Comparison of plication and resection in large-angle exotropia

Abstract

Plication of the rectus muscles is used sparingly as a tightening procedure compared to resection, however, the relative efficacy of these procedures is difficult to assess because the sparse literature comparing the two is further limited by a lack of imaging. This case series attempts to compare the techniques in cases of exotropia along with quantitative assessment of ultrasound biomicroscopy (UBM). Patients with exotropia of 30Δ-50Δ who had undergone first-time horizontal strabismus surgery were recruited and prospectively underwent UBM evaluation 1year after surgery. Plication was performed by folding the anterior part of the medial rectus muscle posteriorly and tying it at the insertion to the sclera. Resection was performed in a routine manner. Deviation and motility were assessed postoperatively, when UBM was performed. Only patients with basic comitant exotropia without any vertical pattern were included. During the study period, 15 patients underwent resection of the medial rectus and 13 underwent plication. The two groups were age and deviation matched preoperatively. The patients undergoing plication and resection fared equally in terms of postoperative deviation (P=0.81) and abduction limitation (P=0.169). UBM could identify and quantify plication in all cases with excellent agreement with the operative data (intraclass correlation coefficient=0.886; P=0.000). Medial rectus plication or resection performed for similar angles of exotropia produced quantitatively similar results. Plication offered the advantage of being characteristically identifiable and measurable on UBM.