Primary and secondary superior rectus recessions to correct vertical deviations in Graves' orbitopathy patients

Patients with vertical strabismus and consecutive diplopia due to Graves' orbitopathy (GO) might need recession of the rectus superior muscle. The aim of this retrospective analysis is to provide dose-effect values and motility analysis for these patients.

Dose-effect relations (deviation reduction in primary position per amount of recession in mm), monocular excursions and size of the field of binocular single vision (BSV) were evaluated in three different groups of patients. Group 1 (n = 33) patients with primary fibrosis of superior rectus muscle undergoing recession of the ipsilateral rectus superior, Group 2 (n = 14) superior rectus muscle recession after recession of inferior rectus on the contralateral eye and Group 3 (n = 15) simultaneous ipsilateral superior rectus recession and contralateral inferior rectus muscle recession. Surgery was performed using the dose-effect for inferior rectus recession of 4 prism dioptre (PD,^Δ ) reduction/per mm recession and the intraoperative traction test.

Restoration of BSV in the central 20° of gaze could be reached in 88%, 79% and 67% of patients in the three groups, respectively. Restoration of BSV in downgaze (up to 30°) was a little less successful, 79%, 57% and 53%, respectively. The median dose-effect was 3.2^Δ reduction/mm recession in Group 1 (Spearman correlation r = 0.75, p < 0.0001) and 3.3^Δ /mm in Group 2 (n.s.) and 4^Δ /mm in Group 3 (r = 0.67, p = 0.016). The basis for the improvement was the symmetrization of ductions.

If superior rectus recession is necessary in GO, higher dosing around 3^Δ reduction/per mm recession should be applied. In case of large deviations, combined vertical surgery (inferior rectus and superior rectus contralateral) is required and reasonable (low cyclotorsion). Single-step or two-step procedures lead to similar results.