Postoperative Correction and Drift After Vertical Rectus Muscle Transposition for Total Sixth Cranial Nerve Palsy

PURPOSE: To determine the magnitude of change between the preoperative and postoperative alignment and amount of postoperative drift for two vertical rectus muscle transpositions (VRTs). METHODS: Retrospective review of medical records of patients with total sixth cranial nerve palsy who underwent VRT procedures. The primary outcome measure was the magnitude of esotropia in prism diopters (PD) at the preoperative and postoperative visits. RESULTS: Twenty-seven patients were included. Sixteen had full tendon transposition with Foster augmentation (FTT+FA) and 11 had partial tendon transposition with resection and simultaneous medial rectus recession (PTT+R+MRR). A larger correction was obtained with PTT+R+MRR (mean ± standard deviation [SD]: 52 ± 19 PD; range: 27 to 87 PD) when compared to FTT+FA (mean: 40 ± 13 PD; range: 15 to 68 PD). At postoperative month 2, a greater esotropic drift was noted in the PTT+R+MRR group (16 PD) than the FTT+FA group (6 PD). Although the difference in the amount of correction was not statistically significant (P = .071), the difference in the amount of drift was statistically significant (P = .009). CONCLUSIONS: There was a trend toward greater correction with PTT+R+MRR than FTT+ FA, but it was not statistically significant. FTT+FA had significantly less postoperative drift than PTT+R+MRR. The results suggest that a small immediate postoperative overcorrection may be desirable in some VRT procedures. [J Pediatr Ophthalmol Strabismus. 2019;56(4):238-242.].