Long-term comparison of horizontal rectus surgery with vertical tendon transposition and combined vertical tendon transposition and inferior oblique-weakening in V-pattern exotropia

Purpose To compare the efficacy of bilateral lateral rectus recession with vertical tendon transposition (LRVT) and LRVT combined with inferior oblique (IO) disinsertion for V-pattern exotropia. Methods The medical records of patients who had mild-to-moderate (+1 and +2) inferior oblique overaction (IOOA) and underwent half-tendon-width upward LRVT (transposition group), and LRVT with IO disinsertion (combined surgery group) for V-pattern exotropia and who had at least 3 years of postoperative follow-up were reviewed retrospectively. Results A total of 45 patients were included: 22 in the transposition group and 23 in the combined surgery group. Preoperatively, there were no differences in V pattern, IOOA, or horizontal misalignment in primary position, upgaze, or downgaze between groups. The amount of exotropia in the primary position was 30.2(Delta) +/- 10.7(Delta) in the transposition group, and 31.6(Delta) +/- 14.1(Delta) in the combined surgery group (P = 0.974). A significant decrease in V pattern was observed in the combined surgery group and the transposition group at 6 months and 3 years postoperatively (P < 0.001). The reduction of V pattern in the combined surgery group at 6 months (20.2(Delta) +/- 7.8(Delta) vs 15.6(Delta) +/- 6.9(Delta) [P = 0.02]) and 3 years (20.1(Delta) +/- 8.1(Delta) vs 15.2(Delta) +/- 7.1(Delta) [P = 0.014]) was found to be greater than the transposition group. There were no differences in the success rate in the primary position at 6 months (P > 0.05). Conclusions Both tendon transposition with horizontal rectus surgery and combined tendon transposition and IO-weakening surgery decreased V-pattern exotropia. However, combined surgery had a greater effect on decreasing V pattern in patients with mild-to-moderate IOOA.