Sialorrhea is the unintentional loss of saliva from the mouth and is typically caused by the inability to swallow oral secretions rather than over production of saliva [1]. Sialorrhea is considered normal in children younger than 2 years and is considered abnormal after 4 years of age [1,2]. Neurologic dysfunction, specifically cerebral palsy, is the most common cause of drooling in children [3]. Sialorrhea can have psychosocial implications including social isolation for patients and their families. Additionally, medical complications such as skin irritation, aspiration and speech problems are commonly encountered [1]. Options for drooling include speech and language therapy, palatal appliances, pharamocotherapy and surgery. Pharmacotherapy includes local injection of botulinum toxin into the salivary glands and surgical options include 4-duct ligation of the bilateral parotid and submandibular gland ducts.

Botulinum toxin injection into major salivary glands has been described as a less invasive and effective management option for children with sialorrhea. A large prospective study with 131 children found that approximately half of children benefitted subjectively and objectively from intraglandular botulinum toxin injections, and the median duration for decreased sialorrhea in these patients was 22 weeks [4]. Another study found that botulinum toxin injection can improve sialorrhea and reduce respiratory related hospital admissions in children with saliva aspiration [5]. However, Cochrane review found that no conclusions can be reached on the efficacy of botulinum toxin A, benztropine, or glycopyrrolate given limited data available [6].

Ligation of the bilateral parotid and submandibular gland ducts, also known as 4-duct ligation, has been described as a minimally invasive treatment option for sialorrhea in children. A retrospective study with 38 children found that 71 % of patients had subjective improvement at one year follow up, and that the mean duration of this effect was 52 months [7]. Another prospective study with 30 children found that 93 % of children maintained improvement in their drooling scores at one year follow-up [8]. Although the hope with four-duct ligation is that offers a longer lasting solution to sialorrhea compared to botulinum toxin injection, a study that included 31 children who underwent 4-duct ligation found that there was a 68.8 % drooling recurrence and the mean time to recurrence was 6 months.

Given the abundance of treatment options, practitioners require increased guidance on which drooling interventions to choose to best care for children with drooling. Although 4-duct ligation has a longer duration of effect than botulinum toxin injections, direct comparisons of the efficacy between the two strategies are lacking The purpose of this systematic review is to compare the efficacy and complication rates of botulinum toxin versus 4-duct ligation for the management of sialorrhea in children.