Factors affecting procedural pain in children during and immediately after intramuscular botulinum toxin injections for spasticity.

PURPOSE: To evaluate variables that modulate pain during intramuscular botulinum toxin A injections in children.

METHODS: As part of a Quality Improvement project, this retrospective analysis compared reported pain during and five minutes post injections with patient and procedural variables using subgroup and regression analyses (N= 593 procedures with 249 unique patients).

RESULTS: Mean procedural pain for all procedures (n= 563) was 3.8 ± 3.0. Most children reported no pain (83.8%) or mild pain (12.1%) five minutes after the procedure. Provider, previous patient experience, and dose did not significantly impact pain. Linear regression analysis (R=2 0.64) demonstrated that younger age (p< 0.05), use of vapo-coolant spray or topical anesthetic (p< 0.01), and body region injected (p< 0.01) were significantly associated with increased procedural pain. Logistic regression (R=2 0.14) demonstrated that pain during the procedure (p< 0.001) and older age (p< 0.01) increased the likelihood of pain post-procedure. Utilization of personnel for distraction did not significantly predict pain ratings at either time point.

CONCLUSION: Age, topical anesthesia, and injected region impact procedural pain and in nearly 96% of cases, patients report mild or no pain within five minutes. Additional research into these predictors is necessary, but short-lived procedural pain may suggest that frequent use of sedation/anesthesia is unnecessary.