Aidan Cosgrove

Botulinum toxin A compared with stretching casts in the treatment of spastic equinus: a randomised prospective trial.

Conservative therapies for equinus in cerebral palsy may help to postpone calf surgery in younger children. This study reports a prospective randomised trial of intramuscular botulinum toxin A (BtA) as an alternative to serial casting in 20 children with a dynamic component to calf equinus. Outcome was assessed in the short term to show the effect of one treatment cycle. Assessments were by clinical examination, video gait analysis, and three-dimensional gait analysis. BtA was of efficacy similar to that of serial casting. Tone reduction in the BtA group allowed a more prolonged improvement in passive dorsiflexion, which may allow more opportunity for increase in muscle length. Gait analysis showed an improved mean ankle kinematic pattern in a subsection of both groups, which was maintained at 12 weeks in the BtA group, whereas the cast group relapsed. There were fewer side effects in the BtA group. Median time to reintervention was similar.

Botulinum toxin treatment of spasticity in diplegic cerebral palsy: a randomized, double-blind, placebo-controlled, dose-ranging study

This study evaluated the efficacy and safety of three doses of botulinum toxin A (BTX‐A; Dysport) in 125 patients (mean age 5.2 years, SD 2; 54% male)with dynamic equinus spasticity during walking. Participants were randomized to receive Dysport (10, 20, or 30 units/kg) or placebo to the gastrocnemius muscle of both legs. Muscle length was calculated from electrogoniometric measurements and the change in the dynamic component of gastrocnemius shortening at four weeks was prospectively identified as the primary outcome measure. All treatment groups showed statistically significant decreases in dynamic component compared with placebo at 4 weeks. Mean improvement in dynamic component was most pronounced in the 20 units/kg group, being equivalent to an increase in dorsiflexion with the knee extended at 1920, and was still present at 16 weeks. The safety profile of the toxin appears satisfactory.

The effect of botulinum toxin A on gastrocnemius length : magnitude and duration of response

Thirty‐nine ambulant children (22 with hemiplegia, 17 with diplegia) with spastic cerebral palsy receiving isolated gastrocnemius muscle injection with botulinum toxin A were studied prospectively. The children had a mean age of 6 years (range 3 to 13 years). Measurement of gastrocnemius muscle length was used to estimate the dynamic component of each childs spasticity and to quantify the response. There was a strong correlation between the dynamic component of spasticity before injection and the corresponding magnitude of the response after injection. Children undergoing repeated injections showed similar correlations. A strong correlation was found between the duration of response and the dynamic component. Children with hemiplegia showed twice the duration for a given dynamic component compared with those with diplegia when injected with the same total dose per unit body weight. Long‐term lengthening did not occur for the cohort, although some patients showed a response at a 12‐month follow‐up. By delaying shortening, the injections may have a role in delaying the need for surgery. Injections were well tolerated with few side effects.

ENERGY CONSUMPTION IN CHILDREN WITH SPINA BIFIDA AND CEREBRAL PALSY: A COMPARATIVE STUDY

The authors looked for differences in the energy expenditure patterns of ambulant children with cerebral palsy and spina bifida. Oxygen consumption was measured according to type of cerebral palsy or level of spina bifida lesion, and in healthy children. The rate of oxygen consumption (mL/kg/min) was significantly higher in the children with diplegia than in those with hemiplegia or with spina bifida or the healthy children. Oxygen cost (mL/kg/m) was significantly higher and velocity was significantly slower in all the groups with disability than in the healthy children. The reason children with diplegia consumed more oxygen than other children when walking may be that their abnormal equilibrium reactions impaired their balance and their ability to control their walking speed.

Safety profile and efficacy of botulinum toxin A (Dysport) in children with muscle spasticity.

Botulinum toxin A (BTX‐A) is widely used in the management of muscle spasticity in children. However, at present the dose of BTX‐A for a given patient is selected empirically. The aim of this study is to provide dosage guidelines that are based on risk/benefit assessment. This was a multicentre retrospective study of the safety profile and efficacy of BTX‐A in children with chronic muscle spasticity. Data in 758 patients who received a total of 1594 treatments were analysed (mean age 7.2 years; 429 males, 329 females). Spastic cerebral palsy (CP) was the most common diagnosis (94% of the study sample). Of all treatments 7% resulted in adverse events; incidence was related to the total dose rather than the dose calculated on the basis of body weight. The highest incidence of adverse events was observed in patients who received >1000 IU of BTX‐A per treatment session. The odds of an adverse event was 5.1 times greater for this group of patients than for those who had 250 IU or less (p<0.001). A good overall response to treatment was reported in 82% and treatment goals were fully or partially achieved in 3% and 94% of participants respectively. More patients in the highest dose group reported functional deterioration. Interestingly, multilevel treatments resulted in a better response than single‐level treatments (odds ratio 1.7, 95% CI 1.3 to 2.2, p=0.001).

Musculoskeletal modelling in determining the effect of botulinum toxin on the hamstrings of patients with crouch gait.

