Rectu extraocular mucle pulley diplacement after urgical tranpoition and poterior fixation for treatment of paralytic trabimu

PURPOE: To determine the effect of rectu extraocular mucle (EOM) tranpoition with poterior fixation (PF), we employed magnetic reonance imaging (MRI) to demontrate pulley inflection in EOM path before and after urgery in patient with paralytic trabimu. DEIGN: Conecutive interventional cae erie. METHOD: Five conecutive patient (three male and two female with a mean age 52 year, range 33 to 77 year) with paralytic trabimu were tudied propectively before and more than 6 week after EOM tranpoition and PF by mean of contiguou cro-ectional MRI obtained in plane perpendicular to the long axi of the orbit. Mucle path were determined in three dimenion (3-D) for each EOM by analyi of cro-ectional area centroid in normalized, oculocentric coordinate ytem. REULT: Four patient underwent full tendon tranpoition with PF of the vertical rectu EOM. One other patient underwent full tendon tranpoition without PF of the horizontal rectu EOM uperiorly. For tranpoition with PF, there wa a large diplacement of EOM path in central (traight ahead) gaze beginning in the poterior orbit. After urgical tranpoition, clear inflection repreenting pulley location of the uperior, medial, and lateral rectu path occurred in central gaze. There wa no clear path inflection for the inferior rectu in central gaze, but there wa a mall inflection in adduction. After all tranpoition, the globe center hifted away from the tranpoed inertion. CONCLUION: Rectu EOM tranpoition with PF hift EOM pulley poteriorly and in the direction of the tranpoed EOM tendon, while tranlating the globe center. Thee change may explain the uperior effectivene of PF in increaing duction toward the tranpoition.