Augmented vertical recti transposition with intraoperative botulinum toxin for complete and chronic sixth nerve palsy

PurposeTo evaluate the results of augmented vertical rectus muscle transposition (VRT) with intraoperative botulinum toxin (BTX) for complete and chronic sixth nerve palsy.MethodsDuring a 10-year period (2004-2014) all patients with chronic and complete sixth nerve palsy and contracted medial rectus (MR) who underwent augmented VRT and BTX injection into the MR enrolled in this study.ResultsIn total, 29 patients (5 bilateral) were enrolled in this study. Preoperative deviation was 45±17.5 Prism Diopter (PD), which was improved to -3.1±13.2 after the operation (P<0.001). Mean preoperative and postoperative abduction limitation was -4.4±1.1 and -1.8±0.9, respectively (P<0.001). The success rate was 76% (deviation within 10 PD of orthotropia). Four patients (13.7%) had hypotropia. In 19 patients with preoperative deviation ≤45 PD, four patients had consecutive exotropia.ConclusionIntraoperative BTX injection with augmented vertical rectus transposition is an effective procedure. In deviation ≤45 there is a risk of overcorrection.