Exotropic Duane syndrome with synergistic divergence and no mutations in COL25A1

Synergistic divergence: case series and literature review

Background

To present the data of a series of patients with synergistic divergence, to propose a different modality of surgical correction and to perform a literature review of such a rare entity.

Methods

A retrospective study was performed on all patients who presented with unilateral or bilateral synergistic divergence to the Ophthalmology Department, Cairo University, during the period from January 2007 to July 2016. The demographic data, the results of sensorimotor examination, the surgical procedures performed and the ophthalmological as well as the systemic findings of all patients were collected and tabulated. PubMed was searched for patients with features of synergistic divergence.

Results

Thirteen patients with features of synergistic divergence were identified. The mean age of the patients was 8.9±10.1 years (range 1–40 years). Only one case was orthotropic in the primary position. Lateral rectus orbital wall fixation combined with 8–10 mm medial rectus resection was done in 10 patients. The mean follow-up was 6.6±7.7 months. Exotropia was significantly reduced in all patients. All patients had complete disappearance of synergistic divergence after surgery. A total of 78 patients with features of synergistic divergence were identified from PubMed. Surgery was done for 37 patients. Synergistic divergence disappeared in patients who had lateral rectus extirpation or orbital wall fixation.

Conclusion

Synergistic divergence is a challenging rare condition. We propose that lateral rectus orbital wall fixation combined with medial rectus resection both improves the alignment in primary position and eliminates the synergistic divergence in such patients.