Analgesic Effects of Botulinum Toxin in Children with CP

Assessment of somatosensory profiles by quantitative sensory testing in children and adolescents with and without cerebral palsy and chronic pain

OBJECTIVE

We investigated differences in somatosensory profiles (SSPs) assessed by quantitative sensory testing in children and adolescents with cerebral palsy (CCP) with and without chronic pain and compared these differences to those in a group of typically developed children and adolescents (TDC) with and without chronic pain.

METHOD

All included subjects were consecutively recruited from and tested at the same outpatient orthopedic clinic by the same investigator. The subjects had their reaction times tested. The SSP consisted of the following tests: warmth (WDT), cool (CDT), mechanical (MDT), and vibration (VDT) detection thresholds; heat (HPT), pressure (PPT), and mechanical (MPT) pain thresholds; wind-up ratio (WUR); dynamic mechanical allodynia (DMA) and cold pressor test (CPT) using a conditioned pain modulation (CPM) paradigm.

RESULTS

We included 25 CCP and 26 TDC. TDC without chronic pain served as controls. In TDC with chronic pain, WDT, HPT, HPT intensity, and PPT were higher than in controls. No differences in SSPs between CCP with and without chronic pain were observed. In CCP, the MDT, WDT, CDT, and HPT intensity were higher than in controls. CCP had longer reaction times than TDC. There were no differences regarding the remaining variables.

DISCUSSION

In CCP, the SSPs were independent of pain status and findings on MR images. In all CCP the SSPs resembled TDC with chronic pain, compared to TDC without chronic pain. This suggests that CCP do not have the normal neuroplastic adaptive processes that activate and elicit functional changes in the central and peripheral nervous systems.

Presence and grade of undertreatment of pain in children with cerebral palsy

OBJECTIVES

To investigate if chronic pain in children with cerebral palsy is undertreated with the current pharmacological/non-pharmacological interventions using a pain management index.

METHODS

Parents of 120 children with cerebral palsy between the ages of 2-19 years from our region in Denmark answered a questionnaire about whether their child had everyday pain. When answering in pain, we inquired about pain status and pharmacological/non-pharmacological pain coping interventions. Everyday pain was viewed as chronic pain with acute exacerbations. Pain experienced was divided into worst pain (highest moments of pain intensity) and least pain (lowest moments of pain intensity). To describe and evaluate the effectiveness of pain interventions used, a pain management index was utilized. Everyday pain was assessed using a logistical regression by adjusting for age, sex, and gross motor function classification system level.

RESULTS

59/115 (0.51) of parents answering the questionnaire reported everyday pain. Of those, the median age was 10 years. For pain alleviation, massage was reported by parents as being used by 29/59 (0.49) children and paracetamol by 21/59 (0.36). Pain affected daily life in 44/59 (0.75). By our evaluation 44/59 (0.75) were inadequately treated for their pain. Our evaluation also revealed that 19/59 (0.32) of children in pain had inadequately treated pain combined with an undesirable intensity of least pain.

CONCLUSIONS

Half of the children with cerebral palsy experienced chronic pain according to our pain questionnaire answered by parents. Among these children three-quarters were insufficiently treated for their pain. In the same group, one-third were impacted by pain felt at both its highest and lowest moments of intensity. Massage therapy and paracetamol were the most frequently utilized pain-alleviating interventions. In our cohort, pain was undertreated and likely underdiagnose (Protocol number H-17008823).

