Response to salivary gland botulinum toxin injection does not predict success from surgery for sialorrhoea (drooling) in children with neurodisability.

[UNLABELLED] Drooling is a common problem in children with neurodisability, and refractory cases may require surgery. Our aim was to assess whether a child's response to salivary botulinum toxin injections would predict success or failure from subsequent surgical intervention. Retrospective case note review of all children undergoing drooling surgery between 1st January 2007 and 31st December 2023 at the Royal Hospital for Children, Glasgow. Of all the children who underwent surgery for management of sialorrhoea, we identified 28 who had previously received salivary botulinum toxin injections. One early post-op death from respiratory causes was excluded. Caregivers reported success from surgery in 16 children (59%), defined as complete cessation of drooling or substantial improvement such that no other treatments were required. Surgery was successful in 3 out of 4 children (75%) for whom botulinum toxin injection had previously been successful, and 13 out of 23 (57%) for whom botulinum toxin injection had been ineffective. This difference is not statistically significant (Fisher's exact test p = 0.62).

[CONCLUSION]  More than half of children who have not responded to salivary botulinum toxin injections will go on to have an excellent result from drooling surgery. Response to botulinum toxin should not be used to determine candidacy for surgery.

[WHAT IS KNOWN] • Poor control of saliva is a common cause of morbidity in childen with neurodisablity, and various treatments can be effective including botulinum toxin injections and salivary surgery. • It has been suggested that the respnse to salivary botulinum toxin can be used to decide which children might benefit from definitive salivary surgery.

[WHAT IS NEW] • Saliva reduction surgery is effective in the majority of children regardless of whether or not they previously had a good response to botulinum toxin injections.