Graded recession with or without anterior transposition of the inferior oblique muscle for treatment of unilateral congenital superior oblique palsy

Abstract

Purpose The aim of this study was to evaluate the efficacy of graded inferior oblique muscle recession (8–10 mm) and inferior oblique recession with anterior transposition (12 mm) in adult unilateral congenital superior oblique palsy patients with good binocular vision (strabismus sursoadductorius). Patients and methods This study included 53 patients who presented with pure unilateral strabismus sursoadductorius and stereopsis [mean age: 39.8 (SD±17) years] during the time period between 2011 and 2014. Graded inferior oblique recession (8–10 mm) was performed for 26 patients with vertical deviation (VD) of less than 15° in adduction. Maximal recession with anterior transposition to the temporal side of the inferior rectus muscle insertion was performed for 27 patients with VD of more than 15° in adduction. Horizontal deviations and VD were measured using the alternate prism cover test in five directions of gaze preoperatively and 3 months after the operation. Moreover, subjective quantitative assessment of the angles of deviation, including horizontal deviations, VD, and cyclodeviation, was carried out using Harms’ tangent screen. Results The median effect of the operation on VD in 25° adduction increased from 6° with 8–10 mm recession to 10.5° with maximal recession and anterior transposition to the lateral side of inferior rectus muscle insertion. This was related more to the amount of preoperative VD in adduction than to the amount of inferior oblique recession. The incyclorotatory effect of both procedures was small and not significantly different between the two groups. Three patients had a postoperative hypotropia (2°–5°) with limited elevation. Four patients were planned for further surgery (8%) because of undercorrection in three cases and the appearance of contralateral strabismus sursoadductorius in one case. Conclusion Graded recession of the inferior oblique muscle (8–10 mm) is effective for patients with mild-to-moderate strabismus sursoadductorius. Maximal recession with anterior transposition of the inferior oblique muscle is an ideal approach for patients with marked strabismus sursoadductorius. The rate of undercorrection as well as overcorrection that necessitated reoperations was low.

Keywords

• diplopia
• field of binocular single vision
• inferior oblique muscle
• strabismus sursoadductorius
• superior oblique palsy
• tangent screen