Factors Associated with Improved Surgical Outcomes in Recurrent Exotropia

Min Jung Kim; Seung Hyun Kim

doi:10.3341/jkos.2017.58.6.692

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Kim and Kim: Factors Associated with Improved Surgical Outcomes in Recurrent Exotropia

Original Article

Journal of the Korean Ophthalmological Society 2017; 58(6): 692-697.

Published online: 16 June 2017

DOI: https://doi.org/10.3341/jkos.2017.58.6.692

Factors Associated with Improved Surgical Outcomes in Recurrent Exotropia

Min Jung Kim, MD, Seung Hyun Kim, MD, PhD

Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.

Address reprint requests to Seung Hyun Kim, MD, PhD. Department of Ophthalmology, Korea University Anam Hospital, #73 Inchon-ro, Seongbuk-gu, Seoul 02841, Korea. Tel: 82-2-920-5520, Fax: 82-2-924-6820, ansaneye@hanmail.net

Received 23 June 2016 Revised 10 October 2016 Accepted 2 February 2017

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To investigate the factors that improve the success rate in patients with recurrent exotropia.

Methods

A total of 60 patients who had undergone reoperation for recurrent exotropia and had at least 1 year of follow-up after surgery were included in this study. In total, 43 patients in the group with one-muscle surgery had undergone either unilateral medial rectus resection or unilateral lateral rectus recession, and the other 17 patients in the group with two-muscle surgery had undergone either bilateral medial rectus resection or lateral rectus muscle recession with medial rectus muscle resection of contralateral eye. The main outcome measure was final success rate, which was compared between the 2 groups.

Results

In this study, 41 (95.3%) of 43 patients in the group with one-muscle surgery had successful outcomes, while 2 (4.7%) had undercorrection at the final follow-up examination. On the other hand, 10 (58.8%) of 17 patients in the group with two-muscle surgery had successful outcomes, 5 (29.4%) had undercorrection, and 2 (11.8%) had overcorrection. The success rates were significantly different between the 2 groups (p = 0.001). In addition, preoperative deviation had the largest area under the receiver operator characteristic (ROC) curve for the success rate and exhibited an optimal balance of both sensitivity and specificity using a cut-off value of 25 PD.

Conclusions

Final success rate was higher in the group with one-muscle surgery for the treatment of recurrent exotropia. Surgical outcomes are expected to be higher in patients with preoperative deviation of less than 25 PD.

Keywords: Intermittent exotropia, Recurrent exotropia, Reoperation, Success rate

Figures and Tables

Figure 1

Diagram of study patients. The group with one-muscle surgery and the group with two-muscle surgery. BLR = bilateral lateral rectus muscle; UMR = unilateral medial rectus muscle; BMR = bilateral medial rectus muscle; R&R = lateral rectus muscle recession and medial rectus muscle resection; ULR = unilateral lateral rectus muscle.

Figure 2

Receiver operator characteristic (ROC) graph showing the sensitivity and specificity of the various prism diopters. Preoperative deviation had the largest area under the ROC curve (0.855) for the success rates and exhibited an optimal balance of both sensitivity and specificity using a cut-off value of 24.5 PD (see Table 6).

Table 1

Surgical dose table for patients with recurrent exotropia after 1st operation in the group with one-muscle surgery and the group with two-muscle surgery

UMR = unilateral medial rectus muscle; PD = prism diopters; ULR = unilateral lateral rectus muscle; BMR = bilateral medial rectus muscle; Recession/Resection = lateral rectus muscle recession / medial rectus muscle resection.

Table 2

Preoperative characteristics of patients with one-muscle surgery and two-muscle surgery

Values are presented as mean ± SD unless otherwise indicated.

PD = prism diopters.

^*Mann-Whitney U-test; ^†Pearson chi-square test.

Table 3

Final success rates for the group with one-muscle surgery and the group with two-muscle surgery

Values are presented as n (%) unless otherwise indicated.

PD = prism diopters.

^*Fisher exact test.

Table 4

Subgroup analysis of the success rates according to the types of one-muscle surgery

Values are presented as n (%) unless otherwise indicated.

PD = prism diopters; UMR = unilateral medial rectus muscle; ULR = unilateral lateral rectus muscle.

^*Fisher exact test.

Table 5

Subgroup analysis of the success rates according to the types of two-muscle surgery

Values are presented as n (%) unless otherwise indicated.

PD = prism diopters; BMR = bilateral medial rectus muscle; R&R = lateral rectus muscle recession and medial rectus muscle resection.

^*Fisher exact test.

Table 6

Area under the receiver operator characteristic (ROC) curve, sensitivity, specificity by each cut-off value

PD = prism diopters.

Table 7

Sub-analysis of the success rates for two-muscle surgery group based on prism diopters

Values are presented as n (%) unless otherwise indicated.

PD = prism diopters.

^*Fisher exact test.

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