A comparative crossover study on the treatment of hemifacial spasm and blepharospasm: preseptal and pretarsal botulinum toxin injection techniques

Hemifacial spasm (HFS) and benign essential blepharospasm (BEB) are chronic and disabling abnormal craniofacial movements that produce involuntary eyelid twitching and closure. The efficacy and safety of botulinum toxin type A (BoNT-A) injections have been accepted and widely used for the treatment of HFS and BEB. However, different injection sites may influence the effectiveness, doses, and side effects. The aim of this study is to compare the efficacy, patient satisfaction, and complications of low-dose BoNT-A injections between injection at the preseptal (PS) and the pretarsal (PT) portion of the orbicularis oculi muscle. A total of 40 patients, 31 patients with HFS and 9 patients with BEB, participated in this study. Each patient received both PS and PT BoNT-A injections in a crossover design study. Latency to response, duration of improvement, the Jankovic Rating Scale (JRS), self-response scale, patient satisfaction scale, and complications were compared. Low-dose injections of BoNT-A at the PT portion produced a significantly higher response rate in terms of latency to response, duration of improvement, JRS, self-response scale, and patient satisfaction scale than the PS injections. Major side effects including ptosis and droopy eyelid were observed only after the PS injections. These findings confirmed that low-dose injections of BoNT-A at the PT portion provide more efficacy, patient satisfaction, and fewer complications than the PS injections for the treatment of involuntary eyelid twitching and closure in patients with HFS and BEB.