Comparison of bilateral medial rectus plication and resection for the treatment of convergence insufficiency-type intermittent exotropia

Convergence insufficiency with diplopia: Surgical treatment in adults

OBJECTIVE

To study the outcomes of treatment with central mini-plication of the medial rectus (MR) muscles in adult convergence insufficiency with diplopia.

METHODS

The study sample comprised 9 cases (7 women). The length of MR plication was collected. Other variables reported were postsurgical deviation, overcorrections in the early postoperative period and at the end of follow-up, final horizontal deviation at near and at distance vision, diplopia, and mean follow-up from surgery. Surgical outcome was considered to be favorable when diplopia and symptoms were resolved and final exotropia at near was ≤8 pd at the end of follow-up.

RESULTS

A central mini-plication of the MR was performed in 9 patients (8 unilateral). Mean (± SD) age was 58.66 (21.39) years. Mean near preoperative deviation: 16.22 (± 2.9) pd and distance preoperative deviation: 6.88 (± 4) pd Overcorrection at distance vision was recorded in 5 cases; this resolved by 3 months postoperatively. There was not overcorrection at near vision except one case. None of the cases operated on had overcorrection at the end of follow-up The final horizontal deviation was ≤8 pd at near vision, except for 3 cases (mean: 6.22). Symptoms and diplopia resolved in 8 cases. The mean follow-up was 10.33 months.

CONCLUSION

Central mini-plication of 1 or 2 medial rectus muscles can improve the symptoms and signs of exotropia associated with convergence insufficiency when exercises and the prisms are rejected by the patients and when these approaches have not solved the problem.

How to Better Treat Patients with Intermittent Exotropia: A Review of Surgical Treatment of Intermittent Exotropia

Intermittent exotropia (X(T)) is the most common form of strabismus, especially in Asians. Treatment of X(T) includes occlusion, overminus lens, and surgery, of which, surgery is the mainstay of treatment. Commonly performed surgical procedures for X(T) are bilateral lateral rectus muscle recession or unilateral lateral rectus recession with medial rectus resection; however, it is unclear which of the two surgeries is more effective. The purpose of this review is to provide an insight on the surgical treatment of X(T). Randomized controlled trials, comparative observational studies, and case series with a large number of patients as well as a long follow-up period of over a year were included.

Abnormal cortical morphology in children and adolescents with intermittent exotropia

Purpose

To investigate cortical differences, age-related cortical differences, and structural covariance differences between children with intermittent exotropia (IXT) and healthy controls (HCs) using high-resolution magnetic resonance imaging (MRI).

Methods

Sixteen IXT patients and 16 HCs underwent MRI using a 3-T MR scanner. FreeSurfer software was used to obtain measures of cortical volume, thickness, and surface area. Group differences in cortical thickness, volume and surface area were examined using a general linear model with intracranial volume (ICV), age and sex as covariates. Then, the age-related cortical differences between the two groups and structural covariance in abnormal morphometric changes were examined.

Results

Compared to HCs, IXT patients demonstrated significantly decreased surface area in the left primary visual cortex (PVC), and increased surface area in the left inferior temporal cortex (ITC). We also found increased cortical thickness in the left orbitofrontal cortex (OFC), right middle temporal cortex (MT), and right inferior frontal cortex (IFC). No significant differences were found in cortical volume between the two groups. There were several negative correlations between neuroanatomic measurements and age in the HC group that were not observed in the IXT group. In addition, we identified altered patterns of structural correlations across brain regions in patients with IXT.

Conclusion

To our knowledge, this study is the first to characterize the cortical morphometry of the children and adolescents with IXT. Based on our results, children and adolescents with IXT exhibited significant alterations in the PVC and association cortices, different cortical morphometric development patterns, and disrupted structural covariance across brain regions.

Medial Rectus Muscle Resection Versus Plication: A Comparison of Conjunctival-Scleral Thickness Measured by AS-OCT

PURPOSE

To compare conjunctival-scleral thickness measured with anterior segment optical coherence tomography before and after medial rectus muscle resection and plication for exotropia.