The Relationship between Pain and Spasticity and Tell-Tale Signs of Pain in Children with Cerebral Palsy

Pain and quality of life are closely interrelated in children with cerebral palsy (CCP). Even though 67% of CCP experience pain, it is overlooked and untreated. In this study, our purpose was two-fold: first, to examine the relationship between pain and spasticity by evaluating the effects of AbobotulinumtoxinA/Dysport (BoNT), and second, to describe the symptoms and location of pain in CCP. The subjects were 22 CCP in at least moderate pain. They were evaluated for spasticity by the modified Ashworth and Tardieu scale and for pain by the r-FLACC and the pediatric pain profile. After one injection of BoNT, the subjects were re-evaluated. We found a significant reduction in pain, but no significant relationship between the reduction of pain and spasticity. We found no association between the dose of BoNT and pain or spasticity. Pain in the lower extremity was located primarily in the hip region. The effect of ultrasound-guided intermuscular injections of BoNT suggests that pain in CCP has an extra-articular component. We found that pain in CCP manifests as specific tell-tale signs and problems in daily living. In conclusion, we found no relationship between pain and spasticity. Signs and manifestations of pain are described in detail. Lower extremity (hip) pain seems to have a soft tissue/extra-articular component.

Botulinum Toxin Intervention in Cerebral Palsy-Induced Spasticity Management: Projected and Contradictory Effects on Skeletal Muscles

Spasticity, following the neurological disorder of cerebral palsy (CP), describes a pathological condition, the central feature of which is involuntary and prolonged muscle contraction. The persistent resistance of spastic muscles to stretching is often followed by structural and mechanical changes in musculature. This leads to functional limitations at the respective joint. Focal injection of botulinum toxin type-A (BTX-A) is effectively used to manage spasticity and improve the quality of life of the patients. By blocking acetylcholine release at the neuromuscular junction and causing temporary muscle paralysis, BTX-A aims to reduce spasticity and hereby improve joint function. However, recent studies have indicated some contradictory effects such as increased muscle stiffness or a narrower range of active force production. The potential of these toxin- and atrophy-related alterations in worsening the condition of spastic muscles that are already subjected to changes should be further investigated and quantified. By focusing on the effects of BTX-A on muscle biomechanics and overall function in children with CP, this review deals with which of these goals have been achieved and to what extent, and what can await us in the future.

Time-matched accelerometers on limbs and waist in children with CP give new insights into real-life activities after botulinum toxin treatment: A proof of concept study

PURPOSE

This study aimed to explore the feasibility of using time-matched uniaxial accelerometers for measuring movement in daily life in children with cerebral palsy (CP) before and after botulinum toxin injections.

METHODS

This observational study of clinical care with a pre-post design was set in the home and school environment. Participants included eleven children (4-13 years of age) with CP (GMFCS I-III). The children wore uniaxial accelerometers (ActiGraph, model GT1M) for 4 days on both wrists, the right ankle and around the waist before, 3 weeks and 3 months after BoNT-A injections in the legs. Five children also got BoNT-A in the most affected arm. All injections were given according to clinical indications and routine. The accelerometers were all time-matched to define ambulation, arm swing, voluntary activity of arms, and bimanual activity. The feasibility of wearing accelerometers with this setup was evaluated. A linear mixed model was used for analysis of the percentage time and at which intensity the different activities were performed. The confidence interval demonstrated any difference between the dominant and non-dominant arm.

RESULTS

Time-matching of accelerometers placed on both wrists, the waist, and one ankle is a feasible method of registering ambulation, arm swing during gait, and arm movements while not ambulating. Before injections, the children spent 5.6% of their time ambulating. This value declined to 3.9% at 3 months. Contrary to clinical goals, arm movement did not increase after injecting the most affected arm with BoNT-A, however, injections may have decreased mirror movements, which are often bothersome for the child.

CONCLUSION

A time-matched 4-accelerometer set-up is feasible in children with cerebral palsy. A future study including time-matched multi-axial accelerometers on all four limbs, could provide important information on the effect of BoNT-A in daily life.

Spasticity-related pain in children/adolescents with cerebral palsy. Part 2 IncobotulinumtoxinA efficacy results from a pooled analysis

PURPOSE

This pooled analysis of data from three Phase 3 studies investigated the effects of incobotulinumtoxinA on spasticity-related pain (SRP) in children/adolescents with uni-/bilateral cerebral palsy (CP).

