Lateral Rectus Muscle Tendon Elongation by an Auto Graft from the Resected Medial Rectus Muscle as a Monocular Surgery for Large-Angle Sensory Exotropia

Abstract

Purpose: To evaluate using the resected medial rectus muscle for elongation of the lateral rectus tendon in monocular surgery for large-angle sensory exotropia.

Patients and methods: A prospective case series was carried out in Tanta University hospital from January 2017 to June 2018 including 16 patients with large-angle sensory exotropia ≥50PD. The near and distance angles of exotropia were measured; any restrictions in adduction or abduction were recorded and scaled from -4 to 0. Resection of the medial rectus muscle was done first; the resected segment was attached to the lateral rectus muscle after dissection by mattress sutures, and the muscle was recessed after elongation according to the preoperative distance angles. Successful motor alignment was considered if the angle measurement was within 10 PD of orthotropia at distance after 6 months. The stability of the alignment, any motility restrictions, and patient satisfaction were recorded at each follow-up visit until the 6th month.

Results: The mean age of the study patients was 30.68±13.30 years. The best-corrected visual acuity of the exotropic eyes by logMAR was 1.2±0.3; the mean of the preoperative distance angle of deviation was -72.19 ±14.26 PD. The mean preoperative adduction and abduction restrictions were -1.19 ±1.52 and -1.13 ±1.09, respectively. There was significant improvement in the distance angle of deviation at the last follow-up after 6 months (p=0.001*). Also, there was improvement in both adduction and abduction restriction from the first to last follow-up. Thirteen patients (81.2%) were satisfied at the 6-month follow-up.

Conclusion: Elongation of the lateral rectus muscle by an autograft from the resected medial rectus muscle is an easy, effective procedure for large-angle sensory exotropia. Patients achieve good postoperative alignment with minimal restriction of ocular motility.

Keywords: autograft; lateral rectus elongation; sensory exotropia.

Figure 1

Diagramatic representation of lateral rectus recession after elongation by an autograft from medial rectus muscle, (A and B) amount of recession,(B and C) autograft after suturing to the Lateral rectus muscle.

Figure 2

Diagramatic representation of the difference between (A) maximal recession,(B) supermaximal recession, and (C) maximum recession with elongation.*: The blue dotted line represents maximal recession.**The red dotted line represents supermaximum recession behind the equator. ^ΔThe brown colored segment represents the transplanted medial rectus autograft.^▲Represents the insertion of lateral rectus muscle.

Figure 3

The patient satisfaction questionnaire at the 6th month.

Figure 4

A graph showing post operative improvement of adduction restriction.

Figure 5

A graph showing post operative improvement of abduction restriction.

Figure 6

Intra operative photo showing the autograft segment of resected medial rectus to the recessed lateral rectus muscle showing no adhesions or reactions after six months from the first surgery.