24 CHAPTER 1 METHODS A retrospectiveobservational studywas conducted in childrenwhowere treatedwith at least two subsequent, equally dosed onabotulinum neurotoxin A injections. The effect of onabotulinum neurotoxin A injections was compared within participants to reduce confounding factors and increase reliability in a heterogeneous population. Study population Children aged 4 years or older treated for drooling at the Radboud University Medical Center, Nijmegen, the Netherlands, between 2000 and 2020 were eligible. Children treated for anterior or antero-posterior drooling with at least two onabotulinum neurotoxin A injections with identical dose (25IU/gland) delivered at the same gland(s) were included in this study. The first injection in this study was the first onabotulinum neurotoxin A injection that was administered for the treatment of drooling. Both injections in the submandibular glands and submandibular and parotid glands (combined injection) were included. In our centre the parotid glands are not routinely treated because the submandibular glands are thought to be responsible for 70% of the saliva in a resting situation.14 Children were excluded if dosages of the first or second injection were unknown. Assessments of subsequent injections different in onabotulinum neurotoxin A dose or gland localization were excluded, but previous equal injection within the same children were included. Also, children with a progressive condition (i.e. mitochondrial diseases and metabolic diseases) were excluded. The data were saved in an anonymized protected web-based database according to good clinical practice. This study was approved by the medical ethical committee of the Radboud University Nijmegen Medical Centre (CMO: 2020-6145). Outcome measures Regular standardized assessments were made by a specialized speech and language therapist and included the severity of drooling using the drooling quotient
RkJQdWJsaXNoZXIy MjY0ODMw