Intramuscular Injection Of Botulinum Toxin A Research Articles

A computed tomography study investigating the effects of botulinum toxin injections prior to complex abdominal wall reconstruction

ObjectiveTo explore how intramuscular injection of botulinum toxin A (BTA) affects the lateral abdominal wall (LAW) musculature, abdominal- and hernia dimensions, and muscle structure on computed tomography (CT) in patients scheduled for complex abdominal wall reconstruction (CAWR).MethodsRetrospective analysis of prospectively registered patients who received bilateral intramuscular BTA injections into all three muscles of the LAW. Only patients for which a CT was available before and 3–6 weeks after BTA treatment prior to surgery were analyzed.ResultsFifty-two patients were analyzed. Median hernia width in all patients decreased with 0.4 cm (IQR − 2.1;0.6) (p = 0.023). Median intra-abdominal transverse diameter increased with 0.9 cm (IQR − 0.2;3.3) (p = 0.001) and the intra-abdominal anterior–posterior diameter decreased with 0.5 cm (IQR − 1.3;0.5) (p = 0.017), making the abdomen more oval. Median LAW muscle length increased with 0.9 cm (IQR 0.0;2.4) per side (p < 0.001), muscle thickness decreased with 0.5 cm (IQR − 0.8;− 0.2) (− 25.0%) per side (p < 0.001), and muscle mass decreased with 3.9 cm2 (IQR − 6.4;-1.5) (− 15.8%) per side (p < 0.001). Median HU of the psoas muscles (density) increased with 4.8 HU (IQR 0.4;9.7) (10.3%) per side (p < 0.001). Effects of BTA were more pronounced in patients with a loss of domain (LoD) ≥ 20%.ConclusionsThe main effect of BTA injections is elongation and thinning of the LAW muscles, more than a decrease in hernia width. Concomitantly, the abdomen becomes more oval. An increase of psoas muscles density is seen, associated with offloading of the LAW muscles. Patients with large LoD have a proportionally higher effect of BTA.

Module 2

Spasticity management should be part of a well-coordinated and comprehensive rehabilitation program that is patient-centric and goal-specific. There are a variety of options available for the treatment of spasticity. A usual approach is starting with the least invasive treatment modalities initially and gradually increasing to more complex interventions as this is required. This curriculum considers oral antispasticity drugs in terms of mechanism of action, clinical use, efficacy, and adverse events. It also presents other treatment options, such as chemical neurolysis using phenol and alcohol and chemodenervation using botulinum toxin A (BoNT-A). Therapeutic intramuscular injections of BoNT-A require sound patient selection, accurate muscle selection, and precise localization. The common methods for achieving these are described. The importance of physiotherapy is explained, along with the necessity to combine treatment modalities to address spasticity and the various components of the upper motor neuron syndrome. Recognizing differences in various health-care systems across countries and regions, the authors aim to present various treatment options. While this section of the curriculum highlights the importance of an interdisciplinary effort in managing spasticity, it is understandable that not all treatment options are available uniformly. The challenge to clinicians is to make the most of the management options on hand to optimize outcomes.

A First Clinical Trial on Botulinum Toxin-A for Chronic Muscle-Related Pain in Cerebral Palsy.

Objective: To test if botulinum toxin-A (BoNT-A) is effective in reducing chronic muscle-related pain in adults with spastic cerebral palsy (CP), as compared to placebo.Design: A single-center, double-blind, parallel, randomized placebo-controlled trial. The design included an interim analysis to allow for confirmatory analysis, as well as pilot study outcomes.Setting: Tertiary university hospital.Participants: Adults with spastic CP and chronic pain associated with spastic muscle(s).Intervention: Treatment was one session of electromyographically guided intramuscular injections of either BoNT-A or placebo normosaline.Main Study Outcomes: The primary outcome was the proportion who achieved a reduction of pain intensity of two or more steps on the Numerical Rating Scale 6 weeks after treatment.Results: Fifty individuals were screened for eligibility, of whom 16 were included (10 female, 6 male, mean age = 32 years, SD = 13.3 years). The randomization yielded eight participants per treatment arm, and all completed the study as randomized. The study was stopped at the interim analysis due to a low probability, under a preset threshold, of a positive primary outcome. Four individuals were treatment responders in the BoNT-A group for the primary outcome compared to five responders in the placebo group (p = 1.000). Adverse events were mild to moderate. In exploratory analysis, the BoNT-A group had a trend of continuing reduction of pain at the last follow-up, after the primary endpoint.Conclusions: This study did not find evidence that BoNT-A was superior to placebo at the desired effect size (number needed to treat of 2.5) at 6 weeks after treatment.Trial registration:ClinicalTrials.gov: NCT02434549

