Modified anterior transposition of the inferior oblique muscle

To introduce a modified method of anterior transposition of inferior oblique (ATIO) and compare with traditional method in terms of efficacy and complications.

The medical records of patients who had undergone unilateral ATIO and were followed for at least 6 months were reviewed retrospectively. The patients were divided into two groups according to the surgical method: modified ATIO (modified group, n = 16) and traditional ATIO (traditional group, n = 15). In modified ATIO, the anterior nasal fibers of the inferior oblique muscle were anchored to the sclera and the posterior temporal fibers were folded and buried under the fixed anterior nasal fiber of inferior oblique muscle. In the traditional method, both the anterior and posterior fibers were fixed with individual suturing. Postoperative change in vertical deviation and grade of inferior oblique overaction (IOOA) were analyzed. Complications, including antielevation syndrome, fat adherence syndrome, and lower lid deformity were assessed.

Both modified and traditional methods effectively weakened the action of the inferior oblique muscle. The efficacy of the two methods did not differ in terms of change in vertical deviation (P = 0.225) and grade of IOOA (P = 0.169). Antielevation syndrome occurred more frequently in the traditional group than in the modified group (8/15 vs 2/16, resp. [P = 0.019]). Incidences of fat adherence syndrome (0/15 vs 0/16 [P = 1.0]) and lid deformity (3/15 vs 1/15 [P = 0.678]) were not different.

Modified ATIO was comparable to traditional ATIO in correcting vertical deviation and IOOA and had a lower risk of antielevation syndrome compared with traditional ATIO.