Vertical muscle transposition augmented with lateral fixation.

INTRODUCTION: Full vertical rectus muscle transpositions have been shown to be an effective treatment for lateral rectus palsies and type I Duane syndrome. This operation is usually accompanied by mechanical or botulinum toxin treatment of one or both medial rectus muscles. This series evaluates the effect of augmenting the transposed muscles with lateral fixation sutures.
METHODS: Transposition of the vertical rectus muscles to the lateral rectus muscle was performed in 23 eyes of 21 patients; transposition to the medial rectus muscle was performed in one eye of one of these 21 patients. A lateral fixation suture of 5-0 Dacron polyester filament was placed in the sclera 16 mm posterior to the limbus and adjacent to the lateral rectus muscle, incorporating one fourth of the transposed vertical rectus muscle. Of the 21 patients, five had type I Duane syndrome with a face turn and esotropia in the primary position, seven had a unilateral lateral rectus palsy, two had bilateral lateral rectus palsy, four had an ipsilateral lateral rectus palsy combined with a contralateral lateral rectus paresis (a recess resect procedure was performed on the paretic eye along with the augmented transposition on the paralyzed eye), two had gaze palsies, and one had a unilateral lateral rectus palsy with recurrent esotropia after a transposition procedure performed 16 years previously. Lateral fixation sutures alone were used in the last case listed. Postoperative diplopia-free fields were measured when possible (10 cases).
RESULTS: In most cases (19/23 eyes), alignment was achieved in the primary position with the use of the augmented transposition procedure alone. On average,20 degrees of binocular fusion into the abducted field was obtained. No postoperative limitation of adduction in the transposed eye was noted. Among the patients with Duane syndrome, 80% had elimination of the face turn; one patient had 5 degrees of residual face turn. The one patient with previous transposition surgery alone had an 80% (16 PD) reduction of the recurrent esotropia after placement of lateral fixation sutures. After augmented transpositions, induced vertical deviations in the primary position were uncommon (4/20 patients) and not greater than 2 PD. Significant lid fissure changes were not seen.
CONCLUSIONS: The addition of lateral fixation sutures to full vertical rectus muscle transpositions improves the tonic abducting force of the procedure for patients with lateral rectus palsy and type I Duane syndrome without compromising adduction.