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.

KEYWORDS:

• Exotropia
• extra-large-angle exotropia
• large-angle exotropia
• randomized clinical trial

Acknowledgements

We would like to thank Dr Sumit Kumar Das, Scientist-I. Department of Biostatistics, AIIMS, New Delhi. India.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.