Onabotulinum Toxin A Injections Into the Salivary Glands for Spinal Muscle Atrophy Type I: A Prospective Case Series of 4 Patients

Objective The aim of the study was to investigate the safety and efficacy of onabotulinum toxin A injection to the salivary glands under ultrasound guidance for the treatment of sialorrhea in patients with spinal muscular atrophy type I. Design Prospective case series with four patients with spinal muscular atrophy type I who received onabotulinum toxin A injection to parotid and submandibular glands for sialorrhea as part of clinical care. All four patients received validated surveys for measuring drooling, including objective measures of number of bib changes, and number of mouth wipes before injection and 4-6 wks after injection. Research was limited to survey completion. Scales included the Drooling Severity and Frequency Scale and the Drooling Impact Scale as well as a new scale used in our clinic, the Posterior Drooling Scales looking at coughing/choking and number of aspiration pneumonias. Results There were no adverse events. All four patients showed clinically significant improvements. The improvement in drooling using the Drooling Impact Scale was statistically significant (paired t test, t = 3.243, P = 0.048). All patients improved with number of mouth wipes. Conclusion Ultrasound-guided onabotulinum toxin A injections to the salivary glands may be a safe and effective method of decreasing drooling in patients with spinal muscular atrophy type I.