Y-splitting procedure

The Y-splitting procedure splits the lateral rectus horizontally into a Y and resutures one half above and one half below the muscle's axis. Surgeons use it in Duane retraction syndrome to reduce the upshoot and downshoot of the adducting eye.^1,2

In Duane syndrome the medial and lateral recti contract together during adduction. When the adducting eye is slightly elevated or depressed, the tight lateral rectus and the globe slip relative to each other, and the horizontal recti gain an anomalous vertical pull.^2,3 This vertical pull is called the bridle or leash effect. Splitting the tendon into a Y widens the insertion and reduces the bridle effect.²

Other ways to reduce the upshoot and downshoot are posterior fixation sutures on the horizontal recti or recession of both horizontal recti.^1,2 Recession of both muscles is technically simpler than posterior fixation and also reduces retraction in adduction.²