Purpose: The purpose of the study is to analyze the effectiveness and side effects of botulinum toxin using four different treatment site applications to determine the most successful treatment regime with the least side effects.
Methods: In a prospective trial, 92 patients (50 blepharospasm and 42 hemifacial spasm) were assigned randomly to 1 of 4 different treatment groups (standard [S], brow [B], inner orbital [IO], or outer orbital [OO]). Each treatment group had a different pattern of injection sites in the orbicularis. A total of 285 treatments were given, and the mean follow-up time was 16.4 months.
Results: In the blepharospasm group, patients assigned to the standard group had a significantly longer duration of effect than for those in the brow, inner orbital, and outer orbital groups (8.1 weeks compared with 4.5, 4.2, and 3.1 weeks, respectively; P < 0.001). In the hemifacial spasm group, patients in the outer orbital group had significantly shorter duration of effect than those in standard, brow, or inner orbital group (7.2 weeks compared with 12.6, 12.8 and 10.4 weeks, respectively; P < 0.001). The four major complications of botulinum toxin treatment were epiphora, ocular irritation, ptosis, and diplopia. The inner orbital treatment produced significantly more episodes of ptosis (13% of treatments). However, the standard treatment produced the most epiphora and ocular irritation (18% of treatments).
Conclusions: The position of the injection sites around the orbicularis influences the effectiveness and side effects of botulinum toxin treatment for patients with blepharospasm and hemifacial spasm. The further the treatment is away from the eyelid margin, the lower the risk of ocular side effects. The standard treatment produces the longest duration of effect in the blepharospasm group but with the most transient ocular irritation and epiphora. In the hemifacial spasm group, the brow treatment has an equally long duration of effect as that of the standard treatment with fewer side effects.