Transposition procedures in Duane retraction syndrome

Duane retraction syndrome, or Duane syndrome (DS), is one of several congenital cranial dysinnervation disorders. Patients present with limited horizontal eye movement(s) and globe retraction with eyelid fissure narrowing on attempted adduction due to co-contraction of the lateral and medial rectus muscles in one or both eyes. Various surgical approaches have been proposed to improve binocular alignment, reduce head turn, and minimize undesirable up- or downshoots in DS. Transposition procedures are one such approach, and a number of techniques have been described. These may involve one or both vertical rectus muscles and may or may not include full or partial disinsertion of the rectus muscle(s) from the insertion. Options involving both vertical rectus muscles include full vertical rectus transposition (VRT), partial VRT, rectus muscle union, and other modifications to be discussed. Options involving one vertical rectus muscle include superior rectus transposition (SRT) and inferior rectus transposition (IRT). The effectiveness of any transposition procedure may be enhanced with augmentation (posterior fixation) sutures, resection of the transposed muscle(s), and/or simultaneous weakening of the ipsilateral medial rectus muscle. This review discusses the indications, strengths, weaknesses, and other considerations of these approaches within the context of DS. Since the majority of DS cases are unilateral and most have the esotropic form, this will be the main focus of the review, although other forms will also be discussed.