Effect of Posterior Strut Removal during Orbital Decompression for Graves’ Orbitopathy

Purpose: To assess the effect of posterior strut removal during orbital decompression on exophthalmos reduction and strabismus outcomes in patients with Graves’ orbitopathy (GO).Methods: This retrospective analysis was conducted using the medical records of patients with GO who underwent balanced orbital decompression, balanced orbital decompression with posterior strut removal, or three-wall orbital decompression with strut removal. The preoperative and postoperative exophthalmos measurements were compared to evaluate the efficacy of strut removal in reducing exophthalmos. Patients were further divided into three groups based on the posterior strut removal status (none, unilateral, or bilateral) to evaluate changes in esotropia and vertical strabismus before and after surgery.Results: This study included 61 patients (101 eyes). Balanced orbital decompression was performed in 42 eyes, balanced orbital decompression with posterior strut removal was performed in 14, and three-wall orbital decompression was performed in 45 eyes. The average postoperative exophthalmos reduction was 4.20 ± 0.25 mm in the balanced orbital decompression group, 4.92 ± 0.29 mm in the balanced orbital decompression with posterior strut removal group, and 5.62 ± 0.58 mm in the three-wall orbital decompression group. The reductions in the balanced orbital decompression with posterior strut removal and three-wall orbital decompression groups were statistically significant compared to those in patients who only underwent balanced orbital decompression. The most notable increase in esotropia was observed in the unilateral strut removal group (2.00 ± 1.32 diopters), although this difference was not statistically significant compared to those in other groups. Furthermore, no significant differences in vertical strabismus were observed among the three groups, with a tendency towards reduced strabismus in the bilateral strut removal group.Conclusions: Posterior strut removal during orbital decompression surgery resulted in a significant improvement in exophthalmos, with no significant effect on strabismus.