Does injection of botulinum toxin to salivary glands require ultrasound guidance?

INTRODUCTION: Injection of botulinum toxin into salivary glands is a well-established treatment for sialorrhea in children, but the absolute need for radiological guidance has not been tested. METHODS: Single-centre study in which clinicians of varying seniority attempted blind injection of salivary glands, after which their position within or outside the gland was confirmed by ultrasound guidance before the injection is administered. RESULTS: 117 patients underwent botulinum toxin of salivary glands between November 2008 and August 2023, with 459 glands injected in total. 24 (5 %) glands were injected by medical students, 32 (7 %) by junior trainees (foundation doctors or senior house officers), 343 (75 %) by registrars or senior fellows and 36 (8 %) by consultants. 160 (68 %) of injections to the parotid gland were on target, and 74 (32 %) submandibular gland were on target (P < 0.01). No differences were detected on likelihood of success depending on seniority of practitioner, age of patient or hand dominance. CONCLUSION: Ultrasound guidance ought to be recommended for injection of botulinum toxin into salivary glands regardless of the seniority of the practitioner.