Surgical success and lateral incomitance following three-muscle surgery for large-angle horizontal strabismus

Abstract

To evaluate motor alignment, motility, and sensorial outcomes of simultaneous three-muscle surgery for large-angle horizontal strabismus, with special attention to lateral incomitance and long-term success. The medical records of consecutive patients with large-angle deviations (≥30Δ) who underwent simultaneous surgery on three horizontal muscles to correct esotropia or exotropia were reviewed retrospectively. Successful motor alignment was defined as residual deviation of ≤10Δ and consecutive deviation in primary position of ≤4Δ, with no induced lateral incomitance >5Δ between lateral gazes. Sensory success was defined as an improvement in stereopsis of ≥2 octaves. Surgical procedures included a combination of recessions and resections/plications depending on surgeon preference. The majority of cases were two-muscle recessions combined with one-muscle resection or plication. A total of 19 patients with exotropia and 9 patients with esotropia were included. In the esotropic group, the mean age at surgery was 48±15years and the mean preoperative deviation improved from 45.6Δ ± 11.9Δ to 1.5Δ ± 1.6Δ (P<0.001); there was no undercorrection, recurrence or overcorrection. In the exotropic group, the mean age at surgery was 44±25years, and the mean preoperative deviation improved from 44.1Δ ± 8.7Δ to 5.8Δ ± 9.6Δ (P<0.001), recurrence occurred in 2 (22%). Overall motor success at distance was 85%, with 1 (3.8%) unsuccessful patient due to induced incomitance. Sensory success was 44% for esotropia and 31% for exotropia. No patient lost stereopsis. Patients undergoing three-muscle surgery for horizontal strabismus had good motor outcomes with low incidence of induced lateral incomitance. Motor and sensorial outcomes for esotropia were very stable.