Anterior Transposition of the Inferior Oblique Muscle for Dissociated Vertical Deviation

Abstract

Recently, anterior transposition of the inferior oblique muscle was reported to be an effective treatment for dissociated vertical deviation (DVD), but data on long-term stability have not been reported. A retrospective, longitudinal analysis of 17 consecutive patients (22 eyes) with dissociated vertical deviation and inferior oblique overaction who had an anterior transposition of the inferior oblique for significant dissociated vertical deviation and a minimum of 12 months postoperative follow-up was undertaken. The size and degree of control of the dissociated vertical deviation and the degree of inferior oblique overaction were assessed preoperatively, and postoperatively at 1 week, at 4 to 6 months, and when last seen. The frequency of postoperative hypotropia and elevation deficits were noted. The mean preoperative dissociated vertical deviation measured 13.4 delta, and the mean total vertical deviation measured 16.2 delta in primary position at 6 meters. The mean dissociated vertical deviation at last follow-up measured 6.7 delta, and the mean total vertical deviation was 7 delta. The dissociated vertical deviation remained controlled based on objective evaluation and subjective patient/relative response in 19 of 22 eyes after a mean follow-up of 2 years (range, 1 to 4.9 years). It recurred in one eye by 6 months postoperatively and in 3 eyes at the last examination. The inferior oblique overaction did not recur to a significant extent in any patient. The best results were achieved in eyes with preoperative dissociated vertical deviations less than 15 delta (0 of 11 failures). When the preoperative dissociated vertical deviation measured > 15 delta, 3 of 11 were failures. Postoperative primary position hypotropia was uncommon (1 of 17 patients), whereas 27% of eyes had mild postoperative elevation deficits in abduction and adduction. Anterior transposition of the inferior oblique is an effective treatment for dissociated vertical deviation with inferior oblique overaction but may be less stable in the long term when the preoperative dissociated vertical deviation is in excess of 15 delta.