Botulinum Toxin A and Osteosarcopenia in Experimental Animals: A Scoping Review.

We conducted a scoping review to investigate the effects of intramuscular injection of Botulinum Toxin A (BoNT-A) on bone morphology. We investigated if the muscle atrophy associated with Injection of BoNT-A had effects on the neighboring bone. We used the search terms: osteopenia, bone atrophy, Botulinum Toxin A, Micro-CT, mice or rat. The following databases were searched: Medline, Embase, PubMed and the Cochrane Library, between 1990 and 2020. After removal of duplicates, 228 abstracts were identified of which 49 studies satisfied our inclusion and exclusion criteria. The majority of studies (41/49) reported a quantitative reduction in at least one measure of bone architecture based on Micro-CT. The reduction in the ratio of bone volume to tissue volume varied from 11% to 81% (mean 43%) according to the experimental set up and study time points. While longer term studies showed muscle recovery, no study showed complete recovery of all bone properties at the termination of the study. In experimental animals, intramuscular injection of BoNT-A resulted in acute muscle atrophy and acute degradation of the neighboring bone segment. These findings may have implications for clinical protocols in the use of Botulinum Toxin in children with cerebral palsy, with restraint recommended in injection protocols and consideration for monitoring bone density. Clinical studies in children with cerebral palsy receiving injections of Botulinum are indicated.

Effect of botulinum toxin-A on pain and mouth opening following surgical intervention in oral submucous fibrosis — A controlled clinical trial

The purpose of this trial was to study the effect on pain and mouth opening of intramuscular injection of botulinum toxin-A into masticatory muscles following surgical intervention in oral submucous fibrosis (OSMF) cases. Injections of either botulinum toxin A (BTX-A) (study group) or normal saline (control group) were given 2 weeks prior to surgical intervention in OSMF patients, into the bilateral masseter and temporalis muscles. All patients were evaluated for pain and ease of active physiotherapy at 1 week and 1, 3, and 6 months after surgery using a numerical rating scale and appropriate questionnaires, with comparisons made between the study and control group patients. Electromyographic studies of the masticator muscles were also carried out in all patients before injection, and at 1 month and 6 months after injection. 20 OSMF patients were equally divided into study and control groups (n = 10 each). At 1, 3, and 6 months after surgery, the study group patients showed significantly greater decreases in pain (p-values of 0.007, 0.001, and 0.005, respectively) and greater ease in physiotherapy compared with the control group. EMG recordings of masticator muscles showed a transient drop in microvolt value in the study group 1 month after injection, unlike the control group recordings. It was concluded that preoperative BTX-A injection was a good addition to surgical therapy in the patient group.

Can we justify the continued use of botulinum toxin A in the management of myofascial pain?

We initially conducted a pilot study to evaluate the impact of botulinum toxin A (BtA) on increased masseteric mass associated with pain. After injection we assessed its impact on the muscle mass and the impact, if any, on reported pain, in a group of 10 patients who were refractory to conservative management. Results of this pilot study indicated that clenched and unclenched muscle dimensions showed no significant reduction (-0.82 clenched and -1mm unclenched). However, what did prove to be significant was an improvement in their pain scores as measured on a visual analogue scale (VAS). The mean VAS score before the injection was 8.2, and at six weeks after the injection it was 1.8. Following the pilot study we focused only on patients' pain scores. Our main study included 48 patients (81 muscles) who suffered with pain secondary to increased masseteric size, and had recorded their pain score out of 10 on the VAS before placement of BtA into each affected muscle and again six weeks after the injection. Results showed a mean pre-injection pain score of 7.9 and a mean post-injection pain score of 2.9. Following the results of this study on reported pain alone, our Trust has allowed funding to provide the intramuscular injection of BtA in appropriately selected patients.

