Botulinum toxin-A injection in esotropic Duane syndrome patients up to 2 years of age

Abstract

To evaluate the role of botulinum toxin-A (BTX) injection as the primary treatment for patients with esotropic Duane retraction syndrome ≤2 years of age. The medical records of patients with esotropic Duane syndrome who underwent unilateral or bilateral BTX injection to the medial rectus muscle at or before 2 years of age were reviewed retrospectively. The following data were extracted from the record: laterality, age at the time of injection, primary position deviation, duction deficit, anomalous head posture, globe retraction before and after injection, further surgeries, and complications. Success was defined as permanent resolution of esotropia and head turn in primary position at final follow-up. A total of 15 patients (14 unilateral, 1 bilateral) were included. Before BTX injection the mean primary esotropia at near with full cycloplegic refraction was 29.3Δ ± 14.4Δ; the mean head turn, 23° ± 11°. Mean duration of follow-up was 37±29months (range, 7-96months). Orthotropia and resolution of head turn was achieved in 7 patients (46.7%). In subgroup analysis, success rate gradually decreased from 100% in patients ≤7months of age to 33.3% in patients 8-12months of age, and 20% in patients >12months of age. Seven patients (46.7%) required surgery (medial rectus recession and/or superior rectus transposition) because of residual head turn and esodeviation following BTX. In this patient cohort, orthotropia in primary position and correction of head turn were achieved with a single BTX injection in about half of the patients ≤2 years of age and all patients ≤7months of age. BTX injection early in infancy can obviate the need for surgery in esotropic Duane syndrome.