Negative effects on oral motor function after submandibular and parotid botulinum neurotoxin A injections for drooling in children with developmental disabilities.

The study relied on retrospective clinical notes, meaning mild negative effects may have been underreported or not documented if parents did not disclose them or if therapists did not deem them substantial. Most children in the concurrent injection group had prior exposure to botulinum toxin in the submandibular glands, which may have influenced their tolerance or reporting of side effects compared to treatment-naive patients. The study could not account for concurrent skeletal muscle botulinum toxin injections, which some literature suggests may increase the risk of negative effects. Data were collected over 20 years, and while assessments were standardized, changes in clinical practice or parent awareness over time may have influenced reporting.

Do not interpret the absence of severe effects in this cohort as proof that concurrent injections are safer than submandibular injections alone. The study population consisted mostly of children who had already tolerated submandibular injections without severe issues, creating a selection bias that may have excluded those most susceptible to severe complications.