augmented vertical rectus muscle transposition with intraoperative botulinum toxin for complete and chronic sixth nerve palsy

purpose: to evaluate the results of augmented vertical rectus muscle transposition with intraoperative botulinum toxin for complete and chronic sixth nerve palsy. methods: during a 10 years period (1381-1390) all patients with chronic and complete sixth nerve palsy, and contracted medial rectus (mr) underwent augmented vertical rectus muscle transposition with botulimum toxin injection into the mr. demographics such as age, gender and etiology, and pre- and postoperative data including deviation, limitation of abduction, success rate and complications were analyzed. results: 29 patients (5 bilateral) were enrolled into this study. trauma (48%) and congenital or unknown causes (31%) were the most common etiology. 14 (49.3%) cases were female and 15 (51.7%) were male. mean age at enrollment was 26.5±19.8 years. preoperative deviation was 45±17.5 pd which was improved to -3.1±13.2 after the operation (p<0.001). mean correction effect was 48. 1±17.7 pd. mean preoperative and postoperative abduction limitation was -4.4±1.1 and -1.8±0.9 respectively (p<0.001). success rate was 76% (deviation within 10 pe of orthotropia). 4 patients (13.7%) had hypotropia. in 19 patients with preoperative deviation £ 45 pd, four patients had consecutive exotropia. anterior segment ischemia was not seen. conclusion: intraoperative botulinum toxin injection with augmented vertical rectus transposition is an effective procedure. in deviation £ 45 there is a risk of over correction.