Superior Rectus Transposition Research Articles

Superior oblique tendon lengthening and medial rectus transposition in the bilateral aplasia of the inferior rectus muscle

Superior oblique tendon lengthening and medial rectus transposition in the bilateral aplasia of the inferior rectus muscle

Superior rectus muscle transposition (SRT) procedure for Duane syndrome and abducens palsy

Purpose: Vertical rectus transposition (VRT) is used to treat abduction limitation, but new vertical deviations and anterior segment ischemia are concerns. Earl Crouch described superior rectus transposition (SRT), a procedure in which only the superior rectus muscle is transposed temporally. In this study we describe our results using augmented temporal SRT with adjustable medial rectus recession for treatment of Duane syndrome (DS) and sixth nerve palsy.

Vertical rectus muscle transposition and botulinum toxin for complete sixth nerve palsy

Background: Effective surgical treatment of complete unrecovered sixth nerve palsy must include the transfer of abducting power to the temporal aspect of the globe with release of medial rectus contracture nasally. We describe our experience in the treatment of five such patients who underwent full vertical rectus transposition combined with botulinum toxin chemodenervation of the ipsilateral medial rectus muscle.Methods: The five patients all had primarily unilateral complete unrecovered sixth nerve palsy. They all underwent a complete preoperative and postoperative eye examination and an orthoptic assessment. Excursion into abduction was graded from -8 (globe immobilized in extreme adduction) to -4 (abduction as far as primary position) to 0 (full abduction). Abduction saccades and a forced muscle generation test confirmed the presence of complete unrecovered sixth nerve palsy, and forced duction testing measured the degree of medial rectus contracture. All patients received ipsilateral medial rectus injection of botulinum toxin in the preoperative (8 to 2 months before surgery) and perioperative periods, and underwent complete superior rectus-inferior rectus transposition temporally.Results: The average length of follow-up was 21 (range 6 to 48) months. The average preoperative distance alignment was 52 (range 25 to 80) prism dioptres (PD). Vertical rectus transposition combined with botulinum toxin injection resulted in an average distance alignment change of 66 PD (range 50 PD to 82 PD) of exoshift. The average final deviation was 1 PD of esotropia (range 4 PD of esotropia to 6 PD of exotropia). Average abduction improved from -6 (range -3 to -8) preoperatively to -1.7 (range - 1 to -2) postoperatively: Saccades averaged -4 preoperatively and improved to -2 postoperatively. Normal vertical eye movements were preserved in all patients. A total field of single binocular vision was created in all patients, which averaged 55° (range 30° to 75°) in the horizontal meridian. The field of single binocular vision from primary position into abduction averaged 23° (range 18° to 28°).Interpretation: Temporal transposition of the vertical rectus muscles combined with perioperative botulinum toxin injection of the ipsilateral medial rectus muscle is a reliable and effective way of restoring functional binocular vision in patients with complete unrecovered sixth nerve palsy.

Surgical Management of Abduction Deficits

Surgical planning for a sixth nerve palsy or paresis should include an assessment of whether the deficit is complete or incomplete. In cases of incomplete paresis, a recess-resect procedure is appropriate. For small deviations, a single lateral rectus resection is effective, whereas for larger deviations, recession of the contralateral medial rectus, with or without a posterior fixation suture, may improve comitance and the field of single binocular vision. In cases of complete palsy, a superior and inferior rectus transposition procedure is advisable. Augmenting the transposition may allow two muscle surgery alone to be effective. Botulinum toxin may be useful alone, particularly in acute complete palsies, and may be used as an adjunct to transposition surgery.Lost muscles are best addressed by relocating the lost muscle. Failure to find the muscle will necessitate a transposition procedure. If the ipsilateral antagonist is tight, requiring a recession, a vessel sparing procedure should be used for the transposition.Type I Duane syndrome may best be addressed by incorporating a recession of the contralateral medial rectus into the surgical plan. Nevertheless, early results from an augmented transposition procedure show promise in restoring partial abduction of an affected eye.Surgical planning should include a careful history, examination and a discussion of patient expectations.