were responder (ES ≥ 0.2) and 137 children nonresponder (ES < 0.2); mean ES for nonresponder was -0.212 (trivial) and for responder 0.836 (large). After M4 in the third year, 43 children of 86 were responder (ES = 0.881 [large]) and 43 nonresponder (ES = -0.124 [trivial]).

DISCUSSION AND CONCLUSION

Repeated rehabilitation shows a large additional treatment effect to standard of care in 50% of children which is likely due to the intervention, because in the follow-up period (standard of care), no additional treatment effect was observed and the children followed their expected development.

Botulinum Toxin Type A Injections Impact Hamstring Muscles and Gait Parameters in Children with Flexed Knee Gait

The aim of this study was to determine if botulinum toxin type A (BoNT-A) injection into the medial hamstring can improve gait kinematics and muscle-tendon length in spastic cerebral palsy (CP) with a flexed knee gait (FKG). Twenty-nine children with spastic CP (Gross Motor Function Classification System I–III) with FKG were recruited for this prospective study. BoNT-A was injected into the semitendinosus and semimembranosus (SM) muscles under ultrasonography guidance. Assessments included Gross Motor Function Measure (GMFM), Modified Ashworth Scale (MAS), Modified Tardieu Scale (MTS), 3-dimensional computerized gait analysis, calculated SM muscle-tendon length and lengthening velocity during gait using musculoskeletal modeling at baseline, 4 and 16 weeks after the injection. Compared to baseline data, significant improvements in GMFM, MAS, and MTS were demonstrated at weeks 4 and 16, and also a significant increase in maximum knee extension during the stance phase was observed at week 4. In addition, the mean lengthening velocity during the swing phase was increased at week 16 without a change in the SM muscle length. Furthermore, there was a significant increase in anterior pelvic tilt at week 4, compared to baseline data. The significant decrease in hip internal rotation after injection was observed only in children with excessive hip internal rotation at initial contact before injection. BoNT-A injection into hamstrings leads to a significant increase in knee extension and anterior pelvic tilt with an increase in lengthening velocity of SM in spastic CP with FKG.

The Effect of Botulinum Toxin Injections on Gross Motor Function for Lower Limb Spasticity in Children with Cerebral Palsy

The aim of this study was to investigate the use of botulinum toxin type A (BoNT-A) injections and their efficacy on gross motor function for lower limb spasticity in children with spastic cerebral palsy (CP). This retrospective study included 919 injection occasions from 591 children with CP who received a lower limb BoNT-A injection between 2006 and 2016. The Gross Motor Function Measure (GMFM-88), the Modified Ashworth Scale, and the Modified Tardieu Scale were administered before and after injections. Injections were predominantly administered to children under the age of 6 years. The most common muscle injection site was the calf muscle for dynamic foot deformity. The second most commonly injected muscle was the hip adductor among 2–3 year olds and the hamstring muscle among 4–6 year olds. Distal injections were predominantly administered to high-functioning children, whereas proximal injections were typically administered to low-functioning children. Multilevel injections were mostly administered to midfunctioning children. GMFM-88 scores significantly increased post-injection for both high- and low-functioning groups. Younger age at injection and distal injection type were associated with larger improvements on the GMFM-88 at both short- and midterm follow-up. The target muscles for injection varied depending on gross motor functioning and age. Younger age at injection and distal injection type were significantly related with greater gain in gross motor function.

Reliability of Inclinometer-Derived Passive Range of Motion Measures in Youth with Cerebral Palsy

Aims: This study evaluated, for youth with cerebral palsy (CP), the reliability of passive range of motion (PROM) measures taken with an inclinometer, a device that may be simpler to use than a goniometer. Methods: The PROM for elbow and wrist extension, ankle dorsal flexion (knee flexed 90° and fully extended), and the knee popliteal angle of 30 youth with CP (18 boys, 12 girls, 7.0 ± 3.8 years old, classified in Gross Motor Function Classification levels I-V) was measured using an inclinometer. Two physical therapists took the measures during two different sessions, a maximum of 1 week apart. Results: Good mean intra-rater inter-session, inter-rater intra-session, and inter-rater inter-session reliability (ICC = 0.75-0.89), was found for the elbow, ankle, and knee sites. Absolute reliability for these sites and conditions was 7-14° (90% confident) and 10-16° (95% confident). Reliability values for wrist extension were comparable, albeit slight lower. Conclusions: Similar to published values for goniometry, inclinometery yields reliable upper and lower limb PROM measures from ambulatory and non-ambulatory youth with CP whether measures are carried out by different evaluators within or across sessions or whether measures are performed by the same evaluator across sessions.

