Augmented surgery for monocular elevation deficiency
Reviewed by Fiona Rowe

The outcomes are described for augmented lateral rectus superior transposition in cases of acquired monocular elevation deficiency (MED) associated with large hypotropia in primary gaze. The lateral rectus was transposed superiorly and reinserted on sclera between the temporal margin of the superior rectus and superior corner of the lateral rectus original insertion. A single suture was used to create a muscle union posterior fixation suture between the superior and lateral recti, 8mm posterior to their insertion. The suture imbricated one third of the superior and lateral recti muscle widths. In cases with associated esotropia, the lateral rectus was simultaneously resected to target the horizontal angle in primary gaze. This was done in three cases. Mean age of patients was 32 years (10-46). Mean follow-up was 10 months. Mean hypotropia of 35PD (20-60) reduced postoperatively to a mean of 4.67PD (0-14). There was no torsional diplopia postoperatively. One patient also had simultaneous inferior rectus recession and had botulinum toxin (BT) to address vertical deviation in primary gaze. The authors note forced duction testing (FDT) is important as a negative FDT is associated with overcorrection when performing both procedures. The advantage of this procedure is a reduced risk of anterior segment ischaemia. Simultaneous surgery of single muscles (lateral and inferior recti) may reduce risk of overcorrection. Further, this technique allows use of adjustable sutures.

Single horizontal rectus muscle vertical augmented transposition with posterior fixation suture in management of monocular elevation deficiency.
Chen AC, Velez FG, Silverberg M, et al.
STRABISMUS
2021;29(1):51-6.