The Role of Vertical Displacement of the Horizontal Rectus Muscles in the Treatment of Strabismns

Abstract

Obiective To study the role of vertical displacement and transposition of horizontal rectus muscles in the surgical treatment ofstrabismus.Metheds We examinated Sixty-two patients of the deviation in all diagnostic positions by prism and cover test,Binocular motility in preoperation and postoperation.the subjective cyclodeviations were tested by synoptophore and the objective cyclodeviations were showed by fundus photographs.We followed up in a mean period of 6 months (range 1 to 34 months).Results (1)In 26 cases of V-pattern deviation that was not associated with oblique muscle dysfunction, vertical displacement(in the same direction)of bilateral horizontal rectus muscles and vertical displacement (in opposite directions)of monocular horizontal rectus muscles were performed and corrected up 10-30△ and 8-25△ of vertical incomitant deviations respectively.No postoperative cyclodeviation was noted. (2)In 25 cases of A-pattern deviation associated with oblique muscle dysfunction,vertical displacement of the horizontal rectus muscles alone corrected up 8-30△ of vertical incomitant deviations and had residual deviations of 5-25△ between primary position and downgaze position.Combining bilateral weakening of the superior oblique muscles reduced the residual deviations to 2△-8△. (3)In 8 cases of horizontal comitant deviation combined with small angle of vertical deviation, downward transposition or upward transposition of the bilateral horizontal rectus muscles corrected up 2-8△ of hyperdeviation and the residual hyperdeviation was 2-5△. (4)In 3 cases of congenital monocular double elevator palsy,the horizontal rectus muscles were transposed to the two sides of superior rectus tendon to correct up 25-30△ of vertical deviation and the residual vertical deviation was 5△.All of the patients had significant improvement of binocular elevation movements.Comclusions vertical displacement of horizontal rectus muscles can efficiently correct the vertical incomitant deviations of V-pattern strabismus without oblique muscle dysfunction.Bilateral weakening of the superior oblique muscles, along with the vertical displacement of the horizontal rectus muscles, can produce considerable elimination of A-pattern deviations in downgaze;however,this procedure has certain limitations in treating horizontal comitant deviation.Vertical displacement and transposition of horizontal rectus muscles is an effective surgical approach for patients with congenital monocular double elevator palsy. Key words: Vertical displacement of horizontal rectus muscles; Strabismus