Botulinum toxin augmented surgery versus conventional surgery in the management of large-angle concomitant esotropia: A randomized clinical trial.

Background: The surgical management of large-angle concomitant esotropia is challenging with high reoperation rates. This study aims to assess the effectiveness and safety of intraoperative botulinum toxin A (BTA) augmentation compared to surgery alone in large angle concomitant esotropia.

Materials and methods: This is a prospective randomized interventional study. Patients with large angle concomitant esotropia (≥55 prism diopter [PD]) were randomly allocated to either surgery only (Group I) or BTA augmented surgery (Group II). The surgical effect in PD/mm was calculated and compared between the study groups at all follow up intervals. Treatment was considered successful if the patients had orthotropia ± 10 PD at their final examinations.

Results: A total of 23 patients were included in the study, 11 in Group I and 12 in group II. The surgical effect was significantly greater in Group II compared to Group I at all follow up durations. The 1-year surgical effect was 32.5% greater in Group II compared to Group I (5.99 ± 0.69 vs. 4.52 ± 0.91 PD/mm, respectively, P = 0.001). The success rate was greater for Group II compared to Group I (75% vs. 63.64%, respectively), but this difference was not statistically significant (P = 0.901).

Conclusion: Botulinum toxin augmented surgery is a good alternative to surgery alone in the treatment of large angle concomitant esotropia. BTA injection exerts a significant augmentation effect on medial rectus muscle recessions.