The Effect of Bilateral Superior Oblique Tenotomy on Primary Position Horizontal Alignment

To evaluate the effect of superior oblique tenotomy on horizontal deviation at primary position in A-pattern exotropia with bilateral superior oblique overaction.We performed adjustable strabismus surgeries under topical anesthesia in 6 patients with A-pattern exotropia. After adjusting horizontal deviation to orthotropia in primary position by horizontal muscle surgery, we measured angle deviation in up, primary, downgaze position and added bilateral superior oblique tenotomy, and remeasured the angle deviation at same positions. We analyzed the angle deviation at postoperative one day, one month, and three month in comparison with the preoperative value. There were no change of horizontal deviation in primary position in 2 patients, qhile 3 to 8 prism diopter(PD) esotropic shift occurred in 4 patients(average 3.3PD) after bilateral superior oblique tenotomy at last follow-up of 3 month. At 3 month postoperatively, there was a tendency of exotropic shift from esotropia noted at immediate postoperative period. When combined surgeries of superior oblique and horizontal muscle are considered and intraoperative adjustable surgery is not permitted, horizontal muscle surgery can be performed with disregarding the effect of bilateral superior oblique tenotomy on primary position horizontal alignment.

Superior Oblique Tenotomy with Silicone Expander for Superior Oblique Overaetion and Brown Syndrome

Standard procedures for weakening the superior oblique muscle have been associated with significant complications in the treatment of superior oblique overaction and Brown's syndrome. Authors performed a technique for weakening the superior oblique muscle by lengthening the superior oblique tendon with silicone. Lengthening was accomplished by a nasal superior oblique tenotomy and inserting a segment of silicone 240 retinal band between the cut ends of the tendon. This technique was performed on 6 patients (8 eyes), 2 (4 eyes) with superior oblique overaction (SOOA), and 4 (4 eyes) with Brown's syndrome. Preoperatively patients with SOOA demonstrated A-patterns of 26 and 29 prism dioptersrespectively, and versions of +2 or +3 SOOA. Patients with Brown's syndrome demonstrated version of -3 or -4 elevation on adduction. Postoperatively, the A -patterns disappeared and SOOA was improved to 0 or +1, and underaction on adduction improved to 0 or -0.5 in Brown's syndrome. Based on these results, the superior oblique tenotomy with silicone expander is useful in patients with SOOA and Brown's syndrome.