High myopic esotropia: outcomes of surgical management with the Yokoyama technique

OBJECTIVE: Progressive restrictive eso-hypotropia may occur in highly myopic eyes due to elongation of the eyeball and dislocation of the globe out of the muscle cone in the supero-temporal quadrant. Conventional recession/resection surgical procedures are not effective in this type of strabismus. We present our results with the surgical procedure described by Yokoyama in 2001 based on the principle of replacing the globe into the muscle cone by joining the lateral and superior rectus muscles combined with medial rectus recession in selected cases. MATERIALS AND METHODS: The charts of 33 consecutive patients undergone the muscle binding procedure at our institution between 2002 and 2010 were reviewed. Pre-operative coronal MR images demonstrated downward shift of the lateral rectus and inward shift of the superior rectus in the affected eyes. Fourteen patients underwent muscle binding procedure in both eyes combined with medial rectus recession in 18 eyes. The other 19 patients underwent the Yokoyama procedure in one eye. In this latter group, medial rectus recession was performed in all the eyes undergone muscle binding procedure and in 12 patients also in the other eye. The follow-up ranged from 4 months to 8 years (mean: 40 months). RESULTS: All patients resulted improved in their deviation following single surgery. Mean horizontal deviation in primary position decreased from +60 PD before surgery (range: +45/+140 PD) to +15 PD after surgery (range: -18/+ 30 PD). Mean vertical deviation in primary position improved from 15 PD (range: 5/50 PD) to 3 PD (range: 0/15 PD). CONCLUSIONS: The surgical procedure to restore the dislocated eye-ball back into the muscle cone by joining muscle bellies of the lateral rectus and superior rectus muscles is effective for high myopic eso-hypotropia, provided that shift of the lateral and superior rectus is pre-operatively demonstrated by MR or CT images.