Effect of Preoperative Intramuscular Injection of Botulinum Toxin A on Pain and Mouth Opening After Surgical Intervention in Temporomandibular Joint Ankylosis Cases: A Controlled Clinical Trial

The aim of the present study was to determine the effect of intramuscular injection of botulinum toxin A (BTX-A) into the masticatory muscles on the physiotherapy pain and mouth opening outcomes after surgical intervention of temporomandibular joint (TMJ) ankylosis and to verify the effects using electromyographic studies. The study included 20 patients with TMJ ankylosis. The patients were further subdivided into control and interventional groups. The interventional group was given intramuscular injections of BTX-A in the masticator muscles before surgery. Only saline injections were given to the control group. All 20 patients were evaluated for pain and ease of active physiotherapy at the 1-week and 1-, 3-, and 6-month follow-up visits using a questionnaire. Intergroup comparisons were performed for both groups. Electromyographic (EMG) studies were also performed in the intervention group for each patient. EMG recordings were performed of the individual masticator muscle in each patient before injection and at 1 and 3months after injection. The intervention group showed better results with respect to pain during the mouth opening exercises and improvements in mouth opening. All the interventional group patients showed a transient decrease in the microvolt value on the EMG studies of their masticator muscles on injection of BTX-A. BTX-A injection can be a straightforward and useful adjunct to surgical treatment of TMJ ankylosis for the reduction of pain during postoperative physiotherapy.

Longitudinal assessment of gait quality in children with bilateral cerebral palsy following repeated lower limb intramuscular Botulinum toxin-A injections

BackgroundSerial lower limb intramuscular Botulinum toxin-A (BoNT-A) injections are administered to children with bilateral spastic cerebral palsy (BCP) to reduce spasticity, improve walking and functional mobility, and delay the need for orthopaedic surgery. Gait quality is clinically assessed following BoNT-A with 2D video gait assessments (2DVGA) using the Edinburgh Visual Gait Score (EVGS). AimTo determine the effect of three consecutive treatment cycles of lower limb intramuscular BoNT-A injections on gait quality using the EVGS in children with BCP by retrospectively reviewing repeated 2DVGA measures. Methods and proceduresSeventeen children with BCP and dynamic equinus (8 females and 9 males, age mean (SD), 4.0 (2.2) years, GMFCS I=2 and II=15) were included in the study after a retrospective audit of the records of the Queensland Children’s Gait Laboratory (QCGL), Children’s Health Queensland, Brisbane. The medical records of children who attended the QCGL between January 2001 and January 2016 were searched for eligibility. Children who had undertaken pre- and post-treatment 2DVGA for the first three lower limb BoNT-A treatment cycles (6 assessments) were reviewed using the EVGS. BoNT-A treatments were administered 7.7 (2.3) months apart and post-BoNT-A reviews occurred 12.6 (6.7) weeks after injection. Mixed-effects linear regression assessed the change from baseline to each subsequent assessment (p<0.05). Outcomes and resultsEVGS reduced significantly by a mean of 2.4 points from pre- to post-BoNT-A in the first treatment cycle (p=0.001). Compared to baseline, mean total EVGS reduced significantly during the second (pre-BoNT-A −1.7 (p=0.020), post BoNT-A −2.8 (p<0.001)) and third (pre-BoNT-A −2.6 (p=0.001), post BoNT-A −2.4 (p=0.002)) treatment cycles. There was no difference in EVGS between post-BoNT-A in the first treatment cycle and scores for the second and third treatment cycles. Conclusions and implicationsImprovements in gait quality were statistically significant, but did not reach the EVGS smallest real difference value of 4 points. Repeated lower limb intramuscular BoNT-A injections to improve gait quality in children with BCP should be reconsidered.

