A pilot randomized clinical trial comparing muscle transplant versus hang back recession in extra-large angle exotropia.

Abstract

Purpose: For extra-large angle exotropia (>60 prism diopters, PD), single-setting surgical alternatives are scarce; frequently, more than two muscle or two eye procedures are indicated. To evaluate the viability of single eye surgery, a current randomized comparative trial is undertaken.

Methods: Twenty adult patients with extra-large angle exotropia underwent a thorough orthoptic evaluation before being divided into two groups at random. Ten patients in group 1 underwent medial rectus resection (5.5-7.5 mm), followed by transplant-aided lateral rectus recession (effective length: 4-5.5 mm) (9 mm). In group two, ten different patients underwent medial rectus resection (5.5-7 mm), but this time, the lateral rectus recession (9 mm) was aided with a hang-back suture (5-7 mm). The two procedures were compared at baseline and six months post-operatively.

Results: There was no significant difference in the groups' median ages (P = .95). In groups one and two, the median corrections achieved were 81.00 (79.50-85.50) PD and 81.00 (79.75-86.50) PD, respectively. The differences in corrections were statistically insignificant (p = .99). In all patients, abduction limitation was frequently noted in the immediate post-operative period, which improved over time. In each group, there were two patients (>90 prisms) with residual deviation of at least 30 PD, for which the contralateral eyes were operated.

Conclusions: The hang-back recession was as successful as muscle transplant procedure in correcting 80-90 PD of exotropia with notable clinical benefits and ease.