Evaluation of periosteal fixation of lateral rectus and partial VRT for cases of exotropic Duane retraction syndrome

Purpose: The purpose of this study is to evaluate the lateral rectus periosteal fixation and partial vertical rectus transpositioning (VRT) as treatment modalities to correct exotropic Duane retraction syndrome (Exo-DRS). Materials and Methods: Prospective interventional case study of cases of Exo-DRS with limitation of adduction. A total of 13 patients were subdivided into two groups. Six patients underwent only lateral rectus periosteal fixation (group A) and seven patients also underwent partial VRT (group B). Assessment involved prism bar cover test, abduction and adduction range, extent of binocular single visual field and exophthalmometry. These tests were repeated at 1 week, 1 month and 3 months post-operatively and data analyzed. Results: The pre-operative mean values and ranges were 26.2 (Delta) (22-35) exotropia for group A and -21.3 (Delta) (14-30) exotropia for group B. The post-operative mean and range was + 0.6 (Delta) esotropia (+ 20 to -8) for group A and 8 (Delta) (-2 to -20) exotropia for group B. Mean grade of limitation of abduction changed from -3.8 to -3.6 versus -3.6 to -2.8 and mean grade of limitation of adduction changed from -1.9 to -0.7 versus -1.5 to -0.5 in the groups A and B respectively. Mean binocular single visual field changed from 14.7 degrees to 23.3 degrees in group A and 11.8 degrees to 26.4 degrees in the group B respectively. Conclusion: Lateral rectus periosteal fixation is an effective surgery to correct the exodeviation, anomalous head posture and improving adduction in Exo-DRS and partial VRT in addition is effective in improving abduction and binocular single visual fields.