New surgical technique for treating oculomotor nerve palsy

This prospective study found that transposing the split lateral rectus muscle to the medial rectus muscle area yields acceptable aesthetic results for oculomotor nerve palsy.

The procedure the authors performed is a modification of a previously reported surgical technique in which the lateral rectus muscle undergoes Y splitting and the ends are transposed to the medial rectus area pre-equatorially.

In their modification, the upper half of the split lateral rectus muscle was passed under the superior rectus–superior oblique complex and the lower half was passed under the inferior rectus and inferior oblique muscles. The split ends were reattached 1 mm posterior to the superior and inferior borders of the medial rectus muscle insertion.

For muscles that had lost the ability to stretch and strain due to fibrosis, a hang-back technique was used. In some patients, the medial rectus muscle of the same eye was subsequently strengthened or the lateral rectus muscle of the fellow eye was recessed.

Subjects were 10 patients with oculomotor nerve palsy who underwent this procedure at an eye hospital in Istanbul. All patients had a preoperative horizontal deviation of 45 to 90 prism diopters. Final deviation from 0 to 10 prism diopters was considered a success.

During the second month after the procedure, five patients attained stable results. The remaining five, who had postoperative undercorrection between 20 and 30 prism diopters, required further surgeries. Postoperatively, two patients improved their sensorial status in a very limited range of gaze and two patients had symptomatic diplopia. On the final postoperative visit, nine patients achieved successful results.

The authors say that like with other procedures, this surgery achieved alignment in the primary position but no improvement in ocular motility. They add that their technique has the advantage of avoiding the risk of orbital hemorrhage (damage of vortex veins) and globe perforation. They say it resulted in more successful outcomes and overcomes some of the limitations of previous procedures.

They add that this procedure does not require complicated calculations or introduce any foreign tissues or materials into the orbit and it has not been associated with significant complications. Also, it can be performed on children and often results in orthotropia in the primary position via a one-muscle operation with stable long-term results.