Botulinum toxin versus submandibular duct relocation for severe drooling

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.

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 5-17 y) and mean age at the time of surgery was 14 years (range 6-23 y). 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.

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).

Both interventions are effective, but surgery provides a larger and longer-lasting effect.