Graded anterior transposition of the inferior oblique muscle for V-pattern strabismus

PURPOSE To evaluate the efficacy of bilateral graded anterior transposition of the inferior oblique muscle for the correction of V-pattern strabismus associated with inferior oblique overaction. METHODS Medical records of patients who underwent graded anterior transposition of the inferior oblique muscle for bilateral primary inferior oblique overaction associated with V-pattern strabismus were reviewed. The surgical technique entailed recessing and anteriorly transposing the inferior oblique muscle to various locations along the temporal border of the inferior rectus muscle. The amount of anterior transposition was determined by both the severity of the overaction and the extent of the V pattern. We analyzed the changes in inferior oblique muscle overaction and V-pattern strabismus and the frequency of limited elevation after surgery. RESULTS The record review identified 69 patients (138 eyes) who met inclusion criteria. V-pattern esotropia was present in 44 patients (64%) and V-pattern exotropia in 25 (36%). Full correction or undercorrection to <10(Delta) of V pattern was achieved in 82% of esotropia cases and 80% of exotropia cases. Response to surgery was influenced by the severity of the preoperative inferior oblique muscle overaction and the extent of the preoperative V pattern. The grading of the anterior transposition was not a significant independent predictor of surgical response. No patient suffered limitation of elevation postoperatively. CONCLUSIONS Anterior transposition of the inferior oblique muscles corrected V-pattern strabismus and reduced inferior oblique muscle overaction without creating limitation of elevation; however, it is unclear whether grading the transposition contribute to the success of the procedure. (J AAPOS 2012;16:286-290)