Effectiveness of multiple botulinum toxin sessions and the duration of effects in spasticity therapy in children with cerebral palsy

PURPOSE

The aim of this study was to assess the effectiveness of long-term therapy with multiply botulinum neurotoxin (BoNT) injections.

METHODS

In 2004-2010, 60 children with spastic cerebral palsy aged 2-16 were treated multiple botulinum toxin sessions (injections in gastrocnemius muscle and soleus muscles). In each patient, we rated muscle tone by Modified Ashworth Scale, passive range of motion in ankle joint with extended, and flexed knee joint and gait using the Physician Rating Scale. Assessment was done before and after injection, up to eight BoNT sessions.

RESULTS

The generalized additive models showed that a single treatment effect was visible for 3 months. The number of injections did not impact the effectiveness. Improvement in muscle tone was greater in children with hemiplegia than diplegia (β = - 0.294; p = 0.014). Improvement in range of motion with extended knee joint was greater in hemiplegic than diplegic types (β = 0.414; p =0.002), and improvement in range of motion with flexed knee was greater in children with more severe impairment (Gross Motor Function Classification System III vs. I, β = 0.0603, p = 0.025; V vs. I, β = 0.691, p = 0.023). The gait improvement rate decreased with patient age (p = 0.007).

CONCLUSIONS

BoNT therapy is effective regardless of the number of injection sessions and duration of treatment. However, it is affected by the patient's age, type of cerebral palsy, and degree of impairment.

Effect of multilevel lower-limb botulinum injections & intensive physical therapy on children with cerebral palsy

Background & objectives

Botulinum toxin is considered as an effective treatment for spasticity in children with cerebral palsy (CP). However, there are only a few long-term studies, and the effects on motor function have been inconclusive. Moreover, due to its high cost and need for intensive post-injection therapy, utility in context of developing nations has not been established. This retrospective study was undertaken to assess the long term effects of botulinum toxin-A with physical therapy in children with CP.

Methods

This retrospective study was conducted at a tertiary care centre in India, where a limited supply of botulinum toxin was introduced in the year 2009. It was used in a selective group of patients with CP along with intensive physical therapies. All children who received lower-limb botulinum injections over a 42-month period were analyzed. For evaluation of treatment effect, the measurement at 1^st pre-injection assessment and the last measurements, i.e. 12 wk after last injection received by that child were compared.

Results

Twenty nine patients (20 males, median age 51 months) received 69 sessions of botulinum toxin injections in the lower limbs over a 42-month period. Thirteen patients were diplegic, 10 were quadriplegic, five were triplegic and one was hemiplegic. There was a significant improvement in pre- and post-injection scores on Observational Gait Scale (right side 7.1±3.6 to 10.7±3.7, left side 6.7±3.5 to 9.9±3.4), Gross Motor Function Measure Scale (47.9±17.7 to 67.6±17.2), Modified Ashworth Scale, passive range of motion and Gross Motor Function Classification System. Most of the patients showed gain in motor milestones as well.

Interpretation & conclusions

Our results showed that judicious use of botulinum injections along with intensive physio/occupational therapies could yield good results in children with CP.