METHODS

In this prospective observational study, patients with exotropia aged 5 years and older who underwent medial rectus muscle resection or plication through limbal incision of the conjunctiva between April 2016 and June 2018 were enrolled. Conjunctivalscleral thickness was measured with anterior segment optical coherence tomography before and 3 and 6 months after surgery at 1.5 mm (limbus), 4 mm (insertion), and 5.5 mm (tendon) posterior to the scleral spur. One examiner made measurements twice blinded for the initial data. Conjunctival-scleral thickness was compared between groups using the Mann-Whitney U test.

RESULTS

Twenty participants were divided into two groups: resection (n = 11) and plication (n = 9). The respective conjunctival-scleral thicknesses before and 3 and 6 months after surgery in the resection group were as follows: 0.76, 0.90, and 0.86 mm at the limbus; 0.86, 1.18, and 1.12 mm at the insertion; and 1.04, 1.41, and 1.33 mm at the tendon. Corresponding values in the plication group were as follows: 0.74, 0.87, and 0.81 mm at the limbus; 0.84, 1.16, and 1.08 mm at the insertion; and 1.00, 1.39, and 1.27 mm at the tendon. No between-group differences were observed at any location or time.

CONCLUSIONS

No differences in conjunctival-scleral thickness were observed between the resection and plication groups before surgery or at 3 months and 6 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2022;59(4):274-278.].

Slanted recession on bilateral lateral rectus for the treatment of intermittent Exotropia with convergence insufficiency

Purpose

To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (S-BLRc) for the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT) in children and to probe the relationship of the slanted amount and surgical outcomes.

Methods

Retrospective study. Fifty-eight patients with CI-IXT, aged 4 to 10 years old, underwent S-BLRc procedures. According to the different slanted amount between the upper and lower poles of lateral rectus, all the patients were grouped: Group A (slanting 1 mm, n = 22), Group B (slanting 1.5 mm, n = 18) and Group C (slanting 2 mm, n = 18). The successful surgical outcome was defined as deviation in the primary position ranging from exotropia< 8^△ to esotropia< 5^△ both at near and at distant as well as the near-distance difference (NDD) < 5^△. We analyzed and compared the preoperative and postoperative data including deviations both at near and at distance, NDD, objective torsion, horizontal deviation at up and down gaze, lateral incomitance, binocular vision and surgical success rate among three groups.

Results

The average deviations were significantly decreased from − 37.1^△ ± 4.2^△ (−,exotropia) to − 1.4^△ ± 4.6^△ at near (P < 0.05) and from − 25.8^△ ± 3.7^△ to − 0.1 ± 4.1^△ at distance (P < 0.05). The postoperative NDD on average was significantly reduced from 10.0^△ to 1.8^△ in Group A (P < 0.05), from 11.2^△ to 0.8^△ in Group B (P < 0.05) and from 13.3^△ to 0.9^△ in Group C (P < 0.05). There was a significant difference in the mean corrections of NDD among the three groups (8.2^△ in group A, 10.3^△ in group B and 12.4^△ in group C respectively, P < 0,05). All the patients attained various improvement of stereopsis after surgery. None had torsional diplopia, A-V pattern and lateral incomitance after strabismic surgery. Totally, the surgical success rate was 89.7% in our series at the 6- to 8-month follow-up.

Conclusions

Slanted bilateral lateral rectus recession is an effective and safe procedure for the treatment of CI-IXT in children. S-BLRc can successfully collapse exotropia both at distance and at near, decrease NDD and benefit to gain binocular vision. The correction of NDD was associated with the slanted amount.

Efficacy of medial rectus plication versus resection for exotropia: a meta-analysis

OBJECTIVE

To compare the outcomes of medial rectus plication and medial rectus resection procedures in the treatment of exotropia.

