Ocular motility changes after inferomedial wall and balanced medial plus lateral wall orbital decompression in Graves' orbitopathy: a randomized prospective comparative study

Abstract

Objectives: To compare the surgical outcomes of inferomedial wall orbital decompression (IM-OD) and balanced medial plus lateral wall orbital decompression (ML-OD) in patients with inactive Graves' orbitopathy (GO) with regard to exophthalmos reduction and ocular motility abnormalities.

Methods: Forty-two patients with inactive GO eligible for OD were randomly assigned to either the IM-OD or ML-OD groups. Pre and postoperative evaluations included Hertel exophthalmometry, sensory, and motor extraocular motility assessment, standardized photographs in the nine gaze positions, and computed tomography (CT) of the orbits. ClinicalTrials.gov: NCT03278964.

Results: Exophthalmometry reduction was statistically significant in both groups (p<0.001), but was greater in the ML-OD group (p=0.010). New-onset esotropia occurred in 11.1% and 23.5% of patients who underwent IM-OD and ML-OD, respectively, with no statistically significant difference in the frequency of pre and postoperative strabismus in either group. The mean increase in preoperative esotropia was 24±6.9 and 12±8.8 prism diopters in patients who underwent IM-OD and ML-OD, respectively. In the IM-OD group, abduction and elevation worsened at the first (p<0.05) and third (p<0.05) postoperative visits but were restored at 6 months. The versions did not change postoperatively with ML-OD. The preoperative CT-measured medial rectus muscle area predicted new-onset strabismus (p=0.023). Significant postoperative medial rectus muscle enlargement occurred in both groups (p<0.001). Restriction in elevation and abduction was significantly associated with enlarged inferior (p=0.007) and medial rectus muscle areas (p=0.002).

Conclusions: IM-OD is as safe as ML-OD with regard to new-onset strabismus, and represents a good alternative for patients who do not require significant exophthalmos reduction. ML-OD offers greater exophthalmos reduction and smoother postoperative recovery. Patients with preoperative enlarged medial rectus muscle on CT are at risk for new-onset esotropia, and preoperative esotropia is likely to increase after OD.

Conflict of interest statement

No potential conflict of interest was reported.

Figures

Figure 1. Photographs in the nine positions of gaze.

Figure 2. A. Juxtaposition of semitransparent images of primary gaze and levoversion (Photoshop) for quantitative version evaluation.B. Evaluation of levoversion. Right eye: In adduction, the distance between the lateral limbi of the juxtaposed photos is measured (ImageJ). Left eye: In abduction, the distance between the medial limbi is measured (ImageJ).

Figure 3. Computed tomography measurements of the recti muscle areas. A and B. Preoperative (A) and postoperative (B) measurements of a patient submitted to inferomedial wall orbital decompression (IM-OD). C and D. Preoperative (C) and postoperative (D) measurements of a patient submitted to balanced medial plus lateral wall orbital decompression (ML-OD).