Purpose: To report the results of botulinum toxin (BOTOX®, Allergan) type A (BTA) bilateral injection in the treatment of Duane retraction syndrome (DRS) type 1 in patients aged up to 3 years.
Methods: We studied the results of BTA bilateral injection in eight consecutive patients with DRS type 1 and esotropia in primary gaze. Average follow-up was 74 ± 71 months. The main variables analyzed were horizontal and vertical deviation and face turn. Patients were anesthetized with nitrous oxide (N2O). A mean dosage of 5.6 ± 1.8 IU (range 2.5-7.5 IU) of botulinum toxin diluted in 0.9% saline solution was injected under electromyography control in each medial rectus muscle.
Results: Seven patients had one affected eye and one patient had bilateral involvement. The mean preoperative esotropia was 32 ± 10 prism diopters (PD). Three patients (37.5%) had also a vertical deviation. All patients had face turn ranging between 15° and 45° before BTA injection. In the last follow-up, 4 patients were orthotropic (50%), 1 (12.5%) had 3 PD exotropia and 3 (37.5%) had esotropia averaging 25 PD mean. The 3 esotropic patients needed surgical correction. Vertical strabismus improved in 3 patients achieving complete resolution in one of these patients. Two patients, without vertical strabismus before the BTA injection, developed a 5-PD vertical deviation, one of them required surgery. Face turn improved in all patients.
Conclusion: Botulinum toxin injection is an alternative treatment for patients with DRS type 1 presents esotropia and face turn in children up to 3 years of age.