Analgesic Effect of Botulinum Toxin A in Myofascial Pain Syndrome Patients Previously Treated with Local Infiltration of Anesthetic and Steroids

ABSTRACTThe purpose of this study was to evaluate the analgesic effect of botulinum toxin A (BoNTA) injections in patients with myofascial pain syndrome (MPS) who were previously treated with the local infiltration of anesthetic and steroids (LIAS). The study included a retrospective phase and a longitudinal open-label prospective phase, which were conducted on consecutive patients with MPS previously treated with the local infiltration of anesthetic (levobupivacaíne 0.25%) and steroids (triamcinolone 40 mg). Eligible patients were treated with a single intramuscular injection of BoNTA (Botox; Allergan, Inc., Irvine, CA). The treatment efficacy was determined according to the degree of pain relief obtained. Eighty-two patients met the inclusion/exclusion criteria and were included in the study. Successful results were obtained for 32 (39.0%) and 30 (36.6%) patients, during treatment with BoNTA and LIAS, respectively. The mean (standard deviation) length of the analgesic effect was significantly longer with BoNTA (29.6 [SD = 17.7] weeks) than with LIAS (8.5 [SD = 6.4] weeks), P <.0001. As regards the side effects, 19 (23.2%) patients reported transient soreness at the injection site for 2 to 3 days with BoNTA. The MPS patients previously treated with a local infiltration of anesthetic and steroids who then received a single injection of BoNTA experienced significantly reduced pain for a relatively long time.

Occlusal force characteristics of masseteric muscles after intramuscular injection of botulinum toxin A(BTX – A)for treatment of temporomandibular disorder

Our aim was to evaluate the occlusal force and therapeutic efficacy of the masseteric muscles after intramuscular injection of botulinum toxin A (BTX-A) for the treatment of patients with concurrent temporomandibular disorders (TMD) and bruxism. Thirty patients with TMD associated with bruxism were randomised into three groups (n=10 in each group), and treated by bilateral intramuscular injection of BTX-A into the masseter, placebo, or control. We used an occlusal force analysis system to collect several measures of occlusal force such as duration of biting and closing, the maximum occlusal force, and the distribution of occlusal force. The occlusal force in the intercuspid position was reduced in all three groups. There was a significant difference between the BTX-A and placebo groups (F(df=1)=8.08, p=0.01) but not between the control group and the other two(F(df=1)=4.34, p=0.047). The duration of occlusion was significantly increased in the BTX-A group after 3 months’ treatment (t=4.07, p=0.003). The asymmetrical distribution of occlusal force was reduced in all three groups, but not significantly so (Levene's test F(df=2)=0.25, p=0.78,ANOVA F(df=2)=0.50, p=0.61). Treatment of TMD with BTX-A is effective in reducing the occlusal force, but psychological intervention plays an important part in treatment.

27. EMG-guided injection of botulinum toxin A in the treatment of iliopsoas spasticity

Ultrasound guided (US) botulinum toxin A (BT-A) intramuscular injection is an established treatment for the iliopsoas muscle (IM) spasticity, but it is not always possible to use it. The EMG-techniques of IM examination have already been described (Katsavrias et. al, 2005) but not for the intramuscular injection of BT-A. To describe a technique with EMG guidance for the intramuscular injection of BT-A to treat spasticity of the IM and evaluate the efficacy of this technique. The EMG-guided technique for BT-A injection was used on 9 patients (aged 7–59 years) with unilateral or bilateral spasticity of the IM. BT-A dose range from 30 U to 50 U for IncobotulinumtoxinA and OnabotulinumtoxinA, 120 U for AbobotulinumtoxinA. Outcome measures included Modified Ashworth Scale (MAS) for muscle tone and Range of Motion (ROM), assessed before the treatment and after 3, 6 and 12 months. After one year from the first EMG-guided injection of BT-A, MAS score decreased from 3.8 to 1.8 and ROM score increased from −53.1 to −20.8 (p < 0.0001 for all; ANOVA). This EMG-guided technique allows accurate guidance for the injection of BT-A of the IM and it can be considered a viable alternative to the US-guided technique.

