Safety stitch: a modification to postoperatively adjustable suture strabismus surgery of the inferior rectus muscle.

Objective: To introduce a variation of adjustable suture recession surgery of the inferior rectus muscle by adding a non- absorbable "safety stitch" to reduce post surgery overcorrection.

Methods: Eleven patients with vertical strabismus who needed inferior rectus recession were the subjects of this study. The vertical deviation was measured preoperatively, 24 hours after the adjustment, and after a minimum of a year followup. An adjustable suture technique through a limbal incision with a silicon sheet was used. We added a non-absorbable suture in the medial edge of the tendon of the inferior rectus muscle and fixed it at the scleral insertion of the muscle. This area of the inferior rectus tendon was exposed for the adjustment, which was performed 24-48 hours after the surgery. The safety suture was then fastened with a knot and 4-6 prism diopters (pd) of undercorrection in down gaze was intentionally left.

Results: The average preoperative vertical deviation was 17 prism diopters (pd) in primary position, and 21.6 pd in down gaze. Six of the eleven patients were adjusted postop' leaving an average residual vertical deviation of 2 pd in primary position and 4.7 pd in down gaze. After a year of followup, the average vertical deviation was 0.4 pd in primary position and 2 pd in down gaze. Ten of the eleven patients were considered to have "successful" primary surgery using this technique. The eleventh required a second operation for an undercorrection which resulted from inadequate original placement of the safety stitch.

Conclusions: The non-absorbable safety stitch technique provided satisfactory results, superior to previously reported techniques for postop' adjustable recession strabismus surgery of the inferior rectus muscle.