Transposition of the inferior oblique muscle belly without disinsertion for overshoot in adduction treatment.

PURPOSE: To evaluate the efficacy and safety of inferior oblique muscle transposition and myopexy in patients with mild/moderate inferior oblique muscle overaction, with or without diplopia.

METHOD: We retrospectively analysed data for the 12 patients who underwent the technique. Data were collected from October 2018 to September 2021. Surgery was performed by suturing the inferior oblique belly to the sclera at 5 mm posterior to the temporal end of the inferior rectus. All 12 patients had mild hypertropia (≤6 prism diopters [pd]) in primary position and mild/moderate inferior oblique overaction. Mean preoperative hypertropia was 4.42 pd ± 1.62. Diplopia was recorded in 10 cases. The diagnoses were fourth nerve paresis (9), unilateral primary inferior oblique overaction (2) and dissociated vertical deviation (1). Torticollis was observed in 7 cases, 2 had subjective torsion and 2 objective torsion.

RESULTS

Mean age was 46.86 ± 25.1 years (50%: men). Diplopia resolved in 9 of the 10 cases. The mean final vertical deviation was 1.5 ± 2.93 (p = 0.001) pd in straight gaze. Of 7 mild overshoot in adduction, it disappeared in 3 and 4 remained the same. Of 5 moderate overshoot in adduction, 2 improved to mild and 3 disappeared. Torticollis was eliminated in 5 patients and improved in another 2. Mean time from surgery was 14.08 ± 8.05 months. There were no overcorrections.

CONCLUSIONS

Inferior oblique muscle transposition with myopexy is a safe and effective procedure in patients with mild-to-moderate inferior oblique muscle overaction and small-angle hypertropia, with or without diplopia.