Effect of Vertical Displacement of Bilateral Horizontal Muscles in AV Syndrome

Chang, Hae Ran; Kim, Joon Mo

Abstract

We reviewed 20 cases for the surgical effect of the vertical transposition of the horizontal rectus muscle for AV syndrome without significant oblique dysfuction. We performed vertical tranposition of the horizontal rectus muscle with standard recession and resection procedure and followed up at least six months. Sixteen cases were V syndrome and four cases were A syndrome. Medial rectus was moved toward the apex of the A or V, and the lateral rectus was moved to the opposite side of the apex of the A or V. The amount of transposition was adjusted according to the amount of vertical incomitance. If the vertical incomitance was 10delta, 15delta, 20deltaand 25delta, vertical transposition of rectus muscle was 1/4 TW[tendon width], 1/2 TW, 3/4 TW amd 1 TW, respectively. We achieved an average of 12.9deltareduction by 1/4 TW transposition, 14.4deltareduction by 1/2 TW transposition, 13.3delta reduction by 3/4 TW transposition, 19.0deltareduction by 1 TW transposition. We also achieved an average of 5.2delta/mm effect by 1/4 TW transposition, 2.9delta/mm effect by 1/2 TW transposition, 2.4 delta/mm effect by 3/4 TW transposition, 1.9delta/mm effect by 1 TW transposition. The vertical transposition of the horizontal rectus muscle for AV syndrome without significant oblique dysfuction showed good result and the amount of correction per mm of vertical transposition seemed to decrease as the amount of transposition increased, even though the total amount of correction showed a trend toward increasing [Fig.1, 2].