Botulinum toxin versus submandibular duct relocation for severe drooling

Aim  Botulinum neurotoxin type A (BoNT-A) has been described as an effective intervention for drooling and is being increasingly adopted. However, its effectiveness compared with established treatments is still unknown. We undertook a within-participants observational study to examine this. Method  An historic cohort was formed of 19 children and young adults (10 males, nine females) with severe drooling who underwent BoNT-A injections followed by surgical re-routing of the submandibular duct at least 6 months later. Mean age at time of admission was 11 years 5 months (range 5–17y) and mean age at the time of surgery was 14 years (range 6–23y). Fifteen children were diagnosed with bilateral cerebral palsy (CP), three with unilateral CP, and one with non-progressive developmental delay. Gross Motor Function Classification System levels were the following: level I, n=1; level II, n=2; level III, n=7; level IV, n=6; and level V, n=3). The primary outcome was the drooling quotient, which was assessed before each intervention and 8 and 32 weeks thereafter. A multivariate analysis of variance of repeated measures was performed, with the measurement points as the within-participant variables. Results  The drooling quotient was reduced to a greater extent after surgery than after BoNT-A administration (p=0.001). Compared with a baseline value of 28, the mean drooling quotient 8 weeks after surgery was 10, and 32 weeks after surgery was 4 (p<0.001). Among the group treated with BoNT-A, the drooling quotient showed a significant reduction from a baseline value of 30 to 18 after 8 weeks (p=0.02), and a continued but diminished effect after 32 weeks (drooling quotient 22; p=0.05). Interpretation  Both interventions are effective, but surgery provides a larger and longer-lasting effect.