Session: Poster session B

Transposition of the split lateral rectus muscle to 8 mm posterior of the medial rectus muscle insertion in complete oculomotor nerve palsy 

INTRODUCTION Surgical options in complete oculomotor nerve palsy are limited. Utilizing the remaining innervation in the lateral rectus muscle (LR), transposition of the LR redirects eye movement to better alignment of the eyes. The aim of this study is to present the surgical experience with six cases of complete oculomotor nerve palsy.

METHODS Retrospective case series evaluating six consecutive operations on patients with complete oculomotor nerve palsy between May 2018 and October 2023 in which the split LR was transposed nasally. Primary outcome is horizontal and vertical ocular alignment in primary position. Secondary outcomes are abduction and adduction deficits and complications.  

RESULTS A total of six operations were included. The preoperative horizontal deviation ranged from 40ΔXT to more than 90ΔXT and adduction ranged from -30 to +2. In five out of six operations the LR was split in equal parts and reattached 8 mm posterior of the medial rectus (MR) insertion. Three of those five had an added tenotomy of superior and inferior oblique. In one out of six operations the LR was split in a 1/3 superior part and a 2/3 inferior part, both also reattached 8 mm posterior of the MR insertion. Postoperative ocular alignment was enhanced in all cases and ranged from 6ΔET to more than 45ΔXT. Adduction of the operated eye improved in all cases postoperatively and ranged from +1 to +20. However, a marginal decline in abduction was evident in three cases from no limitation preoperatively to -27, -24 and -16 postoperatively. No evident complications were observed after five out of six operations. One patient experienced vision-threatening complications, attributed to an immediate postoperative increase in intraocular pressure.

CONCLUSIONS Transposition of the split LR to 8 mm posterior of the MR insertion in complete oculomotor nerve palsy improved strabismus and adduction movement. Caution should be exercised for complications as choroidal effusion or secondary glaucoma.