A Modified Surgical Technique to Treat Strabismus in Complete Sixth Nerve Palsy

Abstract

Introduction: A lot of different techniques have been proposed in order to manage abduction limitation secondary to sixth nerve palsy; however, anterior segment ischemia remains a concern. The aim of this study was to evaluate the results of augmented vertical recti muscle transposition (VRT) with partial recession of medial rectus muscle (MR) for complete, chronic sixth nerve palsy, a new modified technique that could also minimize the risk for anterior segment ischemia (ASI). Methods: In this nonrandomized 8-year (2009–2017) retrospective review, 20 patients with complete sixth nerve palsy and contracted MR were enrolled. All of them underwent augmented VRT and partial recession of the MR, following a new proposed surgical technique. Only the central part of the MR tendon and belly was recessed by 6.5 mm, leaving 1.5 mm of the upper pole and 1.5 mm of the lower pole of the muscle intact, preserving the circulation of two anterior ciliary arteries. Results: Twenty patients with a mean age of 43 years (range 12–71), all unilateral cases, were enrolled in this study. The mean preoperative deviation was 64.25 ± 10.9 prism diopters (PD) base out (range 50 to 90). In 17 cases (88%), the postoperative deviation was within 10 PD of orthotropia. Two patients (10%) had residual esotropia (15 PD and 20 PD, respectively), and one patient (5%) had 10 PD of hypotropia. The mean preoperative abduction limitation of −5.9 improved to −3.1 (p < 0.0001). None of the cases presented with ASI (success rate 100%). Conclusion: Partial recession of the MR preserving the two anterior ciliary arteries (Kozeis modified technique) with augmented vertical recti muscle transposition is an effective procedure, with a high success rate and is probably less risky for ASI.