Anterior Transposition of the Inferior Oblique Muscle for Primary Unilateral Superior Oblique Muscle Palsy

Abstract

Pur po se: To evaluate the efficacy and safety of unilateral anterior transposition of the inferior oblique (ATIO) muscle in patients with unilateral superior oblique palsy (SOP). Ma te ri al and Met hod: In this study, the medical records of 52 patients with SOP were retrospectively reviewed. The study comprised patients with a preoperative vertical squint of less than 25 prism diopters (PD) and a (+3) - (+4) inferior oblique hyperfunction (IOHF); all cases were Knapp’s class 1 or class 3. The angle shift in the primary gaze position, the presence of abnormal head posture, and IOHF were evaluated before and after surgery. Re sults: The mean postoperative follow-up time was 10 months. The mean preoperative angle of hypertropia at the primary gaze position was 15.3±7.89 PD, and the mean postoperative angle was 0.84±1.49 PD (0-4). Of the 32 patients with head tilt before surgery, 29 (91%) patients recovered fully after surgery. Improvement was noted in 88% of patients with preoperative IOHF. At the postoperative follow-up, none of the patients showed hypotropia in the primary gaze position, limitation of the superior gaze, elevation of lower lid in the superior gaze, or diplopia in the superior gaze position, but in other eyes of three cases, secondary IOHF occurred. Dis cus si on: AIn unilateral SOP accompanied by secondary IOHF that has more than 15 PD squint, ATIO surgery is an effective and safe method for reduction of hypertropia as well as for elimination of IOHF in primary position and abnormal head posture. The short-term complication rate was very low, but a longer follow-up period is required. (Turk J Ophthalmol 2011; 41: 392-5)

Keywords

• Superior oblique palsy
• inferior oblique anterior transposition
• abnormal head position