The Effect of Inferior Oblique Muscle Surgery in Congenital Superior Oblique Palsy

ABSTRACT

PURPOSE: To compare the postoperative results of inferior oblique muscle operation in congenital superior oblique palsy (CSOP) according to the preoperative vertical deviation. METHODS: This study reviewed medical records of 26 patients who were diagnosed as CSOP with the largest vertical deviation at adducted position and incomitant vertical strabismus from May 2003 to April 2004 at hospital. The patients were divided into two groups, the group 1 (18 patients) shows less than 20 prism diopter (PD) vertical deviation at the primary position, the group 2 (10 patients) shows no less than 20 PD vertical deviation at the primary position preoperatively. We performed operation of the inferior oblique muscle (IOM) for both group. We evaluated the surgical effect at the primary position and both lateral gaze after 3 months. and performed reoperation as needed. RESULTS: Mean correction amount of vertical deviation at primary position of two groups were 11.6+/-2.7 PD in the group 1 and 7.4+/-3.5 PD in the group 2. Postoperative vertical deviation was decreased compared to preoperative value and it was statistically significant. But there were statistically significant differences in the corrected amount after inferior oblique muscle operation between two groups at all gazes. Surgical result of group 1 was successful (100%), but in group 2, all failed (100%) and needed reoperation. CONCLUSIONS: This study showed that corrected amount with IOM operation was smaller in CSOP with no less than 20 PD vertical deviation at primary position and incomitant vertical strabismus. It may be taken into consideration when operation for rectus and oblique musle were performed simultaneously in CSOP.