National Patterns of Botulinum Toxin A Use in Children With Cerebral Palsy in Aotearoa New Zealand: A Register Study

AIM: To analyse botulinum toxin A (BTX-A) use in children with cerebral palsy (CP) in a high-resource country and explore practice variations. METHODS: Demographic data for 1149 children/young adults enrolled in the New Zealand Cerebral Palsy Register (born 2002-2018) were linked with hospital procedural records (2002-2023) and analysed using multivariable regression models. RESULTS: Seven hundred and twenty-five of 1149 children (63%) had ≥ 1 BTX-A episode by age 15 years (n = 3734 episodes), with 101 (8.8%) having ≥ 10 episodes. From 2009 to 2023, between 15% and 25% of children < 15 years old had one or more BTX-A injections per year. Three thousand and four hundred episodes (91%) were under general anaesthesia, 3290 (88%) were linked to the orthopaedic surgical service and only 55 (1.5%) were linked to otorhinolaryngology service. Children classified as gross motor classification system (GMFCS) Levels II and III were more likely to have BTX-A compared to GMFCS Level I (odds ratio (OR) 2.21 (95% CI 1.56, 3.11) and 3.11 (1.85, 5.22). Repeat injections were more common at GMFCS Levels III or IV hazard ratio 1.48 (1.25, 1.74) and 1.33 (1.13, 1.56). Those children living within a health district with a tertiary hospital (628; 55%), had twice the odds of ever receiving BTX-A [OR 1.97 (1.49, 2.62)] and were younger at first episode. CONCLUSIONS: BTX-A is widely used in childhood CP in New Zealand, particularly for those with moderate functional limitations. Total level of BTX-A use remained similar from 2009 to 2023 but appears to be influenced by both individual clinical features and availability of local tertiary hospital services.