Clinical effects of surgical treatment of high myopic strabismus fixus by modified Yokoyama's surgery combined with medial rectus muscle recession

Abstract

Objective: To analyze clinical effects of modified Yokoyama's surgery combined with medial rectus muscle recession for treatment of high myopic strabismus fixus. Methods: Retrospective analysis of records of 9 patients (14 eyes) with high myopic strabismus fixus treated from February 2013 to December 2016 in the Department of Ophthalmology, Xiangya Hospital, Central South University. All patients underwent modified Yokoyama's surgery. The temporal 1/2 of the superior rectus (SR) and the superior 1/2 of the lateral rectus (LR) were united 12 to 14 mm, combined with medial rectus muscle recession. The angle of deviation of primary position, the mobility of the affected eye, and the change of CT imaging were observed and analyzed before and 6 months after surgery. Statistical analysis was performed by Mann-Whitney U test. Results: The patients were 5 females and 4 males with an average age of (60±10) years. The duration of high myopia was (33.33±6.61) years. The refractive power was (-23.32±5.95) D, and the axial length was (33.04±2.63) mm. The recession mount of medial rectus was (7.2±2.1) mm (4.0-10.0 mm) intraoperatively. At 6 months, the median esotropia improved from 130 (80-140) prism diopter (PD) to 0 (0-10) PD, and the hypotropia from 20 (15-25) PD to 0 (0-5) PD. The median abduction limitation decreased from -3 (-4--1) to -1 (-2-0), and the median limitation of elevation decreased from -2 (-4--1) to 0 (-1-0). The angle of esotropia and hypotropia significantly improved (Z=-2.67, -2.70; P=0.008, 0.007), and the restriction of abduction and elevation decreased (Z=-3.35, -3.24; both P=0.001). Only 3 patients' CT images were enrolled in a comparative study. Preoperative orbital CT scans showed inferior LR displacement and medial SR displacement with the posterior portion of the eyeball to the superotemporal quadrant of the orbit. After surgery, the mean reduction ratio of dislocation degree of the 3 patients was 28.97%, the dislocation of LR and SR was reduced, and the posterior global part was correctly positioned within the orbit. Conclusions: The modified Yokoyama's surgery combined with medial rectus muscle recession can effectively correct high myopic strabismus fixus, recover the eyeball anatomical position, and evidently improve eye mobility. The clinical effects are satisfactory. (Chin J Ophthalmol, 2019, 55: 670-676).