Medial transposition of the split lateral rectus muscle used as a primary procedure for treatment of complete third nerve palsy.

Purpose: This case series aims to study the effect of medial transposition of the split lateral rectus (MTSLR) muscle used as a primary procedure for surgical management of complete third nerve palsy.

Methods

A retrospective review of all cases with complete third nerve palsy which underwent surgical intervention in a tertiary care center from 2019 to 2023 was undertaken, and only cases underwent isolated MTSLR as a primary procedure were included. Data collection included age, etiology, laterality, follow-up, preoperative and postoperative deviation, and postoperative complications.

Results

A total of 12 patients (14 eyes) were identified, and mean follow-up after surgery was 15.4 months (range; 7-37 months). Mean age at time of surgery was 34.5 years (range; 2-65 years). Right eye was involved in 5 patients, left eye in 5 patients, while two cases were bilateral. Surgical success (within 10PD of orthotropia) was achieved in all patients. Mean primary gaze exotropia (XT) improved from 96.2PD before surgery (range; 60-130 PD) to 1.8PD after surgery (range; 6PD ET to 8PD XT) (p ˂ .0001). Mean primary position Hypotropia, which was present in 5 cases only, improved from 4.2PD (range 5-14PD) to 0.7PD (range 0-4PD). Abduction significantly declined from a mean of 0 to -3.9 postoperatively, with no significant improvement of limited adduction. No postoperative complications have been encountered, apart from transient postoperative horizontal diplopia in one patient which resolved spontaneously.

Conclusion

MTSLR muscle attains long term acceptable aesthetic results and functional alignment when used as a primary procedure for treatment of complete oculomotor nerve palsy, with low rate of postoperative complications.