Purpose: To evaluate the long-term results of early treatment of infantile strabismus with botulinum toxin A injection and its incidence on secondary oculomotor surgery.
Patients and methods: A cohort of 74 cases of children presenting infantile strabismus, aged 7-36 months (mean, 18 months), received no more than two injections of 5 IU of botulinum in both medial recti. Secondary surgery was performed when horizontal and/or vertical deviation persisted.
Results: The patients were examined 2-7 years after the last injection (mean, 3.5 years). Forty cases needed only one injection. We found 46 (62%) cases of microtropia (from -4 to +4 PD), 17 cases of esotropia less than 20 PD, eight cases of esotropia greater than 20 PD, and three cases of exotropia. Horizontal deviation was improved in 82.4% of the cases. The only predictive factor of failure was the presence of high adduction (p<0.05). DVD was found at the same frequency in all groups (50%). Twenty-seven cases (35%) had secondary surgery, 19 of which were associated with vertical surgery. The relaxant role of botulinum seems to be clearly proven given that we only found 22% of esodeviation persisting under general anesthesia with myoresolution during secondary surgery (approximately 70% in untreated cases).
Conclusions: Early treatment of infantile strabismus with botulinum seems effective and safe, improving 82.4% of our cases. Medical treatment is, however, still mandatory. Only 35% of our cases needed secondary surgery versus 70% of patients in spontaneous progression. The amount of horizontal surgery seems reduced after botulinum treatment. Vertical factors, found in 70% of operated cases, seem a major factor of instability of the results.