Efficacy of Repeated Botulinum Toxin Type A Injections for Spastic Equinus in Children with Cerebral Palsy-A Secondary Analysis of the Randomized Clinical Trial

Botulinum toxin A is considered an important tool to control spasticity in children with cerebral palsy. Several factors are known to affect the efficacy of botulinum toxin, such as dosage, appropriate muscle selection and application, age, and accompanying therapy. A multicenter, double-blind, randomized, prospective phase III clinical trial of botulinum toxin A for the treatment of dynamic equinus in 144 children with cerebral palsy was performed to compare the efficacies of letibotulinumtoxin A and onabotulinumtoxin A. Secondary analyses were performed to evaluate factors that affected the outcome, focusing on the number of times injections were repeated. Effectiveness was defined as a change of 2 or more in the physician’s rating scale. Multivariate regression analyses were performed with multiple variables. The first injection of botulinum toxin A significantly improved D subscale of Gross Motor Function Measure-88 scores at 3 months compared to repeated injections (p < 0.05). After 6 months, patients who had one injection or none before the study showed significantly better outcomes than those who had more than one injection in terms of observational gait scores.

Virtual Normalization of Physical Impairment: A Pilot Study to Evaluate Motor Learning in Presence of Physical Impairment

Motor learning is a critical component of the rehabilitation process; however, it can be difficult to separate the fundamental causes of a learning deficit when physical impairment is a confounding factor. In this paper, a new technique is proposed to augment the residual ability of physically impaired patients with a robotic rehabilitation exoskeleton, such that motor learning can be studied independently of physical impairment. The proposed technique augments the velocity of an on-screen cursor relative to the restricted physical motion. Radial Basis Functions (RBFs) are used to both model velocity and derive a function to scale velocity as a function of workspace position. Two variations of the algorithm are presented for comparison. In a cross-over pilot study, healthy participants were recruited and subjected to a simulated impairment to constrain their motion, imposed by the cable-driven wrist exoskeleton. Participants then completed a sinusoidal tracking task, in which the algorithms were statistically shown to augment the cursor velocity in the constrained state such that it matched position-dependent velocities recorded in the healthy state. A kinematic task was then designed as a motor-learning case study where the algorithms were statistically shown to allow participants to achieve the same performance when their motion was constrained as when unconstrained. The results of the pilot study provide motivation for further research into the use of this technique, thus providing a tool with which motor-learning can be studied in neurologically impaired populations. This could be used to give physiotherapists greater insight into underlying causes of motor learning deficits, consequently facilitating and enhancing subject-specific therapy regimes.

Should botulinum toxin A injections be repeated in children with cerebral palsy? A systematic review

AIM

The aim of this study was to determine the effects of repeat botulinum toxin A (BoNT-A) injections in children with spastic cerebral palsy (CP) on the basis of a best evidence synthesis.

METHOD

This study included 13 original articles after searching the literature to retrieve information. We used the critical review form produced by McMaster University to determine the methodological quality of the studies, and then confirmed the levels of evidence from Sackett. The studies were also evaluated using the International Classification of Function, Disability and Health - Children and Youth Version (ICF-CY).

RESULTS

A total of 893 children with spastic CP who had been administered repeat BoNT-A injections were evaluated. The evidence level was II in four of the thirteen studies, III in four studies, and IV in five studies. The McMaster review form score was 14 in two studies, 13 in four studies, and 12 in seven studies. The results showed that repeat BoNT-A may be a safe and an effective approach. The first two injections/one repeat especially relieve spasticity and improve fine and gross motor activities.

INTERPRETATION

Future studies to investigate the effectiveness of repeat BoNT-A in children with spastic CP may be planned within the framework of the ICF-CY to include well-designed randomized controlled trials and those conducted on larger homogenous groups.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Botulinum toxin treatment in upper limb spasticity: treatment consistency

This study assessed treatment consistency of botulinum toxin administration in spastic upper limbs under pragmatic conditions, as derived through stability of dosages and between injections intervals. Over a period of 8 years, 153 children (81 with bilateral spastic cerebral palsy, 72 with unilateral) were treated according to accepted, experience-based guidelines with Botox and Dysport. Treatment response was based on assessment of spasticity and attainment of pre-determined goals at 3, 6 and 12 months post each treatment. Mean age at treatment onset was 6y 4mo (SD: 4y 10mo), median F/U, 2.5 years (4 months-6 8/12 years). Number of injection sessions was 1-10; few had more than 6 sessions. In 106 (69.28%) children, more than one anatomic regions of the limb were injected. Most (56.2%), had at least two injection sessions; median time interval between the sessions was 9 months (IQR: 4-35 months, similar for unilateral and bilateral cerebral palsy, p = 0.874). Children >4 years old at the first treatment had longer intervals between sessions (25.8%) compared to younger ones (p = 0.010). The mixed effects models demonstrated that botulinum toxin dosage was stable over subsequent visits (p = 0.144) and that intermediate intervals for subsequent visits were similar to the first one (p = 0.279).

