True muscle transplantation for the management of third nerve palsy

To describe and report the results of 2 different techniques for true muscle transplantation for management of exotropia in patients with third nerve palsy.

A retrospective chart review was conducted on patients with third nerve palsy in whom true muscle transplantation was performed. The resected segment of the medial rectus (MR) muscle was used to lengthen the lateral rectus (LR) muscle before recession. The transplantation was performed using either a free graft technique or a modified continuous graft technique. Ductions, versions, and angles of deviation were evaluated before and after surgery.

A total of 7 patients were identified (mean age: 32 ± 17 years). Two patients had prior LR recession. The mean preoperative angle of deviation was 53 ± 13 PD, and the mean preoperative limitation of adduction was -4. The free graft and the continuous graft techniques were used in 3 and 4 cases, respectively. The median amount of LR recession was 8 mm, and the amount of MR resection ranged from 6 to 8 mm. The mean follow-up was 6.0 ± 4.2 months. Postoperatively, 5 patients had residual exotropia <10 PD. The remaining 2 cases had residual exotropia 15 PD. The mean postoperative limitation of adduction improved to -2.3 ± 0.5. The postoperative limitation of abduction was -1 or less in 6 patients.

True muscle transplantation can be used to correct large exotropia in partially recovered or recurrent third nerve palsy without causing significant limitation of abduction. Undercorrection is associated with smaller amounts of MR resection.