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.