The Effect of Botulinum Toxin Augmentation on Strabismus Surgery for Large-Angle Infantile Esotropia

Abstract

To determine whether botulinum toxin augments the effect of strabismus surgery in pediatric patients with large-angle infantile esotropia. Retrospective, comparative, case series. Setting: Tertiary-care pediatric hospital. Patients with large-angle infantile esotropia. Treatment with botulinum toxin-augmented bilateral medial rectus muscle recessions ("augmented-surgery group") or traditional bilateral medial rectus muscle recessions ("surgery-only group"). The effect of surgery on ocular alignment at 4months, measured in prism diopters of change per mm of surgery (PD/mm). There were 14 patients in the augmented-surgery group and 16 patients in the surgery-only group. The mean effect on alignment was significantly greater in the augmented-surgery group compared to the surgery-only group at 4months (5.7 ± 1.3 vs 4.0 ± 1.4 PD/mm, P= .002) and at 1 year (5.4 ± 1.2 vs 3.7 ± 1.2 PD/mm, P= .002). There was a partial loss of treatment effect between 4months and 1 year in both groups, which was similar in magnitude (P=.57). On linear regression, there was a trend toward a positive correlation between botulinum toxin dose and treatment effect, but this was not statistically significant (P= .09). Botulinum toxin augments the surgical effect of medial rectus muscle recession. Botulinum toxin-augmented surgery may be an alternative to traditional options for large-angle infantile esotropia. A surgical dosing table is proposed for this technique.