This study aimed to determine the effect of hamstring botulinum toxin A (Btx‐A) injection in 10 children with crouch gait in terms of changes in muscle length and lower‐limb kinematics. Before Btx‐A injection limb kinematics were recorded. Maximum hamstring lengths and excursions were calculated by computer modelling of the lower limb. Data were compared with the averaged hamstring lengths of 10 control children. Hamstrings were denned as short if their length was shorter than the average maximum length minus one standard deviation. Gait analysis was repeated 2 weeks after isolated hamstring Btx‐A injection. Pre‐ and postinjection kinematic data and muscle lengths were then compared. Four of 18 injected limbs in three subjects had short medial hamstring before injection, none of the subjects had short lateral hamstrings. Muscle excursion was significantly reduced in the short and adequate maximum muscle length groups. A significant increase in the semimembranosus and semitendinosus length in all of the injected limbs was noted. Only in the short muscle group was a significant increase in muscle excursion observed. Knee extension improved by 13° in the adequate muscle length group and by 15.6° in the short muscle length group. Pelvic tilt and hip flexion increased in both groups non‐significantly. Average walking speed postinjection increased from 0.60 ms‐1 to 0.71 ms‐1. Short hamstrings are over‐diagnosed in crouch gait. Hamstring Btx‐A injection in patients with crouch gait produces significant, repeatable muscle lengthening and improved ambulatory function.

Validity of a 1 minute walk test for children with cerebral palsy

The concurrent validity of a 1 minute walk test at a childs maximum walking speed was assessed in children with bilateral spastic cerebral palsy (BSCP). The distance covered during the 1 minute walk test was compared with the childrens gross motor function as assessed by the Gross Motor Function Measure (GMFM). Twenty-four male and 10 female children with CP (mean age 11y, range 4 to 16y) participated in the study. Gross Motor Function Classification System (GMFCS) levels were; level I (n=3), level II (n=17), level III (n=10), and level IV (n=4). Participants had clinical diagnoses of symmetrical diplegia (n=19), asymmetrical diplegia (n=14), and quadriplegia (n=1). Results showed a significant correlation between GMFM score and the distance covered during the 1 minute walk (r=0.92; p<0.001). There was also a significant decrease in the distance walked with increasing GMFCS level (p<0.001). We concluded that the 1 minute walk test is a valid measure for assessing functional ability in children with ambulatory BSCP. Its cost-effectiveness and user friendliness make it a potentially useful tool in the clinical setting. Further study needs to address its reliability and ability to detect change over time.

Further evidence of validity of the Gait Deviation Index.

In this paper, the relationship of the Gait Deviation Index (GDI) to gross motor function and its ability to distinguish between different Gross Motor Function Classification System (GMFCS) levels was determined. A representative sample of 184 ambulant children with CP in GMFCS levels I (n=57), II (n=91), III (n=22) and IV (n=14) were recruited as part of a population-based study. Representative gait cycles were selected following a 3D gait analysis and gross motor function was assessed using the Gross Motor Function Measure (GMFM). GDI scores were calculated in Matlab. Valid 3D kinematic data were obtained for 173 participants and both kinematic and GMFM data were obtained for 150 participants. A substantial relationship between mean GDI and GMFM-66 scores was demonstrated (r=0.70; p<0.001) with significant differences in mean GDI scores between GMFCS levels (p<0.001) indicating increasing levels of gait deviation in subjects less functionally able. The relationship between the GDI, GMFM and GMFCS in a representative sample of ambulators, lends further weight to the validity of the GDI scoring system. Furthermore it suggests that the subtleties of gait may not be wholly accounted for by gross motor function evaluation alone. Gait specific tools such as the GDI more likely capture both the functional and aesthetic components of walking.

Relevance of the popliteal angle to hamstring length in cerebral palsy crouch gait

The popliteal angle is a widely used clinical means of assessing hamstring length in cerebral palsy patients. The relevance of the popliteal angle as a measure of hamstring length was assessed in this prospective study. Sixteen patients with cerebral palsy with crouch gait had their conventional and modified popliteal angles measured by nine observers on two separate occasions. With use of the conventional and modified forms of the test, 74 and 70%, respectively, of the observed variability was inter-and intraobserver related. The range of SDs for each observer using the conventional test was 7.1-13.6 degrees (average 10.9 degrees ), and with use of the modified form of the test, the range was 6.3-4.2 degrees (average 10.5 degrees ). The maximum hamstring length of each subject during gait was determined by three-dimensional modelling of their lower limbs. The modified popliteal angle measurements of the most repeatable observer demonstrated an inverse relationship between modified popliteal angle and maximum hamstring length (p < 0.01) and muscle excursion (p < 0.01). Only 10 of 32 limbs had short medial hamstrings.

Age-related changes in energy efficiency of gait, activity, and participation in children with cerebral palsy

Aim  The aim of this study was to use a prospective longitudinal study to describe age‐related trends in energy efficiency during gait, activity, and participation in ambulatory children with cerebral palsy (CP).