Joint instability leads to long-term alterations to knee synovium and osteoarthritis in a rabbit model

Joint instability is believed to promote early osteoarthritic changes in the knee. Inflammatory reactions are associated with cartilage degradation in osteoarthritis (OA) but their possible synergistic or additive effects remain largely unexplored. The goal of the present study was to investigate the invivo effects of Botulinum Toxin A (BTX-A) induced joint instability on intraarticular alterations in an otherwise intact rabbit knee joint model. Ten 1-year-old female New Zealand White rabbits (average 5.7kg, range 4.8-6.6kg) were randomly assigned to receive three monthly unilateral intramuscular injections of BTX-A (experimental group), or no treatment (control group). After 90days, all knees were analyzed for specific mRNA levels using RT-qPCR. The synovium and cartilage tissue was assessed for histological alterations using the OARSI scoring system. Cartilage and synovial histology showed significant higher OARSI scores in the BTX-A group animals compared to the untreated controls and contralateral limbs. There were no differences between the untreated control and the contralateral experimental limbs. Gene expression showed significant elevations for collagen I, collagen III, nitric oxide, TGF-β, IL-1 and IL-6 compared to the healthy controls. BTX-A induced joint instability in a muscle weakness model uniquely leads to alterations in gene expression and histological changes in the synovial membranes and cartilage in otherwise intact knee joints. These results lead to the conclusion that joint instability may promote an inflammatory intraarticular milieu, thereby contributing to the development of OA.

Botulinum Toxin A for Nonambulatory Children with Cerebral Palsy: A Double Blind Randomized Controlled Trial

To examine the efficacy and safety of intramuscular botulinum toxin A (BoNT-A) to reduce spasticity and improve comfort and ease of care in nonambulant children with cerebral palsy (CP). Nonambulant children with CP (n = 41; Gross Motor Function Classification System level IV = 3, level V = 38; mean age 7.1 years, range 2.3-16 years, 66% male) were randomly allocated to receive either intramuscular BoNT-A injections (n = 23) or sham procedure (n = 18) combined with therapy. The analysis used generalized estimating equations with primary outcome the Canadian Occupational Performance Measure (COPM) at 4 weeks postintervention and retention of effects at 16 weeks. Adverse events (AE) were collected at 2, 4, and 16 weeks by a physician masked to group allocation. There were significant between group differences favoring the BoNT-A-treated group on COPM performance at 4 weeks (estimated mean difference 2.2, 95% CI 0.8, 3.5; P = .002) and for COPM satisfaction (estimated mean difference 2.2, 95% CI 0.5, 3.9; P = .01). These effects were retained at 16 weeks for COPM satisfaction (estimated mean difference 1.8, 95% CI 0.1, 3.5; P = .04). There were more mild AE at 4 weeks for the BoNT-A group (P = .002), however, there were no significant between-group differences in the reporting of moderate and serious AE. In a double-blind randomized sham-controlled trial, intramuscular BoNT-A and therapy were effective for improving ease of care and comfort for nonambulant children with CP. There was no increase in moderate and severe AE in the children who had BoNT-A injections compared with the sham group.

GRIN: “GRoup versus INdividual physiotherapy following lower limb intra-muscular Botulinum Toxin-A injections for ambulant children with cerebral palsy: an assessor-masked randomised comparison trial”: study protocol

