Displacement of Rectus Muscle Pulleys by Torsional Muscle Surgery for Treatment of Full Macular Translocation-induced Incyclotropia

Purpose To elucidate the coronal plane locations of extraocular muscle (EOM) pulleys following torsional muscle surgery. Design Case report. Methods A 76-year-old man underwent advancement of the anterior part of the inferior oblique muscle to treat full macular translocation–induced incyclotropia. Postoperatively, magnetic resonance imaging was used to obtain contiguous, 2-mm-thick coronal orbital images. On each MRI image, the cross-sectional area and center of the EOM was computed, and all rectus EOM positions were translated to the coordinate origin at the area centroid of the globe at the level of pulleys. Results The superior rectus pulley was displaced temporally, and the lateral rectus pulley was displaced inferiorly more than 2 SD from normal subjects. Coronal plane locations of EOM pulleys of the ipsilateral eye showed extorsion compared with that of the contralesional eye. Conclusions Torsional muscle surgery causes an extorsional shift of the superior and lateral rectus pulleys.