Incidence of symptomatic vertical and torsional diplopia after superior rectus transposition for esotropic Duane syndrome and abducens nerve palsy.

PURPOSE: To report the incidence of symptomatic vertical and torsional diplopia after superior rectus transposition (SRT) for esotropic Duane syndrome and abducens nerve palsy.

METHODS

The medical records of patients with esotropic Duane syndrome or abducens nerve palsy seen at Boston Children's Hospital (2006-2018) and treated with unilateral SRT with or without augmentation was performed. The primary outcome was incidence of postoperative vertical or torsional diplopia in primary position. The secondary outcome was induced vertical deviation in affected side gaze.

RESULTS

A total of 69 patients met inclusion criteria: 32 with abducens nerve palsy and 37 with esotropic Duane syndrome. Vertical alignment changed in both hyper- and hypotropic directions. Median pre- and postoperative vertical deviation in primary gaze was 1.1Δ (10th-90th percentile, 0Δ-6Δ hypertropia) and 0.4Δ (10th-90th percentile, 6Δ hypotropia to 8 Δ hypertropia), respectively. Postoperative vertical diplopia occurred in 7%, including 4 of 49 treated with loop myopexy (8%), 1 of 13 without augmentation (8%), and 0 of 7 treated with sclera-fixated augmentation. All but one was successfully treated with prism or secondary surgery. Intorsional change predominated, but no patient had torsional diplopia post adjustment. Vertical misalignment in affected side gaze increased from 19% to 45% after SRT (P = 0.01).

CONCLUSIONS

In this largest-to-date review of patients treated with SRT, with or without MR recession, no patient developed persistent torsional diplopia, while 7% developed symptomatic vertical diplopia in primary position, similar to the reported incidence after balanced vertical rectus transposition. Vertical misalignment in affected side gaze increased, however fusion is already limited by unresolved esotropia in this field.