Effectiveness of Bilateral Lateral Rectus Resection for Residual Esotropia in Dysthyroid Ophthalmopathy




Purpose


To report one surgeon’s experiences with bilateral lateral rectus resections in dysthyroid ophthalmopathy patients with residual esotropia after initial bilateral medial rectus recession.


Design


Retrospective interventional case series evaluating outcomes.


Methods


Medical records for patients with dysthyroid ophthalmopathy who underwent bilateral lateral rectus resections for persistent esotropia by a single surgeon from June 2012 to June 2015 were retrospectively reviewed. All patients had residual esodeviations following initial bilateral medial rectus recession. The goal of surgery was to obtain fusion in primary gaze and the reading position without prism, with a postoperative deviation equal to or less than 8 Δ at distance and a phoria at near without diplopia.


Results


Seven of the 9 patients were successful in achieving this goal. Preoperative esotropia before resection ranged from 12 Δ to 30 Δ (23.1 Δ ± 10.3 Δ ) at distance and −2 Δ to 40 Δ (14.9 Δ ± 12.3 Δ ) at near. No exodeviation was created at near by the resections, but 1 patient had an asymptomatic exophoria both pre- and postoperatively.


Conclusion


Patients with large horizontal misalignment may have residual esodeviations that are too large for correction with recession alone. Given our findings, we believe resection may be an effective tool in resolving esotropia in certain patients with restrictive strabismus.


Strabismus is a common sequela of dysthyroid ophthalmopathy due to inflammation and fibrosis of the extraocular muscles. The restrictive nature of the disease causes limitation of ocular movement and misalignment of the visual axes. Surgical treatment of the misalignment has traditionally focused on recession rather than resection in order to minimize duction limitations and alleviate restriction. However, patients may still demonstrate a residual deviation following recession. Some authors have suggested that rectus muscle resections may safely and successfully correct the residual deviation. The purpose of this retrospective interventional study is to present a case series that provides one surgeon’s experiences with bilateral lateral rectus resections in Graves ophthalmopathy patients with residual esotropia after initial bilateral medial rectus recession.


Methods


The records of patients with dysthyroid ophthalmopathy who underwent bilateral lateral rectus resection for persistent esotropia between January 10, 2012 and June 24, 2014 by a single surgeon (O.A.C.) at Saint Louis University were retrospectively reviewed. This study was approved by the Institutional Review Board of our institution and conformed to the requirements of the U.S. Health Insurance Portability and Accountability Act. All patients had prior bilateral medial rectus recession without resolution of their esotropia and diplopia in primary gaze and the reading position. No vertical muscle surgery was performed on any patients in this series. Small vertical components were treated nonsurgically. Cases were searched individually to collect data on the following: patient date of birth, date of service, length (mm) of muscle resected, and the preoperative and 3-month postoperative horizontal deviation for near, distance, and lateral gaze.


Baseline and postoperative assessments were performed by the same orthoptist. Ocular deviation was measured with the use of alternate prism and cover test for near at 13 inches and in the diagnostic positions of gaze for distance at 20 feet.


For the resection, a portion of the lateral rectus muscle was excised and the remaining muscle secured to the sclera at its original insertion site. Adjustable sutures were not used for any of the resections. Millimeters resected were based on the standard Parks surgical tables, using size of deviation in prism diopters as the determining factor. As an example, for a 15 prism diopter deviation, a 4-mm resection would be performed. There is a 1 mm increase in the resected amount for each additional 5 prism diopters of deviation up to 40 prism diopters, with modification if the near deviation is greater ( Supplemental Table , available at AJO.com ).


The goal of surgery was to obtain fusion in primary gaze for distance and in the reading position without prism, with a postoperative deviation equal to or less than 8 Δ at distance and a phoria at near without diplopia.


Paired sample t tests were used to find significant changes after surgery using P < .05 as statistically significant. Standard deviations were the measure of variability reported with the mean.




Results


Of the 27 patients with dysthyroid ophthalmopathy who required bilateral medial recession during this period, a total of 9 (33%) had a residual esotropia and underwent subsequent bilateral lateral rectus resection. Patient age ranged from 52 to 78 (66 ± 7.9) years of age on the date of the procedure. Seven of the 9 were female.


Preoperative, surgical, and postoperative measurements for initial bilateral medial rectus recessions are provided in the Table . Mean esotropia (ET) at distance did not improve significantly for our patients when comparing pre- (ET 35.0 Δ ± 21.1 Δ ) and post- (ET 19.9 Δ ± 12.8 Δ ) recession ( P > .1). Patient 6 had zero change in alignment at distance. Mean alignment at near showed a significant change comparing pre- (ET 29.6 Δ ± 18.3 Δ ) and post- (ET 13.1 Δ ± 13.9 Δ ) recession ( P < .05). After the procedure, Patient 7 had an exotropia at near during the 3-month postoperative visit. However, the patient returned 8 months later with an esotropia of 10 Δ and subsequently required bilateral lateral rectus resection ( Table ). This patient demonstrated the greatest change in alignment, 32 Δ and 53 Δ at distance and near, respectively.



Table

Surgical Data for Patients With Dysthyroid Ophthalmopathy































































































































Patient Bilateral Medial Rectus Recession Bilateral Lateral Rectus Resection
Alignment Distance Pre-Op ET (PD) Alignment Near Pre-Op ET (PD) Recession (mm) Alignment Distance Post-Op ET (PD) Alignment Near Post-Op (PD) Alignment Distance Pre-Op ET (PD) Alignment Near Pre-Op ET (PD) Resection (mm) Alignment Distance Post-Op (PD) Alignment Near Post-Op (PD)
1 10 18 3 4 ET 3 14 10 4 X2 0
2 20 30 4 10 ET 2 12 X2 3 0 X4
3 16 8 3.5 12 ET 16 14 16 4.5 0 0
4 18 10 3.5 16 ET 8 16 8 4.5 X1 0
5 70 60 6 42 ET 40 42 40 8 ET 12 ET 14
6 35 38 4.5 35 ET 28 35 28 7 X2 0
7 62 48 6 30 XT 5 30 10 6 ET 20 ET 5
8 30 14 4 12 ET 14 22 12 4.5 E8 0
9 35 40 5 18 ET 12 18 12 4.5 0 0

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Jan 5, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Effectiveness of Bilateral Lateral Rectus Resection for Residual Esotropia in Dysthyroid Ophthalmopathy
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