Effect of graded partial inferior rectus muscle tenotomy in treatment for superior oblique paralysis

Purpose:To evaluate the surgical outcomes for patients with superior oblique paralysis (SOP) who underwent the inferior oblique weakening and the graded partial inferior rectus muscle tenotomy in the contralateral eye. Methods:Medical records were retrospectively reviewed for those SOP patients who had hyperdeviation of 4(triangle) -20(triangle) in the primary position and 8(triangle) -25(triangle) in the downgaze position. Patients were subdivided into three subgroups according to their vertical deviation angle in the downgaze position. They underwent an ipsilateral inferior oblique muscle recession and a graded partial tenotomy of the contralateral inferior rectus muscle. The vertical deviation angles, abnormal head position, and fundus torsion were compared statistically before and after operations. All patients were followed up at least 1 year. Results:Forty-seven patients were included in this study. The mean follow-up period was 17.2 months after surgery (ranging from 12 to 28 months). The vertical deviation angle was averaged preoperatively to 7.74(triangle) +/- 3.23(triangle) in the primary position and 15.30(triangle) +/- 5.92(triangle) in the downgaze position and reduced postoperatively to 0.85(triangle) +/- 1.15(triangle)in the primary position and 1.53(triangle)+/- 1.49(triangle) in the downgaze position (P < 0.001). All patients had an abnormal head position preoperatively and had improved significantly postoperatively. Fundus extorsion had been improved significantly postoperatively. Conclusion:The surgical procedure of IO weakening combined with contralateral graded partial inferior rectus muscle tenotomy is a successful intervention for the correction of small deviation in primary position of SOP.