Improving quality of life of children with cerebral palsy: a systematic review of clinical trials

OBJECTIVE

To systematically review the impact of different interventions on quality of life (QoL) for children with cerebral palsy.

METHODS

English articles were sought from five major English databases from inceptions until March 2010. Keywords used consisted of four components (and their variants): (i) clinical condition: cerebral palsy; (ii) outcome measures: quality of life, well-being; (iii) study design: clinical trials; and (iv) target population: people aged 0-18.

RESULTS

Eight studies satisfied the inclusion criteria, all of which are of good to excellent quality (a Jadad score of 4 or above). The Pediatric Evaluation of Disability Inventory, the Pediatric Quality of Life Inventory, the TNO-AZL Children's Health-Related Quality of Life and the Caregiver Priorities and Child Health Index of Life with Disabilities were used to measure QoL. Significant positive results were reported by two studies using medicinal interventions (diazepam and intrathecal baclofen therapy, effect sizes 5.9, 9.1 respectively) and two studies employing motor control approach training (strength training and exercise training, former effect size being 3.8).

CONCLUSION

Current review suggests that positive effect was shown in medicinal and motor control interventions on QoL. However, no single interventional approach can demonstrate a consistent positive impact on QoL across different studies. Future studies are recommended to (i) provide a clear definition of QoL, and investigate the relationship between symptoms' severity and QoL; (ii) measure outcome at different time points to capture real effects of interventions; and (iii) make more use of valid outcome instruments, either self-report or parent/caregiver proxy reports.

Botulinum toxin a injections to the upper limbs in children with cerebral palsy: duration of effect

We report our experience on the duration of effectiveness of botulinum toxin A injections to the upper extremities of children with cerebral palsy. A retrospective chart review was conducted on 30 consecutive patients (mean age, 9.9 ± 5.0 years) with spastic hemiparesis and quadriparesis. They received 1 to 5 treatments, totaling 56 treatments for the entire cohort. The injected muscles were the pronator teres (50/56), flexor carpi radialis (39/56), biceps (38/56), flexor carpi ulnaris (35/56), opponens (21/56), and adductor pollicis (17/56). Children were assessed for muscle tone and classified according to the Manual Ability Classification System before and after treatment. Functional improvement was apparent after 42 of 56 treatments, and muscle tone decreased significantly (P < .001). The mean duration of the effect was 7.0 ± 3.0 months. We conclude that the effect of botulinum toxin A to the upper limbs is retained for longer periods of time than those reported for lower limbs.

Botulinum toxin injections for pediatric patients with hereditary spastic paraparesis

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

Upper extremity function and occupational performance in children with spastic cerebral palsy following lower extremity botulinum toxin injections

We studied the effect of botulinum toxin A injections to the lower extremities of spastic cerebral palsy children on upper limb body function and occupational performance. A total of 16 children with spastic cerebral palsy, aged 2 to 8 years, Gross Motor Function Classification System levels I-IV, referred to a child neurology outpatient clinic for botulinum toxin A injections to the lower limbs, underwent 4 assessments: 1 month prior to injection, immediate pre injection, and at 1 and 5 to 6 months post injection. Three tools were used to test everyday function (Canadian Occupational Performance Measure and the Pediatric Evaluation of Disability Inventory) and upper extremity body function (Quality of Upper Extremity Skills Test). Significant improvement was documented between the immediate preinjection and the 2 postinjection assessments, indicating that improvement lasted for at least 6 months. Botulinum toxin A injections to the lower extremities in children with cerebral palsy improve upper limb body function and occupational performance.