BackgroundCerebral palsy is the most common cause of physical disability in childhood. Spasticity is a significant contributor to the secondary impairments impacting functional performance and participation. The most common lower limb spasticity management is focal intramuscular injections of Botulinum Toxin-Type A accompanied by individually-delivered (one on one) physiotherapy rehabilitation. With increasing emphasis on improving goal-directed functional activity and participation within a family-centred framework, it is timely to explore whether physiotherapy provided in a group could achieve comparable outcomes, encouraging providers to offer flexible models of physiotherapy delivery. This study aims to compare individual to group-based physiotherapy following intramuscular Botulinum Toxin-A injections to the lower limbs for ambulant children with cerebral palsy aged four to fourteen years.Methods/DesignAn assessor-masked, block randomised comparison trial will be conducted with random allocation to either group-based or individual physiotherapy. A sample size of 30 (15 in each study arm) will be recruited. Both groups will receive six hours of direct therapy following Botulinum Toxin-A injections in either an individual or group format with additional home programme activities (three exercises to be performed three times a week). Study groups will be compared at baseline (T1), then at 10 weeks (T2, efficacy) and 26 weeks (T3, retention) post Botulinum Toxin-A injections. Primary outcomes will be caregiver/s perception of and satisfaction with their child’s occupational performance goals (Canadian Occupational Performance Measure) and quality of gait (Edinburgh Visual Gait Score) with a range of secondary outcomes across domains of the International Classification of Disability, Functioning and Health.DiscussionThis paper outlines the study protocol including theoretical basis, study hypotheses and outcome measures for this assessor-masked, randomised comparison trial comparing group versus individual models of physiotherapy following intramuscular injections of Botulinum Toxin-A to the lower limbs for ambulant children with cerebral palsy.Trial registrationACTRN12611000454976

IM botulinum toxin-A improves ambulation in severe haemophilia and cerebral palsy

Abstract Introduction: The use of BtA in spasticity management is well documented in the literature for the management of hypertonicity in children with cerebral palsy. Methods: We report a case of a 2-year-old boy with severe haemophilia and cerebral palsy who received intramuscular injections of botulinum toxin-A (BtA) to reduce his spastic diplegia lower limb hypertonicity. Results: Following treatment, clinical and formal assessments demonstrated positive changes in ambulation, tolerance of orthotics, functional abilities and musculoskeletal range of movement and no adverse bleeding side effects. Conclusion: The use of BtA should be considered for the management of hypertonicity in children with haemophilia and cerebral palsy.

Evaluation of the effects of botulinum toxin A injections when used to improve ease of care and comfort in children with cerebral palsy whom are non-ambulant: a double blind randomized controlled trial

BackgroundChildren with cerebral palsy (CP) whom are non-ambulant are at risk of reduced quality of life and poor health status. Severe spasticity leads to discomfort and pain. Carer burden for families is significant. This study aims to determine whether intramuscular injections of botulinum toxin A (BoNT-A) combined with a regime of standard therapy has a positive effect on care and comfort for children with CP whom are non-ambulant (GMFCS IV/V), compared with standard therapy alone (cycle I), and whether repeated injections with the same regime of adjunctive therapy results in greater benefits compared with a single injecting episode (cycle II). The regime of therapy will include serial casting, splinting and/or provision of orthoses, as indicated, combined with four sessions of goal directed occupational therapy or physiotherapy.Method/designThis study is a double blind randomized controlled trial. Forty participants will be recruited. In cycle I, participants will be randomized to either a treatment group who will receive BoNT-A injections into selected upper and/or lower limb muscles, or a control group who will undergo sham injections. Both groups will receive occupational therapy and /or physiotherapy following injections. Groups will be assessed at baseline then compared at 4 and 16 weeks following injections or sham control. Parents, treating clinicians and assessors will be masked to group allocation. In cycle II, all participants will undergo intramuscular BoNT-A injections to selected upper and/or lower limb muscles, followed by therapy.The primary outcome measure will be change in parent ratings in identified areas of concern for their child’s care and comfort, using the Canadian Occupational Performance Measure (COPM). Secondary measures will include the Care and Comfort Hypertonicity Scale (ease of care), the Cerebral Palsy Quality of Life Questionnaire (CP QoL–Child) (quality of life), the Caregiver Priorities and Child Health Index of Life with Disabilities Questionnaire (CPCHILD©) (health status) and the Paediatric Pain Profile (PPP) (pain). Adverse events will be carefully monitored by a clinician masked to group allocation.DiscussionThis paper outlines the theoretical basis, study hypotheses and outcome measures for a trial of BoNT-A injections and therapy for children with non-ambulant CP.Trial registrationAustralia New Zealand Clinical Trials Registry:N12609000360213

What are the long-term consequences of botulinum toxin injections in spastic cerebral palsy?

