Background: In the healthcare system in the United Kingdom, a number of patients may be offered botulinum toxin as an alternative to surgery in the treatment of their strabismus. We report on our experience of treating those who have received 25 or more injections.
Methods: A retrospective review of the botulinum toxin clinic database was used to identify patients who underwent 25 or more injections between November 1982 and January 2006. All patients with strabismus who met this criterion were included. A statistical analysis was performed in which we compared aspects of this group with those who had received 24 or fewer injections.
Results: Fifty-seven patients (0.90%) fulfilled our criteria. There were 37 women and 20 men, with a mean age at first injection of 39 years (range, 15 to 80 years). The number of injections per patient ranged from 25 to 68 (mean, 34). The duration of treatment was between 3 and 22 years. The time interval between injections tended to increase in most patients and the angle tended to reduce. There was no statistical difference between the age at first injection, sex, site injected, diagnosis, and complication rate between the long-term group and the group that received 24 or fewer injections. The long-term group, however, had undergone more previous operations (p < or = 0.001) and had a lower degree of binocularity (p </= 0.001).
Conclusions: The treatment of strabismus with botulinum toxin on a long-term basis is practicable and valuable in patients with poor binocular potential, complicated strabismus, or multiple previous strabismus operations. A trend toward fewer injections with time was observed, and no significant adverse effects were observed with long-term treatment.