Partial Rectus Muscle–Augmented Transpositions in Abduction Deficiency Michelle T. Britt, MD, a Federico G. Velez, MD, a Neepa Thacker, MD, a Deborah Alcorn, MD, b R. Scott Foster, MD, b and Arthur L. Rosenbaum, MD a Purpose: Lateral posterior fixation sutures increase the effect of full rectus extraocular muscle transpositions. Partial rectus muscle transposition may be indicated to minimize the risk of anterior ischemia when multiple rectus muscles require surgery to achieve ocular alignment. Purpose: To report a modification of full vertical rectus muscle transposition with lateral posterior fixation sutures for use in patients at risk for anterior segment ischemia. Methods: Ten cases of unilateral split rectus muscle transposition augmented with lateral posterior fixation sutures were analyzed. Five patients had Duane’s syndrome with esotropia in primary position, and five patients had sixth-nerve palsy. Results: Seven patients had a history of ipsilateral rectus muscle surgery, and three patients underwent simultaneous surgery on ipsilateral horizontal rectus muscles. In Duane’s syndrome patients, the preoperative angle of deviation at distance was 15.8  5.8 prism diopters (PD) (range, 10 to 25) compared with 3.2  4.4 PD (range, 0 to 8) postoperatively (P = .005). In patients with sixth-nerve palsy, the preoperative angle of deviation at distance was 45.2  23.9 PD (range, 16 to 80) compared with -5  14.1 PD (range, -30 to 5) postoperatively (P = .004). Postoperative binocular single visual fields enlarged in seven of seven patients. Conclusion: Partial rectus muscle–augmented transposition allows surgery on multiple ipsilateral rectus muscles in (1) Duane’s syndrome patients with esotropia, marked cocontraction, and/or limitation to both horizontal rotations and in (2) sixth-nerve palsy patients with ipsilateral medial rectus tightness. Augmented partial rectus muscle transpositions improve ocular alignment and may enlarge binocular single fields in patients with persistent deviations despite previous muscle surgery. (J AAPOS 2003;7:325–332) E xtraocular rectus muscles transpositions may be in- dicated when limitations to ocular rotations are secondary to minimal or absent muscle force. 1-4 Similar to patients with near complete or complete sixth cranial nerve palsies, Duane’s syndrome patients with se- vere abduction deficit may present with a compensatory face turn and esotropia in primary position. Surgical goals for both patients with a chronic lateral rectus paralysis and Duane’s syndrome include decreasing or eliminating head turn; centering and expanding single binocular visual fields; and increasing abduction while preserving adduc- tion. Full vertical rectus muscle transpositions have been used to treat sixth-nerve palsies and Duane’s syndrome effectively. 1-9 This procedure is often combined with me- dial rectus recession or injection of botulinum toxin. 7 Several modifications to the transposition procedure to improve abduction strength have been described. 5-6 In 1997, Foster 10 reported that vertical muscle transposition, augmented with lateral fixation sutures, increases abduct- ing force while maintaining adduction in patients with Duane’s syndrome or sixth-nerve palsy. Results of more recent studies have also shown that augmentation sutures achieve better results by enhancing the mechanical effects of the transposition. 11-13 A rare but potentially serious complication of strabis- mus surgery is anterior segment ischemia, which usually occurs after surgery on 3 or 4 rectus muscles. 14,15 It has been suggested that iris angiogram filling delays persist months after tenotomy and four recti muscles should never be operated upon even with lengthy intervals be- tween surgeries. 14,16 Anterior segment ischemia has been reported after full vertical rectus muscle–augmented trans- position in an adult patient without previous surgery on the ipsilateral rectus extraocular muscles. 17 Although lat- eral posterior fixation sutures have been shown to increase the effect of the transpositions, 10-13 some patients still require surgery on other extraocular rectus muscles to achieve ocular alignment, which increases the risk for anterior segment ischemia. Patients who have undergone previous surgery, or who may require surgery on multiple rectus muscles to obtain From Jules Stein Eye Institute, University of California Los Angeles a ; and the Department of Ophthalmology, Stanford University, b Stanford, California. Presented at the Annual Meeting of the American Association for Pediatric Ophthalmology and Strabismus, Seattle, Washington, March 23, 2002, under the title “Partial Rectus Muscle Transpositions Augmented With Lateral Posterior Fixation Sutures.” Submitted August 13, 2002. Revision accepted May 13, 2003. Reprint requests: Arthur L. Rosenbaum, MD, 100 Stein Plaza, University of California Los Angeles, Los Angeles, CA, 90095. Copyright © 2003 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2003/$35.00 + 0 doi:10.1016/S1091-8531(03)00180-0 Journal of AAPOS October 2003 325