Muscle spasticity, defined as a velocity dependent resistance to stretch, is the primary impairment of spastic cerebral palsy (CP) and is neural in origin. However, spastic muscle also undergoes significant morphological and structural alterations secondary to spasticity which contribute to muscle weakness, muscle stiffness, restricted joint range of motion, and skeletal deformity. These secondary alterations can progress with age and contribute to a gradual loss of functional capacity during development, including the ability to ambulate independently. There is consensus that intra-muscular botulinum toxin A (BoNT-A) injections can be effective in the management of lower limb spasticity in children with spastic CP. BoNT-A injections can improve gait and delay and reduce the requirement for surgical interventions to treat musculoskeletal deformities when combined with conservative treatments. The study by Alhusaini et al. is one of the first that begins to address the important clinical question of how BoNT-A injections influence the secondary effects of spasticity on joint-level mechanical properties in children with spastic CP. An attractive feature of the study was that the authors assessed ankle joint stiffness and not just joint range of motion. Alhusaini et al. showed that BoNT-A has relatively minor effects on passive mechanical properties of the ankle plantar-flexor muscles at 6-weeks post injection in children with spastic CP aged 4– 10 years with high ankle joint stiffness. This study therefore does not support the efficacy of BoNT-A for treating contractures. What remains unclear at the present time is how BoNT-A might influence other structural and neuro-mechanical properties of the muscle and ⁄or tendon, especially in the longer term. For example, how does BoNT-A affect muscle size, strength, force-length-velocity behaviour, moment arms, co-activation, and tendon compliance? Of increasing concern is evidence from animal studies that intra-muscular BoNT-A injections adversely influence muscle growth in the injected muscle as well as muscles remote from the injection site. For example, Fortuna et al. recently reported up to 95% reductions in rabbit hind limb quadriceps muscle strength following 6 months of repeated BoNT-A injections, which was accompanied by up to 60% reductions in muscle mass. Reductions in strength and mass were also reported for quadriceps muscles in the contralateral limb. These findings point to the possibility that the short-term functional benefits of BoNT-A injections reported in clinical studies in spastic CP may be offset by accelerated structural weakening of muscle. This is important because children aged 2–5 years with spastic CP that have not undergone orthopaedic surgery or commenced BoNT-A injections already have significantly lower calf muscle volume relative to their typically developed peers. BoNT-A is routinely administered to children in this age group and is often repeated over many cycles. Further muscle weakening by BoNT-A would therefore be expected to adversely influence functional capacity. BoNT-A acts to weaken overactive muscles through chemical blockade of the neuromuscular junction. It might be expected that any associated muscle atrophy could contribute to observed improvements in gait following BoNT-A injections. However, during maturation in childhood and adolescence, muscles must increase in size to cope with the increased mechanical loading associated with motor function in activities such as gait. Muscle weakening from BoNT-A could therefore be beneficial in the short-term but detrimental in the longerterm because of impeded muscle growth. Aside from the study by Alhusaini et al., to our knowledge no detailed in vivo studies of the effects of BoNT-A on the active and passive mechanical properties of muscle in children with spastic CP have been conducted. In spite of the widespread use of BoNT-A injections in children with spastic CP for almost two decades, the long-term efficacy of this treatment for improving functional outcomes in children with spastic CP remain relatively unknown. In using a short-term solution we may be creating a long-term problem which could lead to increased costs of care in spastic CP. Long-term trials of the structural and neuro-mechanical responses of muscle to BoNT-A and their consequences for motor function in spastic CP are required. New developments in musculoskeletal modeling and simulation may prove fruitful in linking muscletendon adaptation with gait function in spastic CP.