METHODS

Children/adolescents (ambulant and non-ambulant) were evaluated for SRP on increasingly difficult activities/tasks 4 weeks after each of four incobotulinumtoxinA injection cycles (ICs) using the Questionnaire on Pain caused by Spasticity (QPS; six modules specific to lower limb [LL] or upper limb [UL] spasticity and respondent type [child/adolescent, interviewer, or parent/caregiver]). IncobotulinumtoxinA doses were personalized, with all doses pooled for analysis.

RESULTS

QPS key item responses were available from 331 and 155 children/adolescents with LL- and UL-spasticity, respectively, and 841/444 (LL/UL) of their parents/caregivers. IncobotulinumtoxinA efficacy was evident with the first IC. Efficacy was sustained and became more robust with further subsequent ICs. By Week 4 of the last (i.e. fourth) IC, 33.8-53.3% of children/adolescents reported complete SRP relief from their baseline pain for respective QPS items. Children/adolescents reported reductions in mean LL SRP intensity at levels that surpassed clinically meaningful thresholds. Similarly, parents/caregivers observed complete SRP relief and less frequent SRP with incobotulinumtoxinA. Similar results were found for UL SRP.

CONCLUSION

These findings indicate that incobotulinumtoxinA could bring considerable benefit to children/adolescents with spasticity by reducing SRP, even during strenuous activities.

Measuring Effects on Pain and Quality of Life after Abobotulinum Toxin A Injections in Children with Cerebral Palsy

Sixty-seven percent of children with cerebral palsy (CCP) experience pain. Pain is closely interrelated to diminished quality of life. Despite this, pain is an overlooked and undertreated clinical problem. The objective of this study was to examine the analgesic effect of a single lower extremity intramuscular injection of Abobotulinum toxin A/Dysport in CCP. Twenty-five CCP with at least moderate pain (r-FLACC ≥ 4) during passive range of motion were included. Localized pain and pain in everyday living were measured by r-FLACC and the Paediatric Pain Profile (PPP), respectively. Functional improvements were evaluated by the goal attainment scale (SMART GAS). Quality of life was evaluated by either the CPCHILD or the CP-QOL. The subjects were evaluated at baseline before injection, then after 4, 12, and 28 weeks. Twenty-two subjects had a significant mean and maximum localized pain reduction (p < 0.001) at four weeks post-treatment in 96% (21/22). The reduction was maintained at 12 (19/19) and 28 weeks (12/15). Daily pain evaluated by the PPP was significantly reduced and functional SMART GAS goals were significantly achieved from 4 to 28 weeks. Quality of life improved significantly at four weeks (CPCHILD). Significant functional gains and localized and daily pain reduction were seen from 4 to 28 weeks.

Non-pharmacological and non-surgical treatment of pain in children and adolescents with cerebral palsy: A scoping review

PURPOSE

To explore the existing literature on non-pharmacological and non-surgical pain management in children and adolescents with cerebral palsy (CP).

METHODS

Databases (Cochrane Library, PubMed MEDLINE, Ovid Embase, and PsycINFO) were systematically searched to identify literature on non-pharmacological and non-surgical interventions for relieving pain in children with CP or similar conditions.

RESULTS

Thirteen publications met the inclusion criteria. Based on study designs, the overall level of evidence of the included studies was low, justifying the use of a scoping review. Only three were randomized controlled trials. Pain reduction was reported in 8 of the 13 studies from following interventions: physiotherapy/rehabilitation, massage, cranial osteopathy, swimming and aquatics, and assistive devices. These complementary strategies should not omit conventional treatment, and a multidisciplinary approach using multifaceted treatment of pharmacological and non-pharmacological therapy is recommended to increase the pain-relieving effect.

CONCLUSION

The results indicate that physiotherapy, massage, swimming exercise, and various assistive devices can have pain-relieving effects. We found limited evidence on the topic of non-pharmacological and non-surgical treatment of pain in children with CP. Due to the lack of power in the included studies, no true evidence-based recommendations can be made from the collected articles; thus, further studies with larger cohorts and more power are needed to substantiate evidence-based treatment of pain in children and adolescents with CP.

