Comparison of botulinum toxin with surgery as primary treatment for infantile esotropia

Purpose: To compare bilateral medial rectus muscle injection of botulinum toxin with surgery as primary treatment for infantile esotropia.

Methods: A single-center, prospective, nonrandomized comparative study was undertaken of botulinum toxin versus surgery in children who presented by age 36 months with esotropia onset before 12 months. Successful outcome was defined as ocular alignment within 10Delta of orthotropia after one surgery or 1 to 3 bilateral botulinum injections.

Results: Of 442 subjects, 322 received botulinum toxin (1 injection, 49%; 2, 41%; 3, 10%); 120 had surgery. Motor success was achieved in 66% of surgery patients, compared with 45% of botulinum patients (p < 0.001). Among subjects with deviation >30Delta, surgery achieved 69% success versus 36% with botulinum toxin (relative risk, 1.95; 95% CI, 1.53-2.49). At deviations < or = 30Delta, there was no difference (surgery, 60%; botulinum toxin, 59%; relative risk, 1.03; 95% CI, 0.78-1.35). There were no statistically significant differences in mean pretreatment deviation (botulinum toxin, 38.8Delta; surgery, 38.2Delta) or mean follow-up (botulinum toxin, 22.6 months; surgery, 20.7). Surgery occurred later than botulinum injection (mean age at treatment, 27.0 vs. 16.7 months; p < 0.001) with greater duration of misalignment (21.0 vs 12.5 months, respectively; p < 0.001), but neither variable influenced outcome in multivariate regression.

Conclusions: In this large, nonrandomized prospective cohort, surgery was more successful than botulinum toxin in the treatment of large-angle esotropia. Botulinum toxin appeared most effective for esotropia <30Delta to 35Delta, with a success rate comparable with surgery. Botulinum toxin may be an alternative to surgery in children with small- to moderate-angle infantile esotropia.