Evaluation of Prognostic Factors and Outcomes of Single-Stage Adjustable Strabismus Surgery in Thyroid Eye Disease

PURPOSE: To evaluate the prognostic factors that contribute to favorable surgical outcomes of single-stage adjustable strabismus surgery in thyroid eye disease. METHODS: Retrospective review of clinical case notes were done of all patients who had surgical treatment for strabismus related to thyroid eye disease under the care of a single hospital between January 2005 and December 2012 (n = 30). Factors that possibly influenced the outcome were statistically analyzed for significance. "Successful" surgical outcome was defined as patients whose residual deviation was within 8 prism diopters and free from diplopia in the primary position on postoperative 1 year. RESULTS: Mean preoperative vertical deviation was 17.5 prism diopters (PD) and horizontal deviation was 20.3 PD. Mean follow-up time was 12.4 months. Twenty-four patients (80.0%) had successful surgical results. Four patients (13.3%) needed further surgery due to recurrence of previous strabismus and two patients (6.7%) needed prism glasses due to remaining strabismus. Previous history of proptosis (p = 0.02), optic neuropathy (p = 0.01), intravenous (IV) steroid pulse therapy (p = 0.02), number of times of IV steroid pulse therapy (p = 0.01), and orbital decompression surgery (p = 0.03) were different between success and failure groups. CONCLUSIONS: Single-stage adjustable strabismus surgery under topical anesthesia showed a success rate of 80% for strabismus patients with thyroid eye disease. Patients who previously had proptosis, optic neuropathy, IV steroid pulse therapy, and orbital decompression surgery significantly showed unsuccessful results after strabismus surgery.

The Effect of Cyclosporin A on Delayed Adjustable Strabismus Surgery in Rabbits

The delayed adjustable strabismus surgery may be desirable because the angle of strabismus can be changed after the strabismus surgery. We have studied the effect of 2% cyclosporin A on the delayed adjustable strabismus surgery in rabbits. Two percent cyclosporin A was soaked for 5 minutes for group 4 and 10 minutes for group 5 between the conjunctiva and sclera during the adjustable strabismus surgery on the eyes of New Zealand white rabbits. The eyes in group 1 received only adjustable strabismus surgery, and those in group 2 and 3 received the surgery including 5 minutes and 10 minutes soaking with castor oil, respectively. We evaluated the time of adjustability and measured the traction force and length during adjustment after the adjustable strabismus surgery. We could adjust in all of the 6 eyes in group 4 and 5 two weeks after the surgery. At 1 week, the traction forces were 30.7+/-14.0 (mean+/-SD), 42.0+/-39.6, 31.7+/-7.5, 24.0+/-7.5, and 21.8+/-6.0 gm in group 1, 2, 3, 4, and 5, respectively. The forces in group 4 and 5 were not significantly different from those in group 1, 2, and 3. At 2 weeks, the degrees of adhesion between the conjunctiva and superior rectus muscle, and those between the muscle and sclera were significantly lower in group 4 and 5 than those in group 1, 2, and 3. These results suggest that 2% cyclosporin A soaking is useful to obtain the better results due to the delayed adjustment by decreasing the adhesion around the muscle (J KoreanOphthalmol Soc 41:2115~2123, 2000).

The Effect of Alginic Acid Sodium Salt on Delayed Adjustable Strabismus Surgery

The purpose of this study was to evaluate the effect of the alginic acid sodium salt on the delayed adjustable strabismus surgery by preventing the post operative tissue adhesion. 30 eyes of 15 rabbits had received an adjustable suture surgery. The alginic acid sodium salt of 4% was used during operation in 16 eyes among them by injecting it around the muscle, between the sclera and the conjunctiva. In the 3rd, 5th, 7th, 10th, and 14th day postoperatively, we measured the pulling forces and the moving distances of the muscles during the adjustment. Then the eyes were enucleated and the histopathologic changes of the eyes were determined using the light microscope. The pulling forces and the moving distances of the muscles during the adjustment were significantly different between the alginic acid sodium salt free group and the alginic acid sodium salt used group. In the alginic acid sodium salt used group, the pulling forces were decreased and the moving distances were increased than those of the alginic acid sodium salt free group. The light microscopic examination showed more fibrosis in the alginic acid sodium salt free group than in the alginic acid sodium salt used group. These results suggest that the alginic acid sodium salt is an effective substance for the delayed adjustable suture surgery.

Availability of Polyethylene Film for Reduction of Postoperative Adhesion in Adjustable Strabismus Surgery in Rabbits

Adjustable strabismus surgery sometimes fails because of changes in the angle of deviation which develops a few days after surgery. Therefore, the delayed adjustment was recommended; however, the postoperative tissue adhesion disturbed this delayed adjustment. We studied 20 eyes of 10 rabbits; adjustable strabismus surgery was performed on each of the right lateral rectus muscles by hemichangback technique for control study and the surgery on each left lateral rectus muscle was performed by same methods using polyethylene film. The polyethylene film was wrapped around the muscle allowing it to be placed between the muscle and sclera, and between the muscle and cojunctiva. The mean duration of postoperative tissue adhesion was 1.6 +/- 0.70 days in control group and 18.7 +/- 7.09 days in polyethylene group. These results suggested that the use of polyethylene film provides a valuable resource to defer the adjustment by preventing the postoperative tissue adhesion.

Effects of 5-Fluorouracil on Delayed Adjustment in Experimental Strabismus Surgery

Adjustable sutures increased the rate of success with a single procedure, but sometimes fails because of changes in the angle of deviation which develops a few days after surgery. Therefore, the delayed adjustment was attempted;however, the postoperative adhesion following strabismus surgery make delayed adjustment impossible. We studied 45 eyes of 25 rabbits; adjustable strabismus surgery underwent a hang-back technique in the superior rectus muscle. In experimental group, a sponge was soaked in 5-Fluorouracil, and the sponge was placed between the conjunctiva and the sclera for 5 minutes during the operation. We studied the possible time of delayed adjustment and estimated the minimal forces required for the adjustment. The experimental group A (5-Fluorouracil, 50mg/ml) allowed for a 6 day delayed adjustment after surgery, control group allowed for a 2 day delayed adjustment after surgery. These results suggest that 5-Fluorouracil may valuable resource to delayed adjustment strabismus surgery by reduce postoperative adhesion.

Effects of mitomycin C on delayed adjustment in experimental strabismus surgery

In adjustable strabismus surgery, a satisfactory final result would be achieved with delayed adjustment. However, the postoperative adhesions following strabismus surgery make delayed adjustment impossible. We evaluated the efficacy of mitomycin C in reducing the severity of postoperative adhesions following strabismus surgery and in delaying the time adjustment after surgery. Experimental rabbits underwent a hang-back recession procedure in the superior rectus muscle. A topical application of mitomycin C was made between the conjunctiva and the sclera for 5 minutes during the operation. We then studied the possible time of delayed adjustment and estimated the minimal forces required for the adjustment. The topical application of 0.1 mg/ml mitomycin C between the conjunctiva and sclera allowed for a 2-week delayed adjustment after surgery, and 0.2 mg/ml mitomycin C prevented the adhesions between these tissues and the muscle 5 weeks after surgery. These results suggest that topical mitomycin C may enhance the success rate of strabismus surgery with delayed adjustment and reduce postoperative adhesions.