METHODS

Articles from Pubmed, EMBASE, Web of Science, and Cochrane Library databases until July 2021 with a minimum follow-up period of 1 month were retrieved. No restriction on language was applied. Eligible studies must comply with the inclusion criteria. Only studies with comparisons between unilateral medial rectus plication versus unilateral medial rectus resection, unilateral lateral rectus recession-medial rectus plication (RP) versus unilateral lateral rectus recession-medial rectus resection (RR), or bilateral medial rectus plication(BMRP) versus bilateral medial rectus resection (BMRR) would be included for subsequent analysis. Two primary outcomes were specified: success rate and mean postoperative deviation. Dichotomous data were calculated as pooled odds ratios (ORs) with 95% confidence intervals (CIs) and continuous data as weighted mean differences (WMD) with 95% CIs.

RESULTS

A total of 8 studies with 557 participants were enrolled in the meta-analysis based on the inclusion criteria. Seven studies compared lateral rectus recession + medial rectus plication to unilateral lateral rectus recession + medial rectus resection and one study compared bilateral medial rectus plication to bilateral medial rectus resection. Differences in success rates between plication and resection groups were not statistically significant (OR = 0.66; 95% CI, 0.43-1.02; P = 0.06), and the unsatisfactory effects (the undercorrection and overcorrection rates) between the two groups were comparable. Additionally, there were also no significant differences in postoperative deviation and the amount of exodrift between the two groups.

CONCLUSION

This meta-analysis provides evidence that both the medial rectus plication and medial rectus resection procedures have similar efficacy in the treatment of exotropia.

Plication versus Resection in Horizontal Strabismus Surgery: A Systematic Review with Meta-Analysis

Purpose

The purpose of this review was to compare the efficacy of rectus muscle plication versus resection on the treatment of horizontal strabismus and to evaluate the exodrift after each technique.

Methods

A research was performed in Latin American and Caribbean Literature on Health Sciences (LILACS); MEDLINE; and Cochrane Central Register of Controlled Trial (CENTRAL). The database was searched by 30 June 2019. The selection was restricted to articles published in English, Spanish, or Portuguese. There were no date restrictions in the search. A minimum mean follow-up of six months was required to access the primary outcomes. Motor alignment success was defined as postprocedure deviation within 10 prism diopters (PD) of orthotropia.

Results

Seven studies were eligible for inclusion. The grouped success rate after plication was 66% (95% CI =  [43%–89%]), and the grouped success rate after resection was 68% (95% CI = [43%–89%]). High heterogeneity was observed between the estimations. There was no difference between the mean amount of deviation corrected in prism diopters, when using the mixed-model approach (SMD = 0.12; 95% CI = −0.2–0.44; p=0.45). The undercorrection rates were also analyzed. The combined odds ratio was 1.37 (95% CI = 0.59–3.16; p=0.462), and there was no statistical significance.

Conclusion

Plication of horizontal extraocular muscles reveals to be an alternative to resection in strabismus surgery, with similar results. Exodrift is observed after plication and after resection in the treatment of exotropia, but randomized clinical trials are necessary to analyze and compare the follow-up.

Central Mini-plication of the Medial Rectus for Convergence Insufficiency

Five cases with a mean (± SD) age of 61 (12.02) years are described to study the outcomes of treatment with central mini-plication of the medial rectus (MR) muscles in adult convergence insufficiency with diplopia and near exotropia: mean preoperative deviation: 18 (± 2) pd. Surgical outcome was considered to be favorable when diplopia and symptoms were resolved and final exotropia at near was ≤8 pd at the end of follow-up. A central mini-plication of the medial rectus (MR) muscles was performed in 5 patients (4 unilateral). Overcorrection at distance vision was recorded in 3 cases; this resolved by 3 months postoperatively. There was not overcorrection at near vision in any case. None of the cases operated on had overcorrection at the end of follow-up. The final horizontal deviation was ≤8 pd at near vision, except for 1 case. Symptoms and diplopia resolved in every case but 2/5 required reoperations. The mean follow-up was 8 (2.12) months. Central mini-plication of 1 or 2 medial rectus muscles can improve the symptoms and signs of exotropia associated with convergence insufficiency when exercises and the prisms are rejected by the patients and when these approaches have not solved the problem.