Clinical efficacy of modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia

Abstract

Objective: To investigate the clinical efficacy of the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia. Methods: A retrospective case series study was conducted. Clinical data were collected from patients who underwent the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia at Eye Hospital of Shandong First Medical University from February 2017 to February 2022. During the procedure, the superior rectus and lateral rectus muscles were fully separated. A longitudinal blunt incision was made in the central muscle belly extending posteriorly to 12-14 mm from the muscle insertion. The temporal half of the superior rectus muscle and the upper half of the lateral rectus muscle belly were transposed and secured to the contralateral muscle insertion. Simultaneously, medial rectus muscle recession was performed. Follow-up visits were conducted at 1 week, 1 month, 3 months, and 6 months postoperatively. Patients' ocular alignment, eye movements, improvement in compensatory head posture, objective degrees of strabismus using synoptophore, changes in extraocular muscles and globe position on orbital CT scan were recorded. Surgical complications were also documented. Results: Five patients (8 eyes) were included in this study, including 4 females (7 eyes) and 1 male (1 eye), with an average age of (63±11) years and an average axial length of (34.58±2.25) mm. The medial rectus muscle recession during surgery was (7.6±2.3) mm. Preoperatively, all patients had esotropia with a horizontal range of+15°to+45° and a vertical range of+15°to+45°. Significant limitations in lateral and upward gaze were observed, with a degree of restriction ranging from-3 (-4 to-1). Three patients with bilateral involvement and one patient with unilateral involvement exhibited significant compensatory head postures. One patient with unilateral involvement had no compensatory head posture. Preoperative orbital CT scans indicated nasal displacement of the superior rectus muscle and inferior displacement of the lateral rectus muscle, with the eyeball herniating from the muscle cone. At the 6-month follow-up, all patients achieved nearly orthophoric alignment. Objective degrees of horizontal strabismus ranged from-4°to+7°, and vertical strabismus ranged from 0°to +6°, as determined by synoptophore examination. Eye movements significantly improved, with a degree of restriction of-1 (-2 to-1) for lateral gaze and-2 (-3 to-1) for upward gaze. Compensatory head postures disappeared, and orbital CT scans indicated the eyeball was located within the muscle cone. There were no severe complications such as anterior segment ischemia, muscle adhesions, disease recurrence, secondary glaucoma, or globe penetration. Conclusion: The preliminary clinical outcomes of the modified Yokoyama procedure with extraocular muscle transposition for high myopic eyes with restrictive esotropia are promising.