Botulinum Toxin A in the Treatment of Chronic Tension‐Type Headache With Cervical Myofascial Trigger Points: A Randomized, Double‐Blind, Placebo‐Controlled Pilot Study

To evaluate the efficacy of botulinum toxin A (BT-A) as a prophylactic treatment for chronic tension-type headache (CTTH) with myofascial trigger points (MTPs) producing referred head pain. Although BT-A has received mixed support for the treatment of TTH, deliberate injection directly into the cervical MTPs very often found in this population has not been formally evaluated. Patients with CTTH and specific MTPs producing referred head pain were assigned randomly to receive intramuscular injections of BT-A or isotonic saline (placebo) in a double-blind design. Daily headache diaries, pill counts, trigger point pressure algometry, range of motion assessment, and responses to standardized pain and psychological questionnaires were used as outcome measures; patients returned for follow-up assessment at 2 weeks, 1 month, 2 months, and 3 months post injection. After 3 months, all patients were offered participation in an open-label extension of the study. Effect sizes were calculated to index treatment effects among the intent-to-treat population; individual time series models were computed for average pain intensity. The 23 participants reported experiencing headache on a near-daily basis (average of 27 days/month). Compared with placebo, patients in the BT-A group reported greater reductions in headache frequency during the first part of the study (P = .013), but these effects dissipated by week 12. Reductions in headache intensity over time did not differ significantly between groups (P = .80; maximum d = 0.13), although a larger proportion of BT-A patients showed evidence of statistically significant improvements in headache intensity in the time series analyses (62.5% for BT-A vs 30% for placebo). There were no differences between the groups on any of the secondary outcome measures. The evidence for BT-A in headache is mixed, and even more so in CTTH. However, the putative technique of injecting BT-A directly into the ubiquitous MTPs in CTTH is partially supported in this pilot study. Definitive trials with larger samples are needed to test this hypothesis further.

Ultrasound-guided injection of botulinum toxin A in the treatment of iliopsoas spasticity

Purpose Intramuscular injection of botulinum toxin A (BTX-A) is a common treatment for iliopsoas muscle spasticity, but it is not easy to position the needle in this muscle without guidance. In this paper we describe an ultrasound-guided technique for the intramuscular injection of BTX-A to treat spasticity of the iliopsoas muscle. Its effectiveness was assessed in 10 patients. Method and materials The ultrasound-guided technique for BTX-A injection was used on 10 patients. The needle was inserted into the muscle belly at an angle of 45° along the longitudinal axis of the muscle when allowed by patient's condition. Results In all cases, the iliopsoas muscle was easily identified and both the iliac and psoas components were assessed. Introduction of the needle and drug injection were entirely carried out under ultrasonographic guidance. The procedure was successful in all patients, even in those with a high-grade spasticity, and general anesthesia was not required. Conclusions This ultrasound-guided technique allows accurate guidance for the injection of BTX-A, and it can be considered as an alternate supportive therapy in patients with spasticity and dystonia.

Ultrasound-guided injection of the psoas muscle with Botulinum Toxin A: Novel approach to treating chronic low back pain

Chronic low back pain due to multiple different aetiologies can be very difficult to treat. Previous studies have shown that Botulinum Toxin A (BTX-A) injected into superficial low back muscles as well as deeper injections into the psoas muscles can be beneficial in relieving low back pain. With chronic low back pain, there is often an imbalance between relatively overactive muscles and their less active antagonist muscle. A functional muscle imbalance in the lumbo-pelvic region can promote poor biomechanics and chronicity of pain. We propose a novel injection approach to treating chronic low back pain using BTX-A under ultrasound guidance to target the deeper psoas muscle. Three patients aged 31–47 were given unilateral injections posteriorly into the psoas muscle corresponding to the side of maximal discomfort. 200 U of BTX-A was injected via ultrasound guidance in a 4:1 dilution at the level of the L4 vertebrae. Patients then underwent an active exercise program. The mean VAS score dropped from 7.7/10 (pre) to 4.7/10 (post). Mean score on the Oswestry back pain questionnaire changed from 41/50 to 31.7/50. Based on these results, the potential exists for intramuscular injection of BTX-A to be used as an adjunct to specific muscle re-education and functional rehabilitation in this patient population.