Spasticity-related pain in children/adolescents with cerebral palsy. Part 1: Prevalence and clinical characteristics from a pooled analysis

PURPOSE

A large prospective database from three Phase 3 studies allowed the study of spasticity-related pain (SRP) in pediatric cerebral palsy (CP).

METHODS

Baseline (pretreatment) SRP data occurring during different activities in children/adolescents (aged 2-17 years, ambulant/nonambulant) with uni-/bilateral spastic CP was obtained using the Questionnaire on Pain caused by Spasticity (QPS; six modules specific to spasticity level [lower limb (LL) or upper limb (UL)] and type of respondent [child/adolescent, interviewer, or parent/caregiver]).

RESULTS

At baseline, 331 children/adolescents with LL- and 155 with UL-spasticity completed at least one key item of their modules; LL/UL QPS modules of parent/caregivers were at least partially completed (key items) by 841/444 parents/caregivers. SRP with at least one activity at baseline was self-reported in 81.9% /69.7% (LLs/ULs) of children/adolescents with spasticity. Parents/caregivers observed LL/UL SRP behaviors in 85.9% /77.7% of their children, with multiple body regions affected. SRP negatively affected the great majority of the children in various ways. Child/adolescent-reported mean SRP intensity and parent/caregiver-observed mean SRP behavior frequencies were higher for LLs than ULs, and the level of SRP increased with more physically demanding activities.

CONCLUSION

These data suggest SRP is more common and intense in pediatric CP than generally thought, emphasizing the need for effective, long-term pain management.

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.

Botulinum Toxin A Injection in Treatment of Upper Limb Spasticity in Children with Cerebral Palsy: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Cerebral palsy (CP) is the most common cause of childhood disability globally. Botulinum toxin A injections are widely used to manage limb spasticity in children with CP. Intramuscular botulinum toxin A has been used in the upper limbs of children with CP to manage preoperative and postoperative pain, facilitate nursing, and achieve functional and/or cosmetic improvement of hand position. These goals are achieved primarily through reduction of spasticity. The aim of this review was to assess the evidence for the effect of botulinum toxin A injections used to manage upper limb spasticity in children with spastic CP. Specifically, we examined the role of botulinum toxin A as an adjunctive treatment to other physical therapy modalities. Additionally, we analyzed the associated complications.

METHODS

The literature extraction process involved 4 phases: identification, screening, eligibility, and inclusion. We used a combination of Google Scholar, PubMed, and ScienceDirect. The choice of the search terms was based on the Medical Subject Headings. We extracted the relevant studies using a combination of words or terms related to (1) patient population, (2) pathology, (3) clinical intervention, and (4) anatomical distribution of pathology. Studies were included if they were randomized controlled trials conducted on children and/or adolescents with CP targeting the upper extremities in which botulinum toxin A was used as an adjunctive treatment to a primary intervention.

RESULTS

The literature extraction process yielded 15 randomized controlled trials for inclusion in this review. The total number of participants enrolled in the included studies was 499, with 255 in the intervention group (51%) and 244 controls (49%). All participants in the eligible studies had unilateral spastic CP except for those in 4 studies (27%) with 198 participants (40%) that included a heterogeneous sample of unilateral and bilateral spastic CP. The mean age of participants in the intervention group ranged from 2.6 to 10.7 years among the individual studies. The mean age of participants in the control group ranged from 3.1 to 10.55 years among the individual studies. This review indicated that botulinum toxin A had a positive effect on the degree of spasticity and cosmetic appearance of the injected upper limb. The results with respect to functional gains and quality of life were either conflicting or not significant.

CONCLUSIONS

Randomized controlled trials of botulinum toxin A injection in the treatment of upper limb spasticity in children with CP used variable outcome measures and yielded mixed results. Overall, there is some evidence to support the use of botulinum toxin A as an adjuvant treatment to other physical therapy regimens or placebo to reduce spasticity in the short term. There is insufficient evidence to support its use as an adjunctive treatment to improve upper limb function or quality of life. The complications were acceptable and did not outweigh the clinical gains incurred.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.