Nishida transposition without tenotomy for severe paralytic strabismus: Outcomes and safety

PurposeTo evaluate the clinical outcomes and safety of the Nishida muscle transposition procedure performed without tenotomy or muscle splitting in patients with severe paralytic horizontal or vertical strabismus.MethodsThis retrospective case series included 16 patients with complete paralytic strabismus who underwent Nishida transposition between January 2020 and September 2021. Eleven patients had abducens nerve palsy and five had vertical paralytic strabismus (elevation or infraduction deficiency). The procedure involved scleral fixation of adjacent rectus muscles closer to the paralyzed muscle without tendon disinsertion, preserving anterior ciliary circulation and allowing simultaneous antagonist recession when indicated. Outcomes included ocular alignment in primary position, ocular motility, binocular single vision, and postoperative complications over a follow-up period of 5-15 months.ResultsIn abducens nerve palsy, combined transposition with medial rectus recession-performed using a standardized protocol based on preoperative deviation (6 mm for ≥80 prism diopters [PD] and 5 mm for <80 PD)-achieved a mean correction of 69.2 ± 12.8 PD, whereas isolated transposition resulted in a correction of 29 PD. In vertical paralytic strabismus, the mean correction was 38 ± 19.8 PD. All patients demonstrated improved duction beyond the midline postoperatively. Eight patients achieved binocular single vision in primary position and four with compensatory head posture. No anterior segment ischemia, induced secondary deviations, or other major complications were observed.ConclusionsThe Nishida procedure provides effective and safe correction of severe paralytic strabismus while preserving muscle insertions and anterior ciliary circulation. Its compatibility with simultaneous antagonist recession makes it a valuable single-stage approach for large-angle paralytic deviations.