Purpose: To evaluate the surgical effect of unilateral inferior rectus recession (IR-group) with or without a recession of contralateral superior rectus (IR-SR-group) on squint angle and motility restrictions in Graves' Orbitopathy (GO) patients.
Design: Retrospective case series.
Materials and methods: Primary outcome parameters were the changes of squint angle 3 months and 6-12 months postoperatively. As in a previous study, success was defined as a postoperative vertical squint angle of ≤3° in primary position and on downgaze. Secondary outcome parameters were the influence of surgery on duction range and influence of muscle size on dose-effect response.
Results: Fifty-six patients were included in the study; 31 patients in the IR-group and 25 patients in the IR-SR-group. The amount of (fixed suture) recession ranged from 2 mm to 7 mm. Vertical deviations in primary position changed from 8.0° [95% CI 6.6-9.7°] to 1.0° [95% CI -0.4-6.5°] in the IR-group and from 17.0° [95% CI 15.7-20.0°] to 1.5° [95% CI 0.8-2.9°] in the IR-SR-group. The success rate was 74% in the IR-group and 64% in the IR-SR-group. Elevation significantly improved in both groups (IR-group p = 0.007; IR-SR- group p = 0.000). The volume of vertical rectus muscles as assessed on CT-scans did not influence the dose-effect response.
Conclusions: The highest success rate and highest reduction of depression was found in the IR-group. The total duction range remained stable after strabismus surgery (IR-group) or improved (IR-SR-group). Both squint angle and cyclodeviation remained stable during long time follow-up (6-12 months after surgery).
Keywords: Depression; Graves’ Orbitopathy; diplopia